Enterotypes in asthenospermia patients with obesity

Abstract

The essence of enterotypes is stratifying the entire human gut microbiome, which modulates the association between diet and disease risk. A study was designed at the Center of Reproductive Medicine, Shengjing Hospital of China Medical University and Jinghua Hospital of Shenyang. Prevotella and Bacteroides were analyzed in 407 samples of stool, including 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 group (P/B ≥ 0.01), obesity was a risk factor for a reduced rate of forward progressive sperm motility (odds ratio [OR] 3.350; 95% confidence interval [CI] 1.881-5.966; P < 0.001), and a reduced 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 follicle-stimulating hormone. In enterotype P, body mass index, as a diagnostic indicator of a reduced rate of forward progressive sperm motility and a decreased rate of decreased total sperm motility, had AUC values of 0.627 (P = 0.001) and 0.675 (P < 0.0001), respectively, which were significantly higher than the predicted values in all patients. However, in enterotype B group (P < 0.01), obesity was not a risk factor for asthenospermia, where no significant difference between obesity and sperm quality parameters was observed. This study is tried 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. Thereof, BMI is a risk factor for asthenospermia only in men with enterotype P, but not in men with enterotype B.

Figure 1

Prevotella/Bacteroides (P/B) groups. Histogram plotting frequency of the log-transformed abundance of P/B for all patients.

Figure 2

Correlation between BMI and sperm quality in men with enterotypes P and B. (A) Correlation between BMI and forward progressive sperm motility in men with enterotype P. (B) Correlation between BMI and total sperm motility in men with enterotype P. (C) Correlation between BMI and sperm concentration in men with enterotype P. (D) Correlation between BMI and total sperm count in men with enterotype P. (E) Correlation between BMI and forward progressive sperm motility in men with enterotype B. (F) Correlation between BMI and total motility in men with enterotype B. (G) Correlation between BMI and sperm concentration in men with enterotype B. (H) Correlation between BMI and total sperm count in men with enterotype B. Abbreviations: BMI, body mass index.

Figure 2

Correlation between BMI and sperm quality in men with enterotypes P and B. (A) Correlation between BMI and forward progressive sperm motility in men with enterotype P. (B) Correlation between BMI and total sperm motility in men with enterotype P. (C) Correlation between BMI and sperm concentration in men with enterotype P. (D) Correlation between BMI and total sperm count in men with enterotype P. (E) Correlation between BMI and forward progressive sperm motility in men with enterotype B. (F) Correlation between BMI and total motility in men with enterotype B. (G) Correlation between BMI and sperm concentration in men with enterotype B. (H) Correlation between BMI and total sperm count in men with enterotype B. Abbreviations: BMI, body mass index.

Figure 3

Diagnostic performance of BMI with respect to asthenospermia incidence. (A) Diagnostic potential of enterotypes in predicting the incidence of decreased forward progressive sperm motility. (B) Diagnostic potential of enterotypes in predicting the incidence of decreased total sperm motility. Abbreviations: AUC, area under curve; BMI, body mass index.