Low-level elevation of blood pressure during young adulthood is an independent risk factor for atherosclerosis 20 years later, according to findings of the prospective CARDIA (Coronary Artery Risk Development in Young Adults) Study.
In fact, "young adulthood is a critical period when exposure to suboptimal blood pressure might be particularly harmful," Dr. Mark J. Pletcher and colleagues report in the Annals of Internal Medicine for July 15.
To investigate the long-term effect of early prehypertension, Dr. Pletcher, at the University of California, San Francisco, and his group focused on the 3560 study participants without overt hypertension before 35 years of age. Blood pressure was documented seven times between 1985 and 2005, starting at ages 18-30 years, and coronary calcium - a proxy for atherosclerosis - was assessed by cardiac computed tomography at the end of the study.
Nearly 20 per cent of subjects (635) developed prehypertension - defined as systolic blood pressure of 120 to 139 mm Hg, or diastolic blood pressure of 80 to 89 mm Hg - before age 35.
The duration of systolic prehypertension was strongly associated with the presence and extent of coronary calcium at an average of 44 years of age.
"Compared with participants without any exposure to systolic prehypertension during young adulthood, participants with exposure greater than 30 mm Hg-years were two to three times as likely to have coronary calcium (38 per cent vs 15 per cent; p < 0.001), a coronary calcium score greater than ten (27 per cent vs ten per cent; p < 0.001), and extensive calcification with a score greater than 100 (ten per cent vs three per cent; p < 0.001)," the investigators report.
Even systolic blood pressure elevation in the range of 120 to 129 mm Hg was associated with increased risk of coronary calcium. The observed association was independent of other coronary heart disease risk factors and blood pressure levels after age 35, and consistent across race and sex subgroups.
Dr. Pletcher's group advocates lifestyle modification to treat prehypertension in young adulthood; they don't recommend use of antihypertensive medication in the absence of clinical trial data, cost analyses, and data regarding side effects from long-term medication exposure.
"Optimizing blood pressure in young adults will be a major challenge," they conclude, but efforts to do so "may yield substantial health benefits for individuals and reduce population rates of clinical cardiovascular disease during middle age and beyond."
Ann Intern Med 2008;149:91-99
