Occupational Sitting is associated with Leisure-Time Physical Inactivity among Working Women

Background: The objective of this study is to evaluate the relationship between occupational physical activity and leisure-time physical activity in the Sister Study, a cohort of United States and Puerto Rican women

Methods: We performed a cross-sectional analysis of 27,487 Sister Study women employed for a minimum of 1 year at Sister Study baseline enrollment. Occupational physical activity was self-reported as mostly sitting, mostly standing, mostly walking or heavy labor. We estimated the weekly energy expended for all reported leisure-time activities (sports, exercise, and non-occupational daily activities) in metabolic equivalent (MET) hours per week.  Log-binomial regression was used to model the relationship between occupational physical activity level and leisure-time physical activity (7.5 MET hours per week - the minimal activity recommended by the U.S government), adjusting for potential confounders.

Results: Approximately 17% of women (n= 4,614) did not meet the minimum recommended leisure-time physical activity level.   Compared with women in more active jobs, women in mostly sedentary jobs had a 23% lower prevalence (RR: 0.77, 95%CI: 0.64-0.90) of meeting minimal physical activity guidelines. The association between occupational physical activity and leisure-time physical activity was not modified by age, education, or income.

Conclusions: Occupational sitting is associated with leisure-time physical inactivity in women aged 35-74 years. The results of this study suggest that women in mostly sedentary jobs should be targeted for health promotion strategies that encourage physical activity outside of the workplace.