To systematically search, summarize, and critically appraise the literature to examine whether pet exposure in early life is associated with an increased risk of eczema.
We searched MEDLINE (1950 to June 2006) supplemented by citation lists in retrieved articles and contact with researchers. No language restrictions were imposed.
Cohort studies were sufficiently similar to allow pooled analysis. Meta-analysis was not possible for cross-sectional studies owing to differences in methods and populations.
Incidence or prevalence of eczema.
Evidence from longitudinal studies showed that previous exposure to cats (pooled odds ratio [OR], 0.76; 95% confidence interval [CI], 0.62-0.92), dogs (pooled OR, 0.68; 95% CI, 0.53-0.87), or "any furry pet" (pooled OR, 0.79; 95% CI, 0.74-0.84) is associated with a lower risk of eczema. However, in the only cohort study adjusted for avoidance behavior, this "protective effect" disappeared (for cats: OR, 0.80; 95% CI, 0.33-1.97). Stratified analysis by family history in 2 birth cohort studies showed that dog exposure was protective in patients with atopic families. For cats, 1 study showed reduced risk in atopic families only; the other study showed no effect. Eight cross-sectional studies evaluated past pet exposure; a protective effect was seen in 3 studies for cat, dog, or any pet; no study demonstrated an increased risk.
There was no clear evidence that early pet exposure is associated with increased risks of subsequent eczema. We found some evidence of a possible protective effect of early pet exposure, but this might be explained by avoidance behavior in high-risk families.
"This means that, in practice, it is very difficult to determine children’s exact level of exposure to the various fuels or residues released at home by indoor systems. On the other hand, due to lacking data, this study has not attempted to assess the degree of exposure to fuels in closed places other than their home where children spend much of their time (i.e., schools), the presence of other allergens in domestic environments (i.e., mould, dust, mites, etc.) [32,33], dietary habits  or alternative variables which represent in a more accurate way the social status of the family. Accordingly, it should be taken into account the possible presence of residual confounding in the present analysis. "
[Show abstract][Hide abstract] ABSTRACT: Atopic dermatitis (AD) prevalence has considerably increased worldwide in recent years. Studying indoor environments is particularly relevant, especially in industrialised countries where many people spend 80% of their time at home, particularly children. This study is aimed to identify the potential association between AD and the energy source (biomass, gas and electricity) used for cooking and domestic heating in a Spanish schoolchildren population.
As part of the ISAAC (International Study of Asthma and Allergies in Childhood) phase III study, a cross-sectional population-based survey was conducted with 21,355 6-to-7-year-old children from 8 Spanish ISAAC centres. AD prevalence, environmental risk factors and the use of domestic heating/cooking devices were assessed using the validated ISAAC questionnaire. Crude and adjusted odds ratios (cOR, aOR) and 95% confidence intervals (CIs) were obtained. A logistic regression analysis was performed (Chi-square test, p-value < 0.05).
It was found that the use of biomass systems gave the highest cORs, but only electric cookers showed a significant cOR of 1.14 (95% CI: 1.01-1.27). When the geographical area and the mother’s educational level were included in the logistic model, the obtained aOR values differed moderately from the initial cORs. Electric heating was the only type which obtained a significant aOR (1.13; 95% CI: 1.00-1.27). Finally, the model with all selected confounding variables (sex, BMI, number of siblings, mother’s educational level, smoking habits of parents, truck traffic and geographical area), showed aOR values which were very similar to those obtained in the previous adjusted logistic analysis. None of the results was statistically significant, but the use of electric heating showed an aOR close to significance (1.14; 95% CI: 0.99-1.31).
In our study population, no statistically significant associations were found between the type of indoor energy sources used and the presence of AD.
BMC Public Health 10/2012; 12(1):890. DOI:10.1186/1471-2458-12-890 · 2.26 Impact Factor
"et al., 2007). Out of 11 cohort and crosssectional studies, five reported significant decreases in eczema risk, yet no significant increases were observed, suggesting that dog exposure may be protective against childhood eczema (Langan et al., 2007). Further, we found that children who were exposed to dog and carried the CT or TT genotype at CD14–159C/T had the lowest risk for eczema at both ages 2 and 3. "
[Show abstract][Hide abstract] ABSTRACT: Eczema is very common and increasing in prevalence. Prospective studies investigating environmental and genetic risk factors for eczema in a birth cohort are lacking. We evaluated risk factors that may promote development of childhood eczema in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) birth cohort (n=762) of infants with at least one atopic parent. Objective environmental exposure data were available for each participant. At annual physical examinations, children underwent skin prick tests (SPTs), eczema was diagnosed by a clinician, and DNA was collected. Among Caucasian children, 39% developed eczema by age 3. Children with a pet dog were significantly less likely to have eczema at age one (odds ratio (OR)=0.62, 95% confidence interval (CI): 0.40-0.97) or at both ages 2 and 3 (OR=0.54, 95% CI: 0.30-0.97). This finding was most significant among children carrying the CD14-159C/T CC genotype. Carriers of the CD14-159C/T and IL4Ralpha I75V single-nucleotide polymorphisms (SNPs) had an increased risk of eczema at both ages 2 and 3 (OR=3.44, 95% CI: 1.56-7.57), especially among children who were SPT+. These results provide new insights into the pathogenesis of eczema in high-risk children and support a protective role for early exposure to dog, especially among those carrying the CD14-159C/T SNP. The results also demonstrate a susceptibility effect of the combination of CD14 and IL4Ralpha SNPs with eczema.
Gabriele Saccone, Vincenzo Berghella, Laura Sarno, Giuseppe M Maruotti, Irene Cetin, Luigi Greco, Ali S Khashan, Fergus McCarthy, Domenico Martinelli, Francesca Fortunato, Pasquale Martinelli
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