Effects of genetic factors and dietary electrolytes on blood pressure of rural secondary school students in Hanzhong.

In this study, 24-h urine specimens were collected on 3 consecutive days from 181 adolescents (94 boys and 87 girls), aged 12-16 years, in a rural district--Hanzhong, Shaanxi Province, and sodium, potassium, calcium and magnesium levels were determined. Dietary intake of the four electrolytes and blood pressure were measured in children and their parents on the same consecutive days. The results were as follows: urinary output of calcium and magnesium might not be an appropriate index to reflect intake; after adjusting for age, sex, BMI, heart rate, and parental blood pressure, the ratio of dietary calcium to total calories was negatively related to diastolic blood pressure in the whole group, and the ratio of urinary calcium to creatinine was positively related to systolic blood pressure in girls; not only blood pressure but also its relation to electrolytes are affected by parental blood pressure after adjusting for age, sex, BMI and heart rate.