Enterotypes in asthenospermia patients with obesity

The essence of enterotypes is stratifying the entire human gut microbiome, and enterotypes modulates the association between diet and disease risk.We designed a study at the Center of Reproductive Medicine, Shengjing Hospital of China Medical University and Jinghua Hospital of Shenyang. Prevotella and Bacteroides were measured in stool samples from 178 men with enterotype B (61 normal, 117 overweight/obese) and 229 men with enterotype P (74 normal, 155 overweight/obese). The ratio between Prevotella and Bacteroides abundance, P/B, was used as a simplified way to distinguish the predominant enterotype. In enterotype P, obesity was a risk factor for decreased rate of forward progressive sperm motility (odds ratio [OR] 3.350; 95% confidence interval [CI] 1.881–5.966; P<0.001) and decreased rate of total sperm motility (OR 4.298; 95% CI 2.365–7.809; P<0.001). Obesity was also an independent risk factor (OR 3.131; 95% CI 1.749–5.607; P<0.001) after adjusting for follicle-stimulating hormone. In enterotype P, body mass index (BMI), as a diagnostic indicator of decreased rate of forward progressive sperm motility and decreased rate of decreased total sperm motility, had area under the curve values of 0.627 (P = 0.001) and 0.675 (P<0.0001), respectively, that were significantly higher than the predicted values in all patients. However, obesity was not a risk factor for asthenospermia, and there was no significant difference between obesity and sperm quality parameters in men with enterotype B (P>0.05). Our findings are the first to introduce enterotypes as a population-based individualized classification index to investigate the correlation between BMI and asthenospermia. In our study, overweight/obese men with enterotype P were found to have poorer sperm quality; however, sperm quality was not associated with overweight/obese in men with enterotype B. Besides, BMI is a risk factor for asthenospermia only in men with enterotype P but not in men with enterotype B.