Extracellular histones inhibit complement activation through interactions with complement component C4b

Sexual activity correlates with various health issues, and homocysteine is considered an independent risk factor for cardiovascular events and atherosclerosis. Research on the relation of sexual activity to sexual frequency and homocysteine is sparse.To examine the association between sexual frequency and homocysteine in the general population in the United States.In total, 2,267 eligible participants 20 to 59 years old who had serum homocysteine data and completed a sexual behavior questionnaire were enrolled from the National Health and Nutrition Examination Survey of 2005 to 2006. The correlation between sexual frequency and serum homocysteine levels was analyzed using a linear regression model and an extended-model approach was performed for covariate adjustment.Individuals, especially men, in the lower quartiles of sexual frequency had significantly higher serum homocysteine levels, and a sex difference was identified in subgroup analysis.In a model of quartile-based analysis after adjustment for age, sex, and race and ethnicity, the regression coefficient of the highest quartile of sexual frequency compared with the lowest quartile was −1.326 (P = .012). After further adjustment for multiple covariates, the inverse association between sexual frequency and serum homocysteine levels remained unchanged. Negative trends maintained statistical significance (P for trend < .05). In subgroup analysis by sex, a negative association between sexual frequency and serum homocysteine levels remained unchanged in men even after adjusting for multiple covariates, but not in women.Clinical physicians in primary care should support patients’ sexual activity, and there are implications for health promotion programs.This is the first observational investigation stratified by sex to evaluate the correlation between sexual frequency and serum homocysteine levels. The study was a cross-sectional observational investigation and the causal relation should be evaluated in a follow-up study.Decreased sexual frequency correlated with higher homocysteine levels in a nationally representative sample of US adults, especially men; this might increase the risk of cardiovascular disease or other atherothrombotic events.Yang H-F, Kao T-W, Lin Y-Y, et al. Does Serum Homocysteine Explain the Connection Between Sexual Frequency and Cardiovascular Risk? J Sex Med 2017;14:910–917.