Differences in childhood body mass index between lesbian/gay and bisexual and heterosexual female adolescents: A follow-back study

Abstract

Objective: To determine whether childhood body mass index (BMI), assessed in childhood, differs between lesbian/gay and bisexual (LGB) and heterosexual late adolescents, and whether childhood social stressors impact the association between sexual orientation and childhood BMI.

Methods: Participants included 2,070 late adolescents from the Pittsburgh Girls Study, of whom 233 (11.2%) identified as lesbian or bisexual and 1,837 (88.8%) as heterosexual at ages 17-20 years. Weight and height were used to calculate body mass index (BMI) at ages 10 through 14 years. Data were collected on child reported loneliness at ages 8 to 10 and peer victimization from 10 to 14 years.

Results: LGB females had higher BMIs and greater increases in BMI from ages 10-14 years compared to heterosexual females and reported higher levels of loneliness and peer victimization in childhood. Loneliness moderated the association between sexual identity and changes in BMI; for participants with loneliness scores in the upper quartile, the increase in BMI over time was approximately 30% higher for LGB females compared to heterosexual females. Child report of peer victimization mediated the association between sexual identity and changes in BMI, with nearly 18% of the total effect of sexual identity on BMI over time accounted for by peer victimization.

Conclusions: Lesbian and bisexual adolescents report greater loneliness and peer victimization as children than heterosexual adolescents; these stressors confer risk for higher BMI among LGB females. These data underscore the importance of research on the social determinants of health. The hypothesis that the social stressors may partially account for differences in BMI and other cardiometabolic risk factors between LGB and heterosexual females should be addressed in future research.

Fig 1. Change in body mass index by sexual identity.

BMI = Body Mass Index; heterosexual = heterosexual participants; LGB = lesbian/gay or bisexual participants; CDCP = Center for Disease Control and Prevention. Group effect of sexual identity on BMI: F [1, 1714] = 17.462, p < .001, cohen’s d = .67; Interaction effect of sexual identity by time on BMI: F [2.64, 4517.89] = 4.126, p < .01, cohen’s d = .09. Data are estimated means standard errors at each time point within group. The 85^th percentile is indicated for each age according to data provided by the Centers for Disease Control and Prevention.

Fig 2. Moderation effect of loneliness on the association between sexual identity and changes in BMI from ages 10–14 years.

BMI = Body Mass Index; heterosexual = heterosexual participants; LGB = lesbian/gay or bisexual participants. Average slopes for BMI from ages 10 to 14 years for LGB participants and heterosexual participants at low and high levels of self-reported loneliness at age 8 years. Controlling for race, BMI and peer victimization at age 10, the slope for heterosexual participants did not differ as a function of high loneliness (F [4, 1660] = 1.443, p = .230, cohen’s d = .06), whereas the slope for LGB participants did differ (F [4, 209] = 6.124, p = .014, cohen’s d = .34).