Influence of ageing and some lifestyle factors on male gonadal function: a study in Bulgaria

There are few systematic studies on the relationship between blood testosterone concentrations and the symptoms of androgen deficiency in ageing males. To assess the changes in sex hormone levels with age in relation with some lifestyle factors, the serum levels of total testosterone (TT), sex-hormone binding globulin (SHBG), luteinising hormone (LH) and follicle stimulating hormone (FSH) were measured in 33 men, age range 40-89 years. In addition, free testosterone (FT) and the free androgen index (FAI) were calculated. Seventeen healthy men under 40 years were involved as controls. The men over 40 years revealed significantly decreased TT, FT and FAI, and in the subgroup of men over 60 years, FSH and SHBG were significantly increased. Pearson's analysis showed that TT levels were significantly correlated with body mass index (BMI) (r = -0.464, P < 0.01) and body weight (r = -0.413, P < 0.05). SHBG levels were significantly correlated not only with age (r = +0.407, P < 0.05), but also with LH (r = +0.605, P < 0.001) and alcohol consumption (r = +0.382, P < 0.05). In conclusion, the TT, FT and FAI decreased in males over 40 years, but the alterations in hormone levels with age are more pronounced in men over 60 years. The important determinants of sex hormones are age, BMI and some lifestyle factors.