Low Serum Testosterone and Mortality in Male Veterans

Abstract

Testosterone levels decline with aging, with an average decrease in total serum testosterone levels of approximately 1.5% per year.¹ The prevalence of low serum total testosterone levels is approximately 20% by the age of 50 years and 50% by the age of 80 years. Manifestations of low testosterone include decreased muscle mass and bone mineral density, increased fat mass, central obesity, insulin resistance, decreased libido and energy, irritability, and dysphoria.² In contrast to menopause, in which all women undergo a nearly complete cessation of gonadal estrogen secretion, in men, gonadal androgen secretion decreases gradually and progressively after the age of 30 years, but does not generally cease, and androgen levels remain highly variable in older men. The prevalence of clinical androgen deficiency (symptoms plus low testosterone levels) was recently reported to be about 6% to 12% in middle-aged and elderly men.³ Testosterone levels also decrease with acute and chronic illnesses and with medications such as glucocorticoids and opiates.² Because of the aging of our society, many older men are affected by age-associated low testosterone levels.² In addition, the use of testosterone has increased significantly, with a tripling in prescriptions for testosterone over a 3-year period.⁴ However, despite the marked increase in testosterone use, the overall risks and benefits remain unclear.^4,5