Relationship between healthy lifestyle score and infertility in Iranian men: a population-based case-control study

While the importance of male infertility management is well recognized and the role of individual lifestyle factors in reproductive health has been established, the combined effect of these factors-measured as a healthy lifestyle score (HLS)-on male infertility remains unexplored. Therefore, we assessed the association between HLS and infertility in Iranian men.

This population-based case-control study compared 300 infertile men with 300 fertile controls. A healthy lifestyle score was constructed using information about dietary intakes, dietary habits, physical activity, sleep quality, smoking, depression status, anxiety status, and psychological distress; data on these elements were collected using validated questionnaires. Male infertility was defined according to the sixth edition of the World Health Organization (WHO) criteria 2021 by an andrologist.

Men in the highest HLS category had 44% lower infertility odds than those in the lowest category (OR = 0.56; 95%CI: 0.35-0.89). After full adjustments, this association remained significant, with 45% lower odds in the top vs. bottom quartile (OR = 0.55; 95%CI: 0.34-0.90). In addition, after adjusting for covariates, low psychological distress was the sole lifestyle factor that exhibited a significant inverse association with infertility (OR = 0.49, 95% CI: 0.34-0.71). Normal-weight men in the highest vs. lowest HLS category had 67% and 70% lower infertility odds in crude (OR = 0.33; 95%CI: 0.15-0.75) and fully-adjusted model (OR = 0.30; 95%CI: 0.12-0.74). No association was observed in men with overweight or obesity.

This study revealed that a combined healthy lifestyle score, rather than individual factors including dietary intakes, dietary habits, sleep quality, physical activity, smoking, depression status, anxiety status, and psychological distress, was associated with lower odds of infertility in Iranian men, especially among those with normal weight, suggesting that adherence to a healthy lifestyle pattern can be considered a management strategy for infertility.