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Residency at high altitudes reduced progressive weight gain, obesity
US Air Force and Army service members stationed at high-altitude military facilities were less likely to transition from overweight status to obese status, according to findings published in PLoS One.
Researchers suggested that hypoxia — an oxygen-deficient state — could be utilized as a novel intervention for obesity.
Jameson D. Voss, MD, MPH, a captain in the Air Force, and colleagues surveyed data from 2006 to 2012 containing information on 98,009 service members who were overweight, but not obese, at the time of enlistment (BMI, ≥25 to <30). Previous research on hypoxic effects had shown reductions in appetite and body weight in short-term scenarios, such as high-altitude travel. This study measured body weight in participants with a mean 3.2 years of high-altitude exposure.
“This is the strongest evidence to date that moving to high altitude provides long-term obesity protection,” Voss said in a press release.
Study participants were divided into categories based on the average altitude of their military duty station as calculated by geospatial engineering software. The investigators also gathered data on demographic features, including income and housing allowances.
Data analysis showed a small but sizable portion of the study population was stationed at high altitude (>1.96 km in elevation), with 16,111 person-years observed in that category.
Service members stationed at high altitude had a 41% (95% CI, 35–46) lower hazard rate for obesity vs. those stationed at low altitude (<0.98 km), even after controlling for enlistment BMI, branch of service, time in service, occupation, sex, ethnicity, age and housing allowance.
Unadjusted results were similar (41% lower hazard rate; 95% CI, 35–47).
Some military career occupations were more strongly associated with a reduced risk for obesity at high altitudes. Service members in aircrew occupations had a 46% (95% CI, 34–56) lower hazard rate of an obesity diagnosis than those in health care operations.
Researchers said further study could help clarify the full range of changes that the human body experiences while adapting to long-term residence at high altitudes.
“Some adaptations to high altitude could modify body weight without altering body fat. Hemoconcentration, for example, would reduce total body water and body mass without reducing body fat,” the study researchers said.
Previous research has shown that serum leptin rises at high altitudes and that the leptin receptor is upregulated, which could further reduce hunger and encourage weight loss, according to the investigators.
Disclosure: Some researchers report affiliations with the US Armed Forces.