Abstract
This 15-year prospective cohort study aimed to examine the impact of occupational exposure to noise and respirable flour dust on the incidence of metabolic syndrome (MetS) and its components among 379 flour mill workers in Iran. The cohort was divided into an exposed group (n = 232), comprising workers with chronic exposure to noise and dust, and a non-exposed group (n = 147), including administrative and supervisory staff with minimal exposure. Annual measurements of noise and dust followed NIOSH guidelines, and cumulative exposures were calculated over time. MetS and its components were assessed based on ATP III criteria using clinical and biochemical markers such as fasting blood sugar (FBS), triglycerides (TG), HDL cholesterol, and blood pressure. The results revealed that prolonged exposure to flour dust was associated with borderline increases in the risk of hypertension and hypertriglyceridemia, while noise exposure did not show significant associations with MetS or its components. Significant risk factors for MetS components included body mass index (BMI), age, and type 2 diabetes mellitus (T2DM). Age was a strong predictor of hyperglycemia (HR = 1.08, 95% CI: 1.02-1.14, p = 0.007), and baseline TG levels were significantly associated with hypertriglyceridemia (HR = 1.003, 95% CI:1.001-1.004, p = 0.001). Stratified analyses highlighted increased risks of MetS components among workers with extended working hours and rotational shifts. These findings emphasize the need for workplace interventions to reduce cumulative exposure risks. Future research should investigate potential mechanisms and synergistic effects of multiple occupational hazards.