Résumé

In industrialized populations low male testosterone is associated with higher rates of cardiovascular mortality. However, coronary risk factors like obesity impact both testosterone and cardiovascular outcomes. Here we assess the role of endogenous testosterone on coronary artery calcium in an active subsistence population with relatively low testosterone levels, low cardiovascular risk, and low coronary artery calcium scores. In this cross-sectional community-based study, 719 Tsimane forager-horticulturalists in the Bolivian Amazon aged 40+ years underwent computed tomography (49.8% male, mean age 57.6 years). Coronary artery calcium levels were low; 84.5% had no coronary artery calcium. Zero inflated negative binomial models found testosterone was positively associated with coronary artery calcium for the full sample (IRR= 1.477, 95% CI 1.001-2.170, p=0.031), and in a male-only subset (IRR=1.532, 95% CI 0.993-2.360, p=0.053). Testosterone was also positively associated with clinically relevant coronary atherosclerosis (calcium >100 Agatston units) in the full sample (OR = 1.984, 95% CI 1.202-3.275, p=0.007) and when limited to male only sample (OR= 2.032, 95% CI 1.118-4.816, p=0.024). Individuals with coronary artery calcium >100 had 20% higher levels of testosterone than those with calcium <100 (t=-3.201, p=0.007). Among Tsimane, testosterone is positively associated with coronary artery calcium despite generally low normal testosterone levels, minimal atherosclerosis and rare cardiovascular disease events. Associations between low testosterone and CVD events in industrialized populations are likely confounded by obesity and other lifestyle factors.