Laboratory reference intervals in the assessment of iron status in young children

Pediatric reference intervals for hematology parameters in healthy infants and young children in Iran

INTRODUCTION

Defining accurate age- and sex-specific reference intervals (RIs) for hematology parameters, especially for the pediatric population, is important for making an appropriate clinical diagnosis. To address gaps, we established age-specific RIs for 11 hematologic parameters in Iranian children younger than 30 months for the first time.

METHODS

Fresh whole blood samples collected from a total of 344 participants (males: 158 and females: 186) ages 3 days to 30 months, with a mean age of 12.91 ± 7.15 months, were recruited from healthcare centers in Mashhad, Iran. Hematologic parameters, including complete blood count (CBC), were analyzed on the Sysmex auto-analyzer system (KX-21 N). RIs were calculated with 90% confidence intervals using the direct method based on CLSI Ep28-A3 and C28-A3 guidelines.

RESULTS

None of the CBC parameters required sex partitioning. Of 11 CBC parameters, six required age partitions of 3 days-<4 months, 4-<10, 10-<15, and 4-<30 months. Five parameters (i.e., white blood cell count, mean corpuscular hemoglobin concentration, mean platelet volume, red cell distribution width, and platelet distribution width) did not demonstrate age-specific changes. RIs of red blood cell count and hematocrit, as well as hemoglobin, increased with age, while mean corpuscular volume, mean corpuscular hemoglobin, and platelet count, decreased with age.

CONCLUSION

In this study, we established RIs for 11 hematology parameters in young children. Age partitioning was required for six parameters demonstrating marked changes during the early period of growth and development and necessitating the use of pediatric-specific reference standards.

Adherence to ECCO Guidelines for Management of Iron Deficiency and Anemia in Inflammatory Bowel Diseases Among Israeli Adult and Pediatric Gastroenterologists

OBJECTIVES

The consensus guidelines of the European Crohn's and Colitis Organization (ECCO) for the diagnosis and treatment of iron deficiency anemia (IDA) were published in 2015. We examined the management practices of both adult gastroenterologists (AGs) and pediatric gastroenterologists (PGs) in Israel in treating ID among patients with inflammatory bowel disease (IBD).

METHODS

An 18-question multiple-choice anonymous questionnaire was electronically delivered to AGs and PGs. Questions explored 3 areas of interest: physician demographics, adherence to ECCO guidelines, and management practices of IDA in patients with IBD.

RESULTS

Completed questionnaires were returned by 72 AGs and 89 PGs. Practice setting and years of practice were similar. A large majority of AGs and PGs (89% and 92%, respectively) measure complete blood count (CBC) and serum ferritin (S-Fr) at least every 3 months in outpatients with active IBD, as recommended by the ECCO guidelines. In contrast, in IBD patients in remission, only 53% and 26% of AGs and PGs, respectively ( P < 0.001), reported adherence to ECCO guidelines, measuring CBC and S-Fr every 6 months. The ECCO treatment guidelines recommend that intravenous (IV) iron should be considered the first-line treatment in patients with clinically active IBD, with previous oral iron intolerance and those with a hemoglobin level <10 g/dL. Study results indicate that only 43% of AGs recommend IV iron for these indications, compared to 54% of PGs ( P > 0.1).

CONCLUSIONS

In this study we have demonstrated a relatively low level of adherence to ECCO guideline recommendations among both AGs and PGs, regarding the management of IDA in patients with IBD.

Paediatric reference intervals and curves for haemoglobin and ferritin: protocol for a systematic review and meta-analysis

INTRODUCTION

Reference intervals and reference curves provide clinicians with a point of reference when evaluating patients' laboratory test results. In practical applications, the 2.5th and 97.5th percentiles of healthy reference population are typically used as lower and upper reference limits. Guidelines outlining analytical and methodological steps involved in reference intervals and curves estimation are available and there have been large-scale world-wide initiatives to provide reference intervals and curves for children. However, there is a lack of synthesised evidence regarding the results of such initiatives in general, but specifically in iron-related biomarkers, ferritin (in serum and plasma) and haemoglobin. Objectives of this review are to identify studies that have produced reference intervals and curves for ferritin and haemoglobin in paediatric populations and to synthesise all available evidence. We also aim to quantify heterogeneity across reference intervals and curves and identify and elucidate sources of heterogeneity, including heterogeneity in the methods employed in their development.

METHODS AND ANALYSIS

Using a comprehensive search strategy, we will identify eligible studies. Following electronic databases will be searched from inception: EMBASE, MEDLINE, SCOPUS and The Cochrane Library. We will also perform grey literature search to capture unpublished reference intervals and curves from healthy cohorts. Two researchers will independently screen retrieved citations against eligibility criteria in two stages, focusing first on titles and abstracts and then on full-text articles. Studies that provide reference intervals and curves for ferritin and haemoglobin for paediatric population will be eligible. Data extraction will include study characteristics, characteristics of reference population, methodological and analytical considerations and estimated reference intervals and curves. We will consider narrative synthesis and quantitative synthesis when appropriate.

ETHICS AND DISSEMINATION

Ethical approval is not required as data from already published studies will be used. Results will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42023399802.

Ferric Carboxymaltose Versus Ferrous Fumarate in Anemic Children with Inflammatory Bowel Disease: The POPEYE Randomized Controlled Clinical Trial

OBJECTIVE

To determine whether intravenous (IV) or oral iron suppletion is superior in improving physical fitness in anemic children with inflammatory bowel disease (IBD).

STUDY DESIGN

We conducted a clinical trial at 11 centers. Children aged 8-18 with IBD and anemia (defined as hemoglobin [Hb] z-score < -2) were randomly assigned to a single IV dose of ferric carboxymaltose or 12 weeks of oral ferrous fumarate. Primary end point was the change in 6-minute walking distance (6MWD) from baseline, expressed as z-score. Secondary outcome was a change in Hb z-score from baseline.

RESULTS

We randomized 64 patients (33 IV iron and 31 oral iron) and followed them for 6 months. One month after the start of iron therapy, the 6MWD z-score of patients in the IV group had increased by 0.71 compared with -0.11 in the oral group (P = .01). At 3- and 6-month follow-ups, no significant differences in 6MWD z-scores were observed. Hb z-scores gradually increased in both groups and the rate of increase was not different between groups at 1, 3, and 6 months after initiation of iron therapy (overall P = .97).

CONCLUSION

In this trial involving anemic children with IBD, a single dose of IV ferric carboxymaltose was superior to oral ferrous fumarate with respect to quick improvement of physical fitness. At 3 and 6 months after initiation of therapy, no differences were discovered between oral and IV therapies. The increase of Hb over time was comparable in both treatment groups.

TRIAL REGISTRATION

NTR4487 [Netherlands Trial Registry].

Serum Ferritin Threshold for Iron Deficiency Screening in One-Year-Old Children

The American Academy of Pediatrics recommends universal hemoglobin screening for iron deficiency anemia using hemoglobin <110 g/L at the 1-year-old well child visit. Our retrospective study suggests the need for combined hemoglobin and serum ferritin iron deficiency screening and raising the diagnostic serum ferritin threshold to 24-25 μg/L.

Establishing normal ranges for fetal and neonatal small and large intestinal lengths: results from a prospective postmortem study

Objective

To establish reference intervals (RIs) for fetal and neonatal small and large intestinal lengths.

Methods

Linear measurements on small and large intestines were made upon postmortem examination of 131 preterm and term infants with gestational ages between 13 and 41 weeks. All cases were referred from the Eastern Ontario and Western Québec regions to a tertiary care hospital. Age and sex partitions were considered and RI limits were estimated.

Results

Data consisted of 72 male (54.96%) and 59 female (45.04%) fetuses and neonates with mean gestational age of 25.6 weeks. Results showed that small and large intestinal lengths increased linearly with gestational age. RIs for small intestinal length (cm) of fetuses and neonates aged 13–20 weeks were (21.1, 122.4); of those aged 21–28 weeks were (57.7, 203.8); of those aged 29–36 weeks were (83.6, 337.1); and of those aged 37–41 weeks were (132.8, 406.4). RIs for large intestinal length (cm) of fetuses and neonates from the same four age groups were (5.1, 21.4), (12.7, 39.7), (32.4, 62.4), and (29.1, 82.2).

Conclusions

Establishing accurate RIs for premature and term infants has clinical relevance for pathologists performing postmortem analysis and for surgeons planning postoperative management of patients. The results of this study reaffirm that fetal small and large intestinal lengths increase linearly with gestational age irrespective of sex. Future studies should aim to further investigate the role of possible confounders on growth of fetal intestinal length, including maternal factors such as age and substance use during pregnancy.

Resolution of iron deficiency following successful eradication of Helicobacter pylori in children

AIM

To assess correlation between successful Helicobacter pylori (HP) eradication and resolution of iron deficiency in children, without iron supplementation.

METHODS

Medical records of children diagnosed with HP infection based on endoscopy were retrospectively reviewed. Among those with non-anaemic iron deficiency (NAID) or iron deficiency anaemia (IDA), haemoglobin, ferritin and CRP levels were compared prior and 6-9 months' post-successful HP eradication. Predictors of resolution of iron deficiency following HP eradication were assessed.

RESULTS

Among 60 included children (median age 14.8, IQR12.3-16 years; 62% males), 35% had IDA while the remaining 65% had NAID. Following successful HP eradication, iron normalised in 60% of patients with iron deficiency (ID), without iron supplementation. There were significant improvements in haemoglobin and ferritin concentrations following HP eradication with haemoglobin increasing from 12.3 g/dL to 13.0 g/dL and ferritin increasing from 6.3 μg/L to 15.1 μg/L (p < 0.001). In multiple logistic regression, older age was the only factor associated with resolution of anaemia following HP eradication (OR 1.65, 95% CI 1.16-2.35, p = 0.005).

CONCLUSION

Successful HP eradication could be helpful in improving iron status among children with refractory NAID or IDA. Older age may predict this outcome. Screening for HP might be considered in the workup of refractory IDA or ID.

Iron status in early childhood is modified by diet, sex and growth: Secondary analysis of a randomized controlled vitamin D trial

BACKGROUND & AIMS

During early childhood the risk of iron deficiency (ID) is high. Serum ferritin serves as a marker of iron status. We explored prevalence of ID and iron deficiency anemia (IDA), and identified determinants of iron status in infants and toddlers.

METHODS

We performed a secondary analysis of the Vitamin D intervention in infants (VIDI) study in Finnish healthy term infants. According to study protocol, at 12- and 24-months of age iron status, growth and dietary intakes were evaluated. ID was defined as serum ferritin <10 μg/L and IDA as serum ferritin <10 μg/L and Hb <112 g/L. For the present study, altogether 766 children provided data (N = 498 infants at 12 months, N = 508 toddlers at 24 months).

RESULTS

ID prevalence increased from 14% in infants to 20% in toddlers. IDA prevalence was 3% at both time points. In infants, ID and IDA were more common in boys than in girls (19% vs. 9%, p = 0.001 and 5% vs. 1%, p = 0.039) but no sex-difference in toddlers was observed. Of infants, 30% had daily iron intake below average requirement of 5 mg/day. Higher daily iron intake per body weight (mg/kg) independently associated with higher infant serum ferritin (B (95% CI) 0.30 (0.04, 0.56), p = 0.026). Correlation between iron intake and ferritin was stronger in infants with ID than in infants without ID. Breastfeeding was more common (63% vs. 35%, p < 0.001) among ID infants than in infants without ID. In toddlers, frequent consumption of milk products independently associated with lower ferritin (B (95% CI) -0.03 (-0.05, -0.01), p = 0.001). Consumption of meat and fish associated with better iron status. Serum ferritin at both time points associated with duration of gestation and growth. The association of growth and ferritin was age-dependent in boys, while in girls, faster growth associated consistently with lower ferritin.

CONCLUSIONS

In Northern European healthy infants and toddlers ID is common. The intake of iron remains below recommendations and food consumption and iron intake associate with iron status. Further studies are warranted to assess significance of ID on child development and clinical health outcomes. The project protocol is registered at ClinicalTrials.gov: NCT01723852.

Cut-off points for serum ferritin to identify low iron stores during the first year of life in a cohort of Mexican infants

The aim of this study was to identify serum ferritin (SF) cut‐off points (COPs) in a cohort of healthy full‐term normal birth weight infants who had repeated measurements of SF and haemoglobin every 3 months during the first year of life. The study included 746 full‐term infants with birth weight ≥2,500 g, having uncomplicated gestations and births. Participants received prophylactic iron supplementation (1 mg/day of iron element) from the first to the 12th month of life and did not develop anaemia during the first year of life.

Two statistical methods were considered to identify COPs for low iron stores at 3, 6, 9 and 12 months of age: deviation from mean and cluster analysis. According to the K‐means cluster analysis results by age and sex, COPs at 3 and 6 months for girls were 39 and 21 μg/L and for boys 23 and 11 μg/L, respectively. A single COP of 10 μg/L was identified, for girls and boys, at both 9 and 12 months. Given the physiological changes in SF concentration during the first year of life, our study identified dynamic COPs, which differed by sex in the first semester. Adequate SF COPs are necessary to identify low iron stores at an early stage of iron deficiency, which represents one of the most widespread public health problems around the world, particularly in low‐ and middle‐income countries.

Reference intervals for hemoglobin and mean corpuscular volume in an ethnically diverse community sample of Canadian children 2 to 36 months

Objective

To establish reference intervals for hemoglobin and mean corpuscular volume (MCV) in an ethnically diverse community sample of Canadian children 36 months and younger.

Methods

We collected blood samples from young children at scheduled primary care health supervision visits at 2 weeks, 2, 4, 6, 9, 12, 15, 18, 24, and 36 months of age. Samples were analyzed on the Sysmex XN-9000 Hematology Analyzer. We followed the Clinical and Laboratory Standards Institute guidelines in our analysis. Data were partitioned by sex and also combined. We considered large age partitions (3 and 6 months) as well as monthly partitions. Reference intervals (lower and upper limits) and 90% confidence intervals were calculated.

Results

Data from 2106 children were included. The age range was 2 weeks to 36 months, 46% were female, 48% were European and 23% were of mixed ethnicity. For hemoglobin, from 2 to 36 months of age, we found a wide reference interval and the 90% confidence intervals indicated little difference across age groups or according to sex. For MCV, from 2 to 7 months of age there was considerable decrease in the reference interval, which was lowest during the second year of life, followed by a slight increase in the last months of the third year of life.

Conclusion

These findings suggest adoption of a single hemoglobin reference interval for children 2–36 months of age. Further studies in children under 4 months of age are needed.

Trial registration

TARGet Kids! cohort is registered at ClinicalTrials.gov. www.clinicaltrials.gov. Identifier: NCT01869530.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02709-w.

Functional reference limits: a case study of serum ferritin

Reference intervals depend on the distribution of results within a reference population and can be influenced by subclinical disease. Functional reference limits present an opportunity to derive clinically relevant reference limits from routinely collected data sources, which consist of mixed populations of unhealthy and healthy groups. Serum ferritin is a good example of the utility of functional reference limits. Several studies have identified clinically relevant reference limits through examining the relationship between serum ferritin and erythrocyte parameters. These ferritin functional limits often represent the inflection point at which erythrocyte parameters change significantly. Comparison of ferritin functional reference limits with those based on population distributional reference limits reveals that the lower reference limit may fall below the point at which patients become clinically unwell. Functional reference limits may be considered for any biomarker that exhibits a correlated relationship with other biomarkers.

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)

Appropriate reference intervals are important for correct interpretation of laboratory test results. The primary objective of the present study was to establish pediatric reference intervals for biochemical markers essential in the assessment of iron status. As a secondary objective we calculated the prevalence of iron deficiency according to WHO recommendations. Blood samples were obtained from 1355 healthy children 6-12 years of age participating in the Health Oriented Pedagogical Project (HOPP). For our primary objective, data from 1333 children were used to establish reference intervals for ferritin, iron, transferrin and transferrin saturation. Following the CLSI C28-A3 guidelines, the 2.5^th and 97.5^th percentiles with corresponding 90% confidence intervals, were estimated by the nonparametric method. None of the measured analytes required partitioning for age or sex. The prevalence of iron deficiency was 8.2%, which is higher than reported in other populations.

Intravenous ferric carboxymaltose for iron deficiency anemia or iron deficiency without anemia after poor response to oral iron treatment: Benefits and risks in a cohort of 144 children and adolescents

OBJECTIVE

The objective of this single-center observational study was to determine the clinical and hematologic responses to intravenous ferric carboxymaltose (FCM) in a cohort of pediatric patients with poor response to oral iron therapy. The occurrence of adverse events was systematically recorded for up to 96 hours after infusion.

STUDY DESIGN

A retrospective cohort of 144 consecutive patients aged 18 months to < 18 years with iron deficiency anemia (IDA) or iron deficiency (ID) without anemia was investigated. All patients had failed oral iron therapy. The assessments before and after FCM treatment followed a predefined protocol.

RESULTS

One hundred of 117 (85 %) of patients with complete data achieved the target ferritin level ≥ 30 µg/L after a single FCM dose. Of 77 patients with IDA and complete data, 38 (49%) showed a complete hematological response within 6-12 weeks; a complete or partial response was achieved by 83%. Clinical symptoms improved in 85% of all patients. In 92% of patients (n = 133 /144), FCM infusion was uneventful. During the 96-hour follow-up, five patients reported potentially related symptoms. No serious adverse events occurred.

CONCLUSION

The study confirms the safety and efficacy of FCM in children (aged 18 months and older) and adolescents unresponsive to oral therapy, in real-world experience. Single-dose FCM treatment was followed by clinical improvement with advantages of safety, compliance, and lower cost compared with previous generation parenteral iron preparations that had to be administered in fractionated sessions.

Anemia in Children With Inflammatory Bowel Disease: A Position Paper by the IBD Committee of the North American Society of Pediatric Gastroenterology, Hepatology and Nutrition

Anemia is one of the most common extraintestinal manifestations of inflammatory bowel disease (IBD). It can be asymptomatic or associated with nonspecific symptoms, such as irritability, headaches, fatigue, dizziness, and anorexia. In IBD patients, the etiology of anemia is often multifactorial. Various causes include iron deficiency, anemia of inflammation and chronic disease, vitamin deficiencies, hemolysis, or myelosuppressive effect of drugs. Anemia and iron deficiency in these patients may be underestimated because of their insidious onset, lack of standardized screening practices, and possibly underappreciation that treatment of anemia is also required when treating IBD. Practitioners may hesitate to use oral preparations because of their intolerance whereas intravenous preparations are underutilized because of fear of adverse events, availability, and cost. Several publications in recent years have documented the safety and comparative efficacy of various intravenous preparations. This article reviews management of anemia in children with IBD, including diagnosis, etiopathogenesis, evaluation of a patient, protocol to screen and monitor patients for early detection and response to therapy, treatment including parenteral iron therapy, and newer approaches in management of anemia of chronic disease. This report has been compiled by a group of pediatric gastroenterologists serving on the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) IBD committee, in collaboration with a pediatric hematologist, pharmacist, and a registered dietician who specializes in pediatric IBD (IBD Anemia Working Group), after an extensive review of the current literature. The purpose of this review is to raise awareness of under-diagnosis of anemia in children with IBD and make recommendations for screening, testing, and treatment in this population.

Association of Family Income and Risk of Food Insecurity With Iron Status in Young Children

IMPORTANCE

Iron deficiency (ID) has the greatest prevalence in early childhood and has been associated with poor developmental outcomes. Previous research examining associations of income and food insecurity (FI) with ID is inconsistent.

OBJECTIVE

To examine the association of family income and family risk of FI with iron status in healthy young children attending primary care.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study included 1245 children aged 12 to 29 months who attended scheduled primary care supervision visits from 2008 to 2018 in Toronto, Canada, and the surrounding area.

EXPOSURES

Family income and risk of FI were collected from parent-reported questionnaires. Children whose parents provided an affirmative response to the 1-item FI screen on the Nutrition Screening Tool for Every Toddler or at least 1 item on the 2-item Hunger Vital Sign FI screening tool were categorized as having family risk of FI.

MAIN OUTCOMES AND MEASURES

Iron deficiency (serum ferritin level <12 ng/mL) and ID anemia (IDA; serum ferritin level <12 ng/mL and hemoglobin level <11.0 g/dL). All models were adjusted for age, sex, birth weight, body mass index z score, C-reactive protein level, maternal education, breastfeeding duration, bottle use, cow's milk intake, and formula feeding in the first year.

RESULTS

Of 1245 children (595 [47.8%] girls; median [interquartile range] age, 18.1 [13.3-24.0] months), 131 (10.5%) were from households with a family income of less than CAD $40 000 ($29 534), 77 (6.2%) were from families at risk of FI, 185 (14.9%) had ID, and 58 (5.3%) had IDA. The odds of children with a family income of less than CAD $40 000 having ID and IDA were 3 times higher than those of children in the highest family income group (ID: odds ratio [OR], 3.08; 95% CI, 1.66-5.72; P < .001; IDA: OR, 3.28; 95% CI, 1.22-8.87; P = .02). Being in a family at risk of FI, compared with all other children, was not associated with ID or IDA (ID: OR, 0.43; 95% CI, 0.18-1.02; P = .06; IDA: OR, 0.16; 95% CI, 0.02-1.23; P = .08).

CONCLUSIONS AND RELEVANCE

In this study, low family income was associated with increased risk of ID and IDA in young children. Risk of FI was not a risk factor for ID or IDA. These findings suggest that targeting income security may be more effective than targeting access to food to reduce health inequities in the prevention of iron deficiency.

Maternal ethnicity and iron status in early childhood in Toronto, Canada: a cross-sectional study

OBJECTIVES

This study aimed to evaluate the association between maternal ethnicity and iron deficiency (ID) in early childhood, and to evaluate whether infant feeding practices linked to ID differ between maternal ethnic groups.

METHODS

This was a cross-sectional study of healthy children 1-3 years of age. Adjusted multivariable logistic regression analyses were used to evaluate the association between maternal ethnicity and ID (serum ferritin <12 µg/L) and the association between maternal ethnicity and five infant feeding practices (breastfeeding duration; bottle use beyond 15 months; current formula use; daily cow's milk intake >2 cups; meat consumption).

RESULTS

Of 1851 children included, 12.2% had ID. Compared with the European referent group, we found higher odds of ID among children of South Asian and West Asian/North African maternal ethnicities, and lower odds of ID among children of East Asian maternal ethnicity. Statistically significant covariates associated with higher odds of ID included longer breastfeeding duration and daily cow's milk intake >2 cups. Current infant formula use was associated with lower odds of ID. Children of South Asian maternal ethnicity had higher odds of bottle use beyond 15 months of age and lower odds of meat consumption.

CONCLUSIONS

We found increased odds of ID among children of South Asian and West Asian/Northern African maternal ethnicities. We found a higher odds of feeding practices linked to ID in children of South Asian maternal ethnicity, but not in children of West Asian/North African maternal ethnicity. Culturally tailored approaches to providing guidance to parents on healthy infant feeding practices may be important to prevent ID in early childhood.

TRIAL REGISTRATION NUMBER

NCT01869530.

How to use… iron studies

Iron studies are frequently requested in paediatric practice. They are useful both as a diagnostic tool and as a way of monitoring certain conditions, particularly those causing iron overload. This article outlines the physiology of iron metabolism and discusses laboratory aspects of performing iron studies, including factors influencing interpretation. Clinical scenarios are used to highlight how the tests can be used in different clinical situations.

Establishing a Pediatric Acute-Onset Neuropsychiatric Syndrome Clinic: Baseline Clinical Features of the Pediatric Acute-Onset Neuropsychiatric Syndrome Cohort at Karolinska Institutet

Objectives: Pediatric acute-onset neuropsychiatric syndrome (PANS) is a descriptive clinical entity defined by the abrupt onset of psychiatric and somatic symptoms leading to significant loss of function. Data on well-characterized PANS patients are limited, biomarkers have yet to be identified, and a solid evidence base to guide treatment is lacking. In this study, we present our experience of a systematic evaluation of the first 45 patients included in a Swedish cohort. Methods: During the period 2014-2018, our clinic received 100 referrals regarding suspected PANS. All patients underwent a standardized psychiatric/medical evaluation by a child/adolescent psychiatrist and a clinical psychologist or a nurse. Those with severe symptoms were also assessed by a pediatric neurologist and a pediatric rheumatologist. Laboratory tests were obtained at different time points in an attempt to capture an active disease state. Results: Of the 100 referrals, 45 met strict PANS criteria and consented to participate in a long-term follow-up study. The median age at intake was 7.2 years (range 3.0-13.1) and 56% were male. Ninety-three percent fulfilled both criteria for acute/atypical onset of PANS symptoms and having had an infection in relation to onset. Sixteen percent had an onset of an autoimmune or inflammatory disorder in temporal relation to the onset of PANS-related symptoms. The most common onset symptoms were obsessive-compulsive disorder (89%), anxiety (78%), and emotional lability (71%). Twenty-four percent had a preexisting autoimmune disease (AD) and 18% a preexisting psychiatric/neuropsychiatric diagnosis. Sixty-four percent of biological relatives had at least one psychiatric disorder and 76% at least one AD or inflammatory disorder. Complement activation (37%), leukopenia (20%), positive antinuclear antibodies (17%), and elevated thyroid antibodies (11%) were the most common laboratory findings. Conclusions: In our PANS cohort, there was a strong indication of an association with AD. Further work is needed to establish whether any of the potential biomarkers identified will be clinically useful. Long-term follow-up of these patients using the Swedish national registers will enable a deeper understanding of the course of this patient group.

Higher Body Mass Index Is Associated with Iron Deficiency in Children 1 to 3 Years of Age

OBJECTIVES

To examine the association between body mass index (BMI) and iron deficiency in early childhood, while considering the influence of low-grade systemic inflammation.

STUDY DESIGN

Healthy children ages 1-3 years were included in a cross-sectional analysis. Age- and sex-standardized World Health Organization BMI z score (zBMI) was calculated using height/length and weight measurements; iron status was assessed by serum ferritin; inflammation was assessed by C-reactive protein (CRP). Children with CRP ≥10 mg/L were excluded because this may indicate acute systemic inflammation. Adjusted multivariable regression analyses were used to investigate the association between zBMI and both serum ferritin (µg/L), and iron deficiency (serum ferritin <12 µg/L). We performed prespecified subgroup analyses according to CRP level (normal [≤1.0 mg/L] and low-grade inflammation [>1.0 mg/L to <10.0 mg/L]).

RESULTS

Of 1607 children included, 20% were categorized as with zBMI >1, 13% had iron deficiency, and 18% had low-grade inflammation. Higher zBMI was associated with lower serum ferritin (-1.51 µg/L, 95% CI -2.23, -0.76, P < .0001) and increased odds of iron deficiency (OR 1.28, 95% CI 1.10, 1.50, P = .002). Though there was no interaction between zBMI and CRP for the adjusted linear regression model (P = .79) or logistic regression model (P = .43), children with low-grade inflammation had a higher serum ferritin (P < .0001).

CONCLUSIONS

Higher zBMI is associated with increased risk for iron deficiency in children between 1 and 3 years, and should be considered as a risk factor in targeted screening. Further research is needed to better understand the relationship between serum ferritin and CRP for children in all weight categories.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01869530.

Screening for Iron Deficiency in Early Childhood Using Serum Ferritin in the Primary Care Setting

OBJECTIVES

The American Academy of Pediatrics recommends universal screening for anemia using hemoglobin at 12 months. However, hemoglobin lacks diagnostic accuracy for iron deficiency, and the optimal age for screening has not been determined. Our objective was to assess a screening strategy for iron deficiency using serum ferritin.

METHODS

We conducted a cross-sectional study of children 1 to 3 years old attending a health supervision visit. We examined the relationship between child age and serum ferritin, age and hemoglobin, hemoglobin and serum ferritin, and the prevalence of elevated C-reactive protein (CRP).

RESULTS

Restricted cubic spline analysis (n = 1735) revealed a nonlinear relationship between age and serum ferritin (P < .0001). A linear spline model revealed that from 12 to 15 months, for each 1-month increase in age, serum ferritin levels decreased by 9% (95% confidence interval [CI]: 5 to 13). From 15 to 24 months, the rate of change was nonsignificant. From 24 to 38 months, for each month increase in age, serum ferritin increased by 2% (95% CI: 1 to 2). For hemoglobin, from 12 to 24 months, the rate of change was nonsignificant. From 24 to 38 months, for each 1-month increase in age, hemoglobin increased by 20% (95% CI: 9 to 32). Compared with the serum ferritin cutoff of <12 μg/L, the hemoglobin cutoff of <110 g/L had a sensitivity of 25% (95% CI: 19 to 32) and a specificity of 89% (95% CI: 87 to 91). Elevated CRP ≥10 mg/L occurred in 3.3% (95% CI: 2.5 to 4.2).

CONCLUSIONS

Screening for iron deficiency using serum ferritin at 15 or 18 months may be a promising strategy. For children at low risk for acute inflammation, concurrent measurement of CRP may not be necessary.