Prevalence and Factors of Gallstone Disease in the High-Altitude Tribal Population of Spiti Valley, Northern India: A Population-Based Cross-Sectional Study

Background: Gallstone disease shows marked geographic variation, but epidemiological data from native Himalayan high-altitude populations remain limited. This study estimated gallstone prevalence in native adults from Spiti Valley and evaluated whether altitude was independently associated with disease after accounting for demographic and metabolic factors. Methods: This community-based cross-sectional study was conducted in Spiti Valley, Himachal Pradesh, India. Using stratified random sampling, 450 native residents aged 30-70 years were enrolled across three altitude strata: low (<3500 m), mid (3501-4000 m), and high (>4000 m), with 150 participants in each group. All participants underwent fasting abdominal ultrasonography. Age, sex, body mass index, hypertension, diabetes mellitus, Helicobacter pylori status, fatty liver, and hepatitis B surface antigen status were recorded. Variables considered clinically relevant, together with the altitude group, were entered into multivariable logistic regression. Results: Overall gallstone prevalence was 21.3% (96/450). Crude prevalence was 24.0% in the low-altitude group, 24.7% in the mid-altitude group, and 15.3% in the high-altitude group; the difference across strata was not statistically significant (p=0.089). Participants with gallstone disease were older and had higher body mass index and more frequent fatty liver on univariate analysis. In the multivariable model, age (aOR 1.04 per year, 95% CI 1.01-1.06; p=0.001), female sex (aOR 2.04, 95% CI 1.19-3.51; p=0.010), and fatty liver (aOR 1.79, 95% CI 1.05-3.06; p=0.032) remained independently associated, whereas altitude did not. Conclusion: Native Spiti highlanders had a high overall gallstone burden, but the principal signal was not an independent altitude effect. This finding highlights a high-risk native Himalayan population.