An insulin receptor gene polymorphism is associated with diastolic blood pressure in Chinese subjects with components of the metabolic syndrome

Insulin resistance has been described as a possible underlying link for the clustering of Type 2 diabetes mellitus, hypertension, obesity, and dyslipi demia, known as the metabolic syndrome. Mutations within the insulin recept or have been associated with hypertension in some white and Oriental popula tions. We examined the relationship between the insulin receptor NsiI restriction fragment-length polymorphism (RFLP) and biochemical and anthropometric para meters associated with these disorders in 933 Chinese subjects. Of the 933 subjects, 117 were control subjects and 816 had one or more components of t he metabolic syndrome: 59.7% hypertension, 64.6% glucose intolerance, 55.3% dyslipidemia, and 53.3% obesity. The prevalences of the N1 allele and N1N1 genotype were 74.4% and 55.8%, re spectively, in the whole population. No differences were observed in the ge notype and allele frequency distributions between the control group and the cohorts with glucose intolerance, hypertension, or dyslipidemia alone or i n combination. Using one-way ANOVA, there was a weak relationship between the insulin rece ptor genotypes and diastolic blood pressure (DBP), P = .069. The DBP was si gnificantly higher in subjects carrying the N1N1 genotype in both the total population (80 +/- 13 v 76 +/- 12 mm Hg, P = .038) and subjects with gluco se intolerance (80 +/- 12 v 76 +/- 10 mm Hg, P = .048). Using stepwise mult iple regression, the insulin receptor NsiI polymorphism was found to be an independent predictor of DBP in this Chinese population, P = .018. Age, gen der, and body mass index (BMI) were also included in the analysis and were all significantly associated with diastolic DBP. To conclude, the insulin receptor gene NsiI RFLP is associated with DBP in these Chinese subjects. (C) 2000 American Journal of Hypertension, Ltd.