title: Diabetes incidence and glucose intolerance prevalence increase with higher outdoor temperature.
abstract: OBJECTIVE
  Rising global temperatures might contribute to the current worldwide diabetes epidemic, as higher ambient temperature can negatively impact glucose metabolism via a reduction in brown adipose tissue activity. Therefore, we examined the association between outdoor temperature and diabetes incidence in the USA as well as the prevalence of glucose intolerance worldwide.
  
  
  METHODS
  Using meta-regression, we determined the association between mean annual temperature and diabetes incidence during 1996-2009 for each US state separately. Subsequently, results were pooled in a meta-analysis. On a global scale, we performed a meta-regression analysis to assess the association between mean annual temperature and the prevalence of glucose intolerance.
  
  
  RESULTS
  We demonstrated that, on average, per 1°C increase in temperature, age-adjusted diabetes incidence increased with 0.314 (95% CI 0.194 to 0.434) per 1000. Similarly, the worldwide prevalence of glucose intolerance increased by 0.170% (95% CI 0.107% to 0.234%) per 1°C rise in temperature. These associations persisted after adjustment for obesity.
  
  
  CONCLUSIONS
  Our findings indicate that the diabetes incidence rate in the USA and prevalence of glucose intolerance worldwide increase with higher outdoor temperature.
authors.affiliation: Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Lisanne L
authors.initials: LL
authors.lastname: Blauw
authors.affiliation: Department of Neurology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: N Ahmad
authors.initials: NA
authors.lastname: Aziz
authors.affiliation: Department of Neurology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Martijn R
authors.initials: MR
authors.lastname: Tannemaat
authors.affiliation: Delft University of Technology , Delft , The Netherlands.
authors.forename: C Alexander
authors.initials: CA
authors.lastname: Blauw
authors.affiliation: Department of Gerontology and Geriatrics , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Anton J
authors.initials: AJ
authors.lastname: de Craen
authors.affiliation: Division of Endocrinology, Department of Medicine , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Hanno
authors.initials: H
authors.lastname: Pijl
authors.affiliation: Division of Endocrinology, Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands; Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Patrick C N
authors.initials: PC
authors.lastname: Rensen
keywords: Brown Adipose Tissue; Environment; Epidemiology; Type 2 Diabetes