Racial/Ethnic Differences in Occupational Physical Activity and Obesity in the Massachusetts' Working Population **

BACKGROUND:  

Regular physical activity is strongly associated with weight stability and reduced abdominal obesity. The current Physical Activity Guidelines for Americans and Healthy People 2020 recommend adults engage in moderate- and vigorous-intensity physical activity weekly for substantial health benefits. These Guidelines don’t differentiate types of physical activity and count physically active occupations toward meeting the recommendations. Existing studies show occupational physical activity (OPA) to be protective against obesity. Yet, there are known racial/ethnic differences in OPA levels and obesity prevalence. Therefore, we examined the association of OPA and obesity in the Massachusetts’ working population and how it varied by racial/ethnic groups.

METHODS:  

We analyzed 30,568 currently employed adults in the Massachusetts’ Behavioral Risk Factor Surveillance System (BRFSS) data for odd years 2003-2009. Obesity was defined as body mass index ≥ 30.0kg/m2. From responses to the BRFSS question ‘When you are at work, which of the following best describes what you do?’, OPA was categorized as High (‘Mostly heavy labor or physically demanding work’, ‘Mostly walking) and Low (‘Mostly sitting or standing’). Unadjusted prevalence was estimated with SAS SURVEYMEANS. Prevalence ratios (PRs) were estimated using multivariable binomial regression (SAS GLIMMIX), adjusting for age, gender, leisure-time physical activity, fruit and vegetable consumption, and education and stratifying by race/ethnicity.

RESULTS:  

Average prevalence of obesity among Massachusetts’ workers was 19.7% (95% Confidence interval (CI): 19.0-20.3%). Obesity prevalence was higher among Black non-Hispanics (NH) (27.2%, CI: 23.8-30.7%) and Hispanics (21.6%, CI: 18.7-24.6%) compared to White NH (19.8%, CI: 19.1-20.6%). Hispanics (48.1%, CI: 44.2-51.9%) and Black NH (34.7%, CI: 30.7-38.8%) were more likely to report high OPA than White NH (29.7%, CI: 28.8-30.6%). Overall, adjusting for other factors, high OPA was inversely associated with obesity (PR: 0.90, CI: 0.83-0.98). Stratified by race/ethnicity, high OPA was significantly protective only among White NH (PR: 0.89, CI: 0.81-0.97) but not among Black NH and Hispanics (PR: 0.99, CI: 0.81-1.21).

CONCLUSIONS:  

Racial/ethnic differences in OPA levels and obesity prevail in the Massachusetts’ working population. The differential association of OPA on obesity across racial/ethnic groups suggests underlying differences in types of physical demands at work, e.g. by nature, duration, occupation, and industry, that can influence levels of health benefit gained. Future physical activity guidelines and studies exploring health benefits of OPA should consider these differences.