Alterations in circulating vitamin D metabolites in the young insulin-dependent diabetic.
To assess the relationship between the decreased bone mass observed in young insulin-requiring diabetic patients and vitamin D metabolism, we measured serum 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D concentration in 45 white, insulin-dependent diabetic subjects, 7-18 yr of age. Metacarpal cortical thickness in 87% of these diabetics was below the mean for their respective ages, while 16% had a cortical thickness value greater than 2 sDs below the mean. Serum calcium and phosphate concentrations were normal, immunoreactive parathyroid hormone was in the low normal range, and total serum alkaline phosphatase was elevated compared to age- and sex-matched controls. Circulating 24,25-dihydroxyvitamin D concentrations were significantly elevated, and 1,25-dihydroxyvitamin D was significantly decreased. The increase in 24,25-dihydroxyvitamin D was greater in the diabetics with the most severe bone loss and was maximally increased during the first 5 yr of clinical diabetes. No apparent correlation was seen between metabolic control, as measured by hemoglobin A1C and urine and plasma glucose, and the circulating levels of the vitamin D metabolites. Despite appropriate insulin replacement, alterations in vitamin D metabolism occur in the young insulin-dependent diabetic and could relate to the decrease in cortical bone mass observed in these patients.
D015650:24,25-Dihydroxyvitamin D 3; D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D002112:Calcifediol; D002117:Calcitriol / Q000097:blood; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D004100:Dihydroxycholecalciferols / Q000097:blood; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D007328:Insulin / Q000627:therapeutic use; D008663:Metacarpus / Q000473:pathology; D014807:Vitamin D / Q000097:blood*
D004100:Dihydroxycholecalciferols; D006887:Hydroxycholecalciferols; D007328:Insulin; D014807:Vitamin D; D015650:24,25-Dihydroxyvitamin D 3; D000469:Alkaline Phosphatase; D002117:Calcitriol; D002112:Calcifediol