title: Correlation between Total Solar Irradiance and Glycated Hemoglobin 2 to 3 Months Later in Patients with Diabetes: A Big-Data Analysis.
abstract: OBJECTIVE
  Much attention has been paid recently to a relationship between glucose metabolism and weather. This study investigated the temporal correlation between total solar irradiance (TSI) and glycated hemoglobin (A1C) values in patients with diabetes.
  
  
  METHODS
  In 1531 patients with diabetes who received follow-up care between 2009 and 2013 (type 1 diabetes, 123 patients; type 2 diabetes, 1408 patients; male 53.6%; mean age, 61.2 years), A1C levels were measured a total of 58,830 times. The correlation between mean monthly TSI and mean A1C values from 1 to 4 months later was then examined.
  
  
  RESULTS
  The mean values for TSI and A1C throughout the entire study period were 13.7 MJ/m2and 7.7%, respectively. The correlation coefficient between TSI and mean monthly A1C values at 1 to 4 months was -0.516, -0.734, -0.726 and -0.475, respectively (all p<0.001).
  
  
  CONCLUSIONS
  There was a highly negative correlation between TSI and mean A1C values 2 to 3 months later in this population; thus, this fact may need to be considered when using A1C levels as a glycemic control index in patients with diabetes. Further studies are warranted.
authors.affiliation: Department of Clinical Laboratory, Uenomachi-Kajiya Clinic, Kagoshima, Japan. Electronic address: kinchiku_ukclabo@po14.synapse.ne.jp.
authors.forename: Shigesumi
authors.initials: S
authors.lastname: Kinchiku
authors.affiliation: Division of Community and Family Medicine, Jichi Medical University, Tochigi, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kotani
authors.affiliation: Department of Clinical Laboratory, Uenomachi-Kajiya Clinic, Kagoshima, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Maruguchi
authors.affiliation: Department of Clinical Laboratory, Uenomachi-Kajiya Clinic, Kagoshima, Japan.
authors.forename: Anna
authors.initials: A
authors.lastname: Aikou
authors.affiliation: Department of Internal Medicine, Uenomachi-Kajiya Clinic, Kagoshima, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Uenomachi
authors.affiliation: Department of Internal Medicine, Uenomachi-Kajiya Clinic, Kagoshima, Japan.
authors.forename: Shouko
authors.initials: S
authors.lastname: Kajiya
mesh_terms: D015415:Biomarkers / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000532:radiotherapy; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000532:radiotherapy; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D011379:Prognosis; D013223:Statistics as Topic / Q000379:methods*; D013472:Sunlight
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: A1C; A1c; glycemic control; insulin; insuline; rayonnement ultraviolet; régulation de la glycémie; temps; ultraviolet radiation; weather