Functional Vitamin B12 Status in Lactating Women Living in Rural Indonesia Assessed by Using Dried Blood Spot Methylmalonic Acid Analysis
Bibliographic record
Abstract
Background Low vitamin B12 (B‐12) status in breastfeeding women has been associated with infant B‐12 inadequacy and adverse health outcomes in mothers. Populations in resource‐poor settings are at increased risk for B‐12 deficiency. Dried blood spots (DBSs) are a convenient and minimally invasive tool to collect biological samples in field studies. We have recently developed a method to quantify methylmalonic acid (MMA), the most specific functional biomarker of B‐12 status, in DBSs. The aim of this study was to determine the risk of low B‐12 status among lactating women living in rural Indonesia by assessing DBS MMA in a convenience sample and comparing the results to a reference group of healthy, non‐lactating women. Methods Apparently healthy, lactating women living in Sumedang district of West Java were recruited for this research which is part of a micronutrient survey. DBSs were collected onto Whatman 903 filter paper after pricking either middle or ring finger. MMA was quantified in 8‐mm DBS disks using liquid chromatography‐tandem mass spectrometry. DBS and plasma MMA concentrations of a convenience sample of healthy, non‐lactating women (n=182; 19–35 y) residing in Vancouver BC, Canada, served as reference data. A reference value, suggestive of B‐12 deficiency, was computed as 97.5 th percentile of DBS MMA concentrations from a subset of the Vancouver convenience sample including women with plasma MMA concentrations < 260 nmol/L (n= 146). Results Mean (95% CI) MMA concentration in DBS of Indonesian women (n= 184; aged 27±7 y) was 4.23 (3.90, 4.55) pmol per disk and significantly higher (P= 0.0001; chi‐squared test) than that of Vancouver women [3.18 (2.97, 3.39) pmol per disk; n= 182]. Forty‐three Indonesian women (23 %) had DBS MMA concentrations above the reference value of 5.03 pmol per disk (i.e., the 97.5 th percentile). The rate of Vancouver women (9.3 %; n= 182) who had DBS MMA concentrations above the reference value was significantly lower (P< 0.01; chi‐squared test) than the rate of Indonesian women. Conclusions DBS MMA has the potential to identify populations with increased risk of low B‐12 status. Lactating women living in rural Indonesia seem to have lower functional B‐12 status than healthy, non‐lactating Vancouver women. Thus, rural Indonesian women and their breastfed infants may be at increased risk for B‐12 deficiency and associated adverse health outcomes. Support or Funding Information The study was, in part, funded through Meat & Livestock Australia. YL acknowledges funding from the Canada Research Chair Program of the Canadian Institutes of Health Research and THS acknowledges funding from the University of British Columbia in form of a Four Year Doctoral Fellowship.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".