Inverted U-shaped association between total testosterone with bone mineral density in men over 60 years old

Aging often leads to changes in hormone levels, particularly testosterone, which is thought to significantly affect bone health in older males. This study aimed to explore the link between testosterone levels and bone mineral density in men aged 60 and above. Data from the National Health and Nutrition Examination Survey 2013-2014 were used. Weighted multivariable linear regression models were employed to study the association between testosterone and bone mineral density. Furthermore, a weighted generalized additive model and smooth curve fitting were used to address potential nonlinear patterns in the data. The analysis included 621 elderly men. After accounting for various factors, the study uncovered a Inverted U-shaped correlation between testosterone levels and femoral neck density. Notably, a turning point was identified at the testosterone level of 406.4 ng/dL. Further examination, using different models, showed that testosterone levels in the third quartile (group Q3) were positively linked to bone density. However, contrasting trends were observed in the first (group Q1) and fourth quartiles (group Q4), where testosterone levels displayed a negative relationship with bone density. The results indicate a complex interplay between testosterone levels and bone mineral density in elderly men. The U-shaped trend suggests that both low and high testosterone levels could negatively impact bone health. These findings highlight the importance of maintaining testosterone levels within an optimal range to preserve bone health in aging men.