Insulin resistance, impaired glucose tolerance and alpha-thalassemia carrier state.

BACKGROUND: This study was designed to determine relationship between the glucose metabolism disorder (the insulin resistance and the impaired glucose tolerance) and α-thalassemia.

METHODS: In this historical cohort study, 80Alpha-thalassemia carriers and 80 healthy people were enrolled. The participants had no diabetes familial history and the waist circumference and blood pressure were in normal range (waist circumference of less than 102 cm in men, 88 cm in women and blood pressure <120/80 mmHg). The serum insulin level, fasting blood glucose (after 12 hours fasting) and two-hour plasma glucose during an oral glucose tolerance test (2-h OGTT) were measured. Insulin resistance was estimated according to homeostasis model assessment method (HOMA). Chi-square test, independent sample t-test and the relative risk were used for data analysis.

RESULTS: According to FBS and OGTT results, the percentage of diabetes mellitus and pre-diabetes were 1.3% and 33.8% in Alpha-thalassemia carriers, respectively. The control group showed 2.5% diabetic and 13.8% pre-diabetic cases as well. The relative risk for the glucose tolerance impairment (diabetes and pre-diabetes) was 2.78 (95% CI: 1.31-5.88, P = 0.07).Six and a half percent of the Alpha-thalassemia group and 2.5% in the control group had 2.25 ≤ HOMAIR ≤ 3.59 (an intermediate state of Insulin sensitivity) p = 0.443. In the study, there was no subject with insulin resistance (HOMAIR >3.59).

CONCLUSIONS: The possibility of risk enhancement of the impaired glucose tolerance (pre-diabetes and diabetes mellitus) in patients with α-thalassemia is almost three times greater than the normal population without relationship with insulin resistance. Diabetic and pre-diabetic Alpha-thalassemia carrier state is younger than the general population suffering of these disorders.