Meta-Analytical and Meta-Regression Evaluation of Subclinical Hyperthyroidism's Effect on Male Reproductive Health:...

Subclinical hyperthyroidism (SCH) is a subtle thyroid dysfunction marked by decreased serum thyroid-stimulating hormone (TSH) levels while maintaining a normal thyroid hormone profile. Despite its mild nature, SCH can significantly impact various physiological functions, including male reproductive health. However, the effects of SCH on reproductive hormones and semen quality are less understood compared to overt thyroid disorders. This study employed extensive search methods across various databases from January 2000 to February 2024 to explore the relationship between SCH and Hormonal and Seminal Perspectives. Effect sizes, estimated using the standardized mean difference (SMD) and pooled with a Random-effect model, provided significant insights from 748 participants. Included studies adhered to the following criteria: Patients (male individuals with SCH), Intervention (assessment of reproductive hormones and semen quality), Comparison (SCH patients versus healthy controls), and Outcome (changes in reproductive factors). Significant alterations in reproductive hormones were observed in SCH patients, including reduced LH levels (SMD =  - 0.20; p = 0.007), elevated FSH levels (SMD = 0.25; p = 0.002), and stable testosterone levels (SMD =  - 0.05; p = 0.50). Regarding thyroid profile, SCH was associated with increased FT3 (SMD = 0.15; p < 0.001) and FT4 (SMD = 0.08; p = 0.002) levels, along with decreased TSH levels (SMD =  - 2.00; p < 0.001). Adverse effects on semen quality were also observed. These findings underscore the need to incorporate thyroid health assessments in the evaluation of male infertility, recognizing the impact of minor thyroid hormone deviations on reproductive outcomes.