Sodium Intake, Blood Pressure, and Dietary Sources of Sodium in an Adult South Indian Population

BACKGROUND The association between prevalence of hypertension and its relationship with dietary sodium intake has never been published from large epidemiological studies in the South Indian population before. OBJECTIVES To assess sodium intake and its association with blood pressure, and major dietary sources of sodium in an adult population in southeastern India. METHODS This study included a representative population-based sample of 8080 individuals (57% women) >20 years of age. Individuals with previous history of hypertension and outliers for sodium intake were excluded, resulting in a sample size of 6876, with 4269 from semi-urban/urban and 2607 from rural areas. Baseline measurements included evaluation of systolic (SBP) and diastolic (DBP) blood pressures, anthropometric, sociodemographic, and psychosocial parameters. Based on 24-hour recall, we calculated total daily sodium intake and the percentage contributed by each food group to the total sodium intake. Participants were assigned based on quintiles of dietary sodium intake. Mixed-effects multivariable linear regression models assessed the association of SBP and DBP with sodium intake. FINDINGS Men had higher mean sodium intake (4.1 +/- 2 versus 3.2 +/- 1.7 g/day; P < 0.01) with higher mean SBP and DBP (123/77 versus 117/74 mm Hg; P < 0.01), and higher prevalence of hypertension (22.2% versus 12.9%; P < 0.01) compared with women. Mean dietary sodium intake was significantly higher in the hypertensive men (4.2 +/- 2 g/day) and women (3.2 +/- 1.7 g/day) compared with normotensive men (4 +/- 2 g/day), and women (3.2 +/- 1.7 g/day; P < 0.05). Significant (P < 0.01) increases in SBP and DBP were evident in men, but not women with increasing quintile of sodium intake. After multivariable adjustments, sodium intake was independently associated with SBP, but not DBP, in both sexes. The predominant source of dietary sodium in both semi-urban/urban and rural populations was from homemade foods where salt is part of the traditional recipe. CONCLUSION In a South Indian population, the dietary intake of sodium was higher than recommendations by major dietary guidelines and was an independent predictor of SBP.