Physical Activity and NIDDM in African-Americans: The Pitt County Study

  1. Prabhaker G Khazanie, PHD
  1. Department of Epidemiology, University of Michigan Ann Arbor, Michigan
  2. School of Public Health, and the Institute for Social Research, University of Michigan Ann Arbor, Michigan
  3. School of Medicine, East Carolina University Greenville, North Carolina
  4. School of Public Health, University at Albany, State University of New York Rensselaer, New York.
  1. Address correspondence and reprint requests to Sherman A. James, PhD, Department of Epidemiology, School of Public Health, University of Michigan, 109 Observatory St., Ann Arbor, MI 48109. E-mail: sjames{at}umich.edu.

Abstract

OBJECTIVE Studies directly examining the association between physical activity and NIDDM in African-Americans are rare. Consequently, the strength of this association in this ethnic minority group remains unclear. The current study broadly characterizes the types of physical activity engaged in by a community sample of working-class African-Americans and then quantifies the association between physical activity and NIDDM risk in this population.

RESEARCH DESIGN AND METHODS During the 1993 reexamination of participants in the Pitt County Study in North Carolina, data on NIDDM history, current use of insulin or oral hypoglycemic drugs, and ∼12-h overnight fasting blood glucose (FBG) were obtained from 598 women and 318 men, ages 30-55 years. The presence of NIDDM was determined by current insulin or medication use and FBG ≥ 140 mg/dl. Study participants were assigned to one of four categories of physical activity: strenuous, moderate, low, or inactive.

RESULTS The weighted prevalence of NIDDM in the sample was 7.1%. After adjustment was made for age, sex, education, BMI, and waist-to-hip ratio, NIDDM risk for moderately active subjects was one-third that for the physically inactive subjects (odds ratio [OR], 0.35; 95% CI, 0.12-0.98). The ORs for low (OR, 0.51; 95% CI, 0.20-1.29) and strenuous (OR, 0.65; 95% CI, 0.26-1.63) activity also tended to be lower. A summary OR that contrasted any activity versus no activity was 0.51 (95% CI, 0.23-1.13).

CONCLUSIONS Moderate physical activity was strongly associated with reduced risk for NIDDM in this sample. While replication of these findings is needed, public health interventions designed to increase moderate (leisure-time) physical activity in black adults should be strongly encouraged.

  • Received June 18, 1997.
  • Accepted December 29, 1997.
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