P173 ASSESSMENT OF URINARY SODIUM EXCRETION AND IT'S ASSOCIATION WITH BLOOD PRESSURE IN RURAL COMMUNITY OF BANGLADESH

Background and Objectives: Amount of salt intake has been shown to relate with level of blood pressure. Measuring urinary sodium (Na) is one of the ways to assess that indirectly. This study was carried out to identify the urinary sodium excretion pattern, as a surrogate of salt intake, and its association with blood pressure in a rural community of Bangladesh. Method: In this survey adult subjects were selected randomly from a rural area. Systolic BP ≥140 and/or diastolic BP ≥90mmHg or subjects taking antihypertensive medications were considered for hypertension. The 24 hour urinary sodium excretion (24hUrNa) from spot urine samples was calculated according to formula of Kawasaki et al. Results: Around 1095 subjects participated in this study. Hypertension was present in 23% subjects. Comparison of normotensive vs. hypertensive subjects showed age 40±12 vs. 46±14 years, (p<0.001) without any difference in 24hUrNa excretion as 4.4±1.6 vs. 4.5±1.9 g/day (P=NS) and UrNa/UrCr ratio as 135±96 vs. 147±145 mEq/g (P=NS) in two groups. Further comparisons of four different 24hr urinary Na excretion groups (<2.3, 2.3-3.6, 3.6-4.8 and >4.8 g/day) showed that their distribution is similar in both normotensive and hypertensive groups (7.9 vs. 8.4%, 23.0 vs. 25.3%, 27.9 vs. 23.2% and 41.3% vs. 43.0%, respectively, P=NS). Another analysis of hypertensive subjects with only systolic HTN, diastolic HTN and both BP raised subjects showed similar 24hUrNa excretion among all (4.4±1.8, 4.4±1.5 and 4.8±1.2 g/day, P=NS, respectively). Bivariate correlations showed no relation of blood pressure with urinary Na excretion. The logistic regression analysis showed a strong influence of age, blood sugar, HbA1c, TG, Cholesterol and eGFR on blood pressure. Conclusion: In this study, based on urinary Na excretion, it is found that nearly 90% of the rural population is taking salt above the recommended limit. Higher urinary sodium excretion, an indicator of high salt intakes, has no apparent association with blood pressure among them.