Overweight/obesity among social network members has an inverse relationship with Baltimore public housing residents' BMI

The American Heart Association has encouraged networks research focused on cardiovascular disease and its risk factors, such as obesity. However, little network research has focused on minorities or low-income populations. Our objective was to characterize the relationship between body mass index (BMI) with social network overweight/obesity among public housing residents in Baltimore, MD - a predominantly black, low-income group. We conducted a cross-sectional survey of randomly selected public housing residences (8/2014–8/2015). Adults had their height and weight measured and reported their network members' weight statuses using pictograms. Our dependent variable was respondents' BMI, and independent variable was perceived exposure to overweight/obesity in the social network. We also explored network exposure to overweight/obesity among 1) family members and 2) friends. We used multivariable linear regression adjusted for significant covariates. Our sample included 255 adults with mean age of 44.4 years, 85.5% women, 95.7% black, and mean BMI of 33.2 kg/m ² . Most network members were overweight/obese (56.1%). For every 1% increase in network exposure to overweight/obesity, individuals' BMI decreased by 0.05 kg/m ² (p = 0.06). As network exposure to overweight/obesity among friends increased, individuals' BMI significantly decreased by 0.06 kg/m ² (p = 0.04). There was no significant relationship between BMI and network exposure to overweight/obesity among family members. In conclusion, among Baltimore public housing residents, a statistically significant, inverse association existed between individuals' BMI and overweight/obesity among friends in their social networks. Our results differ from relationships seen in prior studies of other populations, which may be due to racial and/or contextual differences between studies.