DOES THE PRESENCE OF DIABETIC NEPHROPATHY IN PARENTS INFLUENCE THE METABOLIC RESPONSE IN THE OFFSPRING

Non-insulin dependent (Type 2) diabetes mellitus (NIDDM) and long-term complications such as nephropathy have a strong genetic predispositio n, Insulin resistance is thought to be a pathogenetic factor, predispo sing genetically prone individuals to develop the microvascular compli cations of diabetes, To test these hypotheses two groups of young indi viduals were studied: 28 offspring of parents having NIDDM and diabeti c nephropathy (group 1) aged 29.5 +/- 6.1 years, BMI 25.2 +/- 4.7 kg m (-2) and 31 offspring of diabetic parents with no history of nephropat hy, aged 31.6 +/- 4.1 years and BMI 26.3 +/- 4.9 kg m(-2) (group 2). A ll underwent a standard oral glucose tolerance test with measurement s erum insulin levels and serum lipid profile. Urine albumin:creatinine ratio (A/C ratio) and blood pressure were also recorded, Diabetes was detected in 2/28 (7.1 %) and 3/31 (9.7 %) and IGT was detected in 5/28 (25 %) and 8/31 (25 %) of groups 1 and 2, respectively. These differe nces were not statistically significant, but were higher than in a gro up Of non-diabetic controls with healthy parents. Comparison of the no rmoglycaemic subjects (19 and 20 in group 1 and 2, respectively) showe d no significant differences between blood pressure readings, fasting and 2 h plasma glucose, and lipid profiles, Plasma insulin values, fas ting and 2 h, and the area under the graph were also similar in both g roups, indicating an absence of higher insulin response in group 1 in comparison with group 2. These values were also not different from tho se in the non-diabetic controls. A delay in insulin response to glucos e was noted in many of the offspring as indicated by a low Delta I/Del ta G at 30', We conclude that offspring of diabetic parents with nephr opathy do not show higher risk of glucose intolerance or insulin resis tance compared to those with diabetic parents without nephropathy. The relatively high plasma glucose values in the presence of normal insul in secretion in both groups of offspring of diabetic parents suggest t he presence of insulin resistance. (C) 1997 by John Wiley & Sons, Ltd.