Calcium intake and blood pressure in blacks and whites

This study focuses on 1790 residents of Erie County, New York, over age 19, who participated in a study of blood pressure in 1986. Subjects were selected using a highly stratified sampling procedure to obtain a sample that included approximately equal numbers of blacks and whites in three educational strata (less than 12 years, 12 years, and more than 12 years of education). Calcium intake was estimated using questions regarding usual frequency of intake of foods high in calcium and of calcium-containing supplements and antacids. Calcium intake by normotensives tended to be higher than intake by hypertensives; differences were significant for females but not for males. Calcium intake was significantly inversely associated with systolic blood pressure for black females and diastolic blood pressure in black and white females after control for age, education, body mass index, smoking, and alcohol. For other sex-race groups, there was generally a trend (although not significant) toward decreased blood pressure with increased calcium intake. Diastolic blood pressure was inversely associated with calcium from milk and yogurt (but not cheese) for white females. A similar association (although not significant) was found for black females; no association was found for males. No differences were found between blacks and whites in response to calcium. This cross-sectional study provides some additional evidence of a protective effect of calcium intake on blood pressure in both black and white females.