Plasma homocysteine concentration and blood pressure in healthy Iranian adults: the Tehran Homocysteine Survey (2003-2004)

Hypertension is a modifiable risk factor for cardiovascular disease, but its aetiology has not been fully elucidated. Recently, attention has been focused on the direct relations of plasma homocysteine (Hcy) to blood pressure (BP). The purpose of this study was to determine the relationship of Hcy with BP and other cardiovascular disease risk factors. This population-based study was a part of the Cardiovascular Risk Factors Survey and has been designed and conducted based on the methodology of the MONICA/WHO Project. A total of 1214 people aged 25-64 years were recruited using cluster sampling and assessed regarding standardized methods. BP was measured in seated position after a 10-min rest period. Blood samples were gathered and analysed according to standard methods. Variables were assessed in 1191 participants (416 men; 775 women). Mean age was higher in hypertensives compared to normotensives (P<0.001). Mean Hcy was higher in hypertensives, but significant only in men (P<0.031). Concurrent effects of Hcy, folate and vitamin B-12 on hypertension indicated that Hcy acts as a risk factor and folate and vitamin B-12 as protective factors; however, after adjustment, just vitamin B-12 remained as a protective factor. Although we detected a simple correlation of Hcy with BP in Iranian adults, this relationship was no longer significant after applying an adjustment. In light of our observations, it is likely that the increased Hcy levels reported in hypertensive persons are concomitant rather than a precursor of hypertension.