Household cooking fuel and gallbladder cancer risk: a multi-centre case–control study in India

Purpose Gallbladder cancers (GBC), unique to certain geographical regions, are lethal digestive tract cancers, disproportionately affecting women, with limited information on risk factors. Methods We evaluated the association between household cooking fuel and GBC risk in a hospital-based case–control study conducted in the North-East and East Indian states of Assam and Bihar. We explored the potential mediation by diet, fire-vents, ‘daily exposure duration’ and parity (among women). We recruited biopsy-confirmed GBC ( n = 214) men and women aged 30–69 years between 2019 and 2021, and controls frequency-matched by age, sex and region ( n = 166). Information about cooking fuel, lifestyle, personal and family history, female reproductive factors, socio-demographics, and anthropometrics was collected. We tested associations using multivariable logistic regression analyses. Results All participants (73.4% women) were categorised based on predominant cooking fuel use. Group-1: LPG (Liquefied Petroleum Gas) users in the previous 20 years and above without concurrent biomass use (26.15%); Group-2: LPG users in the previous 20 years and above with concurrent secondary biomass use (15.9%); Group-3: Biomass users for ≥ 20 years (57.95%). Compared to group-1, accounting for confounders, GBC risk was higher in group-2 [OR: 2.02; 95% CI: 1.00–4.07] and group-3 [OR: 2.01; 95% CI: 1.08–3.73] (p-trend:0.020). These associations strengthened among women that attenuated with high daily consumption of fruits-vegetables but not with fire-vents, ‘daily exposure duration’ or parity. Conclusion Biomass burning was associated with a high-risk for GBC and should be considered as a modifiable risk factor for GBC. Clean cooking fuel can potentially mitigate, and a healthy diet can partially reduce the risk among women.