Estimating sodium intake from spot urine samples at population level: a validation and application study in French adults. Issue 2 (16th July 2019)

• Record Type: Journal Article
• Authors: Emeville, Elise; Lassale, Camille; Castetbon, Katia; Deschamps, Valérie; Salanave, Benoît; Vernay, Michel; Guergour, Dorra; Faure, Patrice; Hercberg, Serge; Galan, Pilar; Kesse-Guyot, Emmanuelle; Verdot, Charlotte
• Is Part Of: British journal of nutrition. Volume 122:Issue 2(2019)
• Page Start: 186
• Page End: 194
• Publication Date: 2019-07-16
• Subjects: Salt intake, -- Urinary sodium excretion, -- Spot urine samples, -- Predictive INTERSALT equation; Nutrition -- Periodicals; 572.4
• DOI: 10.1017/S0007114519000886
• Languages: English
• ISSNs: 0007-1145

Abstract

Abstract: The aim of this study was to assess the validity of the predictive INTERSALT equation using spot urine samples to estimate 24-h urinary Na (24-hUNa) excretion and daily Na intake among the French adult population. Among 193 French adults ('validation sample'), we assessed the validity by comparing predicted 24-hUNa excretion from spot urine and measured 24-hUNa excretion from 24-h urine collections. Spearman correlation coefficients and Bland–Altman plots were used and we calculated calibration coefficients. In a nationally representative sample of 1720 French adults ('application sample'), the calibrated predictive equation was then applied to the spot urine Na values to estimate 24-hUNa excretion and daily Na intake. In that sample, predicted Na intake was compared with that estimated from 24-h dietary recalls. Results were adjusted and corrected using calibration coefficients. In the validation sample, the measured 24-hUNa excretion was on average 14 % higher than the predicted 24-hUNa (+13 % for men and +16 % for women). Correlation between measured and predicted 24-hUNa excretion was moderate (Spearman r 0·42), and the Bland–Altman plots showed underestimation at lower excretion level and overestimation at higher level. In the application study, estimated daily salt intake was 8·0 g/d using dietary recalls, 8·1 g/d using predicted INTERSALT equation and 9·3 g/d after applying calibration coefficients calculated in the validation study. Despite overall underestimation of 24-hUNa excretion by spot urinary Na, the use of predictive INTERSALT equation remains an acceptable alternative in monitoring global Na intake/excreted in the French population but its use is not advised at the individual level.