Sedentary Behavior and Cancer: A Systematic Review of the Literature and Proposed Biological Mechanisms - Cancer Epidemiology ...
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Cancer
Review Epidemiology,
Biomarkers
& Prevention
Sedentary Behavior and Cancer: A Systematic Review of
the Literature and Proposed Biological Mechanisms
Brigid M. Lynch
Abstract
Background: Sedentary behavior (prolonged sitting or reclining characterized by low energy expenditure)
is associated with adverse cardiometabolic profiles and premature cardiovascular mortality. Less is known for
cancer risk. The purpose of this review is to evaluate the research on sedentary behavior and cancer, to sum-
marize possible biological pathways that may underlie these associations, and to propose an agenda for
future research.
Methods: Articles pertaining to sedentary behavior and (a) cancer outcomes and (b) mechanisms that
may underlie the associations between sedentary behavior and cancer were retrieved using Ovid and Web
of Science databases.
Results: The literature review identified 18 articles pertaining to sedentary behavior and cancer risk, or to
sedentary behavior and health outcomes in cancer survivors. Ten of these studies found statistically signifi-
cant, positive associations between sedentary behavior and cancer outcomes. Sedentary behavior was asso-
ciated with increased colorectal, endometrial, ovarian, and prostate cancer risk; cancer mortality in women;
and weight gain in colorectal cancer survivors. The review of the literature on sedentary behavior and bio-
logical pathways supported the hypothesized role of adiposity and metabolic dysfunction as mechanisms
operant in the association between sedentary behavior and cancer.
Conclusions: Sedentary behavior is ubiquitous in contemporary society; its role in relation to cancer risk
should be a research priority. Improving conceptualization and measurement of sedentary behavior is nec-
essary to enhance validity of future work.
Impact: Reducing sedentary behavior may be a viable new cancer control strategy. Cancer Epidemiol Biomarkers
Prev; 19(11); 2691–709. ©2010 AACR.
Introduction sence of whole-body movement, for example, watching
television or working at a computer (6). Sedentary behav-
There is considerable epidemiologic research suggesting ior is not a synonym for physical inactivity, which describes
that physical activity can reduce the risk and progression of the absence of health-enhancing physical activity in every-
several cancers (1-3). Emerging evidence suggests that sed- day life (8). It is thus possible for an individual to achieve or
entary behavior has deleterious health consequences that exceed physical activity recommendations (30 minutes or
are distinct from the beneficial effects of moderate- to more of moderate-to vigorous-intensity activity, 5 days
vigorous-intensity physical activity (4, 5). A unique seden- per week), yet spend the majority of his or her waking
tary behavior physiology, with different biological processes hours sitting (4). Within epidemiologic and health behavior
from traditionally understood exercise physiology, has research, measurement of adults' sedentary behavior has
been hypothesized (5). Hence, it is possible that sedentary typically focused on television viewing time, one of the
behavior could independently contribute to cancer risk. most frequently reported leisure-time pursuits (9).
Sedentary behavior describes activities of low (≤1.5 A number of epidemiologic studies have shown seden-
metabolic equivalents) energy expenditure (6, 7). It is char- tary behavior to be independently associated with chron-
acterized by prolonged sitting or lying down and the ab- ic disease–related risk factors such as central adiposity,
elevated blood glucose and insulin, and other cardiome-
tabolic biomarkers in healthy adults (10-17). Such
Author's Affiliation: Department of Population Health Research, Alberta metabolic attributes are hypothesized to be operative in
Health Services, Calgary, Alberta, Canada
the development and progression of cancer. It is therefore
Corresponding Author: Brigid M. Lynch, Department of Population
Health Research, Alberta Health Services, 1331 29th Street Northwest,
biologically plausible that sedentary behavior may be a
Calgary, Alberta, Canada T2N 4N2. Phone: 403-521-3217; Fax: 403- contributing factor to some types of cancer. Endogenous
270-8003. E-mail: brigid.lynch@albertahealthservices.ca sex hormones, inflammation, and vitamin D also present
doi: 10.1158/1055-9965.EPI-10-0815 as plausible biological pathways by which sedentary be-
©2010 American Association for Cancer Research. havior might additionally contribute to cancer risk (18).
www.aacrjournals.org 2691
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Lynch
The purpose of this report is 3-fold: (a) to systematical- tinct predictor variable independent from physical activ-
ly review studies examining associations of sedentary be- ity (i.e., sedentary was not simply defined as no reported
havior with cancer risk or health outcomes in cancer participation in physical activity). Studies in which the
survivors; (b) to describe and review evidence on the bi- term “sedentary” was used to describe an activity level
ological pathways that may underlie such associations; assigned based on participants' job title (usually from in-
and (c) to formulate recommendations for future research dustry and occupation codes) were excluded on the basis
on sedentary behavior and cancer. that this method of categorization may more accurately
reflect a lack of physical labor within their occupation
Materials and Methods rather than a high volume of prolonged sitting. Studies
where participants reported their level of occupational
Search strategy sitting were included.
A comprehensive literature search strategy was devel-
oped in consultation with a librarian from the Tom Baker Data extraction
Cancer Knowledge Centre (Calgary, AB, Canada). Ovid Where multiple articles from the same study were
(MEDLINE, EMBASE, PsycINFO), and Web of Science found, data were extracted from the most recent article
(Science Citation Index Expanded, Social Sciences Cita- (cohort studies) or the original article (case-control stud-
tion Index, Arts and Humanities Citation Index, Confer- ies). Methodologic details from each article were collect-
ence Proceedings Citation Index-Science, Conference ed, including information about the study design,
Proceedings Citation Index-Social Science and Humani- sample, and measures of sedentary behavior used. The
ties) databases were searched for publications up to June risk reductions extracted from each study represent the
2010. Articles on sedentary behavior were found to be highest versus lowest category of sedentary behavior as-
cross-indexed under several subject terms: “physical ac- sessed. Study results were defined null if the relative
tivity,” “exercise,” “motor activity,” and “health behav- risks (RR) or odds ratios (OR) fell between 0.9 and 1.1,
ior.” These subject terms were combined with the inclusive. If the lower limit of the 95% confidence inter-
keywords “sedentary behavior,” “sitting,” “television,” vals (95% CI) was ≥0.95, the results were considered of
and “TV” to form the search strategy for identifying ar- borderline statistical significance. Average risk reductions
ticles specifically pertaining to sedentary behavior (pro- (the unweighted mean of the point estimates) were calcu-
longed sitting or lying down). lated to allow comparisons across cancer sites. Where
To address the first aim of this report, the keywords more than one type of sedentary behavior was assessed,
“cancer,” “neoplasm,” and “tumor” were included in the point estimate for total sitting time (or the sedentary
the search to identify articles concerning incident cases behavior that accounted for the greatest amount of time)
of cancer, cancer mortality, and health outcomes poten- was used for the average risk reductions.
tially related to prognosis in cancer survivors. To identify
literature pertaining to proposed biological pathways, Results
keywords associated with adiposity (adiposity, over-
weight, obesity, weight gain), sex hormones (sex hor- Literature search results
mones, estrogen, androgen, sex hormone binding Figure 1 describes the number of articles identified at
globulin), metabolic dysfunction (insulin, glucose, insulin each stage of the literature search strategy. The majority
resistance, c-peptide, insulin like growth factor), inflam- of articles retrieved by the Ovid and Web of Science da-
mation (C-reactive protein, interleukin-6, tumor necrosis tabases were rejected on the basis that “sedentary” was
factor-α, leptin, adiponectin, resistin) or vitamin D (vita- a term used to denote no participation in moderate- to
min D, 25-hydroxyvitamin D) were added. The author vigorous-intensity physical activity.
reviewed the titles and abstracts of all articles identified For the review on sedentary behavior and cancer, 18
by the literature search to assess their relevance. relevant articles were identified (21-38). For sedentary be-
The reference lists of articles identified by the literature havior and adiposity, 76 articles originating from 62 stud-
search were also screened for additional relevant articles, ies were selected for review (10, 12, 13, 15-17, 39-103). The
as were the reference lists of several recent review articles literature search on sedentary behavior and biological
on the health effects of sedentary behavior (4-6, 19, 20). mechanisms identified 17 articles from 11 studies relating
The early-view and in-press articles from journals that to sedentary behavior and metabolic dysfunction (10-14,
had published papers meeting the review criteria were 17, 52, 84, 89, 101, 103-109), and one article each for sed-
also examined. entary behavior and sex hormones (109), inflammation
(107), and vitamin D (110).
Inclusion and exclusion criteria
Inclusion criteria for retrieved articles included being Sedentary behavior and cancer
written in English, published between 1980 and June The study design, population characteristics, methods
2010, and composed of nonpregnant adult study partici- of assessing sedentary behavior, and the main results
pants (not children or adolescents). To be included in the (fully adjusted risk estimates for highest versus lowest
review, sedentary behavior had to be assessed as a dis- level of sedentary behavior) of each of the 18 studies
2692 Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 Cancer Epidemiology, Biomarkers & Prevention
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Sedentary Behavior and Cancer
Figure 1. Literature search strategy.
examining the association between sedentary behavior risk increases were found for colorectal cancer (average in-
and cancer outcomes are described in Table 1. Ten studies crease 78%; refs. 21, 26, 33), followed by ovarian cancer
quantified the association between sedentary behavior (66%; refs. 30, 35), prostate (39%; ref. 29), and endometrial
and cancer risk (21, 23-26, 28-31, 33, 35), whereas four re- (34%; refs. 23-25, 31) cancer. For breast cancer, the highest
ported the relationship between sedentary behavior and weekday television-viewing category was associated with
cancer mortality (22, 27, 32, 34). Three articles examined an 18% risk reduction for premenopausal women; howev-
the association of sedentary behavior with adiposity or er, this risk reduction was not statistically significant. The
weight gain in cancer survivors (36-38). associations of weekend television viewing with breast
Sedentary behavior and cancer risk. Six of the 11 can- cancer risk in premenopausal women, and weekday and
cer risk studies were prospective cohort studies (23, 25, weekend television viewing with postmenopausal breast
26, 29-31), four were case-control studies (24, 28, 33, cancer risk, were null (28).
35), and one was a randomized controlled trial (21). The randomized controlled trial had a sample of 29,133
The association between sedentary behavior and cancer male smokers (21), whereas the prospective cohort studies
risk was investigated in four studies of endometrial can- had large, population-representative samples (21, 23, 25,
cer (23-25, 31): three of colorectal cancer (21, 26, 33), two 26, 29-31). Three of the case-control studies included in this
of ovarian cancer (30, 35), and one each of breast (28) and review were hospital based (28, 33, 35); the other case-
prostate (29) cancer. control study was population based (24). There was
Statistically significant, positive associations between considerable variation in sample sizes in the case-control
sedentary behavior and cancer were found in 8 of the 11 studies: The breast cancer case-control study recruited
studies (21, 23, 24, 26, 29, 30, 33, 35). An additional study 1,866 cases and 1,873 controls (28), whereas the colorectal
had a borderline statistically significant, positive associa- cancer case-control study had 180 cases and 180 controls (33).
tion (25), and one observed a nonstatistically significant The sedentary behavior exposure measures used in the
risk increase (31). One study observed a nonstatistically studies included single items assessing nonoccupational
significant cancer risk reduction among the women who sitting time (23, 30, 31), total sitting time (25, 26), or tele-
reported watching the most television (28). The greatest vision viewing time (25, 26, 33). Two studies included
www.aacrjournals.org Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 2693
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.2694
Cancer Epidemiol Biomarkers Prev; 19(11) November 2010
Lynch
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Table 1. Studies investigating the associations of sedentary behavior and cancer
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Sedentary behavior and breast cancer risk
Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Mathew Case- 1,866 cases treated at Histologically Time spent watching TV No statistically significant Age, locality, religion,
et al., control one of four hospitals confirmed during weekdays and associations between TV marital status, education,
2009 (28) study. in South India; 1,873 incident primary weekends. Patients time and breast cancer in socioeconomic status,
controls matched by breast cancer. were asked to report either premenopausal or residence status, BMI,
5-y age group and TV time from the year postmenopausal women. waist and hip sizes,
place of residence preceding diagnosis. Weekday TV ≥180 vswww.aacrjournals.org
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Table 1. Studies investigating the associations of sedentary behavior and cancer (Cont'd)
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Colbert et al., Randomized 29,133 men from the 152 colon and Predefined categories for Compared with men who Colon cancer: age,
Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
2001 (21) controlled Alpha-Tocopherol, 104 rectal cancers (a) occupational activity reported a lifetime of supplement group, BMI,
trial. Beta-Carotene identified through (from mainly sitting to moderate/heavy work, cigarettes per day.
Cancer Prevention the Finnish heavy physical work) and men whose occupation Rectal cancer: age,
study, who smoked Cancer Registry. (b) usual leisure-time involved mainly sitting supplement group.
≥5 cigarettes/d and activity (sedentary, e.g., had a significantly
were ages 50-69 y watching TV to heavy increased risk of colon
at baseline. fairly regularly, (RR, 2.22; 95% CI,
e.g., running) in the 1.28-3.85) and rectal
past 12 mo. (RR, 2.00; 95% CI,
1.03-3.85) cancer. Men
whose leisure time was
mostly sedentary,
compared with active,
also had elevated but
nonsignificantly risk
(colon RR, 1.22; 95% CI,
0.88-1.69; rectal RR,
1.08; 95% CI, 0.73-1.59).
Cancer Epidemiol Biomarkers Prev; 19(11) November 2010
Steindorf Case-control 180 cases treated at a Histologically Time spent watching TV time was positively Education, total
et al., study. Polish hospital, and confirmed incident TV in leisure time associated with increased energy intake.
2000 (33) 180 age- and sex- cases of colon (h/d). Categorized risk of colorectal cancer
matched controls and rectal cancer. as tertiles. (OR, 2.22; 95% CI,
selected from patients 1.19-4.17 for2696
Cancer Epidemiol Biomarkers Prev; 19(11) November 2010
Lynch
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Table 1. Studies investigating the associations of sedentary behavior and cancer (Cont'd)
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Gierach et al., Prospective 70,351 women from 1,052 incident Predefined categories for Sitting time ≥7 vswww.aacrjournals.org
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Table 1. Studies investigating the associations of sedentary behavior and cancer (Cont'd)
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Zhang et al., Case- 254 women under Epithelial ovarian Number of hours spent in Watching TV >4 vs 10 vs 6 vs2698
Cancer Epidemiol Biomarkers Prev; 19(11) November 2010
Lynch
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Table 1. Studies investigating the associations of sedentary behavior and cancer (Cont'd)
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Patel et al., Prospective 123,216 U.S. adults 19,230 deaths Predefined categories Sitting ≥6 vs 0 towww.aacrjournals.org
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.
Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Table 1. Studies investigating the associations of sedentary behavior and cancer (Cont'd)
Authors Design Sample Outcome Measure of sedentary Results Adjustment for confounding
behavior
Sedentary behavior and health outcomes in cancer survivors
Lynch et al., Cross- 111 breast cancer Objectively assessed Accelerometer-measured Sedentary time not Age, ethnicity, total energy
2010 (36) sectional survivors (mean waist circumference sedentary behavior associated with waist intake, moderate- to
study. age 69) from and BMI. (Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Lynch
predetermined occupational activity categories in which corded within the follow-up period ranged between 570
“mostly sitting” was an option for participants to select (34) and 125 (22), making many site-specific cancer mor-
(21, 29); one of these studies also included an item on tality analyses unfeasible.
usual leisure-time activity, with response categories that Sedentary behavior was assessed using fairly crude self-
included “sedentary” (“reading,” “watching TV”; ref. 21). report measures. Television viewing on weekdays and
One study administered two items asking for time spent weekends was assessed over the past 7 days (22) or the past
watching television on weekdays and weekends sepa- year (34); other studies asked participants to report the to-
rately (28), and one study asked five questions relating tal amount of time spent sitting (27) or the amount of time
to different occupational and leisure-time sedentary ac- spent sitting outside of work (32) on a usual day, using pre-
tivities (35). Finally, one study asked participants about determined categories. Three studies adjusted their hazard
occupational activity across the lifespan. Participants as- ratio estimates for a range of sociodemographic, health be-
signed an intensity level to the main tasks of each job, havior (including physical activity), and cardiometabolic
and occupational sedentary time was derived from all confounders (22, 32, 34). The mortality analyses of the
time reported from work activities coded as “mainly sit- fourth study were adjusted for age, smoking status, alcohol
ting down” (24). consumption, leisure-time physical activity, and the Phys-
The reference recall periods for the sedentary behavior ical Activity Readiness Questionnaire, which asks partici-
measures also varied. Two studies directed participants pants to report whether they have a range of exercise
to report their usual behavior (26, 28), five studies re- contraindications such as heart conditions (27).
ferred to average daily time over the past year (21, 23, Sedentary behavior in cancer survivors. Three studies,
25, 30, 31), two studies asked participants to recall aver- one prospective (38) and two cross-sectional (36, 37),
age daily time 5 years prior (33, 35), and one study exam- examined associations of sedentary behavior with adi-
ined lifetime occupational sitting (24). posity in cancer survivors. A cross-sectional study of
To address the question of how sedentary behavior was breast cancer survivors reported a positive association
associated with colorectal cancer, the randomized con- for accelerometer-assessed sedentary time with waist cir-
trolled trial data were analyzed as for a prospective cohort. cumference (β = −9.81; 95% CI, −15.84 to −3.78) and BMI
Cox proportional hazards models estimated the RRs; (β = −3.58; 95% CI: −6.69 to −0.46) in models adjusted for
models were adjusted for intervention group and age, age, ethnicity, and total energy intake. However, these
body mass index (BMI), smoking (colon cancer), or inter- associations were attenuated by further adjustment for
vention group and age (rectal cancer). The risk estimates moderate- to vigorous-intensity physical activity (36). A
reported by the prospective cohort studies were adjusted cross-sectional study of sedentary time and adiposity in
for a comprehensive range of potentially confounding prostate cancer survivors found no discernible associa-
variables (23, 25, 26, 29-31). All but one of the prospective tion (37). In a prospective study of colorectal cancer
studies controlled for physical activity in fully adjusted survivors, recall of average daily television viewing time
models (23, 25, 26, 29, 30). There was considerable varia- over the past month (≥5 versusPublished OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Sedentary Behavior and Cancer
confounders, including physical activity; however, energy vention. The overweight adult participants were assigned
intake was not assessed and accounted for (38). to either a 50% reduction of their usual television viewing
(intervention) or usual television viewing (control). Parti-
Biological pathways cipants in the intervention group experienced a greater re-
An overview of hypothesized mechanisms by which duction in BMI than participants in the control group;
sedentary behavior may contribute to the development however, the between-group difference was not statisti-
and progression of cancer is illustrated in Fig. 2. This cally significant (98). Five of the 10 prospective cohort
figure suggests that adiposity accumulated through sed- studies found statistically significant, positive associa-
entary behavior is likely an independent contributor to tions between sedentary behavior and measures of adi-
cancer and a mediating variable on the other pathways. posity or weight gain (15, 89-92). The risk estimates for
Adiposity. Adiposity may facilitate carcinogenesis highest versus lowest categories of sedentary behavior
through a number of pathways, including increased ranged from a RR of 1.94 (95% CI, 1.51-2.49) for obesity
levels of sex hormones, insulin resistance, chronic inflam- (BMI >30 kg/m 2 ) at follow-up (15) to an OR of 1.18
mation, and altered secretion of adipokines (111, 112). (95% CI, 1.12-1.24) for weight gain of >5% from baseline
There is convincing evidence that excess body weight in- to follow-up (92). One prospective study, which had only
creases cancer risk (particularly colon, postmenopausal measured sedentary behavior at follow-up, found a posi-
breast, endometrial, kidney, and esophageal) and cancer- tive association (OR, 1.49; 95% CI, 1.21-1.83) between
related mortality (3, 113-115). weight gain (from baseline to follow-up) and higher levels
Sixty-two studies that met review criteria addressed the of sedentary behavior at follow-up (93). A second pro-
association between sedentary behavior and adiposity spective study found that baseline sedentary behavior
(see Table 2). The randomized controlled trial assessed (assessed by individually calibrated heart rate monitor-
the effect of a 3-week television-viewing-reduction inter- ing) did not predict fat mass, BMI, or waist circumference
Figure 2. Biological model of hypothesized pathways from sedentary behavior to cancer. TNF-α, tumor necrosis factor-α; IL-6, interleukin-6; CRP, C-reactive protein.
www.aacrjournals.org Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 2701
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Lynch
Table 2. Results from epidemiologic studies of proposed biological pathways and sedentary behavior
Proposed biological pathway Type of study design, association between sedentary behavior and pathway,
and number of studies*
Cross-sectional studies Prospective studies
+ Nonsignificant + Nonsignificant
Adiposity 42 (12; 16; 39-79) 9 (61; 80-88) 6 (15; 89-93) 5 (94-98)
Sex hormones 1 (109)
Metabolic dysfunction 4 (52; 101; 105; 108) 3 (17; 84; 109) 1 (14) 3 (89; 106; 107)
Inflammation 1 (107)
Vitamin D 1 (110)
NOTE: +, Statistically significant, positive (deleterious) association between sedentary behavior and biological pathway; nonsignif-
icant, no statistically significant association between sedentary behavior and biological pathway. None of the studies reviewed
reported statistically significant negative associations between sedentary behavior and biological pathway.
*Some studies assessed multiple biomarkers and therefore may have multiple associations indicated; some studies produced more
than one publication.
at follow-up; however, baseline measures of adiposity sig- SHBG) in 565 premenopausal women. No statistically
nificantly and independently predicted the amount of significant associations were found, although a nonsig-
sedentary time at follow-up (94). nificant trend was observed for the association between
There were 51 cross-sectional studies of sedentary be- sitting and follicular estrone (109).
havior and adiposity or related measures (e.g., BMI or Metabolic dysfunction. Insulin resistance describes di-
waist circumference), of which 42 found statistically sig- minished ability to maintain glucose homeostasis, and is
nificant associations (12, 16, 39-79), and one further often characterized by hyperinsulinemia and hyperglyce-
study showed a borderline positive association (80). mia. Insulin resistance may promote the development of
Among the studies where the outcome was defined as cancer by several pathways. Neoplastic cells use glucose
BMI ≥25 kg/m2, the ORs for highest versus lowest cat- for proliferation; therefore, hyperglycemia may promote
egories of sedentary behavior ranged from 1.27 (95% CI, carcinogenesis by providing an amiable environment for
0.23-6.95) to 2.27 (95% CI, 1.55-3.32; refs. 41, 46, 51, 54, tumor growth (120). High insulin levels increase bioavail-
57, 60, 62, 64, 66, 68, 71, 74, 80, 85, 86, 116). Where BMI able insulin-like growth factor-I, which is involved in cell
≥30 kg/m2 was the study outcome, ORs for highest differentiation, proliferation, and apoptosis (121). Insulin
versus lowest sedentary behavior ranged from 1.20 can also indirectly increase bioavailability of estrogen
(95% CI, 1.00-1.40) to 2.52 (95% CI, 1.81-3.51; refs. 48, and androgen (122). A recent meta-analysis showed
50, 56, 60, 70, 73, 77, 78). increased risks of colorectal and pancreatic cancers asso-
Sex hormones. Exposure to biologically available sex ciated with elevated levels of circulating insulin and
hormones is a risk factor for hormone-related cancers, blood glucose (123). Mixed results were found for breast
particularly breast, endometrial, and prostate cancers and endometrial cancer; however, recently published,
(117, 118). Levels of sex hormone binding globulin large prospective studies have reported positive associa-
(SHBG) may also affect cancer risk; SHBG binds to sex tions between insulin and breast and endometrial cancer
hormones, rendering them biologically inactive (111, risk (124, 125).
117). Adiposity can amplify the association between sex Four prospective and seven cross-sectional studies of
hormones and cancer risk. In postmenopausal women, sedentary behavior and biomarkers of metabolic dys-
the main source of circulating estrogen is from androgen function (glucose, insulin, insulin resistance, C-peptide,
aromatization, which commonly occurs in adipose tissue insulin-like growth factor-I or insulin-like growth factor
(117, 118). Further, visceral adipose tissue is thought to be binding protein-3, or a combination of these measures)
important in the production of adipocytokines, which in- were identified by this review (Table 2). A statistically
fluence estrogen biosynthesis (119). significant association was observed in one of the four
Only one study identified by this review assessed the prospective studies. Baseline sedentary behavior (de-
relationships between sedentary behavior and sex hor- fined by heart rate observations below an individually
mones (Table 2). Tworoger and colleagues examined predetermined threshold) was independently associated
cross-sectional associations of sitting time (at work and with fasting plasma insulin at follow-up in a sample of
home) with sex hormone levels (estradiol, free estradiol, 376 middle-aged adults (β = 0.004; 95% CI, 0.009-0.006;
estrone, estrone sulfate, testosterone, free testosterone, ref. 14). The other prospective studies examined seden-
androstenedione, DHEA, DHEA sulfate, progesterone, tary behavior and insulin (106, 107) or fasting plasma
2702 Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 Cancer Epidemiology, Biomarkers & Prevention
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Sedentary Behavior and Cancer
glucose levels (89), and no significant associations were pausal breast cancer risk (136), and reduced pancreatic
observed. Four of the seven cross-sectional studies cancer risk (137).
found statistically significant, positive associations be- There are limited data on the association between sed-
tween sedentary behavior and metabolic biomarkers. entary behavior and vitamin D status. A cross-sectional
Positive associations were observed with insulin (52), in- analysis in the British Birth Cohort showed a significant,
sulin resistance (101, 105), and 2-hour glucose (108), but sex- and season-adjusted difference in adult participants'
not with fasting plasma glucose (17, 84, 108) or insulin- 25(OH)D levels across television-viewing time categories
like growth factors (109). (110). Vitamin D deficiency (25[OH]DPublished OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Lynch
behavior with sex hormones, inflammation, and vitamin energy expenditure characterized by prolonged sitting.
D. The potential biological pathways considered by this “Physical inactivity” best describes the absence of
review may also underlie the relationship between phys- health-enhancing physical activity.
ical activity and cancer (111, 118, 139). However, it is pos- Given that research on sedentary behavior and cancer
sible that sedentary behavior may also exert its influence is in its early stages, there are opportunities to improve
through other mechanisms, as it initiates some unique methods of sedentary behavior measurement before fur-
cellular processes that are qualitatively different from ex- ther research efforts are expended. Objective measure-
ercise responses. Hamilton and colleagues have shown in ment of sedentary behavior, by accelerometers or heart
studies of laboratory rats that sedentary behavior has a rate monitors, provides many advantages; however,
differentially greater effect on lipoprotein lipase regula- these methods cannot differentiate between different con-
tion than exercise training (4, 140). Additionally, Hamilton's texts or types of sedentary behaviors. Newer techniques
group identified genes in skeletal muscle whose expression for measuring sedentary behavior include combined
is most sensitive to inactivity. They hypothesized that sensing (a combination of motion and heart rate monitor-
these genes may be involved in the initial muscle adapta- ing; ref. 146) and triaxial raw data accelerometers that re-
tions to repeated episodes of sedentary behavior, and in cord acceleration data in three (vertical, mediolateral, and
the etiology of diseases for which sedentary behavior is anterior-posterior) axes. Nevertheless, it is not always
a risk factor (141). practical or affordable to use instruments such as these
Sedentary behavior is ubiquitous in contemporary so- in large epidemiologic studies. Hence, the development
ciety. The high prevalence of obesity and other “lifestyle and validation of comprehensive self-report measures
diseases” is frequently linked to technological advances of sedentary behavior is required (9, 147).
that have automated many domestic and occupational Additional observational studies are needed to quanti-
tasks, which in the past would have required significant fy the associations of sedentary behavior with cancer risk
physical exertion (20, 142). Public health efforts have fo- and outcomes (particularly survival), and also with bio-
cused on increasing participation in discretionary (usual- markers that may be operative in the pathogenesis and
ly leisure-time) physical activity as a key strategy for progression of cancer. Future studies would benefit from
combating chronic disease. Based on accumulating evi- the explicit assessment and control of confounding
dence of the detrimental health effects of sedentary be- factors, particularly measures of adiposity, moderate- to
havior, it has been suggested that future public health vigorous-intensity physical activity, and energy intake.
guidelines for physical activity will also incorporate re- The possible interactive effect of sedentary behavior
commendations to reduce prolonged sitting time (5). and physical activity is also an important question that
Currently, cancer prevention guidelines recommend par- has not been adequately addressed by studies to date.
ticipation in regular physical activity, although there is The deleterious effect of sedentary behavior has been
uncertainty regarding optimal dose and timing of physi- shown even among individuals engaging in high levels
cal activity for cancer prevention (143). Physical activity of physical activity in studies examining all-cause mortal-
is also recommended for cancer survivors, and there is ity (32) and cardiometabolic biomarkers (13). The ques-
accumulating evidence on its quality, and quantity, of life tion of how the detrimental effects of sedentary
benefits (144). To determine whether reducing sedentary behavior are mediated by level of physical activity needs
behavior concurrently with appropriate increases in also to be addressed in relation to cancer risk. Prospective
physical activity may be a viable new cancer control cohort studies are required to investigate cancer sites for
strategy, additional research is required. which there are plausible biological pathways between
sedentary behavior and cancer, such as postmenopausal
Recommendations breast and lung cancer. Insulin resistance, insulin-like
Research on physical activity and health frequently growth factors, adipokines, and vitamin D are mechan-
characterizes individuals who report no participation in isms that might underlie such associations (18).
purposive physical activity as “sedentary” (5). This is Observational studies are also needed to examine asso-
evidenced by the huge disparity between the number ciations with biomarkers; how sedentary behavior may be
of articles retrieved by the search terms “sedentary be- associated with mechanisms operative in cancer patho-
havior” and “cancer” and the number of articles included genesis have only begun to be explored, and there are nu-
in this review. This definition, however, aggregates truly merous avenues for inquiry to be pursued. Findings from
sedentary behaviors (prolonged sitting or lying down) experimental studies may offer insight into biological
with light-intensity activities that are difficult to measure pathways to be explored in epidemiologic studies. For ex-
by questionnaire. Light-intensity physical activities, ample, a recent trial found that 2 weeks of bed rest with
which include routine domestic or occupational tasks, eucaloric diet activated a proinflammatory response, as
are the predominant determinant of variability in adults' indicated by increases in plasma C-reactive protein and
total daily energy expenditure (145). Hence, sedentary interleukin-6, and decreases in interleukin-10 (148). In an-
behavior should be considered as a distinct construct, in- other laboratory trial, lifelong sedentary behavior in mice
dependent of physical activity. As such, the term “seden- led to accelerated muscle mitochondrial dysfunction and
tary behavior” should be applied to activities of low increased levels of mitochondrial oxidative damage (149).
2704 Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 Cancer Epidemiology, Biomarkers & Prevention
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Sedentary Behavior and Cancer
A decline in mitochondrial function may contribute to terventions that reduce or break up extended periods of
neoplastic transformation and metastasis (150). Whereas sedentary behavior.
the results of bed-rest studies and experiments in labora- Finally, future research will need to extend beyond the
tory mice may not extrapolate to free-living humans, randomized, controlled trial design to address translation
these findings suggest that the associations of sedentary into health promotion programs that aim to change
behavior with markers of inflammation and mitochondri- knowledge, beliefs, and attitudes toward sedentary be-
al function warrant investigation. havior. Well-designed primary prevention programs
Future research directions suggested for sedentary should be guided by relevant frameworks; thus, there
behavior and cancer risk are also applicable to studies is a need for assessment of how comprehensive models
of cancer survivors. Issues of cancer survivorship are of health behavior change can be applied to the diffusion
becoming increasingly important as worldwide trends of sedentary behavior interventions (155). Decreasing
in aging continue and diagnostic and treatment techni- sedentary behavior might also be approached through
ques improve. Currently, there are an estimated 12 mil- changes to the social and physical environment (4, 5).
lion cancer survivors in the United States (144). Cancer
survival is associated with significant decrements in Conclusions
health status and an increased risk of death from non-
cancer causes (151). The burden of survival includes an The first studies of sedentary behavior and cancer have
increased risk of morbidity and premature mortality shown that prolonged sitting is independently associated
related to comorbid chronic diseases, such as type 2 di- with colorectal, endometrial, ovarian, and prostate cancer
abetes and cardiovascular disease (152, 153). The role risk; cancer mortality in women; and with weight gain in
of sedentary behavior in cancer survival is largely un- colorectal cancer survivors. Future research in this area
explored; however, it could plausibly contribute to the will establish whether reducing sedentary behavior is a
progression of cancer and the development of comor- novel and viable cancer control strategy.
bid chronic disease.
Understanding the sociodemographic correlates of Disclosure of Potential Conflicts of Interest
sedentary behavior in the broader population at risk for
developing cancer, and in specific populations of cancer No potential conflicts of interest were disclosed.
survivors, is another research priority. The contextual de-
terminants, or behavior settings (154, 155), in which these Acknowledgments
different populations are most likely to engage in seden-
tary behavior also need to be determined. Classifying The author thanks Yongtao Lin (Tom Baker Cancer Knowledge Centre)
for conducting the literature database searches, and Drs. Christine
the characteristics of the most sedentary individuals Friedenreich (Department of Population Health Research, Alberta
and the contexts in which sedentary behavior is most Health Services) and Neville Owen (Cancer Prevention Research
Centre, School of Population Health, The University of Queensland)
likely to occur is useful for identifying prime candidates for their helpful suggestions during the development and writing of
for intervention (156). this review.
Should sedentary behavior be consistently associated
with cancer risk and health outcomes in cancer survivors, Grant Support
intervention trials will be necessary to establish the effi-
cacy of reducing sedentary behavior to reduce cancer in- National Health and Medical Research Council Public Health Training
Fellowship (586727) and an Alberta Innovates-Health Solutions Fellowship.
cidence and cancer progression/recurrence. Such trials,
ideally as randomized controlled trials, will also be need- Received 07/27/2010; revised 08/30/2010; accepted 08/30/2010;
ed to compare the relative merits of various types of in- published OnlineFirst 09/10/2010.
References
1. Friedenreich CM. Physical activity and cancer prevention: from the population health science of sedentary behavior. Exerc Sport
observational to intervention research. Cancer Epidemiol Bio- Sci Rev 2010;38:105–13.
markers Prev 2001;10:287–301. 6. Owen N, Bauman A, Brown W. Too much sitting: a novel and
2. Irwin ML, Mayne ST. Impact of nutrition and exercise on cancer important predictor of chronic disease risk? Br J Sports Med
survival. Cancer J 2008;14:435–41. 2009;43:81–3.
3. World Cancer Research Fund, American Institute for Cancer 7. Ainsworth BE, Haskell WL, Whitt MC, et al. Compendium of
Research. Food, nutrition, and physical activity, and the pre- physical activities: an update of activity codes and MET intensities.
vention of cancer: a global perspective. Washington, DC: Med Sci Sports Exerc 2000;32:S498–516.
AICR; 2007. 8. Salmon J, Dunstan DW, Owen N. Should we be concerned about
4. Hamilton MT, Healy GN, Dunstan DW, Zderic TW, Owen N. Too children spending extended periods of time in sedentary pur-
little exercise and too much sitting: inactivity physiology and the suits even among the highly active? Int J Pediatr Obes 2008;3:
need for new recommendations on sedentary behavior. Curr Car- 66–8.
diovasc Risk Rep 2008;2:293–8. 9. Clark BK, Sugiyama T, Healy GN, Salmon J, Dunstan DW, Owen N.
5. Owen N, Healy GN, Matthews CE, Dunstan DW. Too much sitting: Validity and reliability of measures of television viewing time and
www.aacrjournals.org Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 2705
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Lynch
other non-occupational sedentary behaviour of adults: a review. 31. Patel AV, Feigelson HS, Talbot JT, et al. The role of body weight in
Obes Rev 2009;10:7–16. the relationship between physical activity and endometrial cancer:
10. Dunstan DW, Salmon J, Owen N, et al. Associations of TV viewing Results from a large cohort of US women. Int J Cancer 2008;123:
and physical activity with the metabolic syndrome in Australian 1877–82.
adults. Diabetologia 2005;48:2254–61. 32. Patel AV, Bernstein L, Deka A, et al. Leisure time spent sitting in
11. Dunstan DW, Salmon J, Healy GN, et al. Association of television relation to total mortality in a prospective cohort of US adults. Am
viewing with fasting and 2-h postchallenge plasma glucose levels in J Epidemiol 2010;172:419–29.
adults without diagnosed diabetes. Diabetes Care 2007;30:516–22. 33. Steindorf K, Tobiasz-Adamczyk B, Popiela T, et al. Combined risk
12. Healy GN, Wijndaele K, Dunstan DW, et al. Objectively measured assessment of physical activity and dietary habits on the develop-
sedentary time, physical activity, and metabolic risk: The Australian ment of colorectal cancer. A hospital-based case-control study in
Diabetes, Obesity and Lifestyle Study (AusDiab). Diabetes Care Poland. Eur J Cancer Prev 2000;9:309–16.
2008;31:369–71. 34. Wijndaele K, Brage S, Besson H, et al. Television viewing time
13. Healy GN, Dunstan DW, Salmon J, Shaw JE, Zimmet PZ, Owen N. independently predicts all-cause and cardiovascular mortality: the
Television time and continuous metabolic risk in physically active EPIC Norfolk study. Int J Epidemiol. In press 2010.
adults. Med Sci Sports Exerc 2008;40:639–45. 35. Zhang M, Xie X, Lee AH, Binns CW. Sedentary behaviours and
14. Helmerhorst HJF, Wijndaele K, Brage S, Wareham NJ, Ekelund U. epithelial ovarian cancer risk. Cancer Causes Control 2004;15:
Objectively measured sedentary time may predict insulin resistance 83–9.
independent of moderate- and vigorous-intensity physical activity. 36. Lynch BM, Dunstan DW, Healy GN, Winkler E, Eakin E, Owen N.
Diabetes 2009;58:1776–9. Objectively measured physical activity and sedentary time of breast
15. Hu FB, Li TY, Colditz GA, Willett WC, Manson JE. Television watch- cancer survivors, and associations with adiposity: findings from
ing and other sedentary behaviors in relation to risk of obesity and NHANES (2003-2006). Cancer Causes Control 2010;21:283–8.
type 2 diabetes mellitus in women. JAMA 2003;289:1785–91. 37. Lynch BM, Dunstan DW, Winkler E, Healy GN, Eakin E, Owen N.
16. Jakes RW, Day NE, Khaw KT, et al. Television viewing and low par- Objectively assessed physical activity, sedentary time and waist
ticipation in vigorous recreation are independently associated with circumference among prostate cancer survivors: findings from the
obesity and markers of cardiovascular disease risk: EPIC-Norfolk National Health and Nutrition Examination Survey (2003-2006). Eur
population-based study. Eur J Clin Nutr 2003;57:1089–96. J Cancer Care. In press 2010.
17. Wijndaele K, Duvigneaud N, Matton L, et al. Sedentary behaviour, 38. Wijndaele K, Lynch BM, Owen N, Dunstan DW, Sharp S, Aitken JF.
physical activity and a continuous metabolic syndrome risk score in Television viewing time and weight gain in colorectal cancer sur-
adults. Eur J Clin Nutr 2009;63:421–9. vivors: a prospective population-based study. Cancer Causes
18. Friedenreich CM, Neilson HK, Lynch BM. State of the epidemiologic Control 2009;20:1355–62.
evidence on physical activity and cancer prevention. Eur J Cancer. 39. Aadahl M, Kjaer M, Jorgensen T. Influence of time spent on TV
2010;46:2593–604. viewing and vigorous intensity physical activity on cardiovascular
19. Williams DM, Raynor HA, Ciccolo JT. A review of TV viewing and its biomarkers. The Inter 99 study. Eur J Cardiovasc Prev Rehabil
association with health outcomes in adults. Am J Lifestyle Med 2007;14:660–5.
2008;2:250–9. 40. Al-Mahroos F, Al-Roomi K. Obesity among adult Bahraini popula-
20. Brown WJ, Bauman AE, Owen N. Stand up, sit down, keep moving: tion: impact of physical activity and educational level. Ann Saudi
turning circles in physical activity research? Br J Sports Med 2009; Med 2001;21:183–7.
43:86–8. 41. Banwell C, Lim L, Seubsman SA, Bain C, Dixon J, Sleigh A. Body
21. Colbert LH, Hartman TJ, Malila N, et al. Physical activity in relation mass index and health-related behaviours in a national cohort of 87
to cancer of the colon and rectum in a cohort of male smokers. 134 Thai open university students. J Epidemiol Community Health
Cancer Epidemiol Biomarkers Prev 2001;10:265–8. 2009;63:366–72.
22. Dunstan DW, Barr ELM, Healy GN, et al. Television viewing time 42. Bowman SA. Television-viewing characteristics of adults: correla-
and mortality: the Australian Diabetes, Obesity and Lifestyle Study tions to eating practices and overweight and health status. Prev
(AusDiab). Circulation 2010;121:384–91. Chron Disease 2006;3:1–11.
23. Friberg E, Mantzoros CS, Wolk A. Physical activity and risk of 43. Cleland VJ, Schmidt MD, Dwyer T, Venn AJ. Television viewing and
endometrial cancer: a population-based prospective cohort study. abdominal obesity in young adults: is the association mediated by
Cancer Epidemiol Biomarkers Prev 2006;15:2136–40. food and beverage consumption during viewing time or reduced
24. Friedenreich CM, Cook LS, Magliocco AM, Duggan MA, Courneya leisure-time physical activity? Am J Clin Nutr 2008;87:1148–55.
KS. Case-control study of lifetime total physical activity and endo- 44. Cournot M, Ruidavets JB, Marquie JC, Esquirol Y, Baracat B,
metrial cancer risk. Cancer Causes Control 2010;21:1105–16. Ferrieres J. Environmental factors associated with body mass
25. Gierach GL, Chang SC, Brinton LA, et al. Physical activity, seden- index in a population of Southern France. Eur J Cardiovasc Prev
tary behavior, and endometrial cancer risk in the NIH-AARP Diet Rehabil 2004;11:291–7.
and Health Study. Int J Cancer 2009;124:2139–47. 45. Dunton GF, Berrigan D, Ballard-Barbash R, Graubard B, Atienza AA.
26. Howard RA, Freedman DM, Park Y, Hollenbeck A, Schatzkin A, Joint associations of physical activity and sedentary behaviors with
Leitzmann MF. Physical activity, sedentary behavior, and the risk body mass index: results from a time use survey of US adults. Int J
of colon and rectal cancer in the NIH-AARP Diet and Health Study. Obes 2009;33:1427–36.
Cancer Causes Control 2008;19:939–53. 46. Duvigneaud N, Wijndaele K, Matton L, et al. Socio-economic and
27. Katzmarzyk PT, Church TS, Craig CL, Bouchard C. Sitting time and lifestyle factors associated with overweight in Flemish adult men
mortality from all causes, cardiovascular disease, and cancer. Med and women. BMC Public Health 2007;7.
Sci Sports Exerc 2009;41:998–1005. 47. Fitzgerald SJ, Kriska AM, Pereira MA, de Courten MP. Associations
28. Mathew A, Gajalakshmi V, Balakrishnan R, et al. Physical activity among physical activity, television watching, and obesity in adult
levels among urban and rural women in south India and the risk Pima Indians. Med Sci Sports Exerc 1997;29:910–5.
of breast cancer: a case-control study. Eur J Clin Nutr 2009;18: 48. Frank LD, Andresen MA, Schmid TL. Obesity relationships with
368–76. community design, physical activity, and time spent in cars. Am J
29. Orsini N, Bellocco R, Bottai M, et al. A prospective study of lifetime Prev Med 2004;27:87–96.
physical activity and prostate cancer incidence and mortality. Br J 49. French SA, Harnack LJ, Toomey TL, Hannan PJ. Association
Cancer 2009;101:1932–8. between body weight, physical activity and food choices among
30. Patel AV, Rodriguez C, Pavluck AL, Thun MJ, Calle EE. Recreational metropolitan transit workers. Int J Behav Nutr Phys Act 2007;4.
physical activity and sedentary behavior in relation to ovarian 50. Giles-Corti B, Macintyre S, Clarkson JP, Pikora T, Donovan RJ.
cancer risk in a large cohort of US women. Am J Epidemiol 2006; Environmental and lifestyle factors associated with overweight and
163:709–16. obesity in Perth, Australia. Am J Health Promot 2003;18:93–102.
2706 Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 Cancer Epidemiology, Biomarkers & Prevention
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.Published OnlineFirst September 10, 2010; DOI: 10.1158/1055-9965.EPI-10-0815
Sedentary Behavior and Cancer
51. Grujic V, Cvejin MM, Nikolic EA, et al. Association between obesity 73. Stamatakis E, Hirani V, Rennie K. Moderate-to-vigorous physical
and socioeconomic factors and lifestyle. Vojnosanit Pregl 2009;66: activity and sedentary behaviours in relation to body mass index-
705–10. defined and waist circumference-defined obesity. Br J Nutr 2009;
52. Gustat J, Srinivasan SR, Elkasabany A, Berenson GS. Relation of 101:765–73.
self-rated measures of physical activity to multiple risk factors of 74. Thompson M, Spence JC, Raine K, Laing L. The association of tele-
insulin resistance syndrome in young adults: The Bogalusa Heart vision viewing with snacking behavior and body weight of young
Study. J Clin Epidemiol 2002;55:997–1006. adults. Am J Health Promot 2008;22:329–35.
53. Hubert HB, Snider J, Winkleby MA. Health status, health behaviors, 75. Tucker LA, Friedman GM. Television viewing and obesity in adult
and acculturation factors associated with overweight and obesity in males. Am J Pub Health 1989;79:516–8.
Latinos from a community and agricultural labor camp survey. Prev 76. Tucker LA, Bagwell M. Television viewing and obesity in adult
Med 2005;40:642–51. females. Am J Pub Health 1991;81:908–11.
54. Jacoby E, Goldstein J, Lopez A, Nunez E, Lopez T. Social class, 77. Vandelanotte C, Sugiyama T, Gardiner P, Owen N. Associations of
family, and life-style factors associated with overweight and obesity leisure-time internet and computer use with overweight and obesity,
among adults in Peruvian cities. Prev Med 2003;37:397–405. physical activity and sedentary behaviors: cross-sectional study.
55. Jenkins KR, Fultz NH. The relationship of older adults' activities and J Med Internet Res 2009;11:e28.
body mass index. J Aging Health 2008;20:217–34. 78. Vioque J, Torres A, Quiles J. Time spent watching television, sleep
56. Johnson KM, Nelson KM, Bradley KA. Television viewing practices duration and obesity in adults living in Valencia, Spain. Int J Obes
and obesity among women veterans. J Gen Intern Med 2006;21: 2000;24:1683–8.
S76–81. 79. Weiss EC, Galuska DA, Khan LK, Gillespie C, Serdula MK. Weight
57. Kronenberg F, Pereira MA, Schmitz MKH, et al. Influence of leisure regain in US adults who experienced substantial weight loss, 1999-
time physical activity and television watching on atherosclerosis 2002. Am J Prev Med 2010;33:34–40.
risk factors in the NHLBI Family Heart Study. Atherosclerosis 80. Brown WJ, Miller YD, Miller R. Sitting time and work patterns as
2000;153:433–43. indicators of overweight and obesity in Australian adults. Int J Obes
58. Leite MLC, Nicolosi A. Lifestyle correlates of anthropometric 2003;27:1340–6.
estimates of body adiposity in an Italian middle-aged and elderly 81. Kantachuvessiri A, Sirivichayakui C, KaewKungwal J, Tungtrongchitr R,
population: a covariance analysis. Int J Obes 2006;30:926–34. Lotrakul M. Factors associated with obesity among workers in a
59. Liebman M, Pelican S, Moore SA, et al. Dietary intake, eating metropolitan waterworks authority. Southeast Asian J Trop Med Public
behavior, and physical activity-related determinants of high body Health 2005;36:1057–65.
mass index in rural communities in Wyoming, Montana, and Idaho. 82. Khashoggi RH, Madani KA, Ghaznawy HI, Ali MA. Socioeconomic-
Int J Obes 2003;27:684–92. factors affecting the prevalence of obesity among female-patients
60. Lindstrom M. Means of transportation to work and overweight and attending primary health centers in Jeddah, Saudi Arabia. Ecol
obesity: a population-based study in southern Sweden. Prev Med Food Nutr 1994;31:277–83.
2008;46:22–8. 83. Ballard M, Gray M, Reilly J, Noggle M. Correlates of video game
61. McDowell MA, Hughes JP, Borrud LG. Health characteristics of US screen time among males: body mass, physical activity, and other
adults by body mass index category: results from NHANES 1999- media use. Eat Behav 2010;10:161–7.
2002. Public Health Rep 2006;121:67–73. 84. Gao X, Nelson ME, Tucker KL. Television viewing is associated with
62. Mummery WK, Schofield GM, Steele R, Eakin EG, Brown WJ. prevalence of metabolic syndrome in hispanic elders. Diabetes
Occupational sitting time and overweight and obesity in Australian Care 2007;30:694–700.
workers. Am J Prev Med 2005;29:91–7. 85. Musaiger AO, Al-Awadi AHA, Al-Mannai MA. Lifestyle and social
63. Pettee KK, Ham SA, Macera CA, Ainsworth BE. The reliability of a factors associated with obesity among the Bahraini adult popula-
survey question on television viewing and associations with health tion. Ecol Food Nutr 2000;39:121–33.
risk factors in US adults. Obesity 2009;17:487–93. 86. Rissel CE. Overweight and television watching. Aust J Public Health
64. Proper KI, Cerin E, Brown WJ, Owen N. Sitting time and socio- 1991;15:147–50.
economic differences in overweight and obesity. Int J Obes 87. Trinh OTH, Nguyen DN, Phongsavan P, Dibley MJ, Bauman AE.
2007;31:169–76. Prevalence and risk factors with overweight and obesity among
65. Richmond TK, Walls CE, Gooding HC, Field AE. Television viewing Vietnamese adults: Caucasian and Asian cut-offs. Asia Pacific J
is not predictive of BMI in black and Hispanic young adult females. Clin Nutr 2009;18:226–33.
Obesity 2010;18:1015–20. 88. Trinh OTH, Nguyen ND, Phongsavon P, Dibley MJ, Bauman AE.
66. Rodriguez-Martin A, Novalbos Ruiz JP, Martinez Nieto JM, Escobar Metabolic risk profiles and associated risk factors among
Jimenez L. Life-style factors associated with overweight and Vietnamese adults in Ho Chi Minh City. Metab Syndr Relat
obesity among Spanish adults. Nutr Hosp 2009;24:144–51. Disord 2010;8:69–78.
67. Rosmond R, Lapidus L, Bjorntorp P. The influence of occupational 89. Wijndaele K, Healy GN, Dunstan DW, et al. Increased cardio-
and social factors on obesity and body fat distribution in middle- metabolic risk is associated with increased TV viewing time. Med
aged men. Int J Obes 1996;20:599–607. Sci Sports Exerc 2010;42:1511–8.
68. Salmon J, Bauman A, Crawford D, Timperio A, Owen N. The associ- 90. Blanck HM, McCullough ML, Patel AV, et al. Sedentary behavior,
ation between television viewing and overweight among Australian recreational physical activity, and 7-year weight gain among post-
adults participating in varying levels of leisure-time physical activity. menopausal US women. Obesity 2007;15:1578–88.
Int J Obes 2000;24:600–6. 91. Koh-Banerjee P, Chu NF, Spiegelman D, et al. Prospective study of
69. Santos R, Soares-Miranda L, Vale S, Moreira C, Marques AI, Mota J. the association of changes in dietary intake, physical activity, alco-
Sitting time and body mass index, in a Portuguese sample of men: hol consumption, and smoking with 9-y gain in waist circumference
results from the Azorean Physical Activity and Health Study (APAHS). among 16,587 US men. Am J Clin Nutr 2003;78:719–27.
Int J Environ Rese Public Health 2010;7:1500–7. 92. Mekary RA, Feskanich D, Malspeis S, Hu FB, Willett WC, Field AE.
70. Shields M, Tremblay MS. Sedentary behaviour and obesity. Health Physical activity patterns and prevention of weight gain in premen-
Rep 2008;19:19–30. opausal women. Int J Obes 2009;33:1039–47.
71. Sidney S, Sternfield B, Haskell WL, Jacobs DR, Chesney MA, Hulley 93. Brown WJ, Williams L, Ford JH, Ball K, Dobson AJ. Identifying the
SB. Television viewing and cardiovascular risk factors in young energy gap: magnitude and determinants of 5-year weight gain in
adults: the CARDIA study. Ann Epidemiol 1996;6:154–7. midage women. Obesity Res 2005;13:1431–41.
72. Sisson SB, Camhi SM, Church TS, et al. Leisure time sedentary 94. Ekelund U, Brage S, Besson H, Sharp S, Wareham NJ. Time spent
behavior, occupational/domestic physical activity, and metabolic being sedentary and weight gain in healthy adults: reverse or bidi-
syndrome in US men and women. Metab Syndr Relat Disord rectional causality? Am J Clin Nutr 2008;88:612–7.
2009;7:529–36. 95. Taylor CB, Jatulis DE, Winkleby MA, Rockhill BJ, Kraemer HC.
www.aacrjournals.org Cancer Epidemiol Biomarkers Prev; 19(11) November 2010 2707
Downloaded from cebp.aacrjournals.org on February 24, 2021. © 2010 American Association for Cancer Research.You can also read
