title: Seasonal variations of urinary albumin creatinine ratio in Japanese subjects with Type 2 diabetes and early nephropathy.
abstract: OBJECTIVE
  It has been recognized that blood pressure shows a seasonal variation, but it remains unknown whether diabetic nephropathy shows a seasonal variation. In the present study, we investigated the change in urinary albumin/creatinine ratio in relation to the season in Japanese patients with Type 2 diabetes.
  
  
  METHODS
  A total of 430 subjects (275 male, 155 female) with Type 2 diabetes and early nephropathy (defined by UACR 30-300 mg/g creatinine) were included. One year was divided into four seasons and each season was defined as winter (December-February), spring (March-May), summer (June-August), and fall (September-November), and systolic and diastolic blood pressure, serum creatinine levels, and the urinary albumin/creatinine ratio were examined. The estimated glomerular filtration rate was also calculated and evaluated.
  
  
  RESULTS
  The mean age (± SE) was 64.8 ± 0.8 years. The mean systolic blood pressure was significantly higher in winter than in summer (136 ± 0.68 vs. 133 ± 0.68 mmHg, P < 0.001). The urinary albumin/creatinine ratio showed a significantly higher value in winter than in summer (72.8 ± 4.4 vs. 54.6 ± 3.4 mg/g creatinine, P < 0.001). The curve of seasonal variation of this ratio showed a similar change to that of systolic blood pressure. No significant seasonal variation was observed in estimated glomerular filtration rate and diastolic blood pressure.
  
  
  CONCLUSIONS
  Our results suggest that there is a hitherto unknown seasonal variation in the urinary albumin/creatinine ratio, and that it may be necessary to consider this seasonal change, especially when performing an intervention study of nephropathy.
authors: Center for Diabetes and Endocrinology, The Tazuke Kofukai Foundation Medical Research Institute Kitano Hospital, Osaka, Japan.
authors: Y
authors: Y
authors: Wada
authors: Y
authors: Y
authors: Hamamoto
authors: H
authors: H
authors: Ikeda
authors: S
authors: S
authors: Honjo
authors: Y
authors: Y
authors: Kawasaki
authors: K
authors: K
authors: Mori
authors: H
authors: H
authors: Koshiyama
mesh_terms: D000419:Albuminuria / Q000503:physiopathology / Q000652:urine*; D044466:Asian People; D001794:Blood Pressure; D003404:Creatinine / Q000652:urine*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology / Q000652:urine*; D003928:Diabetic Nephropathies / Q000503:physiopathology / Q000652:urine*; D005260:Female; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012621:Seasons; D013997:Time Factors
chemical_list: D003404:Creatinine; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human