Table 1.
Characteristics of included studies (summary table)
| First author, year/name of study | Patients, No. | 24‐h Urine | Dietary assessment (FFQ) | Discretionary salt accounted for | 24‐h Urine and FFQ concurrent | Method(s) of comparison | |
|---|---|---|---|---|---|---|---|
| Bedford, 201121 | 102 | Single collection | FFQ (National Cancer Institute) (124 items), past 12 mo, analyzed with a Canadian version of the nutrient database | No | No | Correlation (0.21) | |
| Charlton, 200822 | 284 | Three collections, PABA, urine volume, and urinary creatinine concentration used to assess completeness | Salt‐specific FFQ (42 items), previous 7 d | Yes | Yes | Correlation (0.173); κ (0.0318) categorizing high (>2400 mg/d) vs low (<2400 mg/d) sodium intake | |
| Day, 2001/EPIC‐Norfolk cohort study23 | 123 | Six collections, PABA used to assess completeness | 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 | Yes | Sample variance, correlation (0.36), regression analysis | |
| Ferreira‐Sae, 200924 | 132 | Single collection | Salt‐specific FFQ (44 items), past 12 moNutwin database software developed by Federal University of Sao Paulo | In a separate questionnaire | No | Correlation | |
| Freedman, 2015/Nutrition Biomarker Study for WHI 2004–200518, 25 | 544 | Single collection, PABA and self‐report used to assess completenessTotal excretion divided by 0.86a | WHI FFQ, past 3 mo, nutrient databaseNutrition Data System for Research, University of Minnesota to analyze the results | N/S | 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 studies, average correlation 0.16 (men 0.17, women 0.15), average attenuation factor of 0.08 (95% CI, 0.04–0.13) |
| Freedman, 2015/OPEN study 1999–200018, 26 | 484 | Two collections PABA and self‐report used to assess completenessTotal excretion divided by 0.86a | FFQ, past 12 mo: single Diet History Questionnaire developed and evaluated at the National Cancer Institute | No | 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 study18, 27 | 465 | Two collections, self‐report, volume and creatinine excretion used to assess completenessTotal excretion divided by 0.86a | FFQ, past 12 moA single FFQ (Harvard) was administered 1 to 14 mo after the beginning of the study | N/S | 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 2006–200918, 28 | 263 | Two collections, PABA used to assess completenessTotal excretion divided by 0.86a | FFQ, past 12 moAdministered onceNational Cancer Institute Diet History Questionnaire | No | 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 2007–200918, 29 | 450 | Single collectionTotal excretion divided by 0.86a | FFQ, past 3 moWHI FFQ and the nutrient database Nutrition Data System for Research, University of Minnesota was used to analyze the results | N/S | 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 Study30 | 97 | Single collection | FFQ, past 12 mo, adapted from CSIRO FFQ for Melbourne Chinese to assess usual intake (110 items)Portion sizes and nutrient intakes were estimated using the 1990 Australian Food Composition Tables | N/S | N/S | N/S | |
| Kelly, 2015/Food Choice at Work study31 | 50 | Single collection, PABA used to assess completeness | FFQ version of EPIC (150 food items) adapted for Irish population, past 12 mo, nutrient values from Food Standards Agency and McCance and Widdowson's Food Composition Tables | No | 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, 200932 | 62 | Two collections, creatinine excretion used to assess completeness | CSIRO Australia FFQ developed in the 1980s and subsequently evaluated in 1991, designed to estimate usual food and drink intake during the past 12 mo, with nutrient composition derived from four sources: the Australian nutrient database, British Food Composition Tables, USDA food tables, and manufacturers’ data | N/S | No | Correlation (0.352) (P < 0.01); agreement in rankings by quintile; weighted κ 0.31 (quintiles of distribution); regression analysis | |
| Li, 201433 | 964 | Single collection, PABA used to assess completeness | FFQ, N/S | Yes | N/S | Correlation (0.07); mean difference; proportion underestimated and overestimated | |
| Murikami, 2012/Japanese Dietetic Students’ Study for Nutrition and Biomarkers20 | 1043 | Single collection, creatinine excretion used to assess completeness | 150 items, past 1 moStandard Tables of Food Composition in Japan used | Yes | 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, 201334 | 108 | Single collection | Sodium‐specific FFQ (15 foods), past 12 mo | No | N/S | Mean and medians stated only | |
| Sasaki, 2003/JPHC study)35 | 89 | Two collections, PABA used to assess completeness | FFQ (138 items), past 12 mo | N/S | Yes. | Correlation (men 0.24, women −0.10) | |
| Sasaki, 199836 | 223 | Single collection, creatinine excretion used to assess completeness | Diet history (FFQ, 138 items), preceding mo | Yes (“seasonings”) | No | Urinary dietary ratio (mmol); mean (SD) men 0.97 (0.66), women 0.84 (0.46): correlation for log transformed data (men 0.09, women 0.16); adjustedb correlation (men 0.14, women 0.23) | |
| Trijsburg, 2015/DuPLO study37 | 198 | Two collections, PABA used to assess completeness | Two FFQ (180 items) 7 mo apart, past mo | No | 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 of Women's Health Initiative Observational Study; N/S, not stated; OPEN, Observing Protein and Energy Nutrition; PABA, para‐amino benzoic acid; SD, standard deviation.
a
Consumption estimated assuming 86% of ingested sodium excreted in the urine.
b
Adjusted for total energy intake and urinary creatinine excretion.