Physical Activity, Television Viewing Time, and 12-Year Changes in Waist Circumference.
OBJECTIVE
Both moderate-to-vigorous physical activity (MVPA) and sedentary behavior can be associated with adult adiposity. Much of the relevant evidence is from cross-sectional studies or from prospective studies with relevant exposure measures at a single time point before weight gain or incident obesity. This study examined whether changes in MVPA and television (TV) viewing time are associated with subsequent changes in waist circumference, using data from three separate observation points in a large population-based prospective study of Australian adults.


METHODS
Data were obtained from the Australian Diabetes, Obesity, and Lifestyle study collected in 1999-2000 (baseline), 2004-2005 (wave 2), and 2011-2012 (wave 3). The study sample consisted of adults age 25 to 74 yr at baseline who also attended site measurement at three time points (n = 3261). Multilevel linear regression analysis examined associations of initial 5-yr changes in MVPA and TV viewing time (from baseline to wave 2) with 12-yr change in waist circumference (from baseline to wave 3), adjusting for well-known confounders.


RESULTS
As categorical predictors, increases in MVPA significantly attenuated increases in waist circumference (P for trend < 0.001). TV viewing time change was not significantly associated with changes in waist circumference (P for trend = 0.06). Combined categories of MVPA and TV viewing time changes were predictive of waist circumference increases; compared with those who increased MVPA and reduced TV viewing time, those who reduced MVPA and increased TV viewing time had a 2-cm greater increase in waist circumference (P = 0.001).


CONCLUSIONS
Decreasing MVPA emerged as a significant predictor of increases in waist circumference. Increasing TV viewing time was also influential, but its impact was much weaker than MVPA.
1Physical Activity and Behavioural Epidemiology Laboratories, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, AUSTRALIA; 2Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN; 3Faculty of Sport Sciences, Waseda University, Saitama, JAPAN; 4School of Design, Swinburne University of Technology, Melbourne, Victoria, AUSTRALIA; 5School of Population Health, University of South Australia, Adelaide, AUSTRALIA; 6Centre for Physical Activity and Nutrition Research, Deakin University, Melbourne, Victoria, AUSTRALIA; 7School of Sports Science, Exercise and Health, the University of Western Australia, Perth, AUSTRALIA; 8School of Population Health, the University of Queensland, Brisbane, QLD, AUSTRALIA; 9School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Victoria, AUSTRALIA; 10School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, AUSTRALIA; 11School of Population and Global Health, Melbourne University, Melbourne, Victoria, AUSTRALIA; and 12Department of Medicine, Monash University, Melbourne, Victoria, AUSTRALIA.
A I
AI
Shibata
Koichiro
K
Oka
Takemi
T
Sugiyama
J O
JO
Salmon
David W
DW
Dunstan
Neville
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Owen
D000328:Adult; D000368:Aged; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D057185:Sedentary Behavior; D013690:Television; D013997:Time Factors; D055105:Waist Circumference