National surveys in the U.S. have shown an increased incidence of diagnosed diabetes through 2009 followed by consistent reductions. Whether similar population-level changes are occurring in A1C, fasting glucose (FPG), and fasting insulin (FI) is unknown. It is also unknown whether changes in these glucose metabolism measures vary by socioeconomic position (SEP). We analyzed morning fasting data on 22,492 men and non-pregnant women aged ≥20 years without any diabetes from the National Health and Nutrition Examination Survey 1988 through 2016. Family income to poverty ratio (IPR) and education level were used as measures of SEP (Table). We adjusted all estimates for age, sex, and race/ethnicity accounting for the sampling design using linear/quantile regression. There were significant increases in mean levels of A1C (annual percentage change: 0.1%) and FI (1.8%) from 1988-1994 to 2011-2016 (all p <0.05) and no statistically significant changes in FPG. Patterns for medians of measurements by SEP and year were similar (Table). The risk of hyperinsulinemia was increasing among the U.S. adults, especially among lower IPR population. The increases in insulin levels in the context of little changes in glucose levels suggests a worsening of insulin resistance at the population level.

Y.J. Cheng: None. G. Imperatore: None. K.M. Bullard: None. C. Mercado: None. E.W. Gregg: None.

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