Abstract
Comparative studies on serum calcium and magnesium levels were carried out among the male and female inhabitants (aged 40 and over) of two inland agricultural districts (farm villages H and U) and one urban district (city S) in the Tohoku area of Japan, districts where the rates of mortality from cerebrovascular diseases were significantly different.
(1) Serum calcium levels in males and females in the two villages were lower than those in city S. No significant difference was observed in magnesium levels among the three districts; the male values tended to be lower than the female values.
(2) Comparison between summer and winter levels of calcium and magnesium in the serum as measured in village U revealed that the calcium level was higher in winter while the reverse was true in the case of the magnesium level.
(3) Health conditions, as judged by stature, body weight, skinfold thickness and specific gravity of blood, were worse in the agricultural districts than in the urban district.
(4) Blood pressure levels, both systolic and diastolic, were equal in the three districts. No seasonal variation was observed.
These observations, together with the results of a nutritional survey, suggest that the low calcium level in the serum, due to insufficient dietary intake of the mineral is closely related to the higher incidence of cerebrovascular diseases in the farm villages of Tohoku.
