Body mass index, sexual behaviour, and sexually transmitted infections: an analysis using the NHANES 19992000 data
Reported, January 10, 2012
Factors determining human sexual behaviour are not completely understood, but are important in the context of sexually transmitted disease epidemiology and prevention. Being obese is commonly associated with a reduced physical attractiveness but the associations between body mass index, sexual behaviour and the risk of acquiring sexually transmitted infections has never been studied.
Data on 979 men and 1250 women were available for analysis. Obese (mean number of partners for men:1.12, women: 0.93) and overweight (mean for men: 1.38, women: 1.03) individuals reported fewer partners than individuals of normal BMI (mean for men:2.00, women: 1.15) in the last year (p < .0.01 & p < 0.05 for men, p < 0.05 & n.s. for women). The same relationship held for lifetime partners in men (mean 11.94, 18.80, and 22.08 for obese, overweight and normal BMI respectively (p < 0.05 & n.s. for obese and overweight vs normal respectively), but not in women (mean 7.96, 4.77, and 5.24 respectively). HSV-2 antibodies were significantly correlated with the number of lifetime partners in both men and women, with the odds of being HSV-2 positive increasing by 0.6% (p < 0.01) and 2.7% (p < 0.01) for men and women respectively. HSV-2 antibodies increased with age, even after adjustment for lifetime partners (p < 0.01). Being obese (HSV-2 prevalence 15.9 and 34.9% for men and women respectively) or overweight (HSV-2 prevalence 16.7 and 29.3 for men and women respectively) was not associated with HSV-2 antibodies (HSV-2 prevalence for normal BMI: 15.6 and 23.2% respectively), independent of whether the association was adjusted for life time sexual partners or not. There was evidence of substantial misreporting of sexual behaviour.
Obese and overweight individuals, especially men, self report fewer sex partners than individuals of normal weight, but surprisingly this is not reflected in their risk of HSV-2 infection. HSV-2 antibodies provide information not contained in self-reported number of partners and may better estimate sexual risk than self-reported behaviour.
Obesity is a risk factor for many chronic diseases, including diabetes and cardiovascular disease, and is a major causes of preventable death in Western countries, and increasingly also in developing countries. In addition, obesity can also be a psychological problem as a slender posture is associated with physical and social attractiveness, and in most Western countries dieting, exercising etc. are multi-billion industries. Some individuals, in particular women, apparently perceive obesity as a more acute problem than cigarette smoking, which they use for weight control.
Despite widespread recognition that physical attractiveness correlates strongly (inversely) with body mass index (BMI), there appears to be a dearth of studies on the effectiveness of slimness in attracting sex partners, the choice of sex partners, and whether this may pose a risk for acquiring sexually transmitted infections. In addition to mere physical attractiveness psychological factors associated with BMI may also play a role in sexual behaviour.
Sexual behaviour surveys have been carried out in many countries, and their methodology has been extensively researched. However, with rare exceptions these studies appear to have ignored the issue of body mass index as one of the few objectively measurable dimensions of physical attractiveness as a correlate of actual sexual behaviour; and those that did, appear to have included only opportunistic samples, and did not actually measure BMI. Perhaps, this is because measurement of BMI involves physical examination, whereas most of these surveys are based on questionnaires or interviews.
We therefore decided to explore the relationship between obesity, sexual behaviour, and the risk of acquiring sexually transmitted infections, and estimate reported rates of partner change and the risk of Herpes Simplex Type 2 (HSV-2) antibody prevalence, a marker of cumulative sexual risk, as a function of body mass index, adjusting for other behavioural and demographic variables. For this, we used the (publicly available, free of charge) USA, National Health and Nutrition Examination Survey (NHANES) 19992000 data[8
Obese and overweight individuals, especially men, self report fewer sex partners than individuals of normal weight, but surprisingly this is not reflected in their risk of HSV-2 infection. HSV-2 antibodies provide information not contained in self-reported number of partners and may better estimate sexual risk than self-reported behaviour.
Credits: Nico JD Nagelkerke,Roos MD Bernsen,Sema Sgaier,and Prabhat Jha
Department of Community Medicine, United Arab Emirates University, Al Ain, UAE
More Information at:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1559603/?tool=pubmed