Evaluation of Sperm DNA Fragmentation amongst Infertile Black Africans. A Nigerian Study

Abstract

Background : Male infertility is approaching an epidemic proportion. Almost 50% of all cases of infertility may be associated with a male factor. The diagnostic usefulness of sperm DNA integrity is now accessible as an additional tool to Seminal Fluid Analysis. Objective : To assess sperm DNA fragmentation index (SDFI) in male infertility and its relationship with obesity, alcohol consumption and cigarette smoking among infertile Nigerians. Patients and Methods : Patients who presented for infertility at three health facilities of Nordica Fertility Center in Lagos, Asaba and Abuja cities in Nigeria. STATA 13 was used for student’s t-test to compare the means of continuous variables among smokers and non-smokers and among alcohol consumers and non-consumers. Linear regression analysis was employed to assess the correlation between SDFI as dependent variable and some independent variables. Results : There was no significant difference in the SDFI of men aged <40 years compared to older men. There was also no significant difference in the proportion of men with SDFI of <25% and of ≥25% regardless of their age group. The mean SDFI of men with normal BMI (30.8%) was significantly lower (t = &#8722; 1.80, P-value = 0.04) than that of obese men (30.2%). Obese men were 2.12 times as likely to have SDFI ≥25% compared to normal weight men (χ ² &#45; 2.16, P-value = 0.14, OR = 2.12, 95% CI: 0.77, 5.80). Mean SDFI of men who consume alcohol (37.1%) was significantly higher (t = &#8722; 1.97, P-value = 0.03) than that of those who did not consume alcohol. Although Pearson’s correlation matrix (r) indicated that sperm DNA fragmentation index was positively correlated with history of infertility (r = 0.01), groin surgery (r = 0.04), mumps (r = 0.04) and sexually transmitted illness (r = 0.04), however the degree of correlation was not significant (P-value ≥ 0.5) in each case. Conclusion : This is the first report in Black Africa that describes a correlation between sperm DNA integrity, as measured by the halo test and age, BMI and alcohol consumption. Men with normal BMI were more likely to have excellent to good SDFI and hence good fertility potential. Data from this study indicate that the infertile men had significantly higher sperm DNA fragmentation. Obese men and those engaged in alcohol consumption also had higher sperm DNA fragmentation indices.