The medicalization of testosterone: reinventing the elixir of life

Association between cardiometabolic index and testosterone levels in adult men: NHANES 2011-2016

OBJECTIVE

Exploring the relationship between the cardiometabolic index (CMI) and serum testosterone levels as well as testosterone deficiency in American adult males. Additionally, comparing the diagnostic value of the CMI with several common obesity and metabolism indices for identifying testosterone deficiency.

METHODS

This cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016. Serum testosterone levels and testosterone deficiency were used as dependent variables, with the cardiometabolic index as the independent variable. Multivariable regression was used to assess the relationship between the independent and dependent variables, while subgroup analyses were performed to ensure the stability of the results. Smooth curve fitting was utilized to evaluate the nonlinear relationship between the CMI and testosterone levels. Receiver operating characteristic curves (ROC) were plotted for several obesity and metabolism prediction indices and the area under the curve was calculated to compare the specificity and sensitivity of each diagnostic index in the diagnosis of testosterone deficiency.

RESULTS

Among 3541 adult male participants, CMI is negatively associated with serum testosterone levels and positively associated with testosterone deficiency. In the fully adjusted model, for every unit increase in CMI, serum testosterone decreased by 14.89 ng/dl. Comparing the highest quartile to the lowest quartile of CMI, each unit increase in CMI, serum testosterone decreased by 98.58 ng/dl. Furthermore, each unit increase in CMI was associated with a 16% increase in incidence of testosterone deficiency. By plotting the ROC curves, we found that the AUCs for Lipid Accumulation Product (LAP), Body Mass Index (BMI), Weight Adjusted Waist Index (WWI), CMI, Visceral Adiposity Index (VAI) and Triglyceride glucose index (TyG) were 0.73, 0.72, 0.71, 0.69, 0.66, and 0.66 respectively.

CONCLUSION

Elevated levels of CMI are associated with lower testosterone levels and an increased risk of testosterone deficiency. The predictive value of the LAP was superior to that of CMI, while the predictive value of CMI was higher than VAI and TyG.

Sex Hormones and Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study and Mendelian Randomization Analysis

Background

Sex steroid hormones, including testosterone and estradiol, play significant roles in various aspects of pulmonary health and diseases. However, although there were a few studies trying to link sex hormones with COPD, their effect remained limited due to small sample size and insufficient causal results. This study aims to investigate the association between sex hormones and chronic obstructive pulmonary disease (COPD) based on the National Health and Nutrition Examination Survey (NHANES) database and evaluate causality via a two-sample Mendelian randomization (MR).

Methods

Data from NHANES 2013-2016 were enrolled for the cross-sectional study. The association between sex hormones and COPD was evaluated via multivariable logistic regression. Sex-stratified analysis, subgroup analyses and interaction tests were performed to further evaluate the correlation. For MR analysis, data were collected from genome-wide association studies and FinnGen datasets. The inverse-variance-weighted (IVW) approach, along with four other approaches, was applied in the analysis. Further sensitivity analysis was conducted to assess the existence of pleiotropy and heterogeneity.

Results

7,617 eligible participants were enrolled in the cross-sectional analysis. Negative associations were observed in both testosterone-COPD (OR 0.770, 95% CI 0.626, 0.948, p = 0.018) and estradiol-COPD (OR 0.794, 95% CI 0.688, 0.915, p = 0.005) relationships after covariate adjustments. However, the results from IVW-MR analysis showed that no causal relationship was observed in either the testosterone-COPD (OR 0.83, 95% CI 0.53, 1.29, p = 0.407) or estradiol-COPD (OR 0.74, 95% CI 0.23, 2.38, p = 0.616) relationship, which was also supported by the other four approaches (all p values > 0.05).

Conclusion

Although a significant negative association was observed between sex hormones and COPD, the results of MR analysis did not support the causality of this relationship. Our study suggested that sex hormones may indirectly rather than directly affect the development of COPD via potential covariates, which warranted further investigations.