Cross-sectional associations between occupational and leisure-time sitting, physical activity and obesity in working adults.
OBJECTIVE
To examine associations between occupational and leisure-time sitting, physical activity and obesity in working adults.


METHODS
We analyzed data from workers from the 2007-08 Australian National Health Survey (n=10,785). Participants reported their activity at work (mostly sitting, standing, walking, or heavy labor), transport-related walking, leisure-time sitting and physical activity. Body mass index was objectively measured. Adjusted Cox proportional hazard regression models examined associations between occupational activity category, leisure-time sitting, physical activity and obesity risk.


RESULTS
Substantial proportions of men (42%) and women (47%) mostly sit at work. Workers with sitting jobs were significantly more likely to be sufficiently active during leisure-time than workers with mostly standing, walking or heavy labor jobs (RR=0.88, 0.80, 0.86 respectively). Workers with mostly sitting jobs had significantly higher overweight/obesity risk than workers with mostly standing jobs (RR=0.88, 95% CI: 0.82-0.95) independent of physical activity and leisure-time sitting. Workers with leisure-time sitting of less than four hours per day had significantly lower obesity risk than workers with four or more hours per day of leisure-time sitting (RR=0.77, 95%CI: 0.69-0.87) independent of physical activity and occupational activity.


CONCLUSIONS
Sitting time and physical activity are independently associated with obesity. Leisure-time sitting may have a stronger association with obesity risk than occupational sitting.
Prevention Research Collaboration, Sydney School of Public Health, University of Sydney, Australia. josephine.chau@sydney.edu.au
Josephine Y
JY
Chau
Hidde P
HP
van der Ploeg
Dafna
D
Merom
Tien
T
Chey
Adrian E
AE
Bauman
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001315:Australia / Q000453:epidemiology; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009765:Obesity / Q000453:epidemiology / Q000209:etiology*; D009790:Occupations / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D012306:Risk; D012307:Risk Factors; D057185:Sedentary Behavior; D012737:Sex Factors; D055815:Young Adult