Population-based reference intervals for ferritin, iron, transferrin and transferrin saturation and prevalence of iron deficiency in 6-12-year-old children: the Health Oriented Pedagogical Project (HOPP)

Cohort-Based Reference Values for Serum Ferritin and Transferrin and Longitudinal Determinants of Iron Status in European Children Aged 3-15 Years

BACKGROUND

Reference values of ferritin and transferrin for European children do not exist.

OBJECTIVE

We aimed to provide sex-, age-, and body mass index (BMI)-specific serum ferritin and transferrin reference percentiles of 3-15-y-old children based on cohort data and to investigate determinants of iron status.

METHODS

A total of 3390 ferritin and 3416 transferrin measurements from children residing in 8 European countries participating in the IDEFICS/I.Family cohort (https://www.isrctn.com/ISRCTN62310987) at baseline (W0) and 6 y later (W3) were used to estimate percentiles using the generalized additive model for location, scale and shape. Associations of serum ferritin and transferrin concentrations with total iron intake, total iron intake additionally adjusted for vitamin C intake, and iron from heme sources were investigated separately with adjustment for sex, age, country of residence, parental education, usual energy intake and BMI z-score in regression models using cross-sectional and longitudinal data.

RESULTS

The age-specific ferritin and transferrin 5th and 95th reference percentiles ranged from 10.9 to 81.1 μg/L and 2.23 to 3.56 g/L, respectively. A deficient iron status was observed in 3% of children at W0 and 7% of children and adolescents at W3, respectively. At both waves, a higher iron intake from heme sources was positively associated with serum ferritin {W0: β = 3.21 [95% confidence interval (CI): 0.71, 5.71]; W3: β = 4.48 [95% CI: 2.09, 6.87]}, that is, children consuming one mg more heme iron had a 3.21 and 4.48 μg/L higher ferritin concentration. Adherence to a mainly vegetarian diet was associated with a lower chance for sufficient serum ferritin cross-sectionally at W3 [odds ratio (OR) 0.40 (95% CI: 0.21, 0.81)] and longitudinally [OR 0.35 (95% CI: 0.15, 0.93)].

CONCLUSIONS

Age-, sex-, and BMI-specific reference percentiles of serum ferritin and transferrin concentrations based on cohort data are provided for European children aged 3-15 y and may be used in clinical practice.

Nutrient deficiencies in children with celiac disease during long term follow-up

BACKGROUND

Celiac disease (CD) is associated with malabsorption and consequential nutritional deficiencies. Patients with CD must follow a gluten-free diet (GFD), which is also associated with nutrient deficiencies. Despite the clinical significance, consensus is lacking on the pattern and frequency of nutrient deficiencies in CD and the usefulness of assessment during follow-up. The aim was to investigate the presence of micronutrient and protein deficiencies in pediatric patients with CD after starting a GFD and receiving standard clinical care, taking disease activity into account.

METHODS

This single center retrospective chart review aimed to map the occurrence of nutrient deficiencies, determined in serum samples derived during follow-up in an expertise center for pediatric CD. Serological micronutrient levels were determined during routine clinical visits up until 10 years in children with CD on a GFD.

RESULTS

The data of 130 children with CD was included. When pooling the measurements between 3 months and 10 years after GFD initiation, a deficiency in iron, ferritin, vitamin D, vitamin B12, folate and zinc was present in 33%, 21,9%, 21,1%, 2,4%, 4,3% and 8,1% of measurements, respectively. No hypocalcemia or vitamin B6 deficiency was found.

CONCLUSION

The prevalence of deficiency varies amongst nutrients in children following a GFD, a high prevalence of some nutrient deficiencies is noteworthy. This study highlights the necessity to structurally investigate the risk of developing nutrient deficiencies while following a GFD. Knowledge of the risk to develop deficiencies can contribute to achieving a more evidence based approach in the management and follow-up of CD in children.

Hematology reference intervals in 6-12-year-old children: the health-oriented pedagogical project (HOPP)

Reference intervals are essential for correct interpretation of laboratory test results, supporting clinicians in distinguishing between healthy and sick individuals. The present study aims to establish pediatric reference intervals for hematological parameters based on a large population of healthy schoolchildren. Blood samples were obtained from 1351 children 6-12 years of age participating in the Health-Oriented Pedagogical Project (HOPP). Reference intervals for hematological parameters were estimated by the nonparametric method following the CLSI C28-A3 guidelines. Reference intervals were estimated as 2.5th and 97.5th percentiles with corresponding 90% confidence intervals. While hematocrit and MCV required age and sex partitioning, hemoglobin and erythrocytes were partitioned for age. The remaining parameters, MCH, MCHC, platelets and white blood cell counts did not require partitioning. While red blood cell parameters exhibited an increasing trend with age, there was a slight decrease in leukocytes, lymphocytes, basophils and platelets with age. The remaining parameters were stable across our age span.

Age-specific reference values for the 5th generation cardiac troponin T assay in Chinese children

ABSTRACT

The clinical use of the cardiac troponin T (cTnT) assay was limited to the adult population in the diagnosis and prognosis of myocardial injury. However, emerging studies indicated its significant value in the assessment of pediatric cardiology, and it has been routinely measured in most hospitals. Our study investigated the normative values of cTnT in Chinese children and reported the age-specific 99th percentile cut-off for them.A total of 1280 apparently healthy Chinese children were enrolled in our study. Serum levels of cTnT were analyzed on the Roche Elecsys Troponin T Gen 5 STAT assay. According to the Clinical and Laboratory Standards Institute C28-A3 guideline, the 99th percentile upper reference limits (URLs) with 90% confidence intervals (CIs) were calculated in different age subgroups.The 99th percentile URL was 38 (90%CI: 37.0-51.0) ng/L for 1 to <4months old, 26 (90%CI: 25.2-28.5) ng/L for 4 to ≤ 12months old, and 12 (90%CI: 11.1-12.9) ng/L for 1 to 18 years old, respectively. For subjects aged from 1 to 18years, boys had slightly higher cTnT levels than girls (P = .003), while our assay could not measure low cTnT concentrations (≥the limit of detection) in 50% girls.Our study provided age-specific URLs of cTnT for Chinese children, with the 5th generation cTnT assay from Roche Diagnostics. It had significant clinical implications in the interpretation and use of test results for pediatric cardiology.