High homocysteine levels are independently related to isolated systolic hypertension in older adults

Background The association between homocysteine and isolated systolic hypertension in older adults was evaluated using a case-control design, and the relationship between homocysteine and clinical or subclinical atherosclerosis was explored. Methods and Results Cases were 179 adults greater than or equal to 60 years with a systolic blood pressure of greater than or equal to 160 mm Hg and diastolic blood pressure <90 mm Hg. One hundred seventy-one control subjects had the same criteria except systolic blood pressures were <160 mm Hg. All had normal creatinine levels. Homocysteine levels were performed on fasting blood samples that had been stored at -70 degrees C. Atherosclerosis was defined as either a history of clinical disease, an internal carotid stenosis of greater than or equal to 40% by duplex scan, or an ankle/arm pressure ratio of <0.9. The median homocysteine value was 11.5 mu mol/L for cases and 9.9 for control subjects (P<.001). After control for potential confounders, homocysteine remained significantly associated with systolic hypertension (P=.019). For the hypertensive group, there was no apparent association between level of homocysteine and prevalence of atherosclerosis. However, among the normotensive group, the prevalence of atherosclerosis went from 22% in the lowest quintile of homocysteine values to 53% in the fifth quintile, with an odds ratio of 4.1 (fifth quintile in comparison to the first, P<.05). After adjust ment for age, sex, systolic blood pressure, cholesterol, and smoking, this odds ratio increased to 6.4 (P<.01). Conclusions Elevated levels of homocysteine may be related to the cause of isolated systolic hypertension in some individuals. In normotensive older adults, homocysteine appears to be an independent risk factor for atherosclerosis.