Borderline-low testosterone levels are associated with lower left ventricular wall thickness in firefighters: An exploratory analysis

Low testosterone and cardiometabolic risks in a real-world study of US male firefighters

Low serum total testosterone (TT) is associated with increased cardiovascular risk and metabolic derangements, with fatty liver (FL) emerging as an additional cardiometabolic threat. We investigated the associations between TT and cardiometabolic (CM) health in 298 US male firefighters. Cross-sectional data from occupational health examination were analyzed. TT was categorized as low (< 264 ng/dL), borderline (264–399 ng/dL), and reference (400–916 ng/dL). Conventional CM risk factors were compared among TT categories, and between firefighters with and without FL. 81% of firefighters were obese/overweight; almost 40% had FL. In the low-TT group, only 3.1% had normal BMI, while 78.1% had FL. The low-TT group had a worse CM profile, independently of age and BMI, and a fourfold higher adjusted odds of having FL. FL was associated with lower TT, regardless of age, BMI and HbA1c. Having a FL, HbA1c ≥ 5.7% or triglycerides ≥ 150 mg/dL increased the odds for low-TT by 4.1, 2.7 and 6.6 times, respectively. These real-world data reveal strong associations between low-TT and CM risk factors and support a call for action towards screening for low-TT and FL, regardless of age, BMI or dysmetabolic conditions in firefighters. Recognizing cardiometabolic risks in firefighters provides an opportunity to lessen cardiovascular diseases burden.

Testosterone and occupational burnout in professional male firefighters

Background

Very little is known about the biologic predictors of the occupational burnout in firefighters. The aim of this study was to characterize testosterone profile of active firefighters and quantify its association with three domains of the occupational burnout.

Methods

We enrolled 100 firefighters (median age 28 (interquartile range (IQR) 9.8) years with 5 (IQR 9) years in service) of three fire departments in Almaty, Kazakhstan. Demographics, smoking status, health-related quality of life (HRQL) and burnout scores of Maslach Burnout Inventory were assessed using a questionnaire, while total blood testosterone was measured in venous blood. Logistic regression models were used to quantify the association of blood testosterone with each burnout domain in the adjusted for confounders models.

Results

The median blood testosterone level was 14 (IQR 3.5) nmol/l and was only predicted by age (beta − 0.14, p < 0.01, 79% power). There were no differences in blood testosterone levels between occupational groups (Group 1 (firefighters), 14.6 (IQR 3.4); Group 2 (fire truck drivers), 14.7 (IQR 5.6); Group 3 (shift commanders, division heads, department managers and engineers), 14 (IQR 4.1) nmol/l, Kruskal-Wallis p = 0.32) or departments. Testosterone could not predict EX or CY, but had a negative association with PE score reflecting more burnout (odds ratio 1.18 (95% confidence interval 1.01;1.38)), adjusted for age, mental component of HRQL and education.

Conclusions

Firefighters with higher testosterone may develop burnout in PE earlier, and this should be considered for proper work placement within the rescue system.

Borderline-low testosterone levels are associated with lower left ventricular wall thickness in firefighters: An exploratory analysis

Background

Low endogenous testosterone has been associated with increased cardiovascular risk in men.

Objectives

To determine the prevalence of low serum testosterone level (TT) in a cohort of male US career firefighters and to examine its relation with left ventricular wall thickness (LVWT).

Materials and Methods

We conducted a cross‐sectional study among 341 career firefighters, (age: 37.5 ± 10.3 years; BMI: 28.9 ± 4.5 kg/m²), who underwent an occupational medical screening examination. TT quartiles were determined, and LVWT distribution among them was plotted. Then, TT values were categorized as low (<264 ng/dL), borderline (264‐399 ng/dL), reference range (400‐916 ng/dL), and high (>916 ng/dL). To further investigate the association of mildly decreased TT on LVWT, we divided the borderline group into borderline‐low (264‐319 ng/dL) and borderline‐high (320‐399 ng/dL) ranges. LVWT values were classified as low LVWT when <0.6 cm. A multivariate model was used to compare LVWT, age, BMI, systolic blood pressure (SBP), and HbA1c among groups by TT values.

Results

The prevalence of low TT was 10.6% and of borderline was 26.4%, while 58.7% had levels in the reference range. The low‐TT group was older and had higher BMI and SBP as compared to the reference group (P < .01). LVWT values were different among groups (P = .04) and significantly lower in firefighters with borderline‐low TT as compared to the reference group (P < .05). This finding also occurred within obese firefighters (P = .03). The borderline‐low group had a higher adjusted risk for a low LVWT as compared to the reference group [OR: 4.11 (95% CI: 1.79‐9.43)].

Discussion

Our findings highlight the possible relationship between a mild reduction in testosterone levels (borderline) and lower LVWT.

Conclusions

A high prevalence of subnormal TT levels (low and borderline: 37%) was observed in this relatively homogeneous cohort of career firefighters. Mildly decreased TT levels and lower LVWT might represent a preclinical condition and a window of opportunity for cardiovascular preventive interventions in firefighters.