Maternal positive skin prick test results and asthma prediction after early childhood wheezing

High burden of atopy in immigrant families in substandard apartments in Sweden - on the contribution of bad housing to poor health in vulnerable populations

Background

Atopic disorders are a global concern. Studies in migrant populations can illuminate the interplay of genetic and environmental factors. Exposures related to bad housing (indoor dampness, mould growth, crowding etc.) are likely to play a role in how socioeconomic inequalities can turn into health disparities for disadvantaged populations. The sizable immigrant population living in very poor-quality housing in Malmö, Sweden, became the focus of a cross-sectional study.

Objective

To describe atopic disorders and sensitizations in a population living in substandard housing in Malmö, Sweden, with an emphasis on their relation to harmful exposures from the built environment.

Methods

Families were recruited via identification of any children with symptomatic airway afflictions from health care records, and also asymptomatic children from school lists. Interviewer-led health questionnaire data and data from self-reports about living conditions were obtained together with data from home inspections carried out by health communicators. Families underwent skin prick tests (SPT) against common aeroallergens.

Results

As could be expected from background demographic information, it turned out that we effectively studied an immigrant population inhabiting very precarious housing outside the center of Malmö. A total of 359 children from 130 families (total 650 participants) were included. Overall the prevalence of potentially harmful environmental exposures was high (signs of moisture or mould in more than 50% of apartments, indoor smoking in 37% of households). Atopic disorders were common among both adults and children. SPTs showed a spectrum of sensitizations consistent with unselected populations in Sweden. Paternal sensitization in the SPT was associated with higher risk of sensitization for offspring than maternal sensitization. Few statistically significant associations of atopic sensitization with studied environmental exposures were detected (for example objective signs of dampness /mould in bathrooms). There were marked discrepancies between asthma diagnoses obtained from the health records and parental reports of such diagnoses and treatment for their children.

Conclusions

The atopic burden in this selected immigrant population was high, and results point to unmet medical needs. Health care systems caring for such populations need to be aware of their specific health needs; comprehensive asthma and allergy care should include consideration of harmful environmental exposures, adhering to the precautionary principle.

Impaired lipopolysaccharide responsiveness of cord blood mononuclear cells and the risk of asthma: a longitudinal study

BACKGROUND

We previously demonstrated that the proliferative response to lipopolysaccharide (LPS) in cord blood mononuclear cells (CBMCs) is negatively correlated with the induced expression of interleukin (IL)-4. Our aim, therefore, was to examine whether an impaired cellular response to LPS in infancy is associated with the risk for asthma.

METHODS

In a prospective cohort study, the relationship between the CBMC response to LPS and the risk of atopy and wheezing after the age of 4 y was evaluated.

RESULTS

LPS-induced CBMC proliferative responses varied markedly among the 102 infants studied (range, one- to fivefold increase over cells with diluent alone). Ninety-five infants (93%) were followed longitudinally. A higher CBMC proliferative response to LPS was noted in offspring born to nonatopic parents compared with those with at least one atopic parent (P = 0.008). Using a proliferative index cutoff of 2 separated patients into high and low induced IL-4 mRNA responders (P = 0.001). Significantly more children who never wheezed had a greater than twofold LPS-induced CBMC proliferative response compared to those with persistent atopic wheezing (P = 0.046).

CONCLUSION

These results demonstrate that CBMC proliferative responses to LPS is impaired in infants born to atopic parents and may be a risk factor for asthma later in life.

Role of parental atopy in cow's milk allergy: a population-based study

BACKGROUND

A family history of atopy has been considered an independent risk factor for atopic diseases in children.

OBJECTIVE

To relate the risk of an infant developing IgE-mediated cow's milk allergy (IgE-CMA) to the atopic status of parents.

METHODS

Assessment of the parental atopic status of children with IgE-CMA (n = 66) previously identified in a large-scale prospective study was compared with the parental atopic status of a control group of healthy infants (n = 156). The atopic status was identified both by self-reporting and skin prick tests (SPTs).

RESULTS

Analysis for the risk for infants to develop IgE-CMA depended on the assessment method used. No significant differences were noted in self-reported parental atopic status between the IgE-CMA patients and the control group. However, among the subgroup of infants with persistent IgE-CMA (n = 25), maternal but not paternal self-reporting for atopy was more likely compared with parents of the control group (P = .04). In contrast, when analyzed by SPT, in both this persistent subgroup and the total allergic cohort, no significant differences were noted whether analyzed by single parent or both parents and whether the parent tested singly or multiply positive on the SPT.

CONCLUSION

In families with children with persistent IgE-CMA, self-reporting of atopy by parents may be biased. Furthermore, the demonstration of IgE-mediated responses to allergens in parents is insufficient by itself, in a general population cohort, to predict which infants are at greatest risk of developing IgE-CMA.

Natural course and risk factors for persistence of IgE-mediated cow's milk allergy

OBJECTIVE

To describe the natural course of IgE-mediated cow's milk allergy (IgE-CMA) and to determine risk factors for its persistence in a population-based cohort.

STUDY DESIGN

In a prospective cohort study, 54 infants with IgE-CMA were identified from a population of 13 019 children followed from birth. Diagnosis of IgE-CMA was based on history, skin prick test (SPT), and an oral food challenge (OFC) when indicated. Allergic infants were followed for 48-60 months. Families were contacted by telephone every 6 months and asked about recent exposures to milk. OFC was repeated to evaluate for recovery. Clinical characteristics, SPT, and OFC outcomes were compared between infants with persistent IgE-CMA and infants who recovered.

RESULTS

Thirty-one infants (57.4%) recovered from IgE-CMA during the study period. Most infants (70.9%) recovered within the first 2 years. Risk factors for persistence on multivariate analysis included a reaction to <10 mL of milk on OFC (or on first exposure as estimated by the guardian, if OFC was not performed) (P = .01), a larger wheal size on SPT (P = .014), and age of ≤30 days at time of first reaction (P = .05).

CONCLUSIONS

Resolution occurs in most infants with IgE-CMA. Infants reacting to <10 mL of milk or in the first month of life, and those with a larger wheal size on SPT, are at increased risk for persistence.

Early exposure to cow's milk protein is protective against IgE-mediated cow's milk protein allergy

BACKGROUND

The diversity in the perceived prevalence, recovery, and risk factors for cow's milk allergy (CMA) necessitated a large-scale, population-based prospective study.

OBJECTIVE

We sought to determine the prevalence, cross-reactivity with soy allergy, and risk factors for the development of CMA.

METHODS

In a prospective study the feeding history of 13,019 infants was obtained by means of telephone interview (95.8%) or questionnaire (4.2%). Infants with probable adverse reactions to milk were examined, skin prick tested, and challenged orally.

RESULTS

Ninety-eight percent of the cohort participated in the study. The cumulative incidence for IgE-mediated CMA was 0.5% (66/13,019 patients). The mean age of cow's milk protein (CMP) introduction was significantly different (P < .001) between the healthy infants (61.6 +/- 92.5 days) and those with IgE-mediated CMA (116.1 +/- 64.9 days). Only 0.05% of the infants who were started on regular CMP formula within the first 14 days versus 1.75% who were started on formula between the ages of 105 and 194 days had IgE-mediated CMA (P < .001). The odds ratio was 19.3 (95% CI, 6.0-62.1) for development of IgE-mediated CMA among infants with exposure to CMP at the age of 15 days or more (P < .001). Sixty-four patients with IgE-mediated CMA tolerated soy, and none had a proved allergy to soy.

CONCLUSIONS

IgE-mediated CMA is much less common than generally reported. Early exposure to CMP as a supplement to breast-feeding might promote tolerance. Finally, soy is a reasonable feeding alternative in patients with IgE-mediated CMA.

Risk for asthma in offspring of asthmatic mothers versus fathers: a meta-analysis

BACKGROUND

Many human epidemiologic studies demonstrate that maternal asthma confers greater risk of asthma to offspring than does paternal disease. However, a handful have shown the opposite. Given this disparity, a meta-analysis is necessary to determine the veracity and magnitude of the "maternal effect."

METHODOLOGY/PRINCIPAL FINDINGS

We screened the medical literature from 1966 to 2009 and performed a meta-analysis to compare the effect of maternal asthma vs. paternal asthma on offspring asthma susceptibility. Aggregating data from 33 studies, the odds ratio for asthma in children of asthmatic mothers compared with non-asthmatic mothers was significantly increased at 3.04 (95% confidence interval: 2.59-3.56). The corresponding odds ratio for asthma in children of asthmatic fathers was increased at 2.44 (2.14-2.79). When comparing the odds ratios, maternal asthma conferred greater risk of disease than did paternal asthma (3.04 vs. 2.44, p = 0.037). When analyzing the studies in which asthma was diagnosed by a physician the odds ratios were attenuated and no significant differences were observed (2.85 vs. 2.48, N = 18, p = 0.37). Similarly, no significant differences were observed between maternal and paternal odds ratios when analyzing the studies in which the patient population was 5 years or older (3.15 vs. 2.60, p = 0.14). However, in all cases the trend remained the same, that maternal asthma was a greater risk factor for asthma than paternal.

CONCLUSIONS/SIGNIFICANCE

The results show that maternal asthma increases offspring disease risk to a greater extent than paternal disease.

Total and specific IgE associations between New York City Head Start children and their parents

BACKGROUND

Allergy and asthma risk share strong inherited components; however, the relative importance of maternal and paternal atopy in predicting child atopy remain unclear.

OBJECTIVE

We sought to identify relationships between parents' and children's total and specific IgE levels within family units as predictors of allergic risk in children.

METHODS

Total and allergen-specific IgE (to dust mite, cockroach, mouse, and cat) were determined by means of ImmunoCap (Phadia, Inc, Portage, Mich) in a sample of families participating in New York City Head Start programs. Regression models were developed to determine the associations of parents' and children's total IgE levels and sensitization patterns.

RESULTS

Blood specimens were collected from 161 family triads of mother, father, and child (83 boys and 78 girls). At a mean age of 4 years, boys had significantly higher total IgE levels than girls. Boys' total IgE levels were highly correlated with both mothers' (P < .002) and fathers' (P = .002) total IgE levels; girls' total IgE levels were not. Unlike total IgE levels, specific IgE levels among both boys and girls were associated with their mothers' specific IgE levels. Dust mite sensitization among mothers was predictive of children's sensitization to each of the 4 aeroallergens.

CONCLUSION

The strong associations between parents' and children's IgE levels suggest that assessment of parents' total and locally relevant allergen-specific IgE levels might have value in predicting atopy in children of preschool age.