title: Joint associations of smoking and television viewing time on cancer and cardiovascular disease mortality.
abstract: Excessive sitting time and smoking are pro-inflammatory lifestyle factors that are associated with both cancer and cardiovascular disease (CVD) mortality. However, their joint associations have not been investigated. We examined the associations of television (TV) viewing time with cancer and CVD mortality, according to smoking status, among 7,498 non-smokers (34% ex-smokers) and 1,409 current-smokers in the Australian Diabetes, Obesity and Lifestyle Study. During 117,506 person-years (median 13.6 years) of follow-up, there were 346 cancer and 209 CVD-related deaths. Including an interaction between TV time and smoking status in the model significantly improved the goodness of fit for cancer (p = 0.01) but not CVD mortality (p = 0.053). In the multivariate-adjusted model, every additional hr/d of TV time was associated with increased risk of cancer-related (HR 1.23; 95% CI 1.08-1.40), but not CVD-related mortality (HR 1.16; 95% CI 0.97-1.38) in current-smokers. Elevated multivariate-adjusted cancer mortality HRs were observed for current-smokers watching 2 to <4 hr/d (HR 1.45; 95% CI 0.78-2.71) and ≥4 hr/d (HR 2.26; 95% CI 1.10-4.64), compared to those watching <2 hr/d. Current-smokers watching 2 to <4 hr/d (HR 1.07; 95% CI 0.45-2.53) and ≥4 hr/d (HR 1.92; 95% CI 0.76-4.84) did not have a significantly higher risk of CVD mortality, compared to <2 hr/d. No associations were observed for non-smokers. These findings show an association of TV, a common sedentary behavior, with cancer mortality in current-smokers. The association with CVD mortality was less clear. Further exploration in larger data sets is warranted. Limiting TV viewing time may be of benefit in reducing cancer mortality risk in current-smokers.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.|Department of Physiology, School of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia.|Health Innovations Research Institute, RMIT University, Melbourne, VIC, Australia.
authors.forename: Megan S
authors.initials: MS
authors.lastname: Grace
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.|Cancer Epidemiology Centre, Cancer Council Victoria, Melbourne, VIC, Australia.|Melbourne School of Population and Global Health, University of Melbourne, VIC, Australia.
authors.forename: Brigid M
authors.initials: BM
authors.lastname: Lynch
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.
authors.forename: Francis
authors.initials: F
authors.lastname: Dillon
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.|Menzies School of Health Research, Darwin, NT, Australia.
authors.forename: Elizabeth L M
authors.initials: EL
authors.lastname: Barr
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.|Melbourne School of Population and Global Health, University of Melbourne, VIC, Australia.|Swinburne University of Technology, Melbourne, VIC, Australia.|School of Public Health, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Neville
authors.initials: N
authors.lastname: Owen
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia.|School of Public Health, University of Queensland, Brisbane, QLD, Australia.|School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia.|Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia.|School of Exercise and Nutrition Sciences, Deakin University, Burwood, VIC, Australia.|School of Sport Science, Exercise and Health, University of Western Australia, Perth, WA, Australia.|Department of Medicine, Monash University, Melbourne, VIC, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Dunstan
mesh_terms: D000328:Adult; D000368:Aged; D001315:Australia; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000401:mortality; D009765:Obesity / Q000150:complications; D057185:Sedentary Behavior; D012907:Smoking / Q000009:adverse effects*; D013690:Television
keywords: cancer; cardiovascular disease; sedentary behavior; smoking; television viewing