*2.4. Outcome Assessments*

At baseline recruitment, the participants underwent blood pressure and anthropometric assessments as part of the initial study visit. Resting blood pressure was measured using an appropriately sized cuff in seated position for each firefighter. BMI was recorded for all study subjects in kg/m<sup>2</sup> from measured height and weight. Body fat (%) was estimated by a Bioelectrical Impedance Analyzer (BIA) [40,45].

Separately, the firefighters had biochemical indices assessed at fire department-sponsored medical examinations. We used the biochemical measurements gathered at the closest date from the date of study consent within the same 12-month period. Blood samples were also collected after an overnight fast at baseline and at follow-up. Using EDTA collection tubes, up to 15 mL of blood was collected. Plasma and serum were aliquoted, frozen at −80 ◦C, stored, and run in batches. Automated high-throughput enzymatic analysis was used to determine the blood lipid profiles of the firefighters. This analysis achieved coefficients of variation ≤3% for cholesterol and ≤5% for triglycerides, using a cholesterol assay kit and reagents (Ref:7D62–21) and triglyceride assay kit and reagents (Ref:7D74–21) by the ARCHITECT c System, Abbott Laboratories, IL, USA. The lipid measures included total cholesterol, triglycerides, total cholesterol/HDL ratio, HDL-cholesterol, and low-density lipoprotein (LDL)-cholesterol.

## *2.5. Covariate Assessment*

We collected sociodemographic characteristics, medical history, lifestyle habits, and dietary intake from the study's comprehensive lifestyle questionnaire [40].
