Elevated A1C is associated with impaired early-phase insulin secretion rather than insulin resistance in Koreans at high risk for developing diabetes

Tae Nyun Kim, Man Sik Park, Seong Keon Lee, Sae Jeong Yang, Kwan Woo Lee, Moonsuk Nam, Yong Soo Park, Jeong Taek Woo, Young Seol Kim, Sei Hyun Baik

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Abstract

The purpose of this study is to examine the association of A1C with beta-cell dysfunction, insulin resistance, and cardiovascular risk factors in Koreans with the relatively high risk for the future development of diabetes. This cross-sectional study recruited subjects from the pre-diabetic cohort of the Korea National Diabetes Program. Among study subjects (n = 616) aged 21-77 years with a history of hyperglycemia (fasting plasma glucose (FPG) ≥5.5 mmol/mL), analyses were conducted on 504 participants (296 women, 208 men) except for subjects with FPG ≥ 7.0 mmol/L or 120-min post-challenge plasma glucose ≥11.1 mmol/L or A1C ≥ 6.5 %. For insulin sensitivity and β-cell function classified by the categories of A1C levels, ΔIns 30-0/ΔGlu30-0 was lower in the highest quartile group than other groups. Although there was no significant difference in HOMA-IR according to the A1C categories, even lowest A1C group (≤5.3 %) already included many subjects with abnormal glucose tolerance. A1C showed a significant association with hsCRP, number of metabolic syndrome (MetS) components and ΔIns30-0/ΔGlu30-0 after adjusting for age, gender, BMI, and medications whereas HOMA-IR was insignificantly associated with A1C. Stepwise regression analysis for A1C showed that A1C is independently and negatively associated with ΔIns30-0/ΔGlu30-0, and positively associated with hsCRP. Our study showed that higher A1C was associated with impaired early-phase insulin secretion, MetS, and low grade inflammation in Koreans with the relatively high risk for the future development of diabetes.

Original languageEnglish
Pages (from-to)584-591
Number of pages8
JournalEndocrine
Volume42
Issue number3
DOIs
Publication statusPublished - 2012 Dec

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Keywords

  • HOMA-IR
  • Impaired fasting glucose
  • Impaired glucose tolerance
  • Insulinogenic index
  • Metabolic syndrome
  • Pre-diabetes

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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