Early BP changes may signal risk for CAC

Higher blood pressure trajectories among younger adults may place them at risk for coronary artery calcification (CAC) in middle age, according to a study published in the Feb. 5 issue of JAMA.

Norrina B. Allen, PhD, MPH, of Northwestern University’s Feinberg School of Medicine in Chicago, and colleagues used data from 4,681 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were all black and white adults between 18 and 30 at the start of the study in 1985 and 1986 and were followed for 25 years at four U.S. sites. Allen and colleagues calculated mid-BP (blood pressure), a marker of coronary heart disease in young people, at the start of the study, and at two, five, seven, 10, 15, 20 and 25 years.

They identified five mid-BP trajectories: low-stable (21.8 percent), moderate-stable (42.3 percent), moderate-increasing (12.2 percent), elevated-stable (19 percent) and elevated-increasing (4.8 percent). Trajectories with higher BP levels were more likely to have a CAC Hounsfield units (HU) of 100 or more compared with the low-stable group.

The odds ratio (OR) for the moderate-stable group was 1.44; for moderate-increasing, it was 1.86; for elevated-stable, it was 2.28; for elevated-increasing, it was 3.7. The prevalence of a CAC score of 100 HU or more ranged from 4 percent in the low-stable group to 25.4 percent in the elevated-increasing group. Participants taking BP medication in each group had a higher prevalence of CAC compared with others in the same trajectory group who were not taking antihypertensives.

Participants in the low-stable group were more likely to be white, women, better educated and have fewer cardiovascular risk factors. Rapid increases in BP were more likely to occur in African Americans, particularly in women, and the elevated-increasing group had the highest number of African-American men. Smoking and increases in body mass index were associated with rapid BP increases.

The authors argued their findings suggest “an individual’s long-term patterns of change in BP starting in early adulthood may provide additional information about his or her risk of development of coronary calcium.”