South Asian Low-sodium Trial: A Pilot Randomized Controlled Trial

Cardiovascular disease is the leading cause of mortality and morbidity worldwide. Hypertension (HTN) is an important risk factor for cardiovascular disease. According to HTN Canada guidelines, HTN is classified as pre-hypertension (systolic BP of 120-139 mmHg or diastolic BP of 80-89 mmHg), stage one HTN ( systolic BP 140-159 mmHg or diastolic BP 90-99 mmHg) and stage two HTN (greater than or equal to systolic BP of 160 mmHg or greater than or equal to diastolic BP of 100 mmHg) (2). Any increase in blood pressure above optimal confers independent risk of cardiovascular disease, stroke, congestive heart failure, end-stage renal disease, peripheral vascular disease, dementia, atrial fibrillation and retinopathy. South Asian individuals have significantly higher rates of morbidity and mortality from cardiovascular diseases. Hypertension is prevalent in South Asian Canadians with prevalence rate of 17%. Hypertension is a result of various factors, which include excessive alcohol consumption. lack of dietary potassium, physical inactivity, obesity and high dietary sodium intake. High dietary sodium consumption is an important contributor to HTN. and the rapid increase in dietary sodium is contributing to the current epidemic of HTN and cardiovascular disease. Sodium has a positive linear causal relationship to blood pressure based on epidemiological and experimental studies. Sodium intake greater than 2300mg/day has been associated with an increased risk of developing HTN. In addition to HTN, excess sodium intake is associated with higher risk of developing dementia, osteoporosis, stomach cancer, left ventricular hypertrophy and heart failure. The average sodium intake of Canadians is currently estimated at 2760mg/day, which is well above the recommended daily intake of 2300mg/day. South Asians consume significantly higher amounts of sodium with more than 95% of South Asians add salt to their cooking. Sodium intake in South Asians has been reported in different countries as; 3456 mg/day in Pakistan, 3548-3708 mg/day in India, 5863-10,000mg/day in Bangladesh. Although dietary patterns vary considerably in South Asians, addition of salt during food preparation and at the table are common practices across communities. The combination of traditional as well as a western diet results in an increased amount of sodium from conveniently available traditional meals, consumption of bread, pizza, pasta and other processed foods, high sodium spices and addition of salt during cooking.

Interventions aimed at reducing dietary sodium reduces blood pressure as well as cardiovascular morbidity and mortality. Despite the known benefits of sodium reduction interventions in reducing blood pressure in the Caucasian population, there is limited research available to provide evidence that sodium reduction is beneficial in reducing blood pressure in South Asian Canadians with stage one HTN.

The primary purpose of the South Asian Low-sodium Trial (SALT) is to assess feasibility (recruitment, retention, engagement and acceptability) of implementing a six-week low-sodium community-based dietary intervention in South Asian Canadians with stage one HTN. Secondary objectives include assessing knowledge & attitude and self-regulation behaviours. Exploratory objectives are to assess change in systolic BP, diastolic BP and sodium intake.