title: Sedentary behaviors and light-intensity activities in relation to colorectal cancer risk.
abstract: A recent meta-analysis found that sedentary behaviors are associated with an increased colorectal cancer (CRC) risk. Yet, the finding on TV viewing time, the most widely used surrogate of sedentary behaviors, was based on only two studies. Furthermore, light-intensity activities (e.g., standing and slow walking), non-sedentary by posture but close to sedentary behaviors by Metabolic Equivalent Task values, have not been investigated in relation to CRC risk. Thus, we prospectively analyzed the relationships based on 69,715 women from Nurses' Health Study (1992-2010) and 36,806 men from Health Professionals Follow-Up Study (1988 - 2010). Throughout follow-up, time spent on sedentary behaviors including sitting watching TV and on light-intensity activities were assessed repeatedly; incidence of CRC was ascertained. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models from each cohort. A total of 1,119 and 913 incident cases were documented from women and men, respectively. The multivariable HR comparing ≥ 21 versus < 7 hr/week of sitting watching TV was 1.21 (95% CI = 1.02 to 1.43, ptrend =.01) in women and 1.06 (95% CI = 0.84 to 1.34, ptrend =.93) in men. In women, those highly sedentary and physically less active had an approximately 41% elevated risk of CRC (95% CI = 1.03 to 1.92) compared with those less sedentary and physically more active. The other sedentary behaviors and light-intensity activities were not related to CRC risk in women or men. In conclusion, we found that prolonged sitting time watching TV was associated with an increased CRC risk in women but not in men.
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: NaNa
authors.initials: N
authors.lastname: Keum
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Yin
authors.initials: Y
authors.lastname: Cao
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Oh
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Smith-Warner
authors.affiliation: Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Medicine, Harvard Medical School, Boston, USA.
authors.forename: John
authors.initials: J
authors.lastname: Orav
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.
authors.forename: Kana
authors.initials: K
authors.lastname: Wu
authors.affiliation: Department of Oncology, Dana-Farber Cancer Institute, Boston, USA.|Department of Dermatology, the Warren Alpert Medical School of Brown University, Providence, USA.
authors.forename: Charles S
authors.initials: CS
authors.lastname: Fuchs
authors.affiliation: Department of Dermatology, the Warren Alpert Medical School of Brown University, Providence, USA.
authors.forename: Eunyoung
authors.initials: E
authors.lastname: Cho
authors.affiliation: Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, USA.|Department of Medicine, Harvard Medical School, Boston, USA.|Department of Dermatology, the Warren Alpert Medical School of Brown University, Providence, USA.|Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, USA.
authors.forename: Edward L
authors.initials: EL
authors.lastname: Giovannucci
mesh_terms: D000328:Adult; D000368:Aged; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D012307:Risk Factors; D057185:Sedentary Behavior
keywords: TV watching; colorectal cancer; epidemiology; light-intensity activities; sedentary behaviors; sitting