Abstract
Objective: Yamagata Prefecture has the highest percentage of hypertensive patients in the whole of Japan and it has been known for some time that salt intake is particularly high in Northeast Japan where the Prefecture is located. Salt reduction is important in blood pressure management. At our hospital, we added salt intake to Ningen Dock health check-up tests in April 2015 and afterwards examined an association between salt intake and blood pressure in Ningen Dock examinees.
Methods: From among Ningen Dock examinees at our hospital between April 2015 and March 2016, 1,380 (1,034 men, 346 women; mean age 56±11 years) were enrolled as subjects, after excluding 39 who were taking diuretics. Salt intake was estimated from casual urine samples using a formula and an association of salt intake and blood pressure was investigated, dividing subjects into those not taking antihypertensive medication (non-medicated group) and those taking antihypertensive medication (medicated group). Associations between salt intake and obesity, weight and age were also examined.
Results: The mean salt intake for all examinees was 9.03±2.24 (men 9.14±2.24, women 8.71±2.23) g/day so only 26.8% (men 29.1%, women 19.9%) met the Ministry of Health Labour and Welfare recommendations of less than 8 g for men and less than 7 g for women. Although systolic and diastolic blood pressure significantly increased as salt intake increased in the non-medicated group, this association was not observed in the medicated group. Compared to the non-medicated group, salt intake was higher in the medicated group than in the non-medicated group for all age groups. Also, in the medicated group, salt intake increased with weight and was higher in obese persons.
Conclusion: Among the Ningen Dock examinees at our hospital, only around a quarter met the Ministry of Health Labour and Welfare recommendations for salt intake. Compared to the non-medicated group, salt intake was higher in the medicated group. In the non-medicated group, there was a significant association between salt intake and blood pressure, and our results suggested that salt reduction could be effective in reducing blood pressure even if a level of less than 6 g were not achieved.
