As men age, their testosterone level tends to decrease. The male hormone promotes sex drive, sperm production, muscle strength, bone health, heart function, concentration, and energy levels. Thus, many older men are prescribed testosterone supplements. A new study has found that too much of a good thing can be a bad thing. Australian researchers have found that men with normal levels of testosterone live longer than men with too little or too much. They published their findings online on November 20 in the Journal of Clinical Endocrinology & Metabolism.
The researchers noted that testosterone levels decline with age; furthermore, low testosterone levels have been reported to result in earlier death. Therefore, they conducted a study to evaluate mortality in older men in relationship to testosterone (T) levels. In addition, they evaluated mortality associations in regard to dihydrotestosterone (DHT) and estradiol (E2); T is metabolized in the body into DHT and E2. They evaluated the relationship between the three hormones with mortality from any cause (all-cause mortality) as well as from ischemic heart disease.
The study group comprised 3,690 men aged 70 to 89 years who resided in Perth, Western Australia. Early morning blood samples were drawn from 2001 through 2004. The plasma levels of T, DHT, and E2 were measured. During the study period, 974 deaths (26.4%) occurred; 325 of these deaths were due to ischemic heart disease. The men who died had lower baseline T (12.8 ± 5.1 vs. 13.2 ± 4.8 nmol/L), DHT (1.4 ± 0.7 vs. 1.5 ± 0.7 nmol/L), and E2 (71.6 ± 29.3 vs. 74.0 ± 29.0 pmol/L). After adjusting for other risk factors, the researchers found that T and DHT were associated with all-cause mortality. However, higher DHT was associated with lower ischemic heart disease IHD mortality and E2 was not associated with either all-cause or IHD mortality.
The researchers concluded that optimal male hormone levels are a biomarker for survival because older men with midrange levels of T and DHT had the lowest death rates from any cause, while those with higher DHT had lower ischemic heart disease mortality. They recommended that further research should be conducted in this area.
Take home message:
Older men should consider having their testosterone level measured at their annual physical exam. If it is low, testosterone therapy might be beneficial if it is given in a dosage to place the hormone in the normal—but not elevated—range.