Effects of leisure-time and occupational physical activity on total mortality risk in NHANES III according to sex, ethnicity, central obesity, and age.
BACKGROUND
Associations of physical activity with all-cause mortality seem to be quite strong, but little is known about potential effect modifiers as sex, race/ethnicity, age, and obesity.


METHODS
Data of the Third National Health and Nutrition Examination Survey (NHANES III), conducted 1988-1994 with mortality follow-up until 2006, were used to compare mortality risk between different levels of leisure-time physical activity (LTPA) and occupational physical activity (OPA). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).


RESULTS
LTPA (n = 15,307) was inversely associated with all-cause mortality (HR 0.75, 95% CI 0.64-0.88 for regular vs. no LTPA). There was a statistically significant interaction with age (P = .03), with participants over 60 years of age benefitting more from regular or irregular LTPA. OPA was positively associated with all-cause mortality (HR 1.25, 95% CI 0.85-1.84 for high vs. low OPA), particularly among Mexican-Americans (HR 2.28, 95% CI 1.23-4.22); statistically significant interactions were observed for obesity and gender.


CONCLUSIONS
LTPA clearly predicts all-cause mortality. However, associations between OPA and all-cause mortality are unclear and need further research with special regard to ethnic differences.
Division of Cancer Epidemiology and Prevention, Institute of Social and Preventive Medicine, University of Zurich, Switzerland.
Aline
A
Richard
Brian
B
Martin
Miriam
M
Wanner
Monika
M
Eichholzer
Sabine
S
Rohrmann
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002423:Cause of Death; D005260:Female; D006801:Humans; D007899:Leisure Activities; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009749:Nutrition Surveys; D009765:Obesity / Q000453:epidemiology*; D009790:Occupations; D016016:Proportional Hazards Models; D012306:Risk; D012737:Sex Factors; D014937:Work / Q000502:physiology*; D055815:Young Adult