Examining Sedentary Work and BMI Prospectively: Evidence from the National Longitudinal Survey of Youth 1979 (NLSY79)

Tin-chi Lin, Liberty Mutual Research Institute for Safety
Theodore Courtney, Liberty Mutual Research Institute for Safety
David Lombardi, Liberty Mutual Research Institute for Safety
Santosh Verma, Liberty Mutual Research Institute for Safety

We examined workplace sitting time and body mass index (BMI) prospectively using the National Longitudinal Survey of Youth 1979 (NLSY79). The outcome, BMI, was based on self-reported height and weight. Sitting time was extracted from the Occupational Information Network and linked to NLSY79 participants. We used fixed-effects models and conducted a series of sensitivity analyses. Longer sitting time was significantly associated with higher BMI (p < 0.05) for the overall sample. However, the results differed substantially when analyzed by gender. For men, long sitting time was significantly associated with higher BMI (p < 0.01). For women, the association was not statistically significant. Ours is the first prospective study in an occupationally diverse cohort to document an association between BMI and workplace sitting time among men. Our findings provide further support for initiatives to reduce workplace sitting time as a means of reducing the risk of obesity and related health conditions.