by Jen Turner
Research carried out with people living in Colorado, US, has found that Americans who lived well above sea level were less likely to be obese than those in low-lying areas. Reported in the Mail (online), Lead researcher Dr Jameson Voss, from Uniformed Services University in Maryland, said: “I was surprised by the magnitude of the effect… I wasn’t expecting such a consistent pattern as what was emerging.” The study based on data from 400,000 people living in Colorado illustrated that a person’s obesity risk dropped with every 660ft increase in elevation.
To examine obesity rates at different altitudes, the researchers combined information from several databases, including a telephone health survey of 422,603 Americans from 2011. The researchers had information on 236 people who lived at the highest altitude of at least 9,800 feet above sea level. Those people 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 – less than 1,600ft above sea level. After taking into account other factors that could influence the results such as retirement age, the researchers found adults living in the lowest altitude range had a Body Mass Index (BMI) – a measurement of weight in relation to height – of 26.6. That compared to people who lived in the highest altitude range, who had a BMI of 24.2. A healthy BMI falls between 18.5 and 24.9.
Dr Voss considered that the associations persist over the long term, with changes in elevation perhaps affecting appetite hormones, growth and how many calories the body burned. These findings could help explain the difference in obesity rates between states. However, the results are unable to conclude whether moving to an area of high altitude would mean you would automatically loss your excess weight. It would be interesting to study whether obesity prevalence would change if the research participants moved to a lower altitude.
The rapid rise in obesity rates over the last 30 years has been considerably noteworthy for geographers due to its profound implications for the health of populations. A recent paper by Dianna M. Smith, and Steven Cummins explains that, as this rise has occurred over a relatively short biological time scale, it is suggested that changes in the environments to which we are exposed may be to blame, rather than individual genetic endowment. Focusing on developed world nations, this article briefly reviews this emerging ‘ecological’ perspective in the search for the causes of obesity. This article explores how aspects of our environment might disrupt ‘energy balance’ through influencing food consumption and physical activity. It focuses on three hypothesised pathways for environmental risk: the organisation of built physical space, the social environment and the political environment. The article demonstrates that a consideration of scale and context are also important in the search for the environmental drivers of weight gain. For the discerning geographer, these inherent relationships between physical spaces and the body continue to be of interest; with this particular topic generating another avenue of study surrounding the transformation of the individual through space.
Dianna M. Smith, and Steven Cummins, 2008, Obese Cities: How Our Environment Shapes Overweight, Geography Compass, 3(1), 518-535.
J D Voss, P Masuoka, B J Webber, A I Scher and R L Atkinson, 2013, Association of elevation, urbanization and ambient temperature with obesity prevalence in the United States, International Journal of Obesity, DOI: 10.1038/ijo.2013.5.
Want to slim down? Living at a higher altitude can help (and it’s nothing to do with climbing), Mail (online), 13 February 2013.