The Association of Skin Color With Blood Pressure in US Blacks With Low Socioeconomic Status
- Michael J. Klag, MD, MPH;
- Paul K. Whelton, MD, MSc;
- Josef Coresh, AB;
- Clarence E. Grim, MD;
- Lewis H. Kuller, MD, DrPH
- From the Departments of Medicine (Drs Klag and Whelton), Epidemiology (Drs Klag and Whelton), and Health Policy and Management (Dr Klag), The Johns Hopkins University School of Medicine and The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md; the Department of Medicine, Charles R. Drew University School of Medicine, Los Angeles, Calif (Dr Grim); and the Department of Epidemiology, University of Pittsburgh (Pa) School of Public Health (Dr Kuller). Mr Coresh is a student in the School of Medicine, The Johns Hopkins University School of Medicine, and a PhD candidate in the Department of Epidemiology, School of Hygiene and Public Health, The Johns Hopkins University School of Hygiene and Public Health.
Abstract
To determine the association of skin color, measured by a reflectometer, with blood pressure in US blacks, we studied a community sample of 457 blacks from three US cities. Persons taking antihypertensive medications were excluded. Both systolic and diastolic blood pressure were higher in darker persons and increased by 2 mm Hg for every 1-SD increase in skin darkness. However, the association was dependent on socioeconomic status, whether measured by education or an index consisting of education, occupation, and ethnicity, being present only in persons with lower levels of either indicator. Using multiple linear regression, both systolic and diastolic blood pressure remained significantly associated with darker skin color in the lower levels of socioeconomic status, independent of age, body mass index, and concentrations of blood glucose, serum urea nitrogen, serum uric acid, and urinary sodium and potassium. The association of skin color with blood pressure only in low socioeconomic strata may be due to the lesser ability of such groups to deal with the psychosocial stress associated with darker skin color. However, these findings also are consistent with an interaction between an environmental factor associated with low socioeconomic status and a susceptible gene that has a higher prevalence in persons with darker skin color.
(JAMA. 1991;265:599-602)
Footnotes
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Reprint requests to Welch Center for Prevention, Epidemiology and Clinical Research, Carnegie 291, 600 N Wolfe St, Baltimore, MD 21205 (Dr Klag).
