High prevalence of abnormal glucose homeostasis secondary to decreased insulin secretion in individuals with hereditary haemochromatosis.
OBJECTIVE
The prevalence and mechanisms of diabetes in hereditary haemochromatosis are not known. We therefore measured glucose tolerance, insulin secretory capacity and insulin sensitivity in adults with haemochromatosis.


METHODS
Subjects recruited from referrals to a haemochromatosis clinic underwent OGTT and frequently sampled IVGTT. A chart review of former clinic patients was also performed.


RESULTS
The prevalence of diabetes (23%) and IGT (30%) was increased in haemochromatosis compared with matched control subjects (0% diabetes and 14% IGT). Subjects with haemochromatosis and diabetes were overweight (14%) or obese (86%). The prevalence of diabetes, as determined by chart review of fasting glucose values, in subjects who had haemochromatosis and were in the 40-79 years age range was 26%. Overall, patients with haemochromatosis and control subjects had similar values for acute insulin response to glucose and insulin sensitivity. However, patients with haemochromatosis and IGT had a 68% decrease in acute insulin response to glucose (p<0.02) compared with those with NGT. They were not insulin-resistant, exhibiting instead a 62% increase in insulin sensitivity (NS). Haemochromatosis subjects with diabetes exhibited further declines in acute insulin response to glucose, insulin resistance, or both.


CONCLUSIONS
Diabetes and IGT are common in haemochromatosis, justifying screening for diabetes and therapeutic phlebotomy. The major abnormality associated with IGT is decreased insulin secretory capacity. Diabetes is usually associated with obesity and concomitant insulin resistance.
Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA. donald.mcmlain@hsc.utah.edu
D A
DA
McClain
D
D
Abraham
J
J
Rogers
R
R
Brady
P
P
Gault
R
R
Ajioka
J P
JP
Kushner
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D048909:Diabetes Complications / Q000097:blood / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000097:blood / Q000453:epidemiology; D005260:Female; D018149:Glucose Intolerance / Q000150:complications / Q000453:epidemiology*; D006432:Hemochromatosis / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D015995:Prevalence
D001786:Blood Glucose; D007328:Insulin