Background: Decreased bone mineral density (BMD) commonly occurs in elderly and hypogonadal men. While many male infertility patients often have decreased testicular function, little is known about the occurrence of osteopenia in this population. To determine the prevalence of decreased BMD in the infertile male population, the results of BMD measurements in a group of infertile men was determined. The association between BMD and andrologic parameters was also examined.
Methods: In a prospective IRB approved study, men presenting for infertility evaluations were offered BMD determinations with a Schick accuDEXA® scanner utilizing the ring finger of the non-dominant hand. Results of semen analyses, total testosterone, and FSH levels, testicular volume measurements and body mass index (BMI) were collected. The incidence of osteopenia was calculated. The relationship between BMD scores andrologic, hormonal, and physical exam findings was examined individually by linear regression analysis and interactions accounted for by multiple stepwise linear regression analysis.
Results: Of 46 patients ages 18-60, four presented with BMD scores indicative of osteopenia (9%). The prevalence of osteopenia in those patients with total sperm counts of less than 5 million sperm was 21% compared to 3% in those without osteopenia. The mean BMDs differed significantly between those with total sperm counts above and below 5 million (p = 0.035). Individual linear regression analysis correlated BMD scores to age, BMI, total sperm count, total testosterone, and FSH. Total sperm count correlated positively with BMD (r = 0.38, p = 0.01) and average testicular volume (r = 0.32, p = 0.031) while it correlated negatively with FSH (r = - 0.5, p=.003). Age, BMI, and total testosterone did not correlate significantly with BMD. Multiple stepwise linear regression was utilized to develop a model to predict BMD based on total testosterone, total sperm count, age, average testicular volume, and BMI. Analysis revealed that only FSH contributed significantly to the model. ANOVA analysis revealed that neither total testosterone, total sperm count, nor FSH differed significantly between the high, normal, and osteopenia groups.
Conclusions: The incidence of osteopenia in the infertile population is approximately 9%, and is 21% in severely oligospermic patients. BMD correlates significantly with low total sperm count and elevated FSH levels, suggesting that these parameters are risk factors for osteopenia. Consideration should be given to screening severely oligospermic patients for osteopenia.