Abayomi B. Ajayi1, Bamgboye M. Afolabi 2*, Victor D. Ajayi1, Ifeoluwa Oyetunji1, Adedamilola Atiba1, Joy Ehichioya1, Ibukun B. Ayelehin1, Ayodeji T. Adeoye1 and Temilade E. Adesida1

Abstract Background: Available evidence on the role of age, BMI on male infertility has been controversial or inconclusive. With 30-50% of infertility being related to the male and up to 35% of couple’s having more than one problem, the male work-up is equally as important as the female. The synergy of Age and BMI in male infertility has not been much considered. Objective: To investigate the synergy of age and BMI on seminal fluid parameters of black Africans. Methodology: This facility-based study, carried out on 907 sub-fertile males between 2010 and 2015, was descriptive, analytic and crosssectional. Age (years) was categorized into <45 and ≥45. BMI (kg/m2) was divided into underweight (<18.5), normal (18.5-24.9), overweight (25.0-29.9) and obese (≥30). Sperm was collected by masturbation and examined with 60 minutes of collection. STATA 13 statistical software was used for data analysis. Level of significance was set at P-value ≤0.05 Results: Overall means (±SD) of age, BMI and sperm count (x106) were 42.67 (7.12), 27.01 (3.68) and 22.23 (23.04), respectively. Mean sperm volume (ml.) at age <45 years (2.40±1.41) was significantly higher (t=3.37; p=0.0004) than at age ≥45years (2.05±1.58). Compared to normal weight men, semen volume (t=-1.59, P-value=0.05), sperm count (t=-2.02, P-value=0.02) and motility (t=-2.95, P-value=0.002) were significantly lower in obese men. Overweight men aged ≥45 years were approximately 2½ times more likely to produce semen <1.5 ml. In the synergy between age and BMI, age provided a stronger correlation with semen volume than BMI (coef. = -0.030, t=-4.45, P-value=0.00001) while BMI provided a stronger correlation with sperm count (coef. = -0.411, t=-1.98, P-value=0.048) and with progressive motility (coef. = -0.668, t=-3.47, P-value=0.00001) than age. Conclusion: Our data suggest evidence of synergy of age and BMI in the quantity and quality of semen parameters such as volume, liquefaction time, progressive motility and sperm count. Keywords: Age/BMI synergy; Semen parameters; Male infertility; Black Africa; Nigeria; Abbreviations: APA = Advanced paternal age; ART = Assisted Reproduction Technique; BMI = Body Mass Index; DNA = Deoxy-ribonucleic Acid; WHO = World Health Organization

Full Abstract Semen Parameters Associated With Male Infertility in a Sub-Saharan Black Population: The Effect of Age and Body Mass Index