The prevalence and clinical relevance of hyperhomocysteinemia suggesting vitamin B12 deficiency in presumed healthy infants

Assessment of vitamin B12 and homocysteine levels in pregnant women admitted for delivery and cord blood samples of their newborn babies: a multicenter study

BACKGROUND

Vitamin B12, an indispensable micronutrient, is pivotal in numerous physiological processes, with particular significance during pregnancy and fetal development. The increasing adoption of vegetarian diets and the economic challenges associated with accessing animal-based food sources contribute to the prevalence of vitamin B12 deficiency. This study aims to examine the levels of vitamin B12 and homocysteine in pregnant women upon admission for delivery and to analyze corresponding cord blood samples from their newborn infants in a substantial sample within the Istanbul metropolitan area.

MATERIALS AND METHODS

This cross-sectional multicenter study included women aged ≥16 years admitted for delivery and their newborns ≥34 weeks. The demographic data and the results of complete blood counts within the previous 24 hours before birth were recorded. Vitamin B12 and homocysteine levels were measured in maternal and cord blood samples. The study parameters were compared between the groups based on the mothers' and babies' homocysteine and vitamin B12 levels.

RESULTS

The study included 832 pregnant women and 832 neonates. Anemia affected 36% of pregnant women, with a higher frequency in mothers with vitamin B12 deficiency. Seventy-eight mothers and 48.9% of neonates showed Vitamin B12 levels below 200 pg/mL, while elevated homocysteine levels were observed in 30% of mothers and 26% of neonates. Maternal vitamin B12 deficiency was significantly correlated with cord blood B12 deficiency and elevated homocysteine. The median cord blood vitamin B12 level was inversely correlated with the number of previous pregnancies.

CONCLUSION

Vitamin B12 deficiency is extremely common in pregnant women before delivery, significantly correlating to cord blood homocysteine and vitamin B12 levels. However, homocysteine alone is not a reliable marker for maternal vitamin B12 status. Implementing strategies to detect vitamin B12 deficiency and supplying adequate vitamin B12 supplementation during pregnancy holds the potential to enhance maternal and neonatal health in Türkiye.

Vitamin B12 Deficiency Newborn Screening

BACKGROUND

Vitamin B12 deficiency (VitB12D) might cause neuro-developmental impairment in the first year of life. Newborn screening (NBS) for VitB12D was shown to be technically feasible and early treated infants developed favorably. This study aims to evaluate the impact of NBS in prevention of symptomatic infantile VitB12D.

METHODS

In a nationwide surveillance study in cooperation with the German Pediatric Surveillance Unit, incident cases with VitB12D (<12 months of age) were prospectively collected from 2021 to 2022.

RESULTS

In total, 61 cases of VitB12D reported to German Pediatric Surveillance Unit were analyzed, either identified by NBS (N = 31) or diagnosed after the onset of suggestive symptoms (non-NBS; N = 30). Ninety percent of the infants identified by NBS were still asymptomatic, whereas the non-NBS cohort presented at median 4 month of age with muscular hypotonia (68%), anemia (58%), developmental delay (44%), microcephalia (30%), and seizures (12%). Noteworthy, symptomatically diagnosed VitB12D in the first year of life was reported 4 times more frequently in infants who did not receive NBS for neonatal VitB12D (14 in 584 800) compared with those screened for VitB12D as newborns (4 in 688 200; Fisher's Exact Test, odds ratio 4.12 [95% confidence interval: 1.29-17.18], P = .008). The estimated overall cumulative incidence was 1:9600 newborns per year for neonatal VitB12D and 1:17 500 for symptomatic infantile VitB12D.

CONCLUSIONS

NBS for neonatal VitB12D may lead to a fourfold risk reduction of developing symptomatic VitB12D in the first year of life compared with infants without NBS.

The Benefit of Detecting Reduced Intracellular B12 Activity through Newborn Screening Remains Unclear

Vitamin B12 (B12) deficiency (B12D) can have detrimental effects on early growth and development. The Austrian newborn screening (NBS) program targets inborn errors of cobalamin metabolism and also detects B12D. Of 59 included neonates with B12D suspected by NBS, B12D was not further investigated in 16 (27%) retrospectively identified cases, not confirmed in 28 (48%), and confirmed in 15 (25%) cases. NBS and recall biomarkers were recorded. Age at sampling of the dried blood spots for NBS and the 1st-tier methionine/phenylalanine ratio were the strongest parameters to predict B12D (67.4% correct allocations). No differences between cases with confirmed, unconfirmed, or unknown B12D or differences to norms were observed for growth and psychomotor development (Vineland III scales, phone interviews with parents of children between months 10 and 14 of life). B12 intake was below recommendations in most mothers. NBS can detect reduced intracellular B12 activity. No advantage of NBS detection and treatment regarding infant cognitive development or growth could be proven. Since conspicuous NBS findings cannot be ignored, and to prevent exposing newborns to invasive diagnostics, assessment of maternal B12 status during pregnancy seems advisable.

Defining Optimal Cobalamin Status for Neonates and Infants

BACKGROUND

An optimal cobalamin status is necessary for normal neurodevelopment.

OBJECTIVE

To give a description of the epidemiology, pathophysiology and diagnostic challenges related to cobalamin insufficiency in neonates and infants in order to prevent its occurence.

RESULTS

Inadequate cobalamin status is prevalent among neonates and young infants, due to a high prevalence of maternal cobalamin deficiency, exclusive breastfeeding for extended periods and late introduction of animal food. Cobalamin insufficiency is associated with delayed neurodevelopment and subtle clinical symptoms like feeding difficulties, regurgitations and constipation in young infants. Early diagnosis and treatment of impaired cobalamin status is important to prevent neurologic damage.

CONCLUSION

Clinical suspicion of cobalamin insufficiency in infants should infer immediate biochemical testing and a plasma total homocysteine > 5.0 µmol/L indicate cobalamin insufficiency in need of intramuscular treatment with hydroxycobalamin, followed by introduction of animal food after 4 months of age.

Vitamin B12 and Folate Status in Pregnant Females and Their Infants in Norway: Secondary Analysis from the Mommy's Food Study

BACKGROUND

Vitamin B12 and folate are essential micronutrients important for normal infant growth and development.

OBJECTIVES

The aims were to describe vitamin B12 and folate status in pregnant females and their infants according to commonly used status cutoffs and examine the associations between maternal status, maternal supplement use, and breastfeeding and infant status.

METHODS

Pregnant females were recruited at 18 wk gestation in Bergen, Norway. Maternal vitamin B12 and folate status were measured at gestational weeks 18 (n = 136) and 36 (n = 116), and infant status was measured at ages 3 (n = 73) and 6 (n = 74) mo.

RESULTS

At gestational weeks 18 and 36, respectively, 4.4% and 2.6% of the mothers had plasma cobalamin concentrations <148 pmol/L, 0.7% and 6.9% had methylmalonic acid (MMA) concentrations >0.26 μmol/L, and 3.7% and 30% had folate concentrations <10 nmol/L. None of the females had total homocysteine (t-Hcy) concentrations >13 μmol/L or 3 combined indicator of vitamin B12 (cB12) < -0.5. At 3 and 6 mo, respectively, 4.1% and 5.4% of the infants had cobalamin concentrations <148 pmol/L, 63% and 74% had t-Hcy concentrations >6.5 μmol/L, 59% and 66% had MMA concentrations >0.26 μmol/L, and 47% and 60% had cB12 > -0.5. None of the infants had folate concentrations <10 nmol/L. Several of the vitamin B12 biomarkers in infants were associated with maternal vitamin B12 status during pregnancy. Breastfed infants had lower vitamin B12 status (as indicated by plasma cobalamin, t-Hcy, and cB12) than nonbreastfed infants at both 3 and 6 mo. Use of supplements during pregnancy was associated with better vitamin B12 status among infants at 3 and 6 mo, as indicated by infants' cobalamin and t-Hcy concentrations.

CONCLUSIONS

Subclinical vitamin B12 deficiency among infants was common and associated with maternal vitamin B12 status during pregnancy and breastfeeding. Among the mothers, an increase in biochemical folate deficiency was discovered toward the end of gestation. Further studies are needed to investigate clinical consequences. This trial was registered at clinicaltrials.gov as NCT02610959.

Biochemical, Nutritional, and Clinical Parameters of Vitamin B12 Deficiency in Infants: A Systematic Review and Analysis of 292 Cases Published between 1962 and 2022

Pooled data from published reports on infants with clinically diagnosed vitamin B12 (B12) deficiency were analyzed with the purpose of describing the presentation, diagnostic approaches, and risk factors for the condition to inform prevention strategies. An electronic (PubMed database) and manual literature search following the PRISMA approach was conducted (preregistration with the Open Science Framework, accessed on 15 February 2023). Data were described and analyzed using correlation analyses, Chi-square tests, ANOVAs, and regression analyses, and 102 publications (292 cases) were analyzed. The mean age at first symptoms (anemia, various neurological symptoms) was four months; the mean time to diagnosis was 2.6 months. Maternal B12 at diagnosis, exclusive breastfeeding, and a maternal diet low in B12 predicted infant B12, methylmalonic acid, and total homocysteine. Infant B12 deficiency is still not easily diagnosed. Methylmalonic acid and total homocysteine are useful diagnostic parameters in addition to B12 levels. Since maternal B12 status predicts infant B12 status, it would probably be advantageous to target women in early pregnancy or even preconceptionally to prevent infant B12 deficiency, rather than to rely on newborn screening that often does not reliably identify high-risk children.

Early neurological and motor function in infants born moderate to late preterm or small for gestational age at term: a prospective cohort study

BACKGROUND

There are inconsistent findings regarding neurological and motor development in infants born moderate to late preterm and infants born small for gestational age at term. The primary aim of this study was to compare neurological and motor function between preterm, term SGA and term AGA infants aged three to seven months corrected age using several common assessment tools. The secondary aim was to investigate their motor function at two years.

METHODS

In this prospective cohort study, we included 43 infants born moderate to late preterm with gestational age 32-36 + 6 weeks, 39 infants born small for gestational age (SGA) at term with a birthweight ≤ 10th centile for gestational age, and 170 infants born at term with appropriate weight for gestational age (AGA). Neurological and motor function were assessed once in infancy between three to seven months corrected age by using four standardised assessment tools: Hammersmith Infant Neurological Examination (HINE), Test of Infant Motor Performance, General Movements Assessment and Alberta Infant Motor Scale. The Ages and Stages Questionnaire (ASQ-2) was used at two years.

RESULTS

At three to seven months corrected age, mean age-corrected HINE scores were 61.8 (95% confidence interval (CI): 60.5 to 63.1) in the preterm group compared with 63.3 (95% CI: 62.6 to 63.9) in the term AGA group. Preterm infants had 5.8 (95% CI: 2.4 to 15.4) higher odds for HINE scores < 10th percentile. The other test scores did not differ between the groups. At two years, the preterm group had 17 (95% CI: 1.9 to 160) higher odds for gross motor scores below cut-off on ASQ-2 compared with the term AGA group.

CONCLUSIONS

The present study found subtle differences in neurological function between preterm and term AGA infants in infancy. At two years, preterm children had poorer gross motor function. The findings indicate that moderate prematurity in otherwise healthy infants pose a risk for neurological deficits not only during the first year, but also at two years of age when compared with term AGA children.

Vitamin B12 status in infancy and the effect of a vitamin B12 injection in infants with subclinical vitamin B12 deficiency: study protocol for a register-based randomised controlled trial

INTRODUCTION

Vitamin B₁₂ (cobalamin) is crucial for optimal child development and growth, yet deficiency is common worldwide. The aim of this study is twofold; (1) to describe vitamin B₁₂ status and the status of other micronutrients in Norwegian infants, and (2) in a randomised controlled trial (RCT), investigate the effect of vitamin B₁₂ supplementation on neurodevelopment in infants with subclinical vitamin B₁₂ deficiency.

METHODS AND ANALYSIS

Infant blood samples, collected at public healthcare clinics, are analysed for plasma cobalamin levels. Infants with plasma cobalamin <148 pmol/L are immediately treated with hydroxocobalamin and excluded from the RCT. Remaining infants (cobalamin ≥148 pmol/L) are randomly assigned (in a 1:1 ratio) to either a screening or a control group. In the screening group, baseline samples are immediately analysed for total homocysteine (tHcy), while in the control group, the baseline samples will be analysed after 12 months. Screening group infants with plasma tHcy >6.5 µmol/L, are given an intramuscular injection of hydroxocobalamin (400 µg). The primary outcomes are cognitive, language and motor development assessed using the Bayley Scales of Infant and Toddler Development at 12 months of age.

ETHICS AND DISSEMINATION

The study has been approved by the Regional Committee for Medical and Health Research Ethics (ref: 186505). Investigators who meet the Vancouver requirements will be eligible for authorship and be responsible for dissemination of study findings. Results will extend current knowledge on consequences of subclinical vitamin B₁₂ deficiency during infancy and may inform future infant feeding recommendations.

TRIAL REGISTRATION NUMBER

NCT05005897.

A Retrospective Evaluation of the Predictive Value of Newborn Screening for Vitamin B12 Deficiency in Symptomatic Infants Below 1 Year of Age

BACKGROUND

The sensitivity of newborn screening (NBS) in detecting infants that later develop symptomatic vitamin B12 deficiency is unknown. We evaluated the predictive value using NBS algorithms in detecting infants that later were clinically diagnosed with symptomatic B12 deficiency. Furthermore, we investigated whether being born in a hospital using nitrous oxide (N₂O) as pain relief in labor may have had an impact on total homocysteine at NBS.

METHODS

We retrospectively retrieved NBS data and analyzed total homocysteine, methylmalonic acid and methyl citrate on stored NBS dried blood spots (DBS) of 70 infants diagnosed with symptomatic B12 deficiency and compared them to 646 matched and 434 unmatched DBS controls to evaluate the Austrian and Heidelberg B12 NBS algorithms.

RESULTS

The sensitivity of NBS in detecting infants later diagnosed with symptomatic B12 deficiency at median age 10.9 weeks was ≤10%. Total homocysteine was higher in DBS for the unmatched controls who were born in hospitals providing N₂O compared to in hospitals not providing N₂O, with median total homocysteine 4.0 µmol/L compared to 3.5 µmol/L (n = 434, 95% CI 0.04-0.87, p = 0.03).

CONCLUSION

NBS algorithms were unable to identify most infants diagnosed with symptomatic B12 deficiency after the neonatal period. Being born in hospitals providing N₂O may impact total homocysteine at NBS.

Nitrous oxide in labour predicted newborn screening total homocysteine and is a potential risk factor for infant vitamin B12 deficiency

AIM

Risk factors for vitamin B12 deficiency in infants are not fully understood. The aim of the study was to assess predictors of total homocysteine and methylmalonic acid analysed in newborn screening dried blood spots.

METHODS

In a Norwegian case control study, we analysed total homocysteine and methylmalonic acid in newborn screening dried blood spots of 86 infants clinically diagnosed with vitamin B12 deficiency during 2012-2018. Results were compared to 252 healthy infants and 400 dried blood spot controls. Medical records were reviewed, and mothers completed questionnaires.

RESULTS

Both total homocysteine and methylmalonic acid were significantly higher on newborn screening dried blood spots in infants later clinically diagnosed with vitamin B12 deficiency than controls. Multiple regression analysis showed that the dose of nitrous oxide during labour was the strongest predictor for total homocysteine level in newborn screening dried blood spots for all infants, with larger effect in infants later clinically diagnosed with vitamin B12 deficiency than controls.

CONCLUSION

Nitrous oxide dose during labour was a predictor for total homocysteine and may impact the interpretation of total homocysteine analysis in newborn screening. Nitrous oxide is suggested as a contributing risk factor for infants prone to develop vitamin B12 deficiency.

Vitamin B12 (Cobalamin): Its Fate from Ingestion to Metabolism with Particular Emphasis on Diagnostic Approaches of Acquired Neonatal/Infantile Deficiency Detected by Newborn Screening

Acquired vitamin B12 (vB12) deficiency (vB12D) of newborns is relatively frequent as compared with the incidence of inherited diseases included in newborn screening (NBS) of different countries across the globe. Infants may present signs of vB12D before 6 months of age with anemia and/or neurologic symptoms when not diagnosed in asymptomatic state. The possibility of identifying vitamin deficient mothers after their pregnancy during the breastfeeding period could be an additional benefit of the newborn screening. Vitamin supplementation is widely available and easy to administer. However, in many laboratories, vB12D is not included in the national screening program. Optimized screening requires either second-tier testing or analysis of new urine and blood samples combined with multiple clinical and laboratory follow ups. Our scope was to review the physiologic fate of vB12 and the pathobiochemical consequences of vB12D in the human body. Particular emphasis was put on the latest approaches for diagnosis and treatment of vB12D in NBS.

Interrelation between homocysteine metabolism and the development of autism spectrum disorder in children

Evidence is emerging that dysregulation of circulating concentrations of homocysteine, an important intermediate in folate and vitamin B12 metabolism, is associated with autism spectrum disorder (ASD), but comprehensive assessments and correlations with disease characteristics have not been reported. Multivariate ordinal regression and restricted cubic spline (RCS) models were used to estimate independent correlations between serum homocysteine, folate, and vitamin B12 levels and clinical outcomes and severity of children with ASD. After adjusting for confounding factors, serum homocysteine levels were significantly higher in children with ASD than in healthy controls (β: 0.370; 95% CI: 0.299~0.441, p < 0.001). Moreover, homocysteine had a good diagnostic ability for distinguishing children with ASD from healthy subjects (AUC: 0.899, p < 0.001). The RCS model indicated a positive and linear association between serum homocysteine and the risk of ASD. The lowest quartile of folate was positively associated with ASD severity (OR: 4.227, 95% CI: 1.022~17.488, p = 0.041) compared to the highest quartile, and serum folate showed a negative and linear association with ASD severity. In addition, decreased concentrations of folate and vitamin B12 were associated with poor adaptive behavior developmental quotients of the Gesell Developmental Schedules (p < 0.05). Overall, an increased homocysteine level was associated with ASD in a linear manner and is thus a novel diagnostic biomarker for ASD. Decreased concentrations of folate and vitamin B12 were associated with poor clinical profiles of children with ASD. These findings suggest that homocysteine-lowering interventions or folate and vitamin B12 supplementation might be a viable treatment strategy for ASD.

Lower iron stores were associated with supoptimal gross motor scores in infants at 3-7 months

Aim

To investigate associations between iron status and gross motor scores in infants aged 3–7 months.

Methods

In a prospective study, 252 infants aged 3–7 months were examined using the age‐standardised Alberta Infant Motor Scale (AIMS) prior to analysing iron status in 250 infants. Combined AIMS and ferritin results were assessed in 226 infants, whereas AIMS and reticulocyte haemoglobin (ret‐Hb) results were obtained for 61 infants. We used logistic regressions and receiver operator characteristics to analyse our data.

Results

With AIMS z‐score <10th percentile as outcome measure, optimal cut‐off value for ferritin was 51 μg/L (sensitivity 86%, specificity 81%) and 28 pg for ret‐Hb (sensitivity 86%, specificity 85%). The area under the curve for ferritin and ret‐Hb was 0.886 and 0.896, respectively (n = 61). Ferritin <51 μg/L predicted an AIMS z‐score <10th percentile in a logistic regression (OR 3.3, 95% CI 1.4–7.5, p = 0.006, n = 226). Six of 14 (43%) infants with ret‐Hb <28 pg scored <10th percentile on AIMS compared to 1/47 (2.1%) infants with ret‐Hb ≥28 μg/L (Exact, p < 0.001).

Conclusion

Reticulocyte haemoglobin of <28 pg and ferritin <51 μg/L were associated with suboptimal gross motor scores in infants 3–7 months.

Breastfed Infants With Spells, Tremor, or Irritability: Rule Out Vitamin B12 Deficiency

BACKGROUND

In Norway, 5-10% of neonates and infants have biomarkers suggesting vitamin B12 deficiency from newborn screening tests and unselected clinical screening, respectively.

AIMS

The aims were to identify risk factors and describe presenting symptoms and biochemical profiles in infants diagnosed with vitamin B12 deficiency.

METHODS

In this case-control study, we searched hospital medical records for infants younger than one year born in 2011-2018, diagnosed with vitamin B12 deficiency. We compared 85 cases with a control group of 252 infants aged 3-7 months. Parents completed questionnaires.

RESULTS

Of the 85 cases with vitamin B12 deficiency, 80% presented with spells (37%) of apneas, motor seizures, or absences within the first two months of life. Tremor (29%) and irritability (18%) were the most common findings at the first examination. Serum total homocysteine ≥10 μmol/L was found in 77% of cases compared to 28% of controls (P < 0.001). None of the mothers were vegetarians, but 25% reported a previous history of vitamin B12 deficiency and 7% had celiac disease. The dose of nitrous oxide given during labor was significantly associated with infant serum total homocysteine level at diagnosis (r = 0.37, 95% confidence interval = 0.16-0.55, P < 0.001) for cases, but not for controls.

CONCLUSION

Spells, tremor, and irritability are common findings in early infant vitamin B12 deficiency. Nitrous oxide given during labor is proposed as a contributing risk factor to the development of early infant vitamin B12 deficiency.

Reference Material for Hammersmith Infant Neurologic Examination Scores Based on Healthy, Term Infants Age 3-7 Months

OBJECTIVE

To provide a valid, continuous reference interval, including a 10th percentile cut-off, for Hammersmith Infant Neurological Examination (HINE) scores based on 3- to 7-month-old term infants with weight appropriate for gestational age.

STUDY DESIGN

In a prospective study, we examined 168 Norwegian infants at one timepoint with HINE at 3-7 months of age. In 134 of these infants Ages and Stages Questionnaire was completed by their parents at 2 years of age to ensure typical motor development. We calculated a reference interval for HINE scores with the 10th percentile as cut-off for age-dependent optimal scores.

RESULTS

The best fitting mean model for HINE total score was 78.1358 + 9659.231∗1/age in weeks²-5104.174∗natural logarithm(age in weeks)/age in weeks², which explained 49.8% of the variance. The HINE total score 10th percentile cut-off corresponded to 52.1 points at age 12 weeks, 55.6 points at 16 weeks, 59.0 points at 20 weeks, 61.8 points at 24 weeks, and 63.8 points at 28 weeks. We found an excellent intraclass correlation coefficient of 0.953 (0.931-0.968) between 2 examiners. The infants had a typical motor development at 2 years follow-up.

CONCLUSION

We have presented a valid, continuous reference interval and a 10th percentile cut-off for HINE scores for infants age 3-7 months.