SciTeMed News Center
Type 2 diabetes has been prevailing worldwide for many decades. It has been talk of the town for quite a long period of time. But science is taking a step ahead for eradicating it gradually. In 2015, 415 million adults were suffering from diabetes globally. It has been hypothesized that the prevalence will rise by almost 55%, i.e. up to 642 million cases by 2040. In high-income countries 91% of adults affected by diabetes have type 2 diabetes.
A research team led by Professor Patrick Rensen at Leiden University Medical Center set out to investigate whether global increase in temperature was contributing to the growth of current type 2 diabetes, by negatively impacting the glucose metabolism via a reduction in the activity of brown adipose tissue. In the study, the authors specifically hypothesized that incidence and prevalence of glucose intolerance in diabetes increase with rising outdoor temperatures. The study aimed to assess the association between outdoor temperature and glucose metabolism on a countrywide as well as a global scale.
The researchers used data on the incidence of diabetes amongst adults in 50 US states and three territories (Guam, Puerto Rico and Virgin Islands) for the years 1996 to 2009 from the National Diabetes Surveillance System of the Centers for Disease Control and Prevention (CDC). Data on country-wise prevalence rates of raised fasting blood glucose and obesity (BMI≥30) were also obtained through the WHO's Global Health Observatory online data repository system. In addition, country-wise mean annual temperature data for 2014 were obtained via the Climatic Research Unit, University of East Anglia.
The team found that on an average, with per degree Celsius rise in temperature, age-adjusted diabetes incidence increased by 0.314 per 1000. They also found the worldwide prevalence of glucose intolerance in diabetes has increased by 0.17% with per degree rise in temperature. These associations remained after adjusting for obesity. Using their findings, scientists calculated that per degree Celsius rise in environmental temperature could account for more than 100,000 new diabetes cases per year in the United States alone, given a population of nearly 322 million people in 2015.
Notably, although adjustment for important intercountry differences (i.e. age, sex, income and obesity) did not materially change the results on the global level, there may be residual confounding owing to the observational nature of the analyses. Future research is important to investigate the effects of environmental temperature on glucose metabolism and the onset of diabetes.
The study indicated that the diabetes incidence rate in the USA and the prevalence of glucose intolerance worldwide increase with higher outdoor temperature.
Lisanne L. Blauw et al. Diabetes incidence and glucose intolerance prevalence increase with higher outdoor temperature. BMJ Open Diabetes Research and Care. 2017; 5(1):e000317; doi: 10.1136/bmjdrc-2016-000317.