Perinatal Risk Factors for Hay Fever — A Study Among 2550 Finnish Twin Families

Postnatal probiotics and allergic disease in very preterm infants: Sub-study to the ProPrems randomized trial

BACKGROUND

Probiotic supplementation to mothers and/or their term-born infants has been suggested to prevent allergic disease, in particular eczema; however, no studies have investigated probiotics for prevention of allergic diseases in very preterm infants. We evaluated the effect of a postnatal probiotic combination on development of allergic diseases in very preterm infants.

METHODS

This sub-study was an a priori secondary outcome of the ProPrems multi-center, double-blind, placebo-controlled randomized trial (ANZCTR:12607000144415). ProPrems randomized 1099 very preterm infants to receive a probiotic combination or placebo from soon after birth until discharge from hospital or term corrected age (CA), whichever was earlier. Allergic disease (eczema, atopic eczema, food allergy, wheeze, atopic sensitization) was assessed in a subgroup of ProPrems infants (n = 281) as close to 12 months CA as possible by questionnaire, clinical examination, and skin prick tests to common allergens.

RESULTS

There was no difference in eczema incidence between the probiotic and placebo groups (35[30%] of 118 infants vs 37[27%] of 137 infants, respectively, absolute difference 2.65%, 95% CI -8.45 to 13.75). Similarly, the incidence of atopic eczema (6[5%] of 118 vs 3[2%] of 137), food allergy (4[3%] of 124 vs 2[1%] of 154), wheeze (39[31%] of 127 vs 45[29%] of 154), and atopic sensitization (14[13%] of 106 vs 13[11%] of 123) were similar between the probiotic and placebo groups.

CONCLUSION

This study found no effect of postnatal administration of a probiotic combination on the incidence of allergic diseases or atopic sensitization in the first 2 years of life in children born very preterm. Evidence that probiotics are effective for prevention of allergic disease in premature infants remains lacking; adequately powered randomized controlled trials evaluating probiotic supplementation for allergy prevention in very preterm infants are needed.

Neonatal jaundice is a risk factor for childhood allergic rhinitis: a retrospective cohort study

BACKGROUND

This study evaluates the association between neonatal jaundice and childhood allergic rhinitis (AR).

METHODS

Eleven thousand three hundred twenty-eight children were collected from the National Health Insurance Research Database in Taiwan. Their claims data were evaluated from birth to 10 years of age, and they were assigned to either the study (with neonatal jaundice) or the control (without neonatal jaundice) group. The diagnostic criteria for AR were at least three diagnoses of AR at outpatient services, one diagnosis of AR during an admission, or one diagnosis of AR in an emergency department. Mantel-Haenszel odds ratios (ORs) were calculated after adjustment for the following confounders: preterm/low birth weight, neonatal infection, other respiratory conditions, other birth conditions, and gender. AR rate, AR onset time, the use of oral antihistamines/nasal corticosteroids, outpatient visit frequency for AR, lower respiratory infection (LRI) rates, sinusitis/otitis media/conjunctivitis rates, and the effect of phototherapy were evaluated.

RESULTS

After adjustment for the confounding factors, the rate of AR was higher in icteric children (OR, 1.46; 95% confidence interval, 1.24∼1.72). There was a higher incidence of AR in children <4 years old with icterus. The use of oral antihistamines, LRI rates, sinusitis rates, and otitis media rates were higher in the icteric children. There was no association between phototherapy and childhood AR.

CONCLUSION

Neonatal jaundice increased the rate and complications of childhood AR in subjects aged up to 10 years and may be a risk factor for childhood AR.

The Foetal Origins of Adult Disease: Interpreting the Evidence From Twin Studies

Twin studies have a contribution to make to the debate concerning the foetal origins of adult disease. Twins are growth retarded compared to singletons and experience post-natal catch-up growth. However, there is no evidence that twins are at increased risk of cardiovascular disease. Studying whether discordance in size at birth within monozygotic twin pairs is predictive of discordance in later life disease should help resolve whether the association between size at birth and later disease is due to common genetic factors. Results from studies of blood pressure in childhood and adult life looking at these within twin effects are far from conclusive. There are, however, methodological problems in the interpretation of these results, not least of which is the relatively small numbers of twin pairs studied. Studies exploring the effect of zygosity and chorion type on later disease provide may provide a useful extension of the research agenda. In summary, twin studies to date have raised more questions about the foetal origins hypothesis than they have resolved.

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.

Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study

BACKGROUND

Studies have found associations between birth weight and risk of atopic eczema or allergic rhinitis (AR), although this could be due to confounding.

OBJECTIVE

We sought to evaluate associations between fetal growth and the risk of atopic eczema or AR in childhood, controlling for gestational age (GA), shared (familial) environmental and genetic factors.

METHODS

Data on atopic eczema, AR, birth characteristics and confounders were collected from registers and telephone interviews with the parents of 9- and 12-year-old twins. Firstly, cohort analyses on all twins (eczema n=10 132 and AR n=10 896) were performed. Secondly, to control for genetic and shared environment, co-twin-control analyses were performed in twin pairs discordant for atopic eczema (n=480) and AR (n=332).

RESULTS

The rate of atopic eczema increased with birth weight, from 12.6% in twin children <2000 g to 17.3% in children >or=3500 g. The rate of AR varied between 7.8% and 8.8%. In the cohort analyses, the odds ratio (OR) for atopic eczema was 1.62 (95% CI: 1.27-2.06) for 500 g increase in birth weight and 1.00 (95% CI: 0.75-1.33) for AR. In co-twin-control analyses on atopic eczema, OR was 3.93 (95% CI: 1.55-9.98) for 500 g increase in birth weight, with no significant difference between monozygotic and dizygotic twins (P=0.84).

CONCLUSIONS

We found a positive association between fetal growth and childhood atopic eczema, but not AR, independent of GA, shared environmental and genetic factors. This indicates fetal growth affects the immune system, and supports further studies on early mechanisms.

Early-life environment, developmental immunotoxicology, and the risk of pediatric allergic disease including asthma

Incidence of childhood allergic disease including asthma (AD-A) has risen since the mid-20th century with much of the increase linked to changes in environment affecting the immune system. Childhood allergy is an early life disease where predisposing environmental exposures, sensitization, and onset of symptoms all occur before adulthood. Predisposition toward allergic disease (AD) is among the constellation of adverse outcomes following developmental immunotoxicity (DIT; problematic exposure of the developing immune system to xenobiotics and physical environmental factors). Because novel immune maturation events occur in early life, and the pregnancy state itself imposes certain restrictions on immune functional development, the period from mid-gestation until 2 years after birth is one of particular concern relative to DIT and AD-A. Several prenatal-perinatal risk factors have been identified as contributing to a DIT-mediated immune dysfunction and increased risk of AD. These include maternal smoking, environmental tobacco smoke, diesel exhaust and traffic-related particles, heavy metals, antibiotics, environmental estrogens and other endocrine disruptors, and alcohol. Diet and microbial exposure also significantly influence immune maturation and risk of allergy. This review considers (1) the critical developmental windows of vulnerability for the immune system that appear to be targets for risk of AD, (2) a model in which the immune system of the DIT-affected infant exhibits immune dysfunction skewed toward AD, and (3) the lack of allergy-relevant safety testing of drugs and chemicals that could identify DIT hazards and minimize problematic exposure of pregnant women and children.

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.