SECULAR TRENDS IN BLOOD-PRESSURE AMONG ADULT BLACKS AND WHITES AGED 18-34 YEARS IN 2-BODY-MASS INDEX STRATA, UNITED-STATES, 1960-1980

Secular trends in blood pressure among young adults reflect the propor tion of the population at risk of developing hypertension and may be m arkers of progress in primary prevention. National health examination data from three successive surveys were analyzed to assess blood press ure trends for adult blacks and whites aged 18-34 years in two body ma ss index (BMI; weight (kg)/height (m)(2)) strata (< 25 or greater than or equal to 25). Blood pressure was categorized into a four-point ord inal scale using the weighted, within-sex 50th, 75th, and 90th percent iles for 18- to 24-year-old adults in the 1960-1962 survey. The effect s were analyzed with cumulative legit models with alpha = 0.01. The sy stolic blood pressure decreased moderately for 25- to 34-year-old male s and for females except those aged 25-34 years with a BMI of greater than or equal to 25. Diastolic blood pressure increased among males wi th a BMI of greater than or equal to 25 and among white males with a B MI of < 25, but did not show a significant overall trend among females . A BMI of greater than or equal to 25 was associated with substantial ly higher blood pressure in each survey, except for one age-sex-race s ubgroup. Racial differences within BMI were less consistent than the d ifferences across BMI strata. in summary, the situation with respect t o hypertension among females may have improved during this time period but for males may have worsened with respect to diastolic blood press ure. Data for both sexes support a need for population-wide obesity pr evention to reduce the incidence of hypertension.