High C-reactive protein is associated with increased risk of biochemical hypogonadism: a population-based cohort study

Abstract

Context Obesity seems to decrease levels of testosterone. It is still unknown what role inflammation plays in the secretion of testosterone in men. Objective The objective is to study the association between levels of C-reactive protein and testosterone and its role in predicting biochemical hypogonadism in men. Design This was a longitudinal observational study between 2002 and 2014 in Sweden. Patients or other participants At the first visit, a random population sample of 1400 men was included, and 645 men fulfilled a similar protocol at a 10-year follow-up visit. After exclusion, 625 men remained to be included in the final analyses. Main outcome measure(s) Serum concentrations of testosterone and C-reactive protein (CRP) were measured at both visits. Bioavailable testosterone was calculated. Biochemical hypogonadism was defined as total testosterone levels <8 nmol/L. Results At the first visit and in the longitudinal analyses, a strong association was found between high levels of CRP and low levels of calculated bioavailable testosterone even after adjustments for age, waist–hip ratio, hypertension, smoking, type 2 diabetes, and leisuretime physical activity (B = −0.31, 95% CI −0.49 to −0.13, P = 0.001, B = −0.26, 95% CI −0.41 to −0.11, P = 0.001). Similarly, increase with one s. d. in CRP was associated with increased risk of having hypogonadism after adjustment in the final model (odds ratio (OR) 1.76, 95% CI 1.12–2.78, P = 0.015, OR 1.80, 95% CI 1.16–2.78, P =0.008). Conclusions In this representative cohort of men in southwestern Sweden, high levels of CRP were longitudinally associated with low concentrations of calculated bioavailable testosterone and increased risk of biochemical hypogonadism.