Establishing a baseline value for urinary arsenic:selenium ratio in unexposed populations in the United Kingdom
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Bibliographic record
Abstract
The relationship between arsenic (As) and selenium (Se) in the human body is poorly understood. We have investigated the concentrations of urinary As and Se in three ethnic groups (n=63) in the United Kingdom and show that there is a positive correlation (r=0.62, p<0.001) between total concentrations of As and Se and that the ratio of these two elements is stable, with a mean value (±SD) of 0.7±0.4. Furthermore, concentrations of individual arsenic species methylarsonate (MA), dimethylarsinate (DMA) and arsenobetaine (AB) in the urine samples show a positive correlation with total Se (As(III) and As(V) were not detected). The intra-individual variation of the As:Se ratio also remains stable over time, as determined by monitoring a volunteer over a period of one year, and deviates only after recent seafood consumption. It appears that the ratio is also stable across diverse populations across different cultures and continents, evident from our calculation of As:Se ratio from concentrations of these elements found in urine samples from different populations published in the literature. Our study involved analysis of 63 urine samples from three ethnic groups (White Caucasian n=20, Asian n=21 and Somali n=22), 58 urine samples from 29 Ramadan fasting volunteers and 12 from one volunteer whose urine samples were collected over a period of one year. All the participants completed a lifestyle questionnaire and were asked to refrain from eating seafood or fish for three days prior to collection of the sample. Total As and Se in urine were determined by inductively coupled plasma mass spectrometry (ICP-MS). As species (AB, DMA, MA, As(III), As(V)) were determined by using high performance liquid chromatography (HPLC) combined with ICP-MS. Mean ± SD As:Se ratios of 0.8±0.4, 0.7±0.4, 0.4±0.2, 0.7±0.3 and 1.2±0.3 were obtained for the Asian, White Caucasian, Somali, fasting, and one volunteer respectively, giving an overall mean of 0.7±0.4 (SD). It is noteworthy, that when comparing ethnic differences, the Somali group shows a statistically significant lower As:Se ratio (0.4±0.2, p<0.05) compared to Asian and White Caucasian groups; this is ascribed to lower urinary As concentrations in this group. The study over one year with a single volunteer revealed that recent (within 3 days) seafood consumption results in a significantly different (p<0.05) As:Se ratio (4.0). We have calculated from the literature the value of As:Se for populations, exposed to As through drinking water, can range from 2.0–9.6. Based on our own work and the values we calculated from other studies we suggest that the baseline range for mean As:Se ratio is 0.4–1.2, provided that the urine samples are collected in the absence of recent consumption of seafood. The relatively stable As:Se ratio observed in this study suggests a link between these two elements in humans adding support to earlier studies with animals and humans exposed to inorganic arsenic in drinking water which reported interaction between these elements and that Se may play a role in counteracting As toxicity.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 it