The association between serum testosterone and insulin resistance: a longitudinal study

Area of Science:

• Endocrinology
• Metabolic Health
• Population Health

Background:

• Insulin resistance is a growing public health concern.
• Testosterone plays a role in male metabolic health.
• The bidirectional relationship between testosterone and insulin resistance requires further investigation.

Purpose of the Study:

• To investigate the prospective, bidirectional association between testosterone concentrations and insulin resistance in a population-based sample of men.
• To determine if low testosterone predicts future insulin resistance.
• To determine if insulin resistance predicts future testosterone levels.

Main Methods:

• Prospective population study with baseline (2002-2005) and follow-up (2012-2014) assessments.
• Included 1282 men aged 30-74 at baseline, with follow-up data from 546 men.
• Measured fasting plasma glucose, insulin, and hormones; insulin resistance defined by HOMA-Ir.

Main Results:

• Low baseline total testosterone concentrations significantly predicted higher insulin resistance (logHOMA-Ir) at follow-up.
• Men in the lowest testosterone quartile at baseline had significantly higher logHOMA-Ir at follow-up.
• No significant association was found between baseline insulin resistance and follow-up testosterone concentrations.

Conclusions:

• Low testosterone concentrations prospectively predict the development of insulin resistance in men.
• The association appears to be unidirectional, with insulin resistance not predicting future testosterone levels.
• Findings suggest testosterone deficiency may be a risk factor for metabolic dysfunction.