Table Characteristics of included studies describing results of estimated sodium intake from FFQ and 24 hour urinary excretion
| First author, y/Name of Study | Type of study | Participants and setting | No. (final analysis) | 24‐h Urine collection validated for completeness | 24‐h Urinary sodium resultsb (including No. of collections/participant) | Dietary assessment (FFQ) | Discretionary salt accounted for | FFQ sodium resultsb | 24‐h Urine and FFQ concurrent | Method(s) of comparison | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Bedford, 2011 | Cohort | Healthy volunteers aged 19–35 y (100% women)Canada | 102 | N/S | Single collectionMean, 2942 (SD, 1062) mg/d | FFQ (National Cancer Institute) 124 items, past 12 mo, analyzed with a Canadian version of the nutrient database | No | Mean, 2648 (SD, 1089) mg sodium | No | Correlation (0.21) | |
| Charlton, 2008 | Validation | Convenience sample of 180 adults with hypertension and 145 adults with normotension (51% women) aged 20–65 ySouth Africa | 284 | PABA, urine volume, and urinary creatinine concentration | Three collections by tertiles of intake: mean urinary excretion, 3049 (SD, 1182), 3514 (SD, 1659), and 3670 (SD, 2039) mg/d | Salt‐specific FFQ (42 items), previous 7 d | Yes | By ethnicity: mean, 1211 (SD, 641), 1853 (SD, 589), and 1873 (SD, 663) mg/d for black, mixed ancestry, and white ethnic groups, respectively | Yes | Correlation (0.173); κ (0.0318) categorizing high (>2400 mg/d) vs low (<2400 mg/d) sodium intake | |
| Day, 2001/EPIC‐Norfolk cohort study | Validation | Volunteers aged 45–74 y (sex and disease status N/S)United Kingdom | 123 | PABA | Six collections: mean, 3335 mg/d (SD, 1297) Coefficient of variation 0.39 | Two FFQs (130 items) 18 mo apartFFQ self‐administered, past 12 moModified questionnaire from US Nurses’ Health StudyCalculation based on Ministry of Agriculture, Fisheries, and Food composition tables | N/S | Mean, 2766 (SD, 1074) mg/d sodium | Yes | Sample variance; correlation (0.36); regression analysis | |
| Ferreira‐Sae, 2009 | Validation | Patients with hypertension aged 18–85 y (63% women)Brazil | 132 | N/S | Single collectionTotal excretion divided by 0.86aMean, 5384 (SD, 2402) mg/d | Salt‐specific FFQ 44 items, past 12 moNutwin database software developed by Federal University of Sao Paulo | In a separate questionnaire | Including estimates of discretionary salt: mean, 5093 (SD, 267) mg/d | No | Correlation | |
| Freedman, 2015/Nutrition Biomarker Study for WHI 2004–2005 | Validation | Representative healthy sample from WHI dietary modification trial (100% women) Mean age, 70.9 yUnited States | 544 | PABA and self‐reported missing collections | Single collectionTotal excretion divided by 0.86a Geometric mean, 3263 (95% CI, 3155–3373) mg/d | WHI FFQ, past 3 mo, nutrient databaseNutrition Data System for Research, University of Minnesota to analyze the results | N/S | Geometric mean, 2188 (95% CI, 2088–2293) mg/d | No | Bias; attenuation factor of 0.12 (95% CI, 0.03–0.20); correlation adjusted for within‐person biomarker variation for pooled data | Pooled data from five studiesAverage correlation 0.16 (men r = 0.17, women r = 0.15) |
| Freedman, 2015/OPEN study 1999–2000 | Validation | Random sample of healthy participants in the OPEN study aged 40–69 y (46% women)United States | 484 | PABA and self‐reported lost specimens | Two collectionsTotal excretion divided by 0.86a Geometric mean for men, 4502 (95% CI, 4287–4727) mg/d; for women, 3310 (3126–3503) mg/d | FFQ, past 12 moSingle Diet History Questionnaire developed and evaluated at the National Cancer Institute | No | Geometric mean, men 3070 (95% CI, 2920–3227) mg/d; women 2308, (95% CI, 2186–2436) mg/d | No | Bias; attenuation factor of 0.11 (95% CI, 0.00–0.23); correlation adjusted for within‐person biomarker variation for pooled data | |
| Freedman, 2015/AMPM validation study | Validation | Healthy volunteers from AMPM study aged 30–69 y (50% women)United States | 465 | Self‐reported missing collections, volume, and creatinine excretion | Two collectionsTotal excretion divided by 0.86a Geometric mean for men, 4648 (95% CI, 4421–4886) mg/d; for women, 3494 (95% CI, 3330–3666) mg/d | FFQ, past 12 moA single FFQ (Harvard) was administered 1–14 mo after the beginning of the study | N/S | Geometric mean for men, 2188 (95% CI, 2088–2293) mg/d; for women, 1851 (95% CI, 1762–1945) mg/d | No | Bias; attenuation factor of 0.10 (95% CI, 0.00–0.21); correlation adjusted for within‐person biomarker variation for pooled data | |
| Freedman, 2015/Energetics Study 2006–2009 | Validation | Healthy volunteers from Energetics Study aged 21–69 y (64% women)United States | 263 | PABA | Two collectionsTotal excretion divided by 0.86a Geometric mean for men, 3692 (95% CI, 3371–4043) mg/d; for women, 2555 (95% CI, 2345–2783) mg/d | FFQ, past 12 mo,Administered onceNational Cancer Institute Diet History Questionnaire | No | Geometric mean for men, 3377 (95% CI, 3077–3706) mg/d; for women, 2459 (95% CI, 2270–2662) mg/d | N/S | Bias; attenuation factor of −0.05 (95% CI, −0.17 to 0.08); correlation adjusted for within‐person biomarker variation for pooled data | |
| Freedman, 2015/NPAAS 2007–2009 | Validation | Representative sample of healthy participants (mean age, 70.5 y; 100% women) from WHI Observational StudyUnited States | 450 | N/S | Single 24‐h urine collectionUrinary sodium values were divided by 0.86a Geometric mean for women, 3056 (95% CI, 2933–3183) mg/d | FFQ, past 3 mo,WHI FFQ and the nutrient databaseNutrition Data System for Research, University of Minnesota was used to analyze the results | N/S | Geometric mean sodium intake, 2383 (95% CI, 2286–2484) mg/d | N/S | Bias; attenuation factor of 0.08 (95% CI, 0.00–0.17); correlation adjusted for within‐person biomarker variation for pooled data | |
| Hsu‐Hage, 1992/Melbourne Chinese Health Study | Validation | Convenience sample. (sex, age, and disease status N/S)Australia | 97 | N/S | Single collectionMean for men, 4163 mg/d (SD, 1978) and for women, 3542 mg/d (SD, 1702) | FFQ, past 12 mo, adapted from CSIRO FFQ for Melbourne Chinese to assess usual intake (110 items)Portion sizes were estimated and nutrient intakes were estimated using the 1990 Australian Food Composition Tables | N/S | Mean for men, 1334 mg/d sodium and for women, 1196 mg/d sodium | N/S | N/S | |
| Kelly, 2015/Food Choice at Work Study | Validation | Volunteers aged 18–64 y; 36% women, 12% with hypertension)Ireland | 50 | PABA | Single collectionMean, 3174 (SD, 1219) mg/d | FFQ version of EPIC (150 food items) adapted for Irish population, past 12 moNutrient values from Food Standards Agency and McCance and Widdowson's Food Composition Tables | No | Mean, 2967 (SD, 1150) mg/d sodium | N/S | Bland‐Altman, mean difference, 9.1 (95% CI, −5.7 to 24) mmol/d; 95% mean difference, −95.7 to 113.9; AUC, 0.76 (95% CI, 0.6–0.9) | |
| Lassale, 2009 | Validation | Healthy volunteers aged 30–60 y (100% women)Australia | 62 | Creatinine | Two collectionsMean, 2921 (SD, 989) mg/d | CSIRO Australia FFQ developed in the 1980s and subsequently evaluated in 1991, designed to estimate usual food and drink intake over past 12 moWith nutrient composition derived from four sources: the Australian nutrient database, British Food Composition Tables, USDA food tables, and manufacturers’ data | N/S | Mean, 3008 (SD, 1186) mg/d | No | Correlation (0.352) (P < 0.01), agreement in rankings by quintile, weighted κ = 0.31 (quintiles of distribution), and regression analysis | |
| Li, 2014 | Validation | Random sample aged 18–69 y (48% women)Disease status: N/SChina | 964 | N/S | Single collectionMean for men, 5709 (95% CI, 5354–6024) mg/d and for women, 5315 (95% CI, 5000–5591) mg/d | FFQ NS | Yes | Mean for men, 4291 (SD, 3819–4343) and for women, 4016 (SD, 3740–4331) mg/d | N/S | Correlation (0.07), mean difference, and proportion underestimated and overestimated | |
| Murikami, 2012/Japanese Dietetic Students’ Study for Nutrition and Biomarkers | Validation | Volunteers aged 18–22 y (100% women) Disease status N/SJapan | 1043 | Urinary creatinine excretion | Single collectionTotal excretion divided by 0.86a Mean, 3869 (SD, 1491) mg/d | 150 items, past 1 moStandard Tables of Food Composition in Japan | Yes | Mean, 3629 (SD, 1225) mg/d | No | Ratio of FFQ to 24‐h urine values (mean, 1.10; SD, 0.70 significantly different from 1.0); also by energy intake (under‐reporters, acceptable, and over‐reporters of energy intake) | |
| Perin, 2013 | Cross‐sectional | Patients with hypertension, mean age 56.7 y, (52% women)Japan | 108 | Not stated | Single collectionMean, 4814 (SD, 2300) mg/d | Sodium‐specific FFQ (15 foods), past 12 mo | No | Mean, 984 (SD, 1063) mg/d | N/S | Mean and medians stated only | |
| Sasaki, 2003/JPHC study | Validation | Volunteers from representative sample (64% women), age and disease status not statedJapan | 89 | Creatinine excretionResults were no different, so present results with all patients | Two collectionsMean for men, 4669 (SD, 1978) and for women, 4600 (SD, 1702) mg/d | FFQ (138 items), past 12 mo | N/S | Mean for men, 6026 (SD, 2829) and for women, 6026 (SD, 2714) mg/d | Yes | Correlation (men 0.24, women −0.10) | |
| Sasaki, 1998 | Validation | Volunteers (31% women) age and disease status not statedJapan | 223 | Creatinine excretion | Single collectionMean for men, 3795 (SD, 1242) mg/d and for women, 3128 (SD, 1357) mg/d | Diet historyFFQ (138 items), preceding mo | Yes (“seasonings”) | Mean for men, 4508 (SD, 1610) and for women, 4117 (SD, 1357) mg/d sodium | No | Urinary dietary ratio (mmol): mean for men, 0.97 (SD, 0.66) and for women, 0.84 (SD, 0.46); correlation for log‐transformed data (men 0.09, women 0.16); adjustedc correlation (men 0.14, women 0.23) | |
| Trijsburg, 2015/DuPLO study | Validation | Random sample from DuPLO study aged 20–70 y (54% women)Disease status N/SThe Netherlands | 198 | PABA | Two collections. Mean, 3983 (SD, 1264) mg (n = 197) | Two FFQ (180 items), 7 mo apart–past mo | No | Mean sodium intake, 2137 (SD, 708) mg/d | No | Bias (%) (reference urine): −41.6 (underestimate), P < 0.01 | |
Abbreviations: AMPM, Automated Multiple‐Pass Method; AUC, area under the curve; CI, confidence interval; CSIRO, Commonwealth Scientific and Industrial Research Organisation; EPIC, European Prospective Investigation Into Cancer and Nutrition; FFQ, food frequency questionnaire; JPHC, Japan Public Health Center‐Based Prospective Study on Cancer and Cardiovascular Diseases; NPAAS, Nutrition and Physical Activity Assessment Study; N/S, not stated; OPEN, Observing Protein and Energy Nutrition; PABA, para‐amino benzoic acid; SD, standard deviation; USDA, United States Department of Agriculture; WHI, Women's Health Initiative.a Consumption estimated assuming 86% of ingested sodium excreted in the urine. b Combined mean unless results only presented by sub‐group. c Adjusted for total energy intake and urinary creatinine excretion.