Prematurity at birth reduces the long-term risk of atopy

Indications for extensively hydrolyzed cow's milk protein in the neonatal period

A large proportion of prescriptions for extensively hydrolyzed cow's milk protein (CMP) in newborns are not based on any scientific data justifying the indication. Many of these prescriptions are old habits or are based on incomplete data. The aim of this article is to analyze these practices and propose recommendations. The following points are covered: (a) indications for extensively hydrolyzed formula based on studies demonstrating their benefits in these situations-newborns with a proven allergy to CMP and occasional prescription of supplements to breastfeeding; (b) possible indications not based on a high level of evidence-re-initiation of feeding due to necrotizing enterocolitis, short bowel syndrome, re-initiation of feeding of newborns following intestinal surgery, and laparoschisis if neither the mother's own milk nor milk from a lactarium is available; (c) unjustified indications-newborns at risk of atopy, prematurity, severe neurological pathologies, newborns who are hemodynamically unstable and/or have congenital cardiopathy, neonatal hypoxic-ischemic encephalopathy treated with hypothermia, and newborns with esophageal atresia or diaphragmatic hernia. By following this classification, the prescriber will be guided to use the milk best suited to the pathology, bearing in mind that each situation must be adapted individually and the tolerance and effectiveness of the food reassessed from a nutritional and functional point of view.

Preterm birth reduces the risk of IgE sensitization up to early adulthood: A population-based birth cohort study

BACKGROUND

Immunoglobulin E (IgE) sensitization is associated with asthma and allergic diseases. Gestational age influences early immune system development, thereby potentially affecting the process of tolerance induction to allergens.

OBJECTIVE

To study IgE sensitization to common allergens by gestational age from childhood up to early adulthood.

METHODS

Population-based birth cohort, data from the Swedish BAMSE study were used. Allergen-specific IgE antibodies to a mix of common food (fx5) and inhalant (Phadiatop) allergens were analysed at 4, 8, 16 and 24 years. Sensitization was defined as allergen-specific IgE ≥0.35 kU_A /L to fx5 and/or Phadiatop at each time point. Using logistic regression and generalized estimated equations, adjusted odds ratios (aORs) for sensitization in relation to gestational age were calculated. Replication was sought within the Swedish twin study STOPPA.

RESULTS

In BAMSE, 3522 participants were screened for IgE antibodies during follow-up; of these, 197 (5.6%) were born preterm (<37 gestational weeks) and 330 (9.4%) post-term (≥42 weeks). Preterm birth reduced the risk of sensitization to common food and/or inhalant allergens up to early adulthood by 29% (overall aOR = 0.71; 95% CI: 0.52-0.98), and to food allergens specifically by 40% (overall aOR = 0.60; 95% CI: 0.38-0.93). No relation was found between post-term birth and IgE sensitization at any time point. Replication analyses in STOPPA (N = 675) showed similar risk estimates for sensitization to food and/or inhalant allergens (aOR = 0.72; 95% CI: 0.42-1.21), which resulted in a combined meta-analysis aOR = 0.71 (95% CI: 0.54-0.94).

CONCLUSIONS

Our study suggests an inverse association between preterm birth and long-term IgE sensitization.

Atopic Manifestations in Children Born Preterm: A Long-Term Observational Study

(1) Background: Preterm birth exposes the infant to the known risk factors for atopic diseases. We aimed to study the neonatal risk factors and to describe the clinical manifestations of atopy, including the march of symptoms, in a cohort of preschool children born preterm. (2) Methods: We enrolled neonates with gestational age < 32 weeks or birth weight < 1500 g. We classified patients in cases and controls according to the presence of at least one atopic manifestation. (3) Results: We observed 72 cases and 93 controls. Multivariate models showed that the administration of more than one cycle of antibiotics (B 0.902, p = 0.026) and gestational diabetes (B 1.207, p = 0.035) influence the risk of atopy in babies born preterm. In addition, risk of atopic dermatitis was influenced by gestational age < 29 weeks (B -1.710, p = 0.025) and gestational diabetes (B 1.275, p = 0.027). The risk of wheeze was associated with familiarity for asthma (B 1.392, p = 0.022) and the administration of more than one cycle of antibiotics (B 0.969, p = 0.025). We observed a significant reduction in the rate of atopic manifestation after 2 years of life (33.9% vs. 23.8%, p < 0.05). (4) Conclusions: Modifiable (gestational diabetes, antibiotics use) and unmodifiable (familiarity for asthma) conditions influence the risk of atopy in babies born preterm. Extreme prematurity reduces the risk of atopic dermatitis. Preterm babies showed a peculiar atopic march.

Complementary Feeding: Recommendations for the Introduction of Allergenic Foods and Gluten in the Preterm Infant

Background: The aim of this systematic review is to analyze the available literature on the introduction of allergenic foods and gluten among preterm infants. Methods: A systematic review of published studies concerning the introduction of gluten and allergenic foods in preterm infants was performed on PubMed and on the Cochrane Library. Results: Of the 174 PubMed results, 15 papers were considered suitable for the review. A total of 83 records were identified through the Cochrane Library search; eight papers were included in the review. Additional papers were identified from the reference lists of included studies. A secondary search was conducted on the same databases to find recommendations and advice regarding healthy full-term infants that could be translated to preterm infants. Therefore, 59 additional papers were included in the review. Conclusions: Current guidelines for the introduction of solid food cannot be directly transposed to preterm infants. Further research is needed to provide evidence-based guidelines regarding weaning in preterm infants. To date, we can suggest that in preterm infants allergenic foods and gluten may be introduced when complementary feeding is started, any time after 4 months of corrected age, avoiding delayed introduction and irrespective of infants’ relative risk of developing allergy. Avoiding large amounts of gluten during the first few weeks after gluten introduction and during infancy is advised, despite limited evidence to support this recommendation.

Adverse pregnancy outcomes and risk of later allergic rhinitis-Nationwide Swedish cohort study

BACKGROUND

Perinatal conditions may be associated with future allergic disease; however, data are conflicting and incomplete for childhood allergic rhinitis (AR). The aim of this study was to examine pregnancy outcome (cesarean delivery, preterm birth, low birthweight) and offspring AR as defined by national registers.

METHODS

Nationwide longitudinal cohort study using prospectively recorded register data from 1 059 600 singleton livebirths born in Sweden in 2001-2012. Cox regression adjusted for infant sex and maternal factors (age at delivery, country of birth, parity, smoking, body mass index, and asthma/pulmonary disease) estimated hazard ratios (HRs) for AR during childhood.

RESULTS

During the study period 2001-2013, 22 386 (2.11%) children were diagnosed with AR. AR was more common in infants born through cesarean delivery (2.34%) than in those born vaginally (2.10%) (HR = 1.12; 95% confidence interval [95% CI] = 1.08-1.16). This was equivalent to one extra case of AR in 383 children followed up in our study. AR was also associated with moderately preterm birth (≥32-36 weeks of gestation: HR = 1.12, 95% CI = 1.04-1.20), large for gestational age (HR = 1.05, 95% CI = 1.01-1.10), and low (<7) 5-minute Apgar score (HR = 1.15, 95% CI = 1.02-1.30). Similar risk estimates were obtained when we restricted the outcome to ≥2 hospital-based records of AR. No association was observed between very preterm birth, post-term birth, low birthweight, or small for gestational age and AR.

CONCLUSION

Our study indicates an association between pregnancy outcomes and childhood AR, although observed effect sizes were generally modest.

Very Low Birth Weight Preterm Infants have Decreased Celiac Disease Autoimmunity During Childhood and Adolescence

Little is known about the effect of prematurity on later development of celiac disease (CD). We conducted a retrospective analysis of real-world data examining the association between very low birth weight (VLBW) prematurity and later development of CD autoimmunity (CDA) in 3580 infants born between years 2000 and 2012 and their matched controls. At a median of 12 years, VLBW prematurity was negatively associated with later development of CDA with a cumulative prevalence of 5.9 per 1000 versus 10.3 per 1000 (P = 0.02), though more former VLBW premature infants were ever tested for CDA (48.5% vs 37.4%, P < 0.001). The odds ratio for developing CDA among children born preterm at VLBW was 0.57 (95% confidence interval (CI) 0.35-0.92) as compared with matched controls. There was no difference in clinical characteristics of CDA between both groups. In conclusion, VLBW preterm infants present a decreased risk for the development of CDA during childhood and adolescence.

Pulmonary outcomes in adults with a history of Bronchopulmonary Dysplasia differ from patients with asthma

Background

Bronchopulmonary dysplasia (BPD) is a risk factor for respiratory disease in adulthood. Despite the differences in underlying pathology, patients with a history of BPD are often treated as asthmatics. We hypothesized that pulmonary outcomes and health-related quality of life (HRQoL) were different in adults born preterm with and without a history of BPD compared to asthmatics and healthy individuals.

Methods

We evaluated 96 young adults from the LUNAPRE cohort (clinicaltrials.gov/ct2/show/NCT02923648), including 26 individuals born preterm with a history of BPD (BPD), 23 born preterm without BPD (preterm), 23 asthmatics and 24 healthy controls. Extensive lung function testing and HRQoL were assessed.

Results

The BPD group had more severe airway obstruction compared to the preterm-, (FEV₁₋ 0.94 vs. 0.28 z-scores; p ≤ 0.001); asthmatic- (0.14 z-scores, p ≤ 0.01) and healthy groups (0.78 z-scores, p ≤ 0.001). Further, they had increased ventilation inhomogeneity compared to the preterm- (LCI 6.97 vs. 6.73, p ≤ 0.05), asthmatic- (6.75, p = 0.05) and healthy groups (6.50 p ≤ 0.001). Both preterm groups had lower D_LCO compared to healthy controls (p ≤ 0.001 for both). HRQoL showed less physical but more psychological symptoms in the BPD group compared to asthmatics.

Conclusions

Lung function impairment and HRQoL in adults with a history of BPD differed from that in asthmatics highlighting the need for objective assessment of lung health.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1075-1) contains supplementary material, which is available to authorized users.

Cesarean delivery, preterm birth, and risk of food allergy: Nationwide Swedish cohort study of more than 1 million children

BACKGROUND

Little is known about early-life risk factors for food allergy in children.

OBJECTIVES

We examined the association between perinatal characteristics and future risk of food allergy in offspring.

METHODS

This nationwide Swedish cohort study of 1,086,378 children born in Sweden in 2001-2012 used prospectively recorded data from health care registers. Using Cox regression, we estimated hazard ratios (HRs) with 95% CIs for the association between perinatal characteristics (eg, cesarean delivery and preterm birth) and food allergy as defined by diagnoses in the National Patient Register, adjusting for infant sex and maternal factors (age at delivery, country of birth, parity, smoking, body mass index, and asthma/pulmonary disease).

RESULTS

During the 13-year follow-up, 26,732 (2.5%) children were given a diagnosis of food allergy. Food allergy was positively associated with cesarean delivery (HR, 1.21; 95% CI, 1.18-1.25), large for gestational age (HR, 1.15; 95% CI, 1.10-1.19), and low 5-minute Apgar score (HR, 1.22; 95% CI, 1.10-1.36) but negatively associated with very preterm birth (<32 weeks of gestation: HR, 0.74; 95% CI, 0.56-0.98). No association was found between food allergy and moderately preterm birth, low birth weight, or small for gestational age. Risk estimates were similar when the outcome was restricted to 2 records of diagnosed food allergy. In 1,000 children undergoing cesarean delivery, an extra 5 developed food allergy compared with the reference group, suggesting that 17% of food allergy in children born by means of cesarean delivery can be explained by this exposure (attributable fraction).

CONCLUSIONS

Cesarean delivery was associated with increased risk of food allergy, whereas very preterm birth decreased risk.

Does the sex of the preterm baby affect respiratory outcomes?

Being born very preterm is associated with later deficits in lung function and an increased rate of respiratory symptoms compared with term-born children. The rates of early respiratory infections are higher in very preterm-born subjects, which may independently lead to deficits in lung function in later life. As with very preterm-born children, deficits in lung function, increased respiratory symptoms and an increased risk of respiratory infections in early life are observed in late -preterm-born children. However, the rates of respiratory symptoms are lower compared with very preterm-born children. There is some evidence to suggest that respiratory outcomes may be improving over time, although not all the evidence suggests improvements. Male sex appears to increase the risk for later adverse respiratory illness. Although not all studies report that males have worse long-term respiratory outcomes than females. It is essential that preterm-born infants are followed up into childhood and beyond, and that appropriate treatment for any lung function deficits and respiratory symptoms is prescribed if necessary. If these very preterm-born infants progress to develop chronic obstructive airway disease in later life then the impact, not only on the individuals, but also the economic impact on healthcare services, is immense.

Educational aims

To report the effect of the sex of the preterm baby on respiratory outcomes.To explore the short- and long-term respiratory outcomes of preterm birth.

Preterm Birth Affects the Risk of Developing Immune-Mediated Diseases

Prematurity affects approximately 10% of all children, resulting in drastically altered antigen exposure due to premature confrontation with microbes, nutritional antigens, and other environmental factors. During the last trimester of pregnancy, the fetal immune system adapts to tolerate maternal and self-antigens, while also preparing for postnatal immune defense by acquiring passive immunity from the mother. Since the perinatal period is regarded as the most important “window of opportunity” for imprinting metabolism and immunity, preterm birth may have long-term consequences for the development of immune-mediated diseases. Intriguingly, preterm neonates appear to develop bronchial asthma more frequently, but atopic dermatitis less frequently in comparison to term neonates. The longitudinal study of preterm neonates could offer important insights into the process of imprinting for immune-mediated diseases. On the one hand, preterm birth may interrupt influences of the intrauterine environment on the fetus that increase or decrease the risk of later immune disease (e.g., maternal antibodies and placenta-derived factors), whereas on the other hand, it may lead to the premature exposure to protective or harmful extrauterine factors such as microbiota and nutritional antigen. Solving this puzzle may help unravel new preventive and therapeutic approaches for immune diseases.

School-age children enjoyed good respiratory health and fewer allergies despite having lung disease after preterm birth

AIM

This study explored the under-researched area of whether preterm birth or bronchopulmonary dysplasia (BPD) affected hospitalisation rates, allergies or health-related quality of life (HRQoL).

METHODS

We studied 88 schoolchildren born preterm at a mean gestational age of 28.8 weeks (range 24.1-31.9) and matched term-born controls at the mean age of 11 years (range 8-14). Hospitalisations after the first discharge were recorded, skin prick allergy tests were performed and HRQoL was assessed with a parental questionnaire.

RESULTS

Preterm children were hospitalised more than controls (64% versus 39%, p = 0.001), mostly before two years of age. The adjusted odds ratios (OR) for two-year-old preterm-born children being hospitalised for wheezing was 8.2 (95% CI 2.0-34.1). BPD affected 56% of the preterm children, but did not influence hospitalisations, and the positive skin prick rate was similar between the preterm and term-born children (35% versus 48%, p = 0.126). Preterm BPD children had fewer positive skin prick tests than those without BPD. HRQoL was lower in preterm than term children (81.25 ± 10.84 versus 86.80 ± 9.60, p = 0.001).

CONCLUSION

Most health problems experienced by preterm-born schoolchildren occurred before two years of age and were mainly wheezing disorders. BPD decreased atopy but had no influence on hospitalisation rates.

In utero Programming of Allergic Susceptibility

BACKGROUND

Around 30-40% of the world's population will experience allergy, the most common and earliest-onset noncommunicable disease. With a steady rise in the incidence of allergic disease over recent decades, up to 18% of children will suffer a respiratory, food or skin allergy before their 18th birthday. There is compelling evidence that the risk of developing allergy is influenced by early life events and particularly in utero exposures.

METHODS

A comprehensive literature review was undertaken which outlines prenatal risk factors and potential mechanisms underlying the development of allergy in childhood.

RESULTS

Exposures including maternal cigarette smoking, preterm birth and Caesarean delivery are implicated in predisposing infants to the later development of allergy. In contrast, restricted growth in utero, a healthy maternal diet and a larger family size are protective, but the mechanisms here are unclear and require further investigation.

CONCLUSION

To ameliorate the allergy pandemic in young children, we must define prenatal mechanisms that alter the programming of the fetal immune system and also identify specific targets for antenatal interventions.

Which infants with eczema are at risk of food allergy? Results from a population-based cohort

BACKGROUND

The relationship between early onset eczema and food allergy among infants has never been examined in a population-based sample using the gold standard for diagnosis, oral food challenge.

OBJECTIVE

We characterised the risk of challenge-proven food allergy among infants with eczema in the general population.

METHODS

One-year-old infants (n = 4453 meeting criteria for this analysis) were assessed for history of eczema, received a nurse-administered eczema examination and underwent skin prick testing to peanut, egg and sesame. Those with a detectable wheal to one of the test foods underwent an oral food challenge irrespective of wheal size. The risk of food allergy, stratified by eczema severity and age of onset, was estimated using multivariate logistic regression with population sampling weights.

RESULTS

One in five infants with eczema were allergic to peanut, egg white or sesame, compared to one in twenty-five infants without eczema (OR 6.2, 95% CI 4.9, 7.9, P < 0.001). The prevalence of peanut allergy was low in the absence of eczema (0.7% 95% CI 0.4, 1.1). Infants with eczema were 11.0 times more likely to develop peanut allergy (95% CI 6.6, 18.6) and 5.8 times more likely to develop egg allergy (95% CI 4.6, 7.4) by 12 months than infants without eczema. 50.8% of infants (95% CI 42.8, 58.9) with early eczema onset (<3 months) who required doctor-prescribed topical corticosteroid treatment developed challenge-proven food allergy.

CONCLUSION AND CLINICAL RELEVANCE

Eczema, across the clinical severity spectrum in infancy, is a strong risk factor for IgE-mediated food allergy. Infants with eczema were six times more likely to have egg allergy and 11 times more likely to have peanut allergy by 12 months than infants without eczema. Our data suggest that a heightened awareness of food allergy risk among healthcare practitioners treating infants with eczema, especially if early onset and severe, is warranted.

What can reunification of East and West Germany tell us about the cause of the allergy epidemic?

The increase of allergies in East Germany--reaching West German prevalence shortly after the reunification--is considered a model for the allergy epidemic in the western world. Whether such a pattern was observed in all comparison studies and for all allergic manifestations is not known because a complete overview is missing. Hints about possible causal factors for the allergy epidemic could be gained by identifying known risk factors, which explain the observed pattern of allergy development in Germany. Again, an overview about these efforts is missing. We identified 14 cross-sectional studies conducted after 1989 and calculated prevalence ratios (West/East) for asthma, hayfever, eczema and allergic sensitization. Additionally, a tabular overview about the explanatory power of risk factors hypothesized in the nineties and covering outdoor exposure, indoor factors, early childhood influences, nutrition as well as awareness is given. At the time of the German reunification, the prevalence ratio West/East was largest for hayfever and sensitization to birch pollen, less pronounced for the other phenotypes and even less than one for atopic eczema. Hayfever and sensitization to birch pollen also showed the steepest increase in East Germany afterwards. Single-room heating with fossil fuels and living as only child in a family were identified as explaining up to 23.5% of the excess trend in East compared to the trend in West. Hayfever as most typical atopic disease showed the difference in allergy pattern between East and West Germany clearest. Risk factors identified for these phenotypes are completely different (single child) or even act in the opposite direction (single-room heating) from classical risk factors for airway diseases. This might be the most important lesson from the West/East German experience. It already stimulated many other studies focussing on protective factors such as microbial stimulation.

Prematurity, atopy, and childhood asthma in Puerto Ricans

BACKGROUND

Puerto Rican children share a disproportionate burden of prematurity and asthma in the United States. Little is known about prematurity and childhood asthma in Puerto Rican subjects.

OBJECTIVE

We sought to examine whether prematurity is associated with asthma in Puerto Rican children.

METHODS

We performed a case-control study of 678 children aged 6 to 14 years with (n = 351) and without (n = 327) asthma living in San Juan, Puerto Rico. Prematurity was defined by parental report for our primary analysis. In a secondary analysis, we only included children whose parents reported prematurity that required admission to the neonatal intensive care unit. Asthma was defined as physician-diagnosed asthma and wheeze in the prior year. We used logistic regression for analysis. All multivariate models were adjusted for age, sex, household income, atopy (≥1 positive IgE level to common allergens), maternal history of asthma, and early-life exposure to environmental tobacco smoke.

RESULTS

In a multivariate analysis there was a significant interaction between prematurity and atopy on asthma (P = .006). In an analysis stratified by atopy, prematurity was associated with a nearly 5-fold increased odds of asthma in atopic children (adjusted odds ratio, 4.7; 95% CI, 1.5-14.3; P = .007). In contrast, there was no significant association between prematurity and asthma in nonatopic children. Similar results were obtained in our analysis of prematurity requiring admission to the neonatal intensive care unit and asthma.

CONCLUSIONS

Our results suggest that atopy modifies the estimated effect of prematurity on asthma in Puerto Rican children. Prematurity might explain, in part, the high prevalence of atopic asthma in this ethnic group.

Food allergy among low birthweight children in a national survey

The aim of this paper was to investigate the association between birthweight and prevalence of food allergies using a national sample of US children. Adult report of birthweight and child food allergies were obtained for years 2005-2009 from the National Health Interview Survey (NHIS), a cross-sectional household survey of the US population. A total of 51,748 children aged 0-17 years were included in the analyses representing over 73 million children. Multivariable logistic regression analyses examined associations between birthweight categories and food allergies stratified by age and gender; accounting for the complex design of NHIS. Children aged 6-12 years who were born very low birthweight (500-1,499 g) were more likely to have reported food allergy compared to referent (3,000-3,499 g), OR = 1.72; 95% CI: 1.02-2.91. However, there was no clear trend of an association between birthweight and food allergy with increasing or decreasing birthweight across all ages. Estimates were generally stronger in younger male children as compared to estimates in females of the same age group. Marginal associations for respiratory allergy (OR = 1.52; 95% CI: 1.02-2.29) and hay fever (OR = 1.54; 95% CI: 0.93-2.54) were observed among very low birthweight children aged 0-5 years. There was limited evidence for a clear association between birthweight and food allergy. Marginal associations observed in children weighing 500-1,499 g at birth support efforts to minimize preterm births and very low birthweight given the increase in pediatric food allergies and the large number of children born low birthweight each year in the US.

The prevalence and risk factors of allergic and respiratory symptoms in a regional cohort of extremely low birth weight children (<1000 g)

BACKGROUND

Children who were <1000 g (ELBW extremely low birth weight) at birth more frequently present with wheezing which is the most common reason that pediatric consultation is sought. Therefore asthma is diagnosed very often. However is the asthma that is diagnosed in ELBW subjects atopic in origin, or is there a different etiology?

AIM

To determine if ELBW infants are at higher risk for the development of allergic and respiratory symptoms and to establish if there were any specific risk factors for these symptoms.

METHODS

81 children born with a mean birthweight of 845 g (91% of available cohort) were evaluated at the mean age 6.7 years. The control group included 40 full-term children. The children were examined for clinical signs of allergy, and were subjected to the following tests: serum total IgE, skin prick tests (SPT), exhaled nitric oxide measurement (FeNO) and spirometry.

RESULTS

ELBW children had wheezing episodes more often (64% vs. 25%; OR (odds ratio): 5.38; 95% CI (confidence interval): 2.14-13.8) and were diagnosed more frequently with asthma (32% vs. 7.5%; OR: 5.83, 95% CI: 1.52-26) than their term born peers. The most important risk factors for wheezing persistence were hospitalization and wheezing episodes in first 24 months of life. Mean serum tIgE level (geometric mean: 32+/-4 vs. 56+/-4 kU/L; p=0.002) was higher and the number of children with positive results of tIgE level (12% vs. 32%; p=0.02) were more frequent in the control group. Children from the control group also more frequently had SPT, however this data was not statistically significant (11% vs. 24%; p=0.09). All of the ELBW had normal FeNO level (<=20 ppb), but 5 children from the control group had abnormal results (p=0.02). There was no difference between the groups in the occurrence of allergic symptoms.

CONCLUSION

ELBW children have more frequent respiratory, but not allergic problems at the age of 6-7 years compared to children born at term. The need for rehospitalization in the first 2 years of life, was a more important risk factor of future respiratory problems at the age of 7 than perinatal factors, the diagnosis of bronchopulmonary dysplasia or allergy.

Diet for the prevention of asthma and allergies in early childhood: much ado about something?

In the last decades there has been an increase in allergic disease throughout the world, particularly in children. Attempts have been made to identify the causes of this "allergy epidemic" in environmental changes and changes in population hygiene, lifestyle, socioeconomic level, and eating habits that would exert epigenetic effects. Dietetic hypotheses have been mainly focussed in long-chain polyunsaturated fatty acids, vitamin D, antioxidants, Mediterranean diet, and fruits, vegetables and fish consumption. Although the data suggest a certain association between diet and the development of asthma/allergy, there is no evidence that diet has an impact upon the prevalence of such diseases after early infancy. If indeed there is such an impact, it is likely to be confined to the prenatal period and the first months of life - when it is still possible to modulate the development of the respiratory, digestive and immune systems. Thus, once the most appropriate preventive measures have been defined, these should be implemented during pregnancy and lactation. The existing scientific evidence is unable to recommend any primary preventive measure in the general population or in different population subgroups. Special or restrictive diets in pregnant or nursing women are not indicated. Exclusive breastfeeding for six months is questioned, since solid foods should begin to be introduced at around four months of age. Once the atopic process has started, no nutritional strategies have been found to be effective as secondary or tertiary preventive measures. Longitudinal studies in cohorts of pregnant women or newborn infants could help clarify these issues.

Preterm birth reduces the incidence of atopy in adulthood

BACKGROUND

Immunologic pathways are primed in early life. Preterm birth can influence this process and thereby affect whether a person will have atopy later in life. Previous studies on the effects of preterm birth on atopy in adulthood have been inconclusive and limited to children or subjects born moderately preterm.

OBJECTIVE

Our aim was to compare the incidence of atopy among young adults who were born preterm and at very low birth weight (≤ 1500 g) with that of term-born young adults (control subjects).

METHODS

The study comprised 166 adults who were born preterm and at very low birth weight and 172 control subjects, all of whom were from the Helsinki Study of Very Low Birth Weight Adults. We assessed atopic predisposition at ages 18 to 27 years using skin prick tests for 6 common aeroallergens and measurements of serum concentrations of total IgE and 3 types of allergen-specific (cat, birch, and timothy) IgE. We asked the subjects whether they had been given a diagnosis of asthma or allergic rhinitis or had atopic eczema and analyzed data by using logistic or linear regression, adjusting for potential confounding factors.

RESULTS

The risk for having at least 1 positive reaction on a skin prick test was reduced (adjusted odds ratio, 0.43; 95% CI, 0.23-0.79, P = .007), and the concentration of cat-specific IgE was less (25% less; 95% CI, 43% to 2.3% less; P = .033) in sera from very-low-birth-weight subjects compared with that seen in sera from control subjects. Within the very-low-birth-weight group, those born at an earlier gestational age were less likely to have positive skin prick test reactions (adjusted odds ratio for 1 week, 0.82; 95% CI, 0.68-0.98, P = .029) and less likely to have high levels of allergen-specific IgE. Cumulative incidences of atopic disease were similar between adults of very low birth weight and control subjects.

CONCLUSIONS

Young adults born prematurely and at very low birth weight have a lower incidence of atopy than adults who were born full term. This finding supports the hypothesis that the risk for atopy is determined during early stages of development.

Glutamine-enriched enteral nutrition in very low birthweight infants and allergic and infectious diseases at 6 years of age

In a previous randomised controlled trial, we found that glutamine-enriched enteral nutrition in 102 very low birthweight (VLBW) infants decreased both the incidence of serious infections in the neonatal period and the risk of atopic dermatitis during the first year of life. We hypothesised that glutamine-enriched enteral nutrition in VLBW infants in the neonatal period influences the risk of allergic and infectious disease at 6 years of age. Eighty-eight of the 102 infants were eligible for the follow-up study (13 died, 1 chromosomal abnormality). Doctor-diagnosed allergic and infectious diseases were assessed by means of validated questionnaires. The association between glutamine-enriched enteral nutrition in the neonatal period and allergic and infectious diseases at 6 years of age was based on univariable and multivariable logistic regression analyses. Seventy-six of the 89 (85%) infants participated, 38 in the original glutamine-supplemented group and 38 in the control group. After adjustment, we found a decreased risk of atopic dermatitis in the glutamine-supplemented group: adjusted odds ratio (aOR) 0.23 [95% CI 0.06, 0.95]. No association between glutamine supplementation and hay fever, recurrent wheeze and asthma was found. A decreased risk of gastrointestinal tract infections was found in the glutamine-supplemented group (aOR) 0.10 [95% CI 0.01, 0.93], but there was no association with upper respiratory, lower respiratory or urinary tract infections. We concluded that glutamine-enriched enteral nutrition in the neonatal period in VLBW infants decreased the risk of atopic dermatitis and gastrointestinal tract infections at 6 years of age.

Respiratory outcomes and atopy in school-age children who were preterm at birth, with and without bronchopulmonary dysplasia

OBJECTIVE

To assess pulmonary function and the prevalence of atopy in school-age children who were very low birth weight as infants and to compare those who had bronchopulmonary dysplasia to those who did not.

METHOD

We studied 85 (39 male and 46 female) at a mean age of 84 (range, 62 to 107) months who were very low birth weight infants. Bronchopulmonary dysplasia was defined as oxygen dependency at 36 weeks gestational age. We excluded 8 patients (4 for cerebral palsy and 4 for no collaboration). Detailed perinatal and clinical data were collected. Lung function was evaluated using conventional spirometry. Atopy (assessed by the allergy skin-prick test) was considered when at least one positive skin test occurred in a panel of the most common environmental allergens in the local region. Comparisons between the bronchopulmonary dysplasia and no bronchopulmonary dysplasia groups were performed using the Mann-Whitney, x2 and Fisher's exact tests.

RESULTS

We compared the bronchopulmonary dysplasia (n = 13) and no bronchopulmonary dysplasia (n = 64) groups. Atopy was observed in 4 (30.8%) of the bronchopulmonary dysplasia patients and in 17 (26.6%) of the no bronchopulmonary dysplasia patients (p = 0.742). Two (15.4%) patients with bronchopulmonary dysplasia had a family history of atopy vs. 17 (26.6%) in the no bronchopulmonary dysplasia group (p = 0.5). Lung function tests showed airway obstruction in 2 (15.4%) of the bronchopulmonary dysplasia patients and in 10 (15.6%) of the no bronchopulmonary dysplasia patients (p = 1.0). Four (33.3%) of the bronchopulmonary dysplasia patients had small airway obstruction vs. 14 (22.2%) of the no bronchopulmonary dysplasia patients (p = 0.466).

CONCLUSION

Our data showed no significant differences in lung function between bronchopulmonary dysplasia and no bronchopulmonary dysplasia patients at school age and no evidence of an association between atopy and bronchopulmonary dysplasia.

Total and antigen-specific IGE levels in umbilical cord blood

The present study was conducted to learn whether the perinatal and environmental factors could influence the total and antigen-specific IgE levels in umbilical cord blood. Retrospective data were obtained from 173 mother-infant pairs. Total and specific (for children's food, wheat/grass and house dust mite-HDM) cord blood IgE levels were determined using the immunoassay test. The total cord blood IgE was between 0.0-23.08 IU/ml (mean 0.55 ± 2.07 IU/ml; median 0.16 IU/ml). Total IgE levels were significantly higher in boys compared with girls (OR = 2.2; P = 0.007), and in newborns with complicated pregnancy (OR = 2.7; P = 0.003). A greater number of siblings correlated with increases in the total cord blood IgE (P < 0.02). We detected specific IgE in 34 newborns (40 positive tests). A long-standing contact with a cat during pregnancy decreased the specific IgE level for wheat/grass (OR = 3.2; P < 0.07) and for children's food (OR = 5.0; P < 0.04), and the contact with a dog decreased the specific-IgE for wheat/grass (OR = 0.3; P < 0.05). Exposure to tobacco smoke correlated with the positive specific IgE toward house dust mite (OR = 4.7; P = 0.005).

Health and the use of health care services in 5-year-old very-low-birth-weight infants

AIM

We aimed to study the effect of prematurity, time of birth and level of birth hospital on morbidity and the use of health care services at age 5.

METHODS

This national study included all very-low-birth-weight infants (VLBWI, <32 gestational weeks or birth weight < or =1500 g) born in Finnish level II or III hospitals in 2001-2002 (n = 918), and full-term controls (n = 381). Parental questionnaires and register data were used to compare morbidity, and the use of health care services between VLBWI and full-term controls, and within VLBWI according to the time of birth and birth hospital level.

RESULTS

Cerebral palsy, retinopathy of prematurity, other ophthalmic problems, respiratory infections, asthma or chronic lung disease, and inguinal hernia were overrepresented in VLBWI compared with the controls. VLBWI had more outpatient and inpatient days than the controls. The time of birth and birth hospital level were not associated with the use of services or with prematurity-related morbidity.

CONCLUSION

Although morbidity and the use of health care services were increased in the surviving VLBWI, the average use of services was relatively small at age 5. In surviving VLBWI, the time of birth and the birth hospital level did not affect morbidity or the use of services.

Eosinophilia in very low birth weight infants

BACKGROUND

Eosinophilia is common in premature infants, though its clinical significance remains unknown. This study investigated the pattern of eosinophilia and related factors in very low birth-weight (VLBW) infants.

METHODS

The medical records of VLBW infants (birth body weight < 1500 g) admitted to the neonatal intensive care unit of a tertiary care center of Cheng Kung University Hospital between January 2005 and June 2007 were analyzed. Complete blood counts (CBC) with differential leukocyte counts were performed weekly. Eosinophilia was defined as an eosinophil count of more than 0.700 x 10(9)/L. The possible related factors were analyzed.

RESULTS

A total of 142 infants were recruited into the study. Those who did not survive after the first 28 days and those with less than four available CBCs were excluded, leaving 107 infants and 828 CBC measurements. Overall, 19.0% of CBCs (157/828) indicated eosinophilia and 69.0% of all infants had at least one instance of eosinophilia during their hospital stay. Eosinophilia mainly occurred in the third week of life (27.1%), with an average peak eosinophil count of 0.520 x 10(9)/L. There were 37.3% of patients with mild eosinophilia (0.700-0.999 x 10(9)/L), 50.7% with moderate eosinophilia (1.000-2.999 x 10(9)/L), and 12% with severe eosinophilia (> or =3.000 x 10(9)/L). The demographic data and perinatal characteristics of infants with and without eosinophilia were comparable. Medical treatments including mechanical ventilation, antibiotic administration, total parenteral nutrition, intravenous catheterization, transfusion, and body weight gains were similar between the two groups. The eosinophil counts in the first week of life were significantly higher in infants with bronchopulmonary dysplasia (p < 0.05). They were also greater in VLBW infants with sepsis at the first, the third, the fourth, the fifth and the seventh weeks (p < 0.05).

CONCLUSION

Eosinophilia is common in VLBW infants and occurs mainly in the third week of life. Higher eosinophil counts were associated with sepsis and family history of atopic eczema. Bronchopulmonary dysplasia was associated with higher eosinophil counts in the first week of life.

Is there an increased frequency of food allergy in children delivered by caesarean section compared to those delivered vaginally?

AIM

Allergic diseases are increasing. At the same time an increasing number of children are delivered by caesarean section. These children do not get the same contact with their mother's gut flora as babies delivered vaginally. Theoretically, lack of exposure to maternal vaginal and perineal bacteria might change the gut flora, with secondary changes in the immune system. The aim of this study was to investigate whether children delivered by caesarean section were more prone to develop food allergy.

METHODS

Six hundred and nine children were included at birth. At 2-year follow-up, 512 children participated, 171 delivered by caesarean section, 341 born vaginally. The children reported to have symptoms consistent with possible food allergy, were examined at the outpatient clinic. The diagnosis was based on the history, skin prick test (SPT), specific IgE, elimination/challenge test and double blind placebo controlled challenge.

RESULTS

Thirty-five (6.8%) children were diagnosed with adverse reactions to food, 27 with non-IgE-mediated and eight with IgE-mediated allergy. There was no over representation of children born by caesarean section.

CONCLUSION

In this study there seems to be no increased risk for food allergy in the first 2 years of life in children delivered by caesarean section.

Prenatal factors and the development of asthma

PURPOSE OF REVIEW

There is increasing evidence that both prenatal and perinatal events influence both allergic diseases and early-life respiratory morbidity.

RECENT FINDINGS

Studies in the last year have suggested that in-utero exposures including tobacco smoke exposure, dietary exposures including vitamin D, and prenatal infection and exposure to microbial products may modulate both atopy and respiratory disease. There have been studies revealing gene x environment interactions between inflammatory pathway genes and in-utero smoke exposure. There have also been studies which have revealed that prenatal exposure to endotoxin may be protective. On the other hand, a recent study also suggested that chorioamnionitis may increase the risk of recurrent wheezing in combination with preterm birth. Finally, two separate large cohort studies evaluated maternal diet in pregnancy and suggested that vitamin D levels may be protective against asthma and wheezing.

SUMMARY

There is epidemiological evidence for multiple prenatal factors impacting early-life respiratory morbidity. The mechanisms of these factors need further investigation and may act via various pathways which include effects on lung development, allergic and nonallergic inflammation, and airway remodeling. It remains to be determined if some of these early-life factors which predispose to wheezing will all translate into increased risk of asthma.

Age at first introduction of cow milk products and other food products in relation to infant atopic manifestations in the first 2 years of life: the KOALA Birth Cohort Study

OBJECTIVES

Scientific evidence is scarce about timing of solid-food introduction and its association with the development of atopy. We aimed to evaluate any associations between the introduction of cow milk products/other solid food products and infant atopic manifestations in the second year of life, taking into account reverse causation.

METHODS

Data from 2558 infants in an ongoing prospective birth cohort study in the Netherlands were analyzed. Data on the main determinants (introduction of cow milk products and other food products), outcomes (eczema; atopic dermatitis [United Kingdom Working Party criteria]; recurrent wheeze; any sensitization; sensitization against cow milk, hen egg, peanut, and at least 1 inhalant allergen), and confounders were collected by repeated questionnaires at 34 weeks of gestation and 3, 7, 12, and 24 months postpartum. Information on sensitization was gathered by venous blood collections performed during home visits at age 2. Analyses were performed by multiple logistic regression analyses.

RESULTS

More delay in introduction of cow milk products was associated with a higher risk for eczema. In addition, a delayed introduction of other food products was associated with an increased risk for atopy development at the age of 2 years. Exclusion of infants with early symptoms of eczema and recurrent wheeze (to avoid reverse causation) did not essentially change our results.

DISCUSSION

Delaying the introduction of cow milk or other food products may not be favorable in preventing the development of atopy.

Adverse reactions to milk in infants

Aim

To study the age when symptoms of adverse reactions to milk occur, in premature and term children, the debut of various symptoms, immunoglobulin E (IgE)- and non-IgE-mediated reactions and the frequency of tolerance at 1 year.

Methods

Six hundred and eight children, 193 premature and 416 term infants, were followed. Symptomatic children were invited to a clinical examination. The criteria for the diagnosis were: histories of suspected cow's milk allergy (CMA) and proven IgE-mediated reactions to cow's milk or positive elimination/challenge tests.

Results

Twenty-seven out of 555 (4.9%) were diagnosed with adverse reactions to cow's milk. All had symptoms before 6 months of age. The main symptoms were: pain behaviour (13), gastrointestinal symptoms (7), respiratory symptoms, (6) and atopic dermatitis (1). One child had proven IgE to cow's milk. Premature and term infants displayed the same symptoms and age of debut. Thirteen children were tolerant to cow's milk at 1 year.

Conclusion

Adverse reactions to milk start early in life, with pain behaviour, gastrointestinal, and respiratory symptoms being the most common, and rarely atopic dermatitis. Non-IgE-mediated reactions were the most frequent. Symptoms and age of debut were the same in premature and term infants. Half of the children tolerated cow's milk at age 1.

The risk of developing food allergy in premature or low-birth-weight children

BACKGROUND

Premature or low-birth-weight children have increased gut permeability compared with term or normal-birth-weight children.

OBJECTIVE

To determine whether premature or low-birth-weight children have an increased risk of developing food allergy compared with term or normal-birth-weight children.

METHODS

The 1995 Manitoba Birth Cohort was studied using the Manitoba Health Services Insurance Plan (MHSIP) database. This database is a population-based, health care administrative and prescription database. It has records of every child born and subsequent utilization of the provincial health care system. The diagnosis of food allergy (ICD-9-CM code of 693 in hospital/medical claims or a prescription of injectable epinephrine excluding a sole diagnosis of venom allergy) was obtained up until the year 2002. The relative risks of food allergy in premature or low-birth-weight children compared with term or normal-birth-weight children were determined.

RESULTS

A total of 13,980 children were born in 1995 and continue to live in the province of Manitoba. Of these, 592 children (4.23%) were found to have food allergy and epinephrine was prescribed in 316 (2.26%) children. No gestational age or birth weight group had a statistically significant increased risk for food allergy.

CONCLUSION

Prematurity and low birth weight are not associated with a change in risk for development of food allergy in childhood.

CLINICAL IMPLICATIONS

Immaturity of the gastrointestinal tract or immune response does not seem to change the risk for development of food allergies. We ask whether early exposure to food antigens may protect premature children by increasing immune tolerance to those antigens.

Genetic susceptibility to neonatal infection

PURPOSE OF REVIEW

To review current data on genetic factors contributing to the striking susceptibility of neonates to infectious diseases and other adverse outcomes.

RECENT FINDINGS

Although few studies address genetic determinants of neonatal infectious disease susceptibility, several variants in genes involved in the innate immune response have been associated with differential risk for neonatal infection. The most consistent results relate to polymorphisms of tumour necrosis factor-alpha, whereas other gene polymorphisms, such as those of interleukin-6, have yielded conflicting findings. Similar genetic factors may be involved in other inflammatory neonatal diseases. Recent data suggest that genetic variation may influence the pace of immunologic maturation.

SUMMARY

Despite the enormous human and financial costs of infection for neonatal mortality and morbidity worldwide, it remains unclear why neonates are so susceptible. Genetic epidemiologic studies may assist in the identification of critical protective and pathogenic pathways. Despite the current relative lack of robust data, such studies are likely to facilitate the development of interventions that ultimately decrease the significant morbidity and mortality of this highly vulnerable population.

Pediatric food allergy update

Food allergy is mostly a childhood disease that differs from the adult-onset allergy in several aspects, including the prevalence, commonly offending foods, symptomatology, and prognosis. The prevalence is much overestimated by the public, but it probably affects up to 6% of children. In some cases, the diagnosis might be clearly evident, but in most cases an expert evaluation may be needed that usually includes verification by challenge testing. Currently, the management of food allergy is avoidance of the offending foods together with the availability of pharmacologic agents for symptomatic treatment, including self-administered epinephrine. The latter is of utmost importance in highly allergic subjects because accidental trivial exposure is not uncommon. Recent studies promise immunomodulatory agents that might be of potential use for prophylaxis. One such agent is anti-immunoglobulin E, which might be available in the near future.

Perinatal characteristics and obstetric complications as risk factors for asthma, allergy and eczema at the age of 6 years

BACKGROUND

Considerable effort has been put into identifying early determinants for atopic disorders. Many studies have evaluated the role of fetal development and obstetric complications. However, the results are not unequivocal.

STUDY OBJECTIVE

To assess the relationship between perinatal characteristics and obstetric complications, and the presence of reported current asthma, allergy and eczema at the age of 6 years in the framework of a previously conducted study.

METHOD

Seven hundred families in the Netherlands with index children born in 1988-1990 were retrospectively selected. Data were extracted from the Municipal Health Service's records of health examinations of these children and their siblings. These examinations were carried out at the age of 6 years. The records contained data on reported atopic disorders and perinatal characteristics.

RESULTS

Gestational age was inversely related to the risk of asthma (P for trend: 0.03). Children with low birth weight tended to have a lower risk of any allergy, albeit not significant (P=0.07). However, no link was found between neonatal head circumference and atopic disorders. The ratio of neonatal head circumference to birth weight was positively associated with the risk of atopic disorders, especially with the risk of asthma (odds ratio (OR)=1.87; 95% confidence interval (CI(95%))=[1.11, 3.15]). Vacuum extraction was a risk factor for allergy (OR=1.84, CI(95%)=[1.03, 3.28]), but not for asthma. Induced labour was positively associated with the risk of inhalant allergy (OR=2.22, CI(95%)=[1.09, 4.51]) and, to a lesser extent, asthma (OR=1.72, CI(95%)=[0.95, 3.10]). For caesarean section and forcipal extraction there were no such relationships.

CONCLUSIONS

Prematurity is a risk factor for asthma reported at 6 years. A high ratio of head circumference to birth weight is a risk factor for any atopic disorder. Vacuum extraction was associated with a higher risk of allergy, and induced labour is a risk factor for inhalant allergy. All results should be viewed with the possibility of residual confounding.

Intervention during pregnancy and allergic disease in the offspring

The etiology of allergy is multifactorial, with many variables contributing to the final expression of atopic disease. Three breeding grounds are needed to develop allergic disease: the appropriate genetic background, contact with the allergen(s) and environmental factors. Timing and dosing of allergen(s) are of major importance. Contact with (dietary) allergens and various agents such as tobacco smoke and infections occur not only during post-natal life, but also perinatally and even pre-natally. A critical review of published evidence regarding the impact of maternal exposure to antigens during pregnancy on later development of allergy in the offspring can only conclude that more research is urgently needed. Contact with multiple dietary allergens should be in general of benefit to the fetus to develop tolerance. Current knowledge suggests that pregnant women should have a normal diversified diet, avoiding toxic agents such as tobacco and alcohol. The role of maternal intake of poly-unsaturated fatty acids on the development of atopy in the infants needs to be further evaluated. If parental history would be insufficient to determine the fetal risk, preventive measurements would be advisable for all fetuses.

Transient environmental exposures on the developing immune system: implications for allergy and asthma

PURPOSE OF REVIEW

Early environmental exposures have been extensively studied as potential causes of the observed increase in allergic disease over time. Transient fetal or neonatal exposures in particular are of interest in that they may occur during critical windows of immune system development. Due to the tremendous complexity of variables in early life, as well as the difficulty in randomizing many interventions, it is very difficult to properly study these exposures. Some progress, however, has been made and some more candidates for study may be emerging. Of particular interest are micronutrients, whose ever-changing use and immunomodulatory capabilities make them prime targets for study.

RECENT FINDINGS

New risk factors for atopic disease have emerged from the pool of early life interventions, such as caesarian section, prolonged labor and infant multivitamin supplementation. Data are emerging regarding micronutrient status and supplementation and their effects on the developing immune system and risk for allergic disease. Clinical trials have yet to demonstrate much causality but, in some cases, it is too early to make any judgments.

SUMMARY

The gold standard of randomized clinical trials has not borne out a number of proposed early-life allergic risk factors, while other trials are too incomplete to draw any conclusions so far. Properly designed studies for other risk factor interventions may still be achievable, provided that there is a proper understanding of the interventions, populations and outcomes.

Mothers of very low birth weight infants have less atopy than mothers of full-term infants

BACKGROUND

Studies on the pregnancy outcome of asthmatic mothers have suggested an increased rate of preterm deliveries. In contrast, our earlier study suggests that mothers of very low birth weight (VLBW) (<1500 g) infants less frequently had atopy than did mothers of full-term infants.

METHODS

We inquired about symptoms of atopy and doctor-diagnosed atopy in parents of 370 infants of VLBW (<1500 g) and 544 parents of full-term infants. Odds ratios for atopic symptoms and diagnosed atopy were calculated, and groups were compared with a trend test.

RESULTS

Mothers of preterm infants of birth weight (BW) <1000 g significantly less often had physician-diagnosed allergic rhinitis (AR) (P=0.02). Among all the mothers, a trend test showed that maternal AR was significantly (P=0.03) higher in parallel with a higher infant BW. Fathers of infants with different BWs showed no differences in prevalence of atopic symptoms.

CONCLUSION

We thus infer that maternal balance between T-helper type 1 (Th1) and Th2 cells, shifted towards Th2 in those with AR, may have a favourable effect on maintenance of pregnancy before gestational week 30.

Helicobacter pylori and specific immunoglobulin E antibodies to food allergens in children

OBJECTIVES

It has been suggested that chronic Helicobacter pylori infection may increase gastric permeability, predisposing infected children for the development of food allergies. We assessed the presence of food-specific immunoglobulin (Ig)E antibodies in H. pylori positive children and controls.

METHODS

We measured specific IgE values to six major food allergens (Pharmacia CAP-system) in a group of school-aged Caucasian (n = 36) and non-Caucasian (n = 38) children with a known H. pylori status. All children had undergone upper gastrointestinal endoscopy because of abdominal complaints.

RESULTS

Among H. pylori positive children (mean age, 8.8 years; range, 5-15 years, 25 female, 26 male), 33% (17 of 51) had an elevated food-specific IgE level to at least one of the food allergens tested. Unexpectedly, the majority of those with elevated serum food-specific IgE levels (12 of 17) were to cow's milk. Among H. pylori negative children (mean age, 9.3 years; range, 5-15 years, 13 female, 10 male), 26% (6 of 23) of the children had an elevated serum IgE level to at least one of the food allergens tested, and 9% (2 of 23) were positive to cow's milk. The difference in the number of children with an elevated serum IgE level for cow's milk in H. pylori positive and negative children was not significant. The severity of gastritis did not correlate with the presence of food-specific IgEs.

CONCLUSIONS

H. pylori infection had no effect on the manifestation of specific IgE to major food allergens in school-aged children. An IgE response to cow's milk was common among these school-aged children.

Risk factors for food allergy

Food allergy is a common problem that often affects young children. Numerous factors affect the development of food allergy both prenatally and postnatally. These factors are genetic and environmental. Although little can be done post-conception to alter a child's genetic risk for developing food allergy, early identification may permit alterations of the environment in which food allergy develops. Environmental factors operate both prenatally and postnatally. By understanding how these factors affect development of food allergy, it may be possible for parents to modulate the development of this difficult problem in their children.

Respiratory symptoms and lung function in relation to atopy in children born preterm

Respiratory morbidity is a major health problem among children. The aim of this study was to compare the background of respiratory problems of children born preterm with that of children born full-term, with special reference to atopy. The study comprised two cohorts of 10-year-old children: a group of 72 children born preterm with birth weights of less than 1,501 g, and a group of 65 children born full-term with birth weights of over 2,500 g. Histories of respiratory and atopic symptoms, and of risk factors for atopy, were collected with a questionnaire. Predisposition to atopy was verified by skin-prick testing and by measuring serum total and antigen-specific IgEs. Lung function was evaluated by spirometry testing. Children born preterm had significantly more wheezing. In them, the lifetime prevalence of wheezing was 43%, vs. 17% in children born full-term (P = 0.001; odds ratio, 3.71; 95% confidence interval, 1.67-8.25). In the full-term group, wheezing was associated with atopy: 64% of wheezers were atopic; in the preterm group, 23% of wheezers were atopic (difference between groups, P = 0.024). Children born preterm expired significantly lower spirometry values of forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), FEV1/FVC ratio, forced expiratory flow after 50% of vital capacity has been exhaled (FEF50), and forced expiratory flow during middle half of FVC (FEF25-75). In the preterm group, wheezing, asthma, and low gestational age, but not atopy, were significantly associated with lower lung function values. Wheezers of the preterm group who still wheezed at age 10 were significantly more often atopic than those who no longer wheezed (62% vs. 9%, P = 0.006). In conclusion, we demonstrated a significant difference between groups in the association of atopy with respiratory problems. However, although atopy was not associated with a lifetime prevalence of respiratory symptoms in prematurely born children, an atopic predisposition in them was found to associate with persistence of wheezing.

Asthma, lung function and allergy in 12-year-old children with very low birth weight: a prospective study

We assessed the relationship between very low birth weight (VLBW) (<or=1500 g) and the development of asthma, lung function and atopy. The study groups comprised 74 of all 86 (86%) VLBW and 64 of all 86 (74%) matched term children who were prospectively followed for 12 years. A questionnaire on asthmatic and allergic symptoms was completed and skin prick tests, spirometry and hypertonic saline provocation tests were performed at 12 years of age. Cytokine secretion was analysed in stimulated blood leukocyte cultures in 28 VLBW and 23 term children. A history of asthma was more frequent among the VLBW children, as compared with the term children at age 12 (22% vs. 9%, p = 0.046). Among the VLBW children, very preterm birth (gestational age: week 25 to 29) (RR 2.5, 95%CI 1.1-5.8), neonatal mechanical ventilation (RR 2.8, 95%CI 1.2-6.4) and neonatal oxygen supplementation (RR 4.3, 95%CI 1.3-14.0) were significantly associated with a history of asthma by the age of 12 years in univariate analyses. In multivariate logistic regression, neonatal oxygen supplementation >or= 9 days was the only remaining significant risk factor for a history of asthma (adjusted OR 6.7, 95%CI 1.0-44). The VLBW children who required mechanical ventilation during the neonatal period were more likely to have bronchial hyperresponsiveness than those not requiring mechanical ventilation (60% vs. 28%, p = 0.050). The spirometric values were similar among the VLBW and the term children at 12 years. Very low birth weight was not significantly related to allergic rhinoconjunctivitis, eczema or positive skin prick tests. Furthermore, the levels of IL-4, IL-5 and IFN-gamma in stimulated cell cultures were similar in the VLBW and the term children. A history of asthma by 12 years of age was twice as common among the VLBW as the term children, and neonatal oxygen supplementation seemed to be associated with the increased risk. Furthermore, mechanical ventilation during the neonatal period was associated with bronchial hyperresponsiveness at age 12. Very low birth weight per se was not, however, related to atopy.

Neonatal head circumference, neonatal weight, and risk of hayfever, asthma and eczema in a large cohort of adolescents from Sheffield, England

BACKGROUND

Neonatal physical characteristics, including head circumference and birth weight, have been hypothesized to be markers of in utero thymic development. Greater head circumference and lower birth weight have been linked in previous studies to subsequent development of asthma, and greater birth weight has been associated with subsequent development of eczema.

OBJECTIVE

To investigate potential associations between neonatal head circumference and weight and hayfever, asthma and eczema in a cohort of adolescents from Sheffield, England.

METHODS

Responses to a questionnaire inquiring about physician-diagnosed hayfever, asthma and eczema among adolescents in Sheffield, England, were linked to previously recorded measurements of weight at birth and at 1 month and head circumference at 1 month. Logistic regression methods were used to relate diagnoses to neonatal measurements and potential confounders.

RESULTS

The cohort consisted of 10,809 adolescents, of whom 16.5% reported hayfever, 18.0% asthma, and 16.2% eczema. After adjusting for sex, age at the time of the questionnaire, maternal age and gestational age at birth, number of older and younger siblings, time since birth of next older sibling, neonatal sickness, type of neonatal feeding, and maternal and paternal educational backgrounds, hayfever was the only disease associated with neonatal measurements. Comparing the highest with the lowest fifths of distributions, lifetime prevalence of hayfever was positively associated with neonatal head circumference (adjusted odds ratio 1.23, 95% CI 1.03 to 1.47) and with birth weight (1.17, 0.99 to 1.39). Hayfever was inversely related to the ratio of head circumference to birth weight (0.89, 0.75 to 1.05) and to gestational age. The associations with head circumference and birth weight were not substantially altered by further adjustment for gestational age.

CONCLUSION

Greater neonatal head circumference may be associated with an increased risk of hayfever, but the inverse relationship between hayfever prevalence and the ratio of head circumference to birth weight challenges the prior hypothesis that greater head circumference relative to body mass reflects abnormal thymic development in utero, increasing the likelihood of allergic sensitization.

IgG and IgA antibody levels to cow's milk are low at age 10 years in children born preterm

BACKGROUND

Both innate and specific defenses of the preterm infant are even less developed than those of term infants, and the immune systems of preterm infants might be skewed differently at birth. Their immune responses to food antigens started early in life might therefore differ from those of term infants.

OBJECTIVE

We sought to compare antibody levels to cow's milk, ovalbumin, and gliadin at age 10 years in children who had been born either preterm or at term.

METHODS

IgG and IgA isotype antibodies to whole cow's milk, beta-lactoglobulin, alpha-casein, and ovalbumin, as well as IgG antibody levels to gliadin and to tetanus and diphtheria toxoids, were measured for a group of 62 children born preterm and 61 control subjects born at term. These children were studied at the same time for atopy.

RESULTS

Children born preterm had markedly lower levels of antibodies to cow's milk and to its protein fractions (P <.0001 for IgA and IgG antibodies to cow's milk and alpha-casein and IgG beta-lactoglobulin antibodies). IgG gliadin antibodies were also significantly lower in the preterm group (P =.03), although the difference was not significant for IgG ovalbumin antibodies. In the preterm group both those born before gestational week 30 and those given cow's milk-based formula early (before day 50) had the lowest levels of cow's milk antibodies. In the preterm group atopy was associated with low levels of IgG cow's milk antibodies but with high levels of IgG ovalbumin antibodies.

CONCLUSIONS

Early introduction of food antigens into the immature gastrointestinal tract of preterm infants might result in tolerance. The presence of less atopy in these children might also be a result of tolerance development.