Insulin Resistance, the Metabolic Syndrome, and Risk of Incident Cardiovascular Disease in Nondiabetic American Indians
The Strong Heart Study
- Helaine E. Resnick, PHD, MPH1,
- Kristina Jones, MPH1,
- Giacomo Ruotolo, MD, PHD1,
- Arvind K. Jain, MS1,
- Jeffrey Henderson, MD2,
- Weiquan Lu, MD1 and
- Barbara V. Howard, PHD1
- 1MedStar Research Institute, Hyattsville, MD
- 2Black Hills Center for American Indian Health, Rapid City, South Dakota
OBJECTIVE—Insulin resistance (IR) and the metabolic syndrome (MS) are associated with type 2 diabetes and adverse cardiovascular disease (CVD) risk factor profiles. Whether IR and MS predict CVD independently of diabetes and other CVD risk factors is not known. This study examines whether IR and/or presence of MS are independently associated with CVD in nondiabetic American Indians (AI).
RESEARCH DESIGN AND METHODS—We examined 2,283 nondiabetic AI who were free of CVD at the baseline examination of the Strong Heart Study (SHS). CVD risk factors were measured, IR was quantified using the homeostasis model assessment (HOMA), and MS as defined by the National Cholesterol Education Program Adult Treatment Panel (ATP III) was assessed for each participant. Incident CVD and diabetes were ascertained during follow-up.
RESULTS—MS was present in 798 individuals (35%), and 181 participants (7.9%) developed CVD over 7.6 ± 1.8 years of follow-up. Age, BMI, waist circumference, and triglyceride levels increased and HDL cholesterol decreased across tertiles of HOMA-IR. Risk of diabetes increased as a function of baseline HOMA-IR (6.3, 14.6, and 30.1%; P < 0.001) and MS (12.8 vs. 24.5%). In Cox models adjusted for CVD risk factors, risk of CVD did not increase either as a function of baseline HOMA-IR or MS, but individual CVD risk factors predicted subsequent CVD.
CONCLUSIONS—Among nondiabetic AI in the SHS, HOMA-IR and MS both predict diabetes, but neither predicts CVD independently of other established CVD risk factors.
- AI, American Indians
- ATP III, National Cholesterol Education Program Adult Treatment Panel
- CVD, cardiovascular disease
- FG, fasting glucose
- FI, fasting insulin
- FSIVGTT, frequently sampled intravenous glucose tolerance test
- HOMA, homeostasis model assessment
- IR, insulin resistance
- MS, metabolic syndrome
- SHS, Strong Heart Study
Address correspondence and reprint requests to Helaine E. Resnick, PhD, MPH, MedStar Research Institute, 6495 New Hampshire Ave., Suite 201, Hyattsville, MD 20783. E-mail:.
Received for publication 26 June 2002 and accepted in revised form 18 November 2002.
The opinions expressed in this paper are those of the authors and do not necessarily reflect the view of the Indian Health Service (IHS).
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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