Paternal phenotype is associated with microalbuminuria in young adults with Type 1 diabetes mellitus of short duration.

Abstract

Susceptibility to diabetic nephropathy has not yet been causally linked to any genetic factors. We investigated in nuclear families whether parental ambulatory blood pressure, lipids and urine albumin excretion were early markers of risk of microalbuminuria in young adults with Type 1 diabetes. A subset of 98 young adults from the Oxford Regional Prospective Study were followed from diagnosis until aged >or= 16 years and duration of diabetes >or= 5 years (probands). Of these subjects, 24 developed microalbuminuria (males >or= 3.5 mg/mmol; females >or= 4 mg/mmol) and were designated cases, whereas 74 were controls. Family medical history, 24-h ambulatory blood pressure, urine albumin to creatinine ratio (ACR), non-fasting lipid profile and apolipoproteins (A1 and B) were measured in mothers and fathers. The prevalence of a parental hypertension (taking anti-hypertensive medication or daytime blood pressure > 140/90 mmHg), was similar in cases and controls (29% vs. 35%; chi2 test, P = 0.3). The systolic blood pressure night to day ratio and also ACR were higher in the fathers of cases when compared with the fathers of controls [systolic 0.88 (0.08), n = 14 vs. 0.85 (0.12), n = 53, P = 0.041]; [ACR median (IQ range) 0.6 mg/mmol (0.2-16.9) vs. 0.47 mg/mmol (0.3-3.7), P = 0.049]. Paternal night-time systolic blood pressure, night to day systolic blood pressure ratio and ACR were correlated with an index of susceptibility to albuminuria (r = 0.25, P = 0.042, n = 69 and r = 0.28, P = 0.022, n = 0.67 and r = 0.24, P = 0.029, n = 0.85, respectively). Higher paternal ACR and night to day ratio of ambulatory blood pressure, but not parental hypertension or maternal factors, are associated with microalbuminuria in young adults with Type 1 diabetes.