Do triglycerides explain the U-shaped relation between alcohol and diabetes risk? Results from a cross-sectional survey of alcohol and plasma glucose.
The association between alcohol and blood glucose levels, and whether it is modified by other variables, was examined in a cross-sectional survey of 5518 staff aged 40-65 years at worksites in Auckland and Tokoroa, New Zealand. Diabetes was determined by oral glucose-tolerance tests using 1999 WHO criteria. Usual alcohol intake in the previous 3 months, measured by food frequency questionnaire, was related positively with fasting triglycerides and high-density-lipoprotein (HDL)-cholesterol, and unrelated with fasting glucose, but had an approximate U-shaped relationship with 2-h glucose, which varied from an adjusted mean (S.E.) of 5.62 (0.08) mmol/l in non-drinkers, down to 5.34 (0.08) mmol/l in light alcohol drinkers (alcohol <5 g per day), and back up to 5.52 (0.09) mmol/l in heavy drinkers (> or =20 g per day). Adjusting further for triglycerides increased the mean difference in 2-h glucose for all drinking categories compared with non-drinkers, particularly for heavy drinkers (> or =20 g per day), from -0.22 (S.E. = 0.10) to -0.37 (0.10) mmol/l. The confounding effect of triglycerides suggests alcohol may affect the diabetes risk by a mechanism related to the triglyceride metabolism, which in heavy drinkers may counteract the protective effect of improved insulin sensitivity, resulting in the U-shaped relationship between alcohol and diabetes described in previous studies.
Scragg
Robert
R
School of Population Health, University of Auckland, Private Bag, Auckland, New Zealand. r.scragg@auckland.ac.nz
Metcalf
Patricia
P
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000428:Alcohol Drinking / Q000009:adverse effects / Q000097:blood / Q000208:ethnology; D001208:Asia / Q000208:ethnology; D001786:Blood Glucose / Q000032:analysis; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000208:ethnology / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage; D011114:Polynesia / Q000208:ethnology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D000431:Ethanol; D014280:Triglycerides