[Correlation of age, body mass index and obesity-related biochemical indexes with semen quality in males intending for a second child]

Objective: To explore the influence of age, body mass index (BMI) and obesity-related biochemical indexes on semen quality in adult males intending to have a second child in Guangzhou.

Methods: We conducted a questionnaire investigation among 632 adult males seeking medical advice on their intention for a second child at Guangzhou Women and Children's Medical Center from August 2017 to July 2018. We obtained their lipid metabolism indicators and semen parameters, and analyzed the correlation of semen quality with age, BMI, obesity-related biochemical indexes, living environment and occupation.

Results: Age, BMI, season of sperm extraction, living environment and occupation all influenced the semen quality of the males. Age was correlated negatively with the percentage of progressively motile sperm (PMS) (r = －0.109, P < 0.05), BMI positively with the semen volume (r = 0.103, P < 0.05) but negatively with the percentage of morphologically normal sperm (MNS) (r = －0.138, P < 0.05), high-density lipoprotein (HDL) negatively with PMS (r = －0.168, P < 0.01) and the percentage of immotile sperm (IM) (r = －0.135, P < 0.05), low-density lipoprotein (LDL) negatively with the semen volume (r = －0.124, P < 0.01), PMS (r = －0.127, P < 0.05), sperm concentration (r = －0.121, P < 0.05) and total sperm count (r = －0.210, P < 0.01) but positively with IM (r = 0.140, P < 0.01). Multivariate regression analysis showed BMI and LDL to be independent factors influencing the semen volume, uric acid to be an independent factor influencing semen liquefaction time, age, HDL and LDL to be independent factors influencing PMS, age, and HDL to be independent factors influencing IM, LDL to be independent factors influencing total sperm count, while BMI and TG to be independent factors influencing MNS.

Conclusions: Age, BMI, season of sperm extraction, living environment and occupation may affect the semen quality of the males in Guangzhou.