Objective: The purpose of this research is to assess short-term blood pressure change and hypertension incidence, and identify correlates of incident hypertension in the USA and Poland.
Design and methods: Population-based samples aged 45-64 years at enrollment from the Atherosclerosis Risk in Communities (ARIC) and the Pol-MONICA studies: including 3777 whites from Minneapolis, Minnesota, USA suburbs (urban), 3635 whites from Washington County, Maryland, USA (semi-rural) and 3109 blacks from Jackson, Mississippi, USA surveyed in 1987-1989 and 1990-1992; and 389 persons from Warsaw, Poland (urban) and 322 from Tarnobrzeg Province, Poland (semi-rural) surveyed in 1987-1988 and 1992-1993.
Results: Age-standardized systolic and diastolic blood pressures at both screens were 9-20 and 5-9 mmHg higher in the Polish samples than in US blacks, who had higher levels than US whites. Age-adjusted annual hypertension incidence in both Polish male cohorts (6-8%) was higher than that in US white men (4%) and approaching that of US black men (7%); rates were also higher in Polish female cohorts (8-9%) than in US black women (8%), but nearly twice those in US white women (4%). Factors independently related to hypertension incidence included age, family history, smoking, baseline blood pressures and body mass index, and increase in body mass index and alcohol consumption between screenings. After adjustment for these factors, annualized hypertension incidence was similar in US white and Polish men (2.3 and 2.7%) compared with US black men (3.4%), and in US white and Polish women (1.5 and 1.3%) compared with US black women (3.9%).
Conclusions: Despite substantial differences in blood pressure levels and age-standardized hypertension incidence rates, the differences in incidence between Polish and US white men appear to be explained largely by differences in risk factors for hypertension.