A new study has found a possible link between rising number of diabetes cases around the world and global increase in temperatures with one estimate suggesting that with just 1C rise in environmental temperature could account for more than 100,000 new diabetes cases per year in US alone.
Published in the journal BMJ Open Diabetes Research & Care is the study by a team of Dutch researchers from the Leiden University Medical Center who set out to investigate the possible link between increase in global temperatures and the possible impact of this increase on type 2 diabetes growth. The link between the two was the subject of the study because of the function of brown adipose tissue (BAT) and how it is affected by temperatures.
The primary function of BAT is to transfer energy from food into heat and previous studies have shown that exposure to cold stimulates BAT, thus leading to modest weight loss and improved insulin action and sensitivity thereby making a person less likely to develop diabetes. Through the study scientists intended to assess the association of outdoor temperature increase with diabetes incidence and prevalence of glucose intolerance, on a countrywide and global scale.
On analysis of data on diabetes incidence amongst adults in 50 states of the USA and three territories (Guam, Puerto Rico and Virgin Islands) for the years 1996 to 2009 scientists found that on average, per 1C increase in temperature, age-adjusted diabetes incidence increased by 0.314 per 1,000. Similarly, the worldwide prevalence of glucose intolerance increased by 0.17% per 1C rise in temperature. These associations were the same after obesity was taken into account.
Such findings indicated that the diabetes incidence rate in the USA and prevalence of glucose intolerance worldwide did increase with higher outdoor temperature. Using their findings, the authors calculated that a 1C rise in environmental temperature could account for more than 100,000 new diabetes cases per year in the USA alone, given a population of nearly 322 million people in 2015.
This was an observational study, so no firm conclusions can be drawn about cause and effect, but the authors analysed longitudinal state-level data for each state separately before pooling the results.