Applying recovery biomarkers to calibrate self-report measures of sodium and potassium in the Hispanic Community Health Study/Study of Latinos

Authors: MOSSAVAR-RAHMANI, YASMIN - Albert Einstein College Of Medicine; SOTRES-ALVAREZ, DANIELA - University Of North Carolina; WONG, WILLIAM - Children'S Nutrition Research Center (CNRC); LORIA, CATHERINE - National Heart, Lung And Blood Institute(NHLBI, NIH); GELLMAN, MARC - University Of Miami; VAN HORN, LINDA - Northwestern University; ALDERMAN, MICHAEL - Albert Einstein College Of Medicine; BEASLEY, JEANNETTE - New York University; LORA, CLAUDIA - University Of Illinois; SIEGA-RIZ, ANNA - University Of Virginia; KAPLAN, ROBERT - Albert Einstein College Of Medicine; SHAW, PAMELA - University Of Pennsylvania

Submitted to: Journal of Human Hypertension
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2016
Publication Date: 2/16/2017
Citation: Mossavar-Rahmani, Y., Sotres-Alvarez, D., Wong, W.W., Loria, C.M., Gellman, M.D., Van Horn, L., Alderman, M.H., Beasley, J.M., Lora, C.M., Siega-Riz, A.M., Kaplan, R.C., Shaw, P.A. 2017. Applying recovery biomarkers to calibrate self-report measures of sodium and potassium in the Hispanic Community Health Study/Study of Latinos. Journal of Human Hypertension. 31(7):462-473.

Interpretive Summary: A majority of US adults took in more sodium (3,569 mg) and not enough potassium (2,745 mg) every day when compared to the Desirable intakes of less than 2,300 mg of sodium per day and at least 4,700 mg of potassium per day. High sodium and low potassium intakes have been linked to high blood pressure and Hispanics/Latinos are prone to high blood pressure. However, not much is known about the daily intakes of sodium and potassium among Hispanics/Latinos. Therefore, we collected 24-hour urine samples from 447 Hispanics/Latinos aged 18-74 years at four communities in the United States: Miami, Bronx, Chicago and San Diego. The amount of sodium and potassium in the 24-hour urine samples were compared to the sodium and potassium intakes from two 24-hour food intakes reported by the study participants. Based on the 24-hour urine samples, Hispanics/Latinos took in 3,566 mg per day of sodium, well above the desirable level of 2,300 mg per day, and 2,373 mg of potassium per day, well below the desirable intake of 4,700 mg per day. Both sodium and potassium intakes from the self-report food intakes in men were 19.8% and 1.3% lower than the intakes based on the 24-hour urine samples, respectively. Self-report intakes were even lower among women. The study allowed us to generate equations to correct the errors introduced by self-reporting food intake, Hispanic/Latino backgrounds, body fatness, amount of foods consumed away from home, and supplement usage. These equations, first reported among Hispanics/Latinos, have the potential to reduce errors in studying the effects of diet on diseases among Hispanics/Latinos living in the United States.

Technical Abstract: Measurement error in assessment of sodium and potassium intake obscures associations with health outcomes. The level of this error in a diverse US Hispanic/Latino population is unknown. We investigated the measurement error in self-reported dietary intake of sodium and potassium and examined differences by background (Central American, Cuban, Dominican, Mexican, Puerto Rican and South American). In 2010–2012, we studied 447 participants aged 18–74 years from four communities (Miami, Bronx, Chicago and San Diego), obtaining objective 24-h urinary sodium and potassium excretion measures. Self-report was captured from two interviewer-administered 24-h dietary recalls. Twenty percent of the sample repeated the study. We examined bias in self-reported sodium and potassium from diet and the association of mismeasurement with participant characteristics. Linear regression relating self-report with objective measures was used to develop calibration equations. Self-report underestimated sodium intake by 19.8% and 20.8% and potassium intake by 1.3% and 4.6% in men and women, respectively. Sodium intake underestimation varied by Hispanic/Latino background (P<0.05) and was associated with higher body mass index (BMI). Potassium intake underestimation was associated with higher BMI, lower restaurant score (indicating lower consumption of foods prepared away from home and/or eaten outside the home) and supplement use. The R**2 was 19.7% and 25.0% for the sodium and potassium calibration models, respectively, increasing to 59.5 and 61.7% after adjusting for within-person variability in each biomarker. These calibration equations, corrected for subject-specific reporting error, have the potential to reduce bias in diet–disease associations within this largest cohort of Hispanics in the United States.