Association between vitamin A status and lung function in children aged 6-9 years in northern Ethiopia
Bibliographic record
Abstract
The overall aim of the research described in this thesis was to evaluate the effect of vitamin A supplementation on respiratory health, assessed by lung function in children aged 6--9 years. It comprises three studies. The first study determined the magnitude of vitamin A deficiency in the target population in Wukro wereda, Northern Ethiopia. Of the 1339 eligible children identified by house to house surveys, 824 had complete data for vitamin A indicators and anthropometry. Xerophthalmia was detected in 5.8% of the children, 8.4% had serum retinol levels <0.35 mumol/L and 51.1% between 0.35--0.70 mumol/L. Liver vitamin A reserve was also found to be low in 41.0% of the children using the Modified Relative Dose Response (MRDR) and in about 85% of the children, the daily vitamin A intake was below the FAO/WHO basal requirement (<250 RE/day). The second study found that in comparison with children with adequate vitamin A reserve (MRDR < 0.06), those with low reserve (MRDR ≥ 0.06) had forced expiratory volume in one second (FEV1) 48.8 ml (p = 0.006) lower when unadjusted, 23.1 ml (p = 0.04) when partially adjusted for age, gender and height and 14.1 ml (p = 0.20) when fully adjusted for demographic, general health, lung function and household related characteristics. The third study describes the results of a randomized controlled trial (RCT) to evaluate the impact of vitamin A supplementation on respiratory health as assessed by change in FEV1 at 4 months. The average change was 53.3 ml (n = 496) and 53.8 ml (n = 501) in the vitamin A and placebo groups respectively. After adjusting for baseline covariates, the difference between them was -3.6 ml (95%CI: -21.6, 14.4). In sub-analysis of the data, gender and vitamin A status subcategories were found to be effect modifiers. In conclusion, high dose vitamin A supplementation did not show an effect on change in FEV1 at 4 months in children aged 6--9 years with high prevalence of vitamin A deficiency. Sub-analysis findings suggest that the benefits to vitamin A intervention in the study setting can probably be achieved if the other nutritional deficiencies such as zinc are addressed. Moreover, the results also suggest that the effects of vitamin A supplementation on respiratory health status are complex and these need to be taken into account in future studies to assess the clinical and public health implications of vitamin A supplementation in this age group.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".