BLOOD-PRESSURE IN YOUNG BLACK AND WHITES - RELEVANCE OF OBESITY AND LIFE-STYLE FACTORS IN DETERMINING DIFFERENCES - THE CARDIA STUDY

Background Middle-aged black men and women have higher blood pressure, on average, than whites. However, this pattern is inconsistent in chi ldren and adolescents. This study explores how differences in lifestyl e factors in young adulthood may influence blood pressure patterns in the two races. Methods and Results The Coronary Artery Risk Developmen t in Young Adults (CARDIA) study is an ongoing collaborative investiga tion of lifestyle and the evolution of cardiovascular disease risk fac tors in a random sample of young adults ages 18 to 30 years at baselin e (1985 to 1986). Data from four examinations over 7 years were analyz ed with the use of a method that simultaneously examined cross-section al and longitudinal relationships bf lifestyle factors and blood press ure. This study included 1154 black women, 853 black men, 1126 white w omen, and 1013 white men. Blacks had higher systolic blood pressure an d diastolic blood pressure than whites at every examination. Racial di fferences were much greater in women than in men and increased over ti me. Within each sex-race group, average diastolic blood pressure over four examinations was positively associated with baseline age, body ma ss index, and alcohol intake and negatively associated with physical a ctivity, cigarette use, and intake of potassium and protein. Longitudi nal change in diastolic blood pressure was positively associated with changes in body mass index and alcohol intake. After adjustment for ob esity and other lifestyle factors, black-white diastolic blood pressur e differences were reduced substantially: 21% to 75% for men and 49% t o 129% for women. Results for systolic blood pressure were similar. Co nclusions Differences in obesity and other lifestyle factors in young adults largely explain the higher baseline blood pressure and greater increase over time of blacks relative to whites.