Determinants of Racial/Ethnic Disparities in Incidence of Diabetes in Postmenopausal Women in the U.S.

The Women’s Health Initiative 1993–2009

  1. Barbara V. Howard, PHD15
  1. 1Division of Preventive and Behavioral Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
  2. 2Department of Epidemiology and Biostatistics and Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina
  3. 3Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
  4. 4Division of Biostatistics and Epidemiology, University of Massachusetts Amherst, Amherst, Massachusetts
  5. 5Departments of Epidemiology, Medicine and Obstetrics &Gynecology, Center for Metabolic Disease Prevention, University of California Los Angeles, Los Angeles, California
  6. 6Department of Social and Preventive Medicine, School of Public Health and Health Professions, University at Buffalo, The State University of New York, Buffalo, New York
  7. 7RAND Corporation, Santa Monica, California
  8. 8Department of Preventive Medicine, Tongji University School of Medicine, Shanghai, China
  9. 9Stanford Prevention Research Center, Stanford University School of Medicine, Stanford, California
  10. 10Atlanta VA Medical Center, Decatur, Georgia and Division of Endocrinology, Emory University, Atlanta, Georgia
  11. 11Division of Cardiovascular Medicine, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
  12. 12Albert Einstein College of Medicine, Bronx, New York
  13. 13Department of Obstetrics and Gynecology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
  14. 14Department of Public Health Sciences, University of California, Davis, California
  15. 15MedStar Research Institute, Hyattsville, Maryland
  1. Corresponding author: Yunsheng Ma, yunsheng.ma{at}umassmed.edu.

Abstract

OBJECTIVE To examine determinants of racial/ethnic differences in diabetes incidence among postmenopausal women participating in the Women’s Health Initiative.

RESEARCH DESIGN AND METHODS Data on race/ethnicity, baseline diabetes prevalence, and incident diabetes were obtained from 158,833 women recruited from 1993–1998 and followed through August 2009. The relationship between race/ethnicity, other potential risk factors, and the risk of incident diabetes was estimated using Cox proportional hazards models from which hazard ratios (HRs) and 95% CIs were computed.

RESULTS Participants were aged 63 years on average at baseline. The racial/ethnic distribution was 84.1% non-Hispanic white, 9.2% non-Hispanic black, 4.1% Hispanic, and 2.6% Asian. After an average of 10.4 years of follow-up, compared with whites and adjusting for potential confounders, the HRs for incident diabetes were 1.55 for blacks (95% CI 1.47–1.63), 1.67 for Hispanics (1.54–1.81), and 1.86 for Asians (1.68–2.06). Whites, blacks, and Hispanics with all factors (i.e., weight, physical activity, dietary quality, and smoking) in the low-risk category had 60, 69, and 63% lower risk for incident diabetes. Although contributions of different risk factors varied slightly by race/ethnicity, most findings were similar across groups, and women who had both a healthy weight and were in the highest tertile of physical activity had less than one-third the risk of diabetes compared with obese and inactive women.

CONCLUSIONS Despite large racial/ethnic differences in diabetes incidence, most variability could be attributed to lifestyle factors. Our findings show that the majority of diabetes cases are preventable, and risk reduction strategies can be effectively applied to all racial/ethnic groups.

  • Received March 1, 2012.
  • Accepted May 12, 2012.

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  1. Diabetes Care
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