Validity and reliability of a 7‐day fluid diary to estimate average daily water intake
Bibliographic record
Abstract
Water is the most abundant molecule in the human body that undergoes continuous recycling, but often an overlooked nutrient. One of the main reasons that even in large scale studies water intake is not recorded is the lack of validated tools to assess water intake. OBJECTIVE To assess the validity and reliability of a seven‐day fluid diary (7DFD) by comparing it to total water turnover assessed via deuterium oxide. METHODS One hundred one healthy males and females (41±14 y, 76.6±16.9 kg, 1.70±0.09 m, 26.4±5.5 kg·m −2 , 30±11% body fat) from the North West Arkansas were enrolled. Subject participated in the study for four consecutive weeks where the 7DFD was recorded on week two and four. Three doses of D 2 O (0.10 g, 0.05 and 0.08·kg lean body mass −1 , assessed by DXA) were ingested at the beginning of weeks 1, 2 and 3. Urine samples were collected immediately before ingestion of D 2 O, the following day and at the end of each week. Urine D/H, expressed in ppm vs the V‐SMOW standard (155.76 ppm) was measured by mass spectrometry using the H 2 ‐water equilibration method. Water turnover (WTO) was calculated as total body water (TBW, L)/mean residence time of water in the body water pool. Average daily WTO was also estimated from the diary as the sum of: 1) participant entries in 7DFD, 2) water intake from solid foods calculated from a traditional 7 day food record, and, 3) calculated daily metabolic water production. RESULTS WTO assessed either via D 2 O (W2: 3.64±1.20, W4: 3.68±1.31 L/day) or 7DFD (W2: 3.51±1.30, W4: 3.47±1.23 L/day) was not different between weeks 2 and 4 with both methods of estimation ( P >0.05). Water turnover from D 2 O vs the 7DFD was linearly related during week 2 (F[1,95]=144.2, R 2 = 0.61, p <0.001), and week 4 (F[1,85]=92.2, R 2 = 0.52, p < 0.001). Intraclass correlations (95% CI) were 0.77 (0.68–0.84), and 0.74(0.63–0.83) for weeks 2 and 4, respectively. Lastly, the Bland‐Altman analysis for combined mean difference between WTO for D 2 O and 7DFD was 0.167±0.876 L·d −1 , a 95% CI of −1.886–1.552 L·d −1 , with no apparent bias (F[1,180]= 1.0, R 2 =0.005, p = 0.325). CONCLUSION The seven day fluid diary is a reliable and valid tool to estimate water from fluids in adults. Support or Funding Information Funded by Danone Research
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.009 | 0.020 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".