Living at Higher Altitude and Incidence of Overweight/Obesity: Prospective Analysis of the SUN Cohort.
BACKGROUND
Residence at high altitude has been associated with lower obesity rates probably due to hypoxia conditions. However, there is no evidence of this association in a free-living population.


OBJECTIVE
We assessed the association between the altitude where each participant of a Spanish cohort (the SUN Project) was living and the incidence of overweight/obesity.


METHODS
The SUN Project is a dynamic, prospective, multipurpose cohort of Spanish university graduates with a retention rate of 89%. We included in the analysis 9 365 participants free of overweight/obesity at baseline. At the baseline questionnaire, participants reported their postal code and the time they had 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 10 years, we identified 2 156 incident cases of overweight/obesity. After adjusting for sex, age, time of residence at current city, baseline body mass index, physical activity, sedentarism and years of education (≤ 3 years, ≥ 4 years, Master/PhD), those participants in the third tertile (>456 m) exhibited a statistically significant 14% reduction in the risk of developing overweight/obesity in comparison to those in the first tertile (<124 m) (adjusted HR = 0.86; 95% CI: 0.77, 0.96).


CONCLUSIONS
Living in cities of higher altitude was inversely associated with the risk of developing overweight/obesity in a cohort of Spanish university graduates.
University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain.
Jesús
http://orcid.org/0000-0003-0351-4018
J
Díaz-Gutiérrez
University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain.|IDISNA Navarra's Health Research Institute, Pamplona, Spain.|CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain.|Harvard TH Chan School of Public Health, Boston, United States of America.
Miguel Ángel
MÁ
Martínez-González
University of Navarra, Department of History, Art History, and Geography, School of Humanities and Social Sciences, Pamplona, Spain.
Juan José
JJ
Pons Izquierdo
IDISNA Navarra's Health Research Institute, Pamplona, Spain.|CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain.|University of Navarra, Department of Nutrition and Food Sciences and Physiology, School of Pharmacy, Pamplona, Spain.
Pedro
P
González-Muniesa
IDISNA Navarra's Health Research Institute, Pamplona, Spain.|CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain.|University of Navarra, Department of Nutrition and Food Sciences and Physiology, School of Pharmacy, Pamplona, Spain.
J Alfredo
JA
Martínez
University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain.|IDISNA Navarra's Health Research Institute, Pamplona, Spain.|CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain.
Maira
M
Bes-Rastrollo
D000328:Adult; D000531:Altitude; D001835:Body Weight; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000453:epidemiology*; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D011795:Surveys and Questionnaires