Salt intake and blood pressure in Iranian children and adolescents: a population-based study.

Background: Previous studies have reported a high prevalence of hypertension in Iranian students, especially in rural areas. The aim of this study was to investigate the daily intake of salt in students and its association with high blood pressure.
Methods: A random sub-sample was selected from the participants of the second phase of Shahroud schoolchildren eye cohort study and then a random urine sample was tested for sodium, potassium and creatinine. Urine electrolyte esexcretion and daily salt intake were calculated by Tanaka et al.'s formula.
Results: Among 1455 participants (including 230 participants from rural area and 472 girls), the mean age was 12.9 ± 1.7 year and the mean daily salt intake was 9.7 ± 2.6 g (95% CI 9.5-9.8). The mean salt consumption in rural areas [10.8 (95% CI 10.4-11.2)] was higher than urban areas [9.4 (95% CI 9.3-9.6)], in people with hypertension [10.8 (95% CI 10.3-11.3)] was more than people with normal blood pressure [9.4 (95% CI 9.3-9.6)], and in boys [9.8 (95% CI 9.7-10.0)] was more than girls [9.3 (95% CI 9.1-9.6)]. Higher age, BMI z-score, male sex and rural life, were associated with increased daily salt intake. Increased salt intake was associated with increased systolic and diastolic blood pressure.
Conclusion: Daily salt intake in Iranian adolescents was about 2 times the recommended amount of the World Health Organization, was higher in rural areas and was associated with blood pressure. Reducing salt intake should be considered as an important intervention, especially in rural areas.