Outcomes
SECONDARY
The primary outcome was the difference between the two groups in the change from baseline to follow-up in salt intake measured by 24 hour urinary sodium. The secondary outcomes were the differences in the change in blood pressure and in knowledge, attitude, and behaviours between the two groups.Data were collected by well trained field investigators through a specially designed mobile device based electronic data capture system (mEDC, Electronic Data Collection). The urine sample was excluded if the collection time was less than 20 hours or more than 28 hours. If the duration of urine collection was not 24 hours but within 20-28 hours, we calculated adjusted 24 hour urine volume as total volume divided by collection time and multiplied by 24. The calculations of 24 hour urinary sodium and potassium were as follows: sodium (mg/day)=23 (mg/mmol)×concentration (mmol/L)×adjusted 24 hour urine volume (L/day); potassium (mg/day)=39.1 (mg/mmol)×concentration (mmol/L)×adjusted 24 hour urine volume (L/day).The biochemists who made the measurements of urinary electrolytes were unaware of the group to which the participant was allocated. Urine samples were defined as incomplete and excluded from the analysis if the 24 hour urine volume was <500 mL or creatinine was <4.0 mmol for women or <6.0 mmol for men.