Maternal smoking during pregnancy and lactation increases the risk for atopic eczema in the offspring

Development of allergies and asthma in infants and young children with atopic dermatitis--a prospective follow-up to 7 years of age

BACKGROUND

The prognosis of atopic dermatitis is usually good, but the risk of developing asthma and allergic rhinitis is very high. The aim of this study was to follow children with atopic eczema up to school age to chart the course of sensitization and development of clinical allergy, as well as to study risk factors of sensitization.

METHODS

Ninety-four children with atopic dermatitis were followed up to 7 years of age. The children were examined twice a year up to 3 years of age, and thereafter once yearly. At each visit, a clinical examination was performed, and a blood sample was taken. After 3 years of age, skin prick tests (SPTs) with inhalation allergens were performed at each visit. Information was obtained about atopy in the family, feeding patterns during infancy, symptoms of atopic disease, infections, and environmental factors.

RESULTS

During the follow-up, the eczema improved in 82 of the 94 children, but 43% developed asthma and 45% allergic rhinitis. The risk of developing asthma was higher in children with a heredity of eczema. Presence of severe eczema at the time of inclusion in the study was associated with an increased tendency to produce food-specific IgE. An early onset of eczema was associated with an increased risk of sensitization to inhalant allergens, and development of urticaria. Early allergic reactions to food were associated with later reactions to food, allergic rhinitis, urticaria, and sensitization to both food and inhalant allergens. Early feeding patterns, time of weaning, and introduction of solid food did not influence the risk of development of allergic symptoms. A large number of periods or days with fever during the follow-up was associated with an increased risk of developing allergic rhinitis and urticaria.

CONCLUSIONS

Our results confirm the good prognosis for the dermatitis and the increased risk of developing asthma and allergic rhinitis. Development of other allergic symptoms or sensitization was associated with the following factors: a family history of eczema, age at onset of eczema and its severity, early adverse reactions to foods, and proneness to infections.

Gestational nicotine exposure alone or in combination with ethanol down-modulates offspring immune function

Prenatal nicotine exposure has been shown to disrupt the development of a number of peripheral organs. In the current study, we examined the effects of gestational nicotine exposure, alone or in combination with ethanol exposure, on offspring immune function. Timed pregnant rats were treated with either nicotine (6 mg/kg/day) from gestation day 4-20 using subcutaneously implanted osmotic mini-pumps or ethanol administered in the drinking water (15% w/v) from gestation day 10-20. The combined exposure group received both treatments. The ability of offspring T and B cells to proliferate in response to nonspecific stimulation by Concanavalin A or lipopolysaccharide, respectively, was determined on postnatal days 9, 15, 22, 29, 64, and 86. Offspring splenocyte beta(2)-adrenoceptor binding was also measured. Nicotine or nicotine+ethanol suppressed splenocyte responsiveness to Concanavalin A or lipopolysaccharide which was similar in timing and magnitude to that seen with ethanol alone. Splenocytes from these groups remained subresponsive to stimulation well into adulthood. The combined drug treatment caused an overall reduction in spleen beta-adrenergic receptor binding whereas the individual drug treatments did not alter the development of spleen beta-adrenergic receptors.Our results indicate that prenatal nicotine exposure can cause long-term suppression of the proliferative response of offspring immune cells. Moreover, the effects of nicotine+ethanol may cause more severe deficits in adulthood.

Indoor risk factors for atopic eczema in school children from East Germany

This study aimed to investigate the relation between environmental influences such as arsenic, cadmium, lead, and mercury, as well as environmental tobacco smoke, pet keeping, and heating systems on the prevalence of atopic eczema. Therefore, a multicenter cross-sectional study of school children aged 5-14 years, including a standardized questionnaire, blood and urine analyses, and a dermatological examination, was undertaken. A cases-control approach was chosen in order to identify relevant risk factors. A total of 2200 school children (response 79.1%) of two areas (Bitterfeld, Hettstedt) polluted by industrial activities and an agricultural control region (Zerbst) of the former German Democratic Republic were examined. Atopic eczema as identified by dermatological examination and history was the outcome variable of interest. Body burden of arsenic and heavy metals and questionnaire data on environmental tobacco smoke exposure, pet keeping, and heating system were investigated as potential risk factors. The overall prevalence of atopic eczema was 2.6%, with higher prevalences in the industrial areas (2.5 and 2.9%) compared to the control area (1.6%, not significant). Bivariate analyses did not reveal statistically significant associations between atopic eczema and tobacco smoke exposure or the body burden of arsenic and heavy metals. According to multiple logistic regression analysis, atopic eczema was significantly more frequent in predisposed families and those who reported keeping guinea pigs (OR=4.37, CI 2.15-8.91), but not other pets, like dogs, cats, and hamsters. In comparison to a distant heating system, a decreased risk was observed in households with central heating system (OR=0.30, CI 0.10-0.90), whereas the presence of a gas heater with an exhaust pipe connection to the wall was associated with a significantly elevated risk for eczema (OR=8.22, CI 2.44-27.66). The heating system and exposure to certain animal allergens are related to the manifestation of atopic eczema. Further studies are needed to clarify how far a causal relationship is reflected by these findings.

Health effects of passive smoking-10: Summary of effects of parental smoking on the respiratory health of children and implications for research

BACKGROUND

Two recent reviews have assessed the effect of parental smoking on respiratory disease in children.

METHODS

The results of the systematic quantitative review published as a series in Thorax are summarised and brought up to date by considering papers appearing on Embase or Medline up to June 1998. The findings are compared with those of the review published recently by the Californian Environmental Protection Agency (EPA). Areas requiring further research are identified.

RESULTS

Overall there is a very consistent picture with odds ratios for respiratory illnesses and symptoms and middle ear disease of between 1.2 and 1.6 for either parent smoking, the odds usually being higher in pre-school than in school aged children. For sudden infant death syndrome the odds ratio for maternal smoking is about 2. Significant effects from paternal smoking suggest a role for postnatal exposure to environmental tobacco smoke. Recent publications do not lead us to alter the conclusions of our earlier reviews. While essentially narrative rather than systematic and quantitative, the findings of the Californian EPA review are broadly similar. In addition they have reviewed studies of the effects of environmental tobacco smoke on children with cystic fibrosis and conclude from the limited evidence that there is a strong case for a relationship between parental smoking and admissions to hospital. They also review data from adults of the effects of acute exposure to environmental tobacco smoke under laboratory conditions which suggest acute effects on spirometric parameters rather than on bronchial hyperresponsiveness. It seems likely that such effects are also present in children.

CONCLUSIONS

Substantial benefits to children would arise if parents stopped smoking after birth, even if the mother smoked during pregnancy. Policies need to be developed which reduce smoking amongst parents and protect infants and young children from exposure to environmental tobacco smoke. The weight of evidence is such that new prevalence studies are no longer justified. What are needed are studies which allow comparison of the effects of critical periods of exposure to cigarette smoke, particularly in utero, early infancy, and later childhood. Where longitudinal studies are carried out they should be analysed to look at the way in which changes in exposure are related to changes in outcome. Better still would be studies demonstrating reversibility of adverse effects, especially in asthmatic subjects or children with cystic fibrosis.

Epidemiology of allergic diseases

The escalation of allergic diseases (hay fever, asthma, atopic eczema) over recent decades has been linked to an increase in environmental pollutants. The prevalence of hay fever is associated with genetic predisposition, and some reports show an association with urban areas, socioeconomic status, and combined high allergen and automobile exhaust exposure. In asthma, there is also some evidence for geographical variations in prevalence; exercise challenge tests prove positive more often in urban areas than in rural areas. Although genetic predisposition is the strongest single risk factor for atopic eczema, air pollutants may aggravate the condition by acting as unspecific irritants and immunomodulators, leading to increased immunoglobulin E expression. In a study of 678 pre-school children, the influence of maternal smoking habits on individual measures of atopy revealed a positive association between smoking during pregnancy/lactation, and a positive history of atopic eczema. An East-West German comparative study examining different types and levels of air pollution, i.e. sulphurous (industrial; East) and oxidising (urban; West), showed that the prevalence of atopic eczema was greatest in East Germany. When various direct and indirect parameters of air pollution exposure were measured, the greatest association with atopic eczema was found with NOx exposure (indoor use of gas without a cooker hood), and close proximity to roads with heavy traffic. The increased prevalence of atopic eczema cannot be explained by changes in study methodology over time, or conventional risk factors alone; environmental risk factors may be an important contributing factor.