Serum Total Testosterone Levels Predict Cardiovascular Risk In Male Brazilian Firefighters

In the US, cardiac-related incidents are the leading cause of duty-related deaths in firefighters (FF). International data indicates that FFs have an undesirable high prevalence of cardiometabolic (CM) risk factors. Low serum total testosterone (TT) is associated with increased cardiovascular (CV) risk and metabolic derangements. PURPOSE: To investigate the association between endogenous serum total testosterone levels and cardiovascular risk in male Brazilian FF. METHODS: We randomly selected 328 male military FFs (41.2 ± 7.8 yrs; 29.0 ± 4.0 kg/m2) who completed bloodwork and answered questionnaires—a validated questionnaire estimated non-exercise VO2max. TT was measured in the morning, fasting and without exercising for 48 hours. FFs with TT < 400 ng/dL did two TT measurements.TT was classified as low, borderline, reference, or high (see Table 1). The Framingham Risk Score (FRS) was calculated, and CV risk was classified as low risk - FRS < 5%; intermediate risk - FRS 5-20%; high risk - FRS > 20%, or LDL cholesterol ≥190 mg/dL, or reported heart/cerebrovascular conditions. We utilized a generalized linear model based on the gamma distribution to analyze continuous predictors. The association between TT categories and CV risk classification was also analyzed (Chi-square). RESULTS: Serum TT levels independently predicted FRS in crude and adjusted analysis (p ≤ 0.01); an increase of one unit of serum TT (ng/dL) resulted in an FRS decrease of 0.05% (controlling for BMI and VO2max). There was a significant association between the increase in serum TT categories and a decrease in CV risk - p < 0.01 (Table 1). The proportion of high-risk FFs in the low TT range was 3.4 times greater than in the reference range. CONCLUSIONS: We found an association between serum TT levels and CV risk in operationally active male Brazilian FF. Future studies should evaluate if monitoring serum TT levels in FF could help address the complex CM risk assessment in this occupational group.Edital FAPDF Demanda Espontânea 3-2016, projeto 00193.001467/2016; Núcleo de Apoio à Pesquisa - NAP - Instituto Sabin; CAPES PhD scholarship - Finance Code 001 (process number: 88882.384470/2019-01)