Let's get physical: Sexually transmitted infections and body mass index among young adults in the United States

Growing public health concern about dramatic increases in body mass index (BMI) may have impacted how individuals perceive and feel about their bodies. In addition, pervasive thin and muscular body standards are persisting within a societal context where maintaining and achieving a healthy lifestyle and diet has become increasingly difficult. Possibly, sexually transmitted infection (STI) prevalence is influenced by this context. In order to investigate this possibility, this dissertation examined the intersection of BMI and STIs.;Data from the 1999-2004 National Health and Nutrition Examination Survey collected among 20-29 year olds was used to examine associations between STI, sexual behavior, BMI, and weight-related attitudes. Associations between outcomes (STIs, number of partners, coitarche) and exposure (BMI, perception, satisfaction) were examined using logistic regression. To assess associations within categories of BMI, piecewise-continuous linear models were employed. Analyses were stratified by gender.;Prevalence of HSV-2 among underweight men was higher than normal weight (OR=3.59, 95% CI 1.02-12.6) in adjusted analyses. Men perceiving themselves overweight compared to normal weight had 0.36 (95% CI 0.14, 0.96) times higher odds of having a non-viral STI. Among women, HSV-2 varied within categories of BMI, and no associations between non-viral STIs and BMI were seen. Among obese women, the odds of testing positive for HSV-2 increased as BMI increased. Women who were obese, indicated wanting to lose weight, and perceived themselves as overweight had greater odds of reporting <16 years age at first sex compared to women with normal weight, satisfied with their weight, and normal weight perceptions, respectively. Women who perceived themselves as underweight and indicated wanting to gain weight were more likely to have had more partners compared to women perceiving themselves as normal weight and satisfied with their weight, respectively.;This analysis reveals possible disparities in STI prevalence and reported sexual behavior by BMI and weight-related attitudes among men and non-pregnant women. Given these findings, further research into how STI and obesity are related is recommended. Additionally, targeted STI interventions aimed at addressing discourse on body size may be appropriate.