Abstract 16447: Incident Diabetes Among African American Adults in the Jackson Heart Study: Insulin Resistant Adiposity Phenotypes Identify High Risk Non-Obese and Lower Risk Obese Persons
Introduction: Adiposity and insulin resistance (IR) are key risk factors in the development of type 2 diabetes mellitus (T2DM). However, data is lacking on whether IR can further identify subgroups with low T2DM risk among obese individuals and with high risk among non-obese persons. This risk stratification is especially important in the African American (AA) population where obesity and T2DM are highly prevalent, yet the biological determinants of T2DM are not well understood. We hypothesized that IR adiposity phenotypes would identify subgroups of obese and non-obese persons at differing levels of risk for developing T2DM over a 5-year period.
Methods: We characterized a cohort of AA participants without diabetes in the Jackson Heart Study into four distinct IR adiposity phenotypes based on obesity and IR at baseline. Diabetes was defined as: fasting glucose ≥126 mg/dl, HbA1c≥6.5%, use of hypoglycemics, or self-report. IR was measured using the homeostasis model of insulin resistance (HOMA-IR), calculated as [fasting glucose (mmol/L) x fasting insulin (mU/L) / 22.5]. Using multivariable logistic regression, we examined 5-year risk (2000-2005) of developing T2DM within each phenotype.
Results: Of the 3,073 participants (mean age, 53.62 years; 64.14% women), 327 (10.64%) developed diabetes. In multivariable analyses, both non-obese & obese persons with elevated HOMA-IR had a greater risk of developing T2DM compared to non-obese persons with normal HOMA-IR. We also identified a group of obese persons with normal HOMA-IR with low risk of T2DM. There was no significant statistical interaction between IR adiposity phenotypes and gender (p=0.76).
Conclusion: Among obese and non-obese persons, IR differentiated subgroups with high and low risk of T2DM. Understanding the impact of IR on developing T2DM over and above the risk associated with adiposity will enable screening and early intervention for at-risk persons, especially those without apparent obesity.
- © 2013 by American Heart Association, Inc.