Influence of HbA1c and BMI on Lipid Trajectories in Youths and Young Adults With Type 1 Diabetes.

Abstract

To assess the influence of HbA_1c and BMI (measured as BMI z score [zBMI]) on LDL, HDL, and non-HDL trajectories as youths with type 1 diabetes age into early adulthood. Dynamic, retrospective cohort study examining changes in lipid values in 572 youths with type 1 diabetes followed longitudinally for a median of 9.3 years. Through longitudinal modeling, we describe the relationship of HbA_1c and zBMI on lipid values as subjects age after adjusting for other relevant factors, including lipid-lowering medication use. The median number of lipid assessments was 7 (range 2-39). Every 1% increase in HbA_1c was associated with an ∼2-6 mg/dL increase in LDL levels, with a greater increase in LDL levels as subjects progressed from prepubertal to postpubertal age ranges. A 1-SD increase in BMI was associated with a mean LDL increase of 2.1 mg/dL when subjects were 10 years old and increased to a mean of 8.2 mg/dL when subjects were 19 years old. The association between changes in HbA_1c level and zBMI and changes in non-HDL levels as youths aged were similar to the associations found with LDL. The influence of HbA_1c and zBMI on HDL levels was small and not dependent on age. Changes in HbA_1c level and zBMI modestly impact LDL and non-HDL cholesterol and have greater impacts as children age. Addressing elevations in HbA_1c and zBMI as children enter into adolescence and beyond may lead to improvements in lipid levels.