Thursday, February 16, 2012

Blood Pressure

Hypertension is a huge problem in the U.S. among older Americans, as can be seen from this chart based on the results of a 1995 study by Burt and colleagues:

As men reach their 50s, the numbers approach 50% (white males) and exceed that for black males. This is unfortunate. Research has shown that even having high normal blood pressure (130-139/85-89) leads to a 1.6 increase in the hazard ration for cardiovascular disease among men age 35 to 64.

Reductions in sodium have been found to have a great effect the higher the initial blood pressure and the older the patient.

Exercise has also been shown to lead to a significant reduction in blood pressure. A meta-analysis of 54 trials (Seamus and colleages, 2002) showed that previously sedentary adults could decrease systolic blood pressure by 3.8 mm Hg (95% CI, 2.7 to 5.0 mm Hg) and diastolic blood pressure by 2.6 mm Hg (CI, 1.8 to 3.4 mm Hg) with regular aerobic exercise.

Blood pressure problems are even more acute in Europe than in the U.S., making this one of the few areas of health where Americans seem to have an advantage over the slimmer and healthier Europeans.

An article by Kannel (1996) provides a good summary of the issue of hypertension:

Hypertension is one of the most prevalent and powerful contributors to cardiovascular diseases, the leading cause of death in the United States. There is, on average, a 20 mm Hg systolic and 10 mm Hg diastolic increment increase in blood pressure from age 30 to 65 years. Isolated systolic hypertension is the dominant variety. There is no evidence of a decline in the prevalence of hypertension over 4 decades despite improvements in its detection and treatment. Hypertension contributes to all of the major atherosclerotic cardiovascular disease outcomes increasing risk, on average, 2- to 3-fold. Coronary disease, the most lethal and common sequela, deserves highest priority. Hypertension clusters with dyslipidemia, insulin resistance, glucose intolerance, and obesity, occurring in isolation in less than 20%. The hazard depends on the number of these associated metabolically linked risk factors present. Coexistent overt cardiovascular disease also influences the hazard and choice of therapy.

One study from the 1990s showed that blood pressure levels above optimal level led to a significant jump in cardiovascular risks:

After adjustment for demographic and traditional risk factors, normal blood pressure and high normal blood pressure were associated with a 69% and 133% greater risk of incident cardiovascular disease, respectively, compared with optimal blood pressure.

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