PS 18-21 Association between 24-hour urinary sodium excretion and blood pressure among adults

Abstract

Objective: Purpose of the study was to estimate the salt intake, compare salt intake among hypertensive and non-hypertensive, and examine the association between blood pressure and salt consumption based on 24-hour urinary sodium excretion and to explore socioeconomic variations of salt intake among the study population. Design and Method: A cross-sectional study was conducted to estimate and compare salt intake among 168 randomly selected incident-hypertensive and non- hypertensive administrative officers attached to government public administration offices in a district of Sri Lanka. Sample size was calculated to estimate and compare the parameters among hypertensives and non-hypertensives. Blood pressure, 24-hour urine collection, and anthropometric indices were measured. Results: The mean excretion of Na, K, and Na / K molar ratio over 24-hours among hypertensives was 202.56 (SD ± 85.45)mmol 66.28 (SD ± 28.08)mmol and 3.2 (SD ± 1.08) respectively and among non-hypertensives, it was 176.79 (SD ± 82.02)mmol, 59.38 (SD ± 28.4)mmol and 3.2 (SD ± 1.00) respectively. The estimated mean salt among hypertensives and non-hypertensives were 11.91 (SD ± 4.02)g and 10.39 (SD ± 4.18)g per day respectively. Fifty-four percent hypertensives (n = 45) and 32.1 % (n = 27) non-hypertensives had a >5/day estimated salt intake. A positive linear association was observed between salt intake and systolic and diastolic blood pressure in adjusted and unadjusted models. After adjusting for confounding factors 100mmol sodium increase was associated with an average increase of SBP and DBP by 3.1 (95%CI; 2–4.2) and 1.8 (95%CI; 0.89–2.6) mmHg respectively. Higher estimated salt intake was found in managerial-assistants (12.38 ± 5.01 g) compared to senior-officers (10.84 ± 4.9 g) (p Conclusions: The findings suggest that salt intake among administrators is alarmingly higher than the current recommended amount (5 g/day), and high salt intake is positively associated with hypertension. Socio-economic inequalities in salt consumption highlight the importance of considering social differences for successful and equitable implementation of population-wide salt reduction programme as a measure for prevention of hypertension.