RELATIONSHIP OF SMOKING AND ALBUMINURIA IN CHILDREN WITH INSULIN-DEPENDENT DIABETES

Recent evidence suggests the rise in urinary albumin excretion precedi ng diabetic nephropathy may represent a continuum. We therefore studie d factors relating to albumin excretion rate in children with insulin- dependent diabetes. Normal overnight albumin excretion rate was determ ined in 690 healthy schoolchildren. The 95th centile was 7.2 mug min-1 . Patients included 169 children with IDDM aged 12.4 +/- 3.1 years who performed 4.8 +/- 0.4 overnight collections during 15 +/- 0.5 months and were analysed cross sectionally. They were stratified accordingly to mean albumin excretion rate: normal < 7.2 mug min-1, borderline 7.2 -20 mug min-1, microalbuminuria 20-200 mug min-1; 96/169 patients perf ormed 6.4 +/- 0.2 overnight collections during 24 months follow-up and were analysed longitudinally. Cigarette smoking was determined by his tory and urine cotinine levels. Smoking correlated with albumin excret ion rate, independent of age and other variables, in cross-sectional a nd longitudinal analysis (p < 0.003). Smoking was more prevalent in th e borderline albuminuria and microalbuminuria groups (p < 0.004, p < 0 .001). Mean HbA1c during follow-up and mean HbA1c since diagnosis were significantly higher in the microalbuminuric group, compared with the normal patient group. HbA1c since diagnosis, mean blood pressure, lip oprotein(a), and apolipoprotein B did not correlate with albumin excre tion rate, after controlling for other variables. Our findings highlig ht the continuing need for strategies to prevent smoking in this age g roup.