Birth weight relates to blood pressure and microvascular function in normal subjects

Objective The relationship between low birth weight and elevated blood pres sure in adult life is well established but presently unexplained. Both micr ovascular dysfunction and insulin resistance have been proposed as a possib le explanation. We have examined the relation between birth weight and bloo d pressure in 30 healthy subjects exhibiting a wide range of insulin sensit ivity, and assessed whether microvascular function and/or insulin resistanc e may underlie this relationship. Methods Birth weight data were obtained from birth announcements. Blood pre ssure was measured with an ambulatory blood pressure monitor and insulin se nsitivity was assessed by the hyperinsulinaemic, euglycaemic clamp techniqu e. Microvascular function, i.e. capillary recruitment and endothelium-depen dent and -independent vasodilatation in the skin, was evaluated by videomic roscopy and iontophoresis of acetylcholine and sodium nitroprusside. Results Birth weight was significantly associated with blood pressure (r = -0.50; P < 0.05), capillary recruitment (r = +0.52; P < 0.05), acetylcholin e-mediated vasodilatation (r = +0.40; P < 0.05), insulin sensitivity (r = 0.62; P < 0.01) and waist-to-hip ratio (r = -0.42; P < 0.05). Regression an alysis showed a significant association of birth weight with 24 h systolic blood pressure (regression coefficient: -7.6 mmHg/kg; 95% confidence interv al: -13.0 to -1.0). Adjustment for capillary recruitment and waist-to-hip r atio decreased the regression coefficient by 39 and 41%, respectively. The results were similar after adjustment for age, sex or body mass index. Conclusion These results suggest that capillary recruitment and body fat di stribution may partly explain the relationship between birth weight and blo od pressure. J Hypertens 18:1421-1427 (C) 2000 Lippincott Wiliiams & Wilkin s.