People in the United States who live at higher altitudes where the air is thinnest are less likely to be obese than those in low-lying areas, according to a US study.
Using data for more than 400,000 people, researchers who published their results in the International Journal of Obesity found that people who lived closest to sea level were four to five times more likely to be obese, compared to people who live well above sea level in Colorado.
"I was surprised by the magnitude of the effect," said lead author Jameson Voss, from Uniformed Services University of the Health Sciences in Bethesda, Maryland. "I wasn't expecting such a consistent pattern as what was emerging."
About 36 percent of US adults are obese, according to the US Centers for Disease Control and Prevention (CDC). Rates vary across the nation, however, with a higher percentage of obese adults in southern states. Western states, such as Nevada and Colorado, report the fewest obese adults.
The reasons behind the difference are unclear, said Voss and his colleagues, but one possible explanation is differences in elevation - which can affect appetite hormones, growth and how many calories the body burns.
For the study, the researchers combined information from several databases, including a telephone health survey of 422,603 US residents from 2011.
They had information on 236 people who lived at the highest altitude of at least 3,000 meters (about 9,800 feet) above sea level. They all lived in Colorado and tended to smoke less, eat healthier and exercise more.
The researchers also had information on 322,681 people who lived in the lowest altitude range, or less than 500 m (about 1,600 feet) above sea level.
After taking into account other factors that could influence the results, the researchers found that adults living in the lowest altitude range had a Body Mass Index (BMI) - a measure of weight against height - of 26.6. That compared to a BMI of 24.2 for people who lived in the highest altitude range.
A healthy BMI falls between 18.5 and 24.9, and obesity is a score of 30 or more, according to the CDC.
Comments
Comments are closed.