Incarceration and adult weight gain in the National Survey of American Life (NSAL)

Background: The United States has the unenviable distinction of having both the highest obesity rate among Organisation for Economic Co-operation and Development (OECD) member countries and the highest incarceration rate in the world. Further, both are socially patterned by race/ethnicity and socioeconomic position. Incarceration involves various health behaviors that could influence adult weight trajectory. Methods: We evaluated the associations between history and duration of adult incarceration and weight gain using the National Survey of American Life (N = 6082 adults residing in the 48 contiguous states between February 2001 and March 2003). We propensity score-matched individuals to control for the probability of having a history of incarceration. To examine the relation between prior incarceration and adult weight gain, we fit gender-stratified generalized estimating equations controlling for propensity of incarceration history, age, education, income, race/ethnicity, and marital status. Results: For males (N=563), incarceration was associated with about a 1.77kg/m² lower gain in body mass index (BMI) during adulthood, after adjusting for age, education, income, race/ethnicity, and marital status in addition to the propensity of having a history of incarceration (95% CI: -2.63, -0.92). For females (N=286), no significant overall relationship was found between a history of incarceration and adult weight gain. In subgroup analyses among those with an incarceration history, we found no overall association between duration of incarceration and adult weight gain in men or women. In sensitivity analyses, neither tobacco smoking nor parity changed the results. Conclusions: The results of this study indicate that incarceration is associated with a lower transition of weight gain in males, but not in females.