Lower testosterone levels are associated with higher risk of death in men

Background and Objectives Testosterone plays an important role in regulating male development, reproduction and health. Declining levels across the lifespan may reflect, or even contribute to, chronic disease and mortality in men. Methodology Relationships between testosterone levels and male mortality were analyzed using data from multiple samples of the cross-sectional National Health and Nutrition Examination Survey (n = 10 225). Target outcomes included known deaths from heart disease, malignant neoplasms, chronic lower respiratory diseases, cerebrovascular diseases, Alzheimer's disease, diabetes mellitus, influenza and pneumonia, kidney diseases, and accidents or unintentional injuries. Results Results of discrete-time hazard models revealed that lower levels of testosterone were related to higher mortality for the majority of disease categories in either an age-dependent or age-independent fashion. Analysis of all-cause mortality-which included deaths from any known disease-also revealed greater general risk for those with lower testosterone levels. For most disease categories, the hazard associated with low testosterone was especially evident at older ages when mortality from that particular ailment was already elevated. Notably, testosterone levels were not related to mortality risk for deaths unrelated to chronic disease (i.e. accidents and injuries). Conclusions and Implications While the causal direction of relationships between testosterone and mortality risk remains unclear, these results may reflect the decline in testosterone that accompanies many disease states. Accordingly, the relationship between testosterone and male mortality may be indirect; ill individuals are expected to have both lower testosterone and higher mortality risk. Testosterone plays a key role in regulating health and development, particularly for males. Numerous health problems, such as infections and chronic diseases-like diabetes and cancer- have been linked to decreases in testosterone levels. Several studies have also identified relationships between low testosterone levels and higher risk of death in men. While low testosterone could cause increases in men's mortality risk, it is also possible that low testosterone levels may just be a sign of poor health. Men with illness or disease are expected to have both low testosterone levels and higher risk of death. The current research examined relationships between testosterone levels and risk of mortality from several causes of death in 10 255 men. Results revealed that for most mortality categories, including heart disease, cancer, cerebrovascular disease (such as strokes), influenza and pneumonia, and Alzheimer's disease, lower testosterone levels were associated with higher risk of death, particularly among older men. That low testosterone is related to mortality risk from many unique diseases may indicate that low levels of this hormone reflect poor general health. However, additional research is needed to determine whether testosterone levels directly contribute to, or are just a sign of, disease and mortality risk in men.