Vitamin D status, incident diabetes and prospective changes in glucose metabolism in older subjects: the Hoorn study.
OBJECTIVE
Vitamin D deficiency may contribute to impaired glucose metabolism and type 2 diabetes, especially in the elderly population. We aimed to evaluate whether baseline 25-hydroxyvitamin D (25[OH]D) levels are prospectively associated with deterioration of glucose metabolism and the incidence of diabetes.


RESULTS
We examined a subsample from the population based Hoorn study among older men and women. Physical examinations were performed from 2000 to 2001 and included measurements of 25(OH)D. Glucose tolerance tests and HbA1c measurements were performed at baseline and at a follow-up between 2007 and 2009. We included 351 study participants (51% females; 67.9 ± 5.7 years). Baseline 25(OH)D levels were 56.7 ± 18.8 nmol/L and follow-up visits were performed after 7.5 ± 0.5 years. Among 280 study participants without diabetes at baseline we recorded 45 cases of incident diabetes. There was no significant association of 25(OH)D with the incidence of diabetes and with fasting and 2h postload glucose levels at follow-up. In analyses adjusted for age, sex, and baseline HbA1c there was, however, a significant association of 25(OH)D with follow-up HbA1c levels (beta coefficient=-0.085, p=0.085). This association was attenuated after further adjustments for BMI (beta coefficient=-0.079, p=0.064).


CONCLUSIONS
In this study among the older population we observed no significant association of baseline 25(OH)D with glucose metabolism and incident diabetes. We found, however, a non-significant trend towards an inverse association of 25(OH)D with prospective changes in HbA1c that deserves further investigations.
Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria. stefan.pilz@chello.at
S
S
Pilz
K
K
van den Hurk
G
G
Nijpels
C D A
CD
Stehouwer
E
E
Van't Riet
K
K
Kienreich
A
A
Tomaschitz
J M
JM
Dekker
D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000032:analysis; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology*; D005215:Fasting; D005260:Female; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D015994:Incidence; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009752:Nutritional Status; D011446:Prospective Studies; D012307:Risk Factors; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000150:complications
D001786:Blood Glucose; D005947:Glucose; D006442:Glycated Hemoglobin; D014807:Vitamin D; C517652:hemoglobin A1c protein, human