Association between body mass index and varicocele among 211 989 Chinese reproductive‐age males

OBJECTIVES: To explore the relationship between body mass index and varicocele, the range of body mass index that leads to increased odds of varicocele, and the association between body mass index with the position and grade of varicocele. METHODS: We conducted a cross‐sectional study of 211 989 Chinese males aged 18–65 years participated in the National Free Pre‐conception Check‐up Projects from January 2013 to December 2018. Univariate and multivariate logistic regression models were constructed to assess the association between body mass index and varicocele. RESULTS: Overweight and obese males had 13.1% (odds ratio 0.869, 95% confidence interval 0.838–0.902) and 32.3% (odds ratio 0.677, 95% confidence interval 0.632–0.725) lower odds of varicocele than those with normal body mass index, respectively. The association between them was non‐linear, and males with body mass index of 17.74 to 23.09 kg/m(2) had an increased odds of varicocele. The overweight and obese males had lower odds of left and bilateral varicocele, but the right varicocele odds was increased by 63.3% in obese males. CONCLUSION: Body mass index was associated with the odds of varicocele among reproductive‐age males, but the odds varied by position. The effects of weight management and varicocele on fertility should be taken into account in fertility guidance.