An epidemiological study on the relationships of serum calcium and magnesium to blood pressure of inhabitants in rural and urban areas.

Abstract

An epidemiological study on the relationship of serum calcium and magnesium to blood pressure was carried out in the inhabitants in rural area (S area of Taki county in Hyogo prefecture) and urban area (T area in Osaka city).The results obtained were as follows:1) The level of serum calcium was lower in S area than in T area by 0.1mg/dl, on the average. The level of the amount of calcium intake was lower in S area than in T area by 20mg/day, on the average. The calcium levels both tended to decrease with age.2) The level of serum magnesium was lower in S area than in T area by 0.15mg/dl, in each age group. The level was constantly the same in the age groups of the forties, fifties and sixties.3) The level of Ca/ Mg ratio in serum was higher in S area than in T area by 0.3, in each age group. The level tended to decrease with age.4) In the group of normotensive persons in S area, the increase of serum calcium correlated to the decrease of systolic blood pressure. The inhabitants in S area whose levels of systolic blood pressure were lower showed lower serum magnesium and higher Ca/Mg ratio in serum than those in T area whose blood pressures were higher.5) In the higher Ca/Mg ratio group (4.7 and over), there was no apparent effect of dietary salt intake on blood pressure. But, in the lower Ca/Mg ratio group, it was apparent that the systolic blood pressure increased in the higher salt intake group. It seemed that the higher Ca/Mg ratio in serum lessened the effect of salt on blood pressure.These results suggest that the improvement of calcium intake as well as the control of dietary salt intake is practically important for the prevention of hypertension.