Living at higher altitude and incidence of overweight/obesity: prospective analysis of the SUN cohort
Introduction: Residence at high altitude has been associated with lower obesity rates due to hypoxia conditions. However, there is no evidence of this association in a free-living population. Therefore, our objective was to assess the association between the altitude where each participant of the SUN Project is living and the incidence of overweight/obesity. Methods: The SUN Project is a dynamic, prospective, multipurpose co- hort of Spanish university graduates with a retention rate of 90%. We included in the analysis 9,302 participants free of overweight/obesity at baseline. At the baseline questionnaire participants report their postal code and the time they are been living in their city/village. We imputed the altitude of each postal code according to the data of the Spanish National Cartographic Institute and categorized participants in tertiles. We used Cox regression models to adjust for potential confounding variables. Results: During a median follow-up of 8.5 years, we identified 2,099 in- cident cases of overweight/obesity. After adjusting for age, sex, baseline body mass index, time of residence, physical activity (quartiles), sedentary behaviours (quartiles), smoking (non-smokers, current smokers, former smokers), snacking, follow a special diet, total energy intake, and adher- ence to the Mediterranean dietary pattern, those participants in the third tertile (>456 m) exhibited a statistically significant 13% reduction risk for the development of overweight/obesity in comparison to those in the first tertile (<124 m) (adjusted HR: 0.87; 95% CI: 0.77–0.98). Conclusion: Living in cities of higher altitude was associated with a lower risk of developing overweight/obesity in a cohort of Spanish university graduates. Acknowledgement: The SUN Project is funded by the Spanish Government and the Regional Government of Navarra.