SMOKING, ENVIRONMENTAL EXPOSURES, AND CHRONIC LUNG DISEASE AS KEY RISK FACTORS FOR LUNG CANCER IN NORTH SUMATRA.
BACKGROUND Lung cancer remains the leading cause of cancer mortality worldwide, with increasing incidence in many developing countries. Understanding region-specific risk factors is essential for effective prevention strategies. This study aimed to identify major determinants of lung cancer in North Sumatra, Indonesia. MATERIALS AND METHODS A hospital-based observational study with a case-control analytical approach was conducted between August and November 2024 in three referral hospitals in North Sumatra. A total of 240 patients with histologically confirmed lung cancer and 240 controls without malignancy or chronic respiratory disease were included. Participants were comparable by sex and residential area, while age differences between groups were statistically adjusted in the multivariate regression model. RESULTS Smoking exposure differed significantly between cases and controls (p = 0.023). The multivariate analysis identified several independent predictors of lung cancer. Age <45 years increased the risk more than two-fold (OR 2.62; 95% CI 1.10-6.21), whereas age >65 years showed a lower relative risk (OR 0.54; 95% CI 0.33-0.88). The occupational exposure signicantly increased lung cancer risk (OR 1.91; 95% CI 1.13-3.25). Unhealthy indoor environments, characterized by poor ventilation and household pollutant exposure, were also associated with an increased risk (OR 2.53; 95% CI 1.45-4.40). Chronic respiratory diseases, particularly tuberculosis and chronic obstructive pulmonary disease, were more prevalent among cases and contributed to the elevated risk. CONCLUSIONS Smoking exposure, occupational hazards, unhealthy indoor environments, and chronic pulmonary diseases are important determinants of lung cancer in North Sumatra. Public health strategies focusing on tobacco control, improved workplace safety, and reduction of indoor air pollution may substantially reduce lung cancer burden in this region.