Effect of parental smoking on IgE levels in children

Passive Smoking, Potential Atopy and Asthma in the First Five Years

Evidence of prolonged exposure to cigarette smoke was sought in a group of 86 children aged five years and under with moderately severe asthma, and in 1199 infants from a mixed background population of Armed Service and civilian families. Asthmatics with a normal serum IgE (less than +1 s.d. for age) made up almost half of the cases and, compared with those with an elevated serum IgE (+1 s.d. for age or more), a greater proportion were male, had experienced prolonged exposure to cigarette smoke, were from Service families and already had fixed chest deformity. It is suggested that, in addition to facilitating the expression of asthma in young potential atopics, passive smoking may be an important contributory cause of the more severe disease reported in the socalled ‘intrinsic’ group. Perhaps the burden of illness and the extent of exposure noted in this survey will prompt renewed efforts to be made to discourage smoking in families, particularly two years before and for at least five years after the birth of a child.

Meconium microbiota types dominated by lactic acid or enteric bacteria are differentially associated with maternal eczema and respiratory problems in infants

BACKGROUND

Culture-dependent methods have shown that meconium, the newborn's first intestinal discharge, is not sterile, but the diversity of bacteria present in this material needs to be further characterized by means of more sensitive molecular techniques.

OBJECTIVE

Our aims were to characterize molecularly the meconium microbiota in term infants, to assess whether it contributes to the future microbiota of the infants' gastrointestinal tract, and to evaluate how it relates to lifestyle variables and atopy-related conditions.

METHODS

We applied high-throughput pyrosequencing of the 16S rRNA gene to study the meconium microbiota in twenty term newborns from a Spanish birth cohort. For comparison, we characterized the microbiota in fecal samples from seven pregnant women days before delivery and in two series of infant samples spanning the first seven months of life. We also compared our data with vaginal and skin microbiota characterized in independent studies. Different types of meconium microbiota were defined based on taxonomic composition and abundance and their associations with different factors were statistically evaluated.

RESULTS

The meconium microbiota differs from those in adult feces, vagina and skin, but resembles that of fecal samples from young infants. Meconium samples clustered into two types with different bacterial diversity, richness and composition. One of the types was less diverse, dominated by enteric bacteria and associated with a history of atopic eczema in the mother (P = 0.038), whereas the second type was dominated by lactic acid bacteria and associated with respiratory problems in the infant (P = 0.040).

CONCLUSIONS & CLINICAL RELEVANCE

Our findings suggest that the meconium microbiota has an intrauterine origin and participates in gut colonization. Although based on a small population sample, our association analyses also suggest that the type of bacteria detected in meconium is influenced by maternal factors and may have consequences for childhood health.

Hyaluronan and layilin mediate loss of airway epithelial barrier function induced by cigarette smoke by decreasing E-cadherin

Cigarette smoke (CigS) exposure is associated with increased bronchial epithelial permeability and impaired barrier function. Primary cultures of normal human bronchial epithelial cells exposed to CigS exhibit decreased E-cadherin expression and reduced transepithelial electrical resistance. These effects were mediated by hyaluronan (HA) because inhibition of its synthesis with 4-methylumbelliferone prevented these effects, and exposure to HA fragments of <70 kDa mimicked these effects. We show that the HA receptor layilin is expressed apically in human airway epithelium and that cells infected with lentivirus expressing layilin siRNAs were protected against increased permeability triggered by both CigS and HA. We identified RhoA/Rho-associated protein kinase (ROCK) as the signaling effectors downstream layilin. We conclude that HA fragments generated by CigS bind to layilin and signal through Rho/ROCK to inhibit the E-cadherin gene and protein expression, leading to a loss of epithelial cell-cell contact. These studies suggest that HA functions as a master switch protecting or disrupting the epithelial barrier in its high versus low molecular weight form and that its depolymerization is a first and necessary step triggering the inflammatory response to CigS.

Immediate and short-term consequences of secondhand smoke exposure on the respiratory system

PURPOSE OF REVIEW

This review critically evaluates the existing biological evidence regarding the immediate and short-term respiratory consequences of secondhand smoke (SHS).

RECENT FINDINGS

A 1-h exposure to SHS at bar/restaurant levels generates a marked inflammatory reaction and significant decrements on lung function. These deleterious effects of SHS are exacerbated when physical activity follows the SHS exposure, particularly in less fit individuals. The main respiratory effect mechanisms of SHS include a direct induction of growth factors resulting in airway remodelling and alterations in nitric oxide regulation. Pharmacological agents that increase either apical membrane chloride conductance or basolateral membrane potassium conductance may be of therapeutic benefit in patients with diseases related to SHS exposure. Moreover, treatment with statins has shown beneficial effects towards preventing the SHS-induced pulmonary hypertension, vascular remodelling, and endothelial dysfunction.

SUMMARY

Based on recently discovered evidence, even brief and short-term exposures to SHS generate significant adverse effects on the human respiratory system. Future research directions in this area include the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as pharmacological treatments for reversing the SHS-induced airway remodelling.

Biological evidence for the acute health effects of secondhand smoke exposure

A vast number of studies on the unfavorable effects of secondhand smoke (SHS) exist within the international literature, the majority of which evaluate longitudinal epidemiological data. Although limited, the experimental studies that assess the acute and short-term effects of exposure to SHS are also increasing in number. They include cellular, animal, and human studies that indicate a number of pathophysiological mechanisms through which the deleterious effects of SHS may arise. This current review evaluates the existing biological evidence regarding the acute health effects of SHS exposure. Analyses on the inhaled toxicants and the carcinogenicity of SHS are included as well as in-depth discussions on the evidence for acute SHS-induced respiratory, cardiovascular, metabolic, endocrine and immune effects, and SHS-induced influences on oxygen delivery and exercise. The influence of the length of exposure and the duration of the observed effects is also described. Moreover, recent findings regarding the underlying pathophysiological mechanisms related to SHS are depicted so as to generate models that describe the SHS-induced effects on different systems within the human body. Based on the presented biological evidence, it is concluded that brief, acute, transient exposures to SHS may cause significant adverse effects on several systems of the human body and represent a significant and acute health hazard. Future research directions in this area include research on the concentrations of tobacco smoke constituents in the alveolar milieu following SHS exposure, individual susceptibility to SHS, as well as the effects of SHS on neurobehavioral activity, brain cell development, synaptic development, and function.

Influence of environmental factors on IgE production

The prevalence of atopic diseases appears to have increased rapidly, especially in industrialized countries. The increase may be explained by a change in certain environmental factors. This article focuses on the influence of environmental factors on IgE production. Epidemiological or experimental reports have shown that tobacco smoke, virus infection and mercuric chloride may enhance IgE production. We demonstrated the enhancing effect of diesel-exhaust particulates (DEP), which seem to have increased in urban environments, on IgE antibody production. The IgE antibody responses in mice immunized by intraperitoneal injection of antigens mixed with DEP were higher than those in animals immunized with the antigens alone. DEP also had an adjuvant activity for IgE antibody production in mice after entry via the respiratory tract (the natural mode of entry). The enhancing effect of DEP on IgE antibody responses was demonstrated even when a small dose such as 1 micrograms of DEP was given intranasally at three-week intervals. Our further study has indicated that suspended particulate matter including materials other than DEP has an adjuvant activity for IgE antibody production.

Prenatal prediction of infant atopy by maternal but not paternal total IgE levels

BACKGROUND

The atopic history of parents has long been used to predict infant atopy. However, bias from questionnaires of allergic history are also frequently suspected, because a large number of vasomotor rhinitis, intrinsic asthma, and seborrheic dermatitis cases are probably misinterpreted to be atopic diseases.

OBJECTIVE

We attempted to identify a risk factor other than parental atopic history to predict elevated infant IgE levels and infant atopy.

METHODS

A total of 655 core families were prenatally recruited, and finally 545 families completed the study for the prospective analysis of infant atopy at 6 months of age. Atopic history and blood samples of parents were collected in the third trimester during pregnancy. Cord blood (CB) was collected immediately after birth. Infant blood samples and history of infant eczema were collected in the 6-month physical checkup clinic. Blood total IgE and specific IgE levels were determined by use of the Pharmacia CAP system.

RESULTS

In univariate analysis, maternal, but not paternal, atopic history correlated with elevated CB IgE levels and the occurrence of infant eczema. Elevated maternal, but not paternal, total IgE levels (>150 KU/L) significantly correlated with increases of CB IgE levels (median, 0.54 vs 0.17 KU/L, P <.001), infant IgE levels (log-transformed mean values, 1.32 +/- 0.51 vs 1.13 +/- 0.51 KU/L, P <.001), and infant eczema (P =.008). Multivariate logistical regression analysis, however, showed that only maternal total IgE levels correlated with CB and infant IgE levels and the development of infant eczema.

CONCLUSIONS

The maternal, but not paternal, total IgE level correlates with elevated infant IgE levels and infant atopy. This provides a high specificity (83%) and a sensitivity of 34% for prediction of infant atopy. This suggests that maternal factors, placental factors, or both have an impact on perinatal allergic sensitization.

Wheeze associated with prenatal tobacco smoke exposure: a prospective, longitudinal study. ALSPAC Study Team

AIMS

To determine whether maternal smoking during pregnancy is a risk factor for reported wheeze in early childhood that is independent of postnatal environmental tobacco smoke (ETS) exposure and other known risk factors.

METHODS

A total of 8561 mothers and infants completed questions about smoking during pregnancy, ETS exposure, and the mother's recall of wheeze during early childhood.

RESULTS

A total of 1869 (21.8%) children had reported wheeze between 18 and 30 months of age, and 3496 (40.8%) had reported wheeze in one or more of the three study periods (birth to 6 months, 6-18 months, 18-30 months). The risk of wheeze between 18 and 30 months of age was higher if the mother smoked during pregnancy. This relation did not show a dose-response effect and became less obvious after adjustment for the effects of other factors. Average daily duration of ETS exposure reported at 6 months of age showed a dose-response effect and conferred a similar risk of reported wheeze. Factors associated with early childhood wheeze had the following adjusted odds ratios: maternal history of asthma 2.03 (1.74 to 2. 37); preterm delivery 1.66 (1.30 to 2.13); male sex 1.42 (1.28 to 1. 59); rented accommodation 1.29 (1.11 to 1.51); and each additional child in household 1.13 (1.04 to 1.24).

CONCLUSIONS

Maternal smoking during pregnancy may be a risk factor for reported wheeze during early childhood that is independent of postnatal ETS exposure. For wheeze between 18 and 30 months of age, light smoking during the third trimester of pregnancy appears to confer the same risk as heavier smoking.

[Respiratory allergy in children and passive smoking]

Environmental tobacco smoke interacts with the respiratory mucosa by irritation and/or inflammation. Environmental tobacco smoke seems also modulate humoral and cellular immune activity. Thus, environmental tobacco smoke, in all children, increases the risk of superior and inferior airway infections, modifies the growth and the natural evolution of the respiratory function, increases the occurrence of asthma and exacerbates the symptoms of asthma, and creates or exacerbates a bronchial hyperresponsiveness. In atopic children (defined by the presence of at least one positive allergy skin test), environmental tobacco smoke increases the risk of respiratory allergy and exacerbates the symptoms of respiratory allergy. Parental environmental tobacco smoke is a universal toxic which must be avoided in both allergic and non-allergic children.

Prenatal origins of allergic disease

The prevalence of asthma and related allergic disorders has increased considerably over the last 25 years. Because genetic stock has not changed, environmental factors must have influenced the phenotype. Infants who experience the development of allergy already have an altered immune response at birth. We have investigated the development of immune responses during gestation and the effect of maternal allergen exposure during pregnancy and infant exposure in the first month of life on the development of allergy and disease. There was higher specific peripheral blood mononuclear cell proliferation to house dust mite and birch pollen in the third trimester compared with the second trimester, with the first positive responses seen at 22 weeks gestation. Maternal exposure to birch pollen after 22 weeks resulted in higher infant peripheral blood mononuclear cell responses to birch pollen at birth. Infants born at term, with at least 1 atopic parent with asthma, who experienced the development of allergic symptoms and positive skin prick test by 1 year of age had raised proliferative responses to house dust mite at birth compared with those infants with no symptoms. In genetically predisposed individuals, antenatal factors including maternal and thereby fetal exposure to allergens and materno-placental-fetal immunologic interactions are active in determining whether an allergic predisposition is manifested as disease.

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.

Cigarette smoke potentiates house dust mite allergen-induced increase in the permeability of human bronchial epithelial cells in vitro

Although studies have suggested that exposure to cigarette smoke (CS) may be associated with the development of atopy, the mechanisms underlying this are not clearly understood. It has been suggested that CS impairs the barrier function of the airway epithelium, leading to increased access of allergens such as those of the house dust mite (HDM) Dermatophagoides pteronyssinus (Der p) to antigen-presenting cells, with subsequent allergic sensitization. In order to test this hypothesis, we established primary explant cultures of human bronchial epithelial cells (HBEC) in cell culture inserts, and exposed these for 20 min, 1 h, 3 h, and 6 h to CS or air in the absence or presence of 300 ng/ml Der p, and then further incubated the cultures over a period of 24 h. The HBEC cultures were assessed for changes in permeability as measured by changes in: (1) electrical resistance (ER); and (2) passage of 14C-labeled bovine serum albumin (14C-BSA) and Der p allergens across the HBEC cultures. We also assessed the effects of protease inhibitors and the antioxidant glutathione (GSH) in this experimental system. Damage to HBEC cultures was assessed by the release of [51Cr]sodium chromate from prelabeled cells, and by release of lactate dehydrogenase (LDH). Twenty minutes of exposure to CS as compared with exposure to air did not significantly alter either the ER or passage of 14C-BSA across the HBEC cultures. In contrast, incubation with Der p led to a significant increase in the permeability of HBEC cultures, an effect that was enhanced by exposure to CS but was abrogated by the specific protease inhibitors and GSH. Passage of Der p was also increased by exposure to CS. Exposure of HBEC cultures to CS led to a significant release of 51Cr and LDH from these cells as compared with cells exposed to air. This effect was augmented further when HBEC cultures were incubated with Der p. Exposure of HBEC cultures for 1 h, 3 h, and 6 h to CS led to a markedly significant dose- and time-dependent increase in the permeability of these cells. These results suggest that exposure to CS significantly enhances Der p-induced decreases in electrical resistance and the increased passage across HBEC cultures of 14C-BSA and of the Der p allergen itself.

Health effects of passive smoking .5. Parental smoking and allergic sensitisation in children

BACKGROUND

A systematic review was conducted of the effects of parental smoking on immunoglobulin (IgE) levels, skin prick positivity, and allergic rhinitis or eczema in children. Asthma was excluded in order to distinguish more clearly the effect of passive smoke exposure on allergic sensitisation.

METHODS

Thirty six relevant publications were identified after consideration of 692 articles selected by electronic search of the Embase and Medline databases using keywords relevant to passive smoking in children. The search was completed in April 1997 and identified nine studies of IgE in neonates, eight of IgE in older children, 12 which included skin prick tests, and 10 describing symptoms of allergic disease other than asthma or wheezing. A quantitative meta-analysis was possible only for the studies reporting skin prick tests.

RESULTS

Several large studies failed to confirm early reports of a substantial or statistically significant association of maternal smoking with concentrations of total serum IgE in neonates or in older children. No consistent association emerged between parental smoking and allergic rhinitis or eczema. Few of these studies adjusted for potential confounding variables. The quantity and quality of evidence was greatest for skin prick tests, and studies of parental smoking during pregnancy or infancy were broadly consistent in showing no adverse effect on prick positivity (pooled odds ratio 0.87, 95% confidence interval 0.62 to 1.24). There was much greater and statistically significant (p = 0.002) heterogeneity of odds ratios relating current parental smoking to skin prick positivity.

CONCLUSIONS

Parental smoking, either before or immediately after birth, is unlikely to increase the risk of allergic sensitisation in children.

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

BACKGROUND

Maternal smoking during pregnancy has been shown to lead to immunologic changes in the offspring. However, little is known about the influence of this exposure on atopic manifestations.

OBJECTIVE

Our purpose was to investigate the influence of air pollutants on manifestations of atopy in preschool children.

METHODS

Unselected cohorts of a total of 678 5- to 6-year-old preschool children (350 boys, 328 girls) were investigated in areas with different degrees of air pollution in Bavaria. Data on the history of atopic diseases and other relevant factors were obtained by questionnaire. A skin-prick test was performed with common aeroallergens. Manifestation of atopy was defined as personal history of atopic disease or positive prick test to either grass pollen, house dust mite, or cat and analyzed multivariately.

RESULTS

Of all children, 38.9% exhibited at least one manifestation of atopy. Atopic eczema was reported in 7.9% to 15.5%, hayfever in 4.1% to 25.6%, and asthma in 3.0% to 8.1%. Of the mothers, 12.6% smoked during pregnancy or lactation or both. Analysis of the manifestation of atopy including sex, location, nitrogen oxide and sulfur dioxide exposure and maternal smoking as covariates revealed an influence of the maternal smoking during pregnancy/lactation. Of children whose mothers had smoked during pregnancy/lactation, 52.2% exhibited manifestations of atopy in contrast to 35.7% of children of nonsmoking mothers (p < 0.044). A history of atopic eczema was the only component of the variable "manifestation of atopy" that was significantly associated with maternal smoking during pregnancy and lactation. A causal interpretation of this finding, however, was not supported by a follow-up study.

CONCLUSION

Maternal smoking during pregnancy or lactation or both might play a role in the development of atopic eczema and should be avoided.

Allergy development and macromolecular absorption in infants with different feeding regimens during the first three days of life. A three-year prospective follow-up

A group of 129 infants were randomly assigned at birth to one of three feeding regimens: human milk (HM), cow's milk formula (CMF) or a casein hydrolysate formula (CHF) during the first 3 days of life. Blood samples were taken on at 4 days and at 2, 4, 8, 12 and 24 months of age. Macromolecular absorption was analysed by measuring the serum concentration of human alpha-lactalbumin (S-alpha-LA) with a competitive radioimmunoassay (RIA). Total serum IgE was measured by RIA. A family history of allergy correlated to the proportion of infants with allergic symptoms both at 24 and 36 months of age (p = 0.03 and p = 0.04 respectively). In none of the three groups did correlation exist between the duration of breastfeeding and serum alpha-LA, serum IgE, family history of allergy, frequency of allergic symptoms and proportion of infants with infections.

Sensitization to airborne allergens in children with respiratory symptoms

BACKGROUND

Allergy is one of the most common causes of respiratory symptoms in children and youth.

OBJECTIVE

Evaluate the presence and the type of allergic sensitization in a paediatric population with respiratory symptoms.

METHODS

We studied 564 consecutive children, 5 months to 17 years of age, with a male to female ratio (M/F) = 1.4, referred to our outpatient clinic in a 12-month period retrospectively. Patients were arbitrarily divided into four groups (grs) according to their age: gr1 = 5 months to 4 years old (181 patients), gr2 = 4 to 7 years (201 patients), gr3 = 7 to 10 years (96 patients), and gr4 = 10 to 17 years (86 patients). Sensitization to house dust mites, pollens, animal dander, and molds was determined by skin prick testing.

RESULTS

Sensitization to at least one class of allergen occurred in 304 of the 564 patients (53.9%, M/F ratio = 2.0); the percentage of allergic patients increased with age as follows: 29.8% (54 patients) of the patients in gr1, 55.2% (111 patients) in gr2, 68.8% (66 patients) in gr3 and 84.9% (73 patients) in gr4 (chi(2) = 84.1, P < .01). In the entire allergic population and in gr1 to gr3, the most common positive allergic reaction was to house dust mites (P < .01, chi(2) test each comparison). In contrast, gr4 patients showed a nearly equal percentage of sensitization to pollens and to house dust mites (79.5% and 78.1% respectively) (chi(2) = 0.0, P = >.1). Sensitization to only one class of allergen occurred in 51.3% of the allergic patients and the percentage of these monosensitized patients tended to decrease from gr1 to gr4 (chi(2) = 15.2, P < .1). In the monosensitized group, sensitization to house dust mites was the most frequent in gr1 to gr3 (age <10 years) as in the whole sample. In gr4, the frequency of sensitization to house dust mites was similar to that of sensitization to pollens. On the contrary, within the patient group sensitized to two or more allergens (polysensitized patients), sensitization to house dust mites was as frequent as sensitization to pollens already in gr2 as compared with monosensitized patients.

CONCLUSIONS

In children with respiratory symptoms, the percentage of allergic individuals was high and increased with the age of the patients. This phenomenon was associated with an age-related enhancement in the ratio of polysensitized to monosensitized patients and with an age-related increase in the frequency of sensitization to seasonal allergens (ie, pollens).

The development and prediction of atopy in high-risk children: follow-up at age seven years in a prospective randomized study of combined maternal and infant food allergen avoidance

BACKGROUND

The natural history of allergic disease and its potential for prevention merit close examination because of the explosive worldwide increase in the prevalence and morbidity of atopic disorders. This study examines the development of atopy at age 7 years in 165 children in a high-risk cohort, previously reported from birth to age 4 years.

METHODS

In this prospective, randomized, controlled study of food allergen avoidance in infancy, the prophylactic-treated group consisted of infants whose mothers avoided cow's milk, egg, and peanut during the last trimester of pregnancy and lactation and who, themselves, avoided cow's milk until age 1 year (casein hydrolysate supplementation before age 1), egg until age 2 years, and peanut and fish until age 3 years. The control group consisted of maternal/infant pairs who followed standard feeding practices.

RESULTS

Despite a significant reduction in food allergy and milk sensitization before age 2 years, none of the following differed between the groups at age 7 years: food allergy, atopic dermatitis, allergic rhinitis, asthma, any atopic disease, lung function, food or aeroallergen sensitization, serum IgE level, or presence of nasal eosinophils or nasal basophilic cells. Children with food allergy by 4 years evidenced higher 7-year (current) prevalences of allergic rhinitis and asthma (p < 0.01). Atopic diseases/parameters at age 7 years were shown, by multivariate analysis (p < 0.05), to be associated with several genetic and environmental risk factors (male gender, maternal nonwhite ethnicity and asthma, and household smoking), as well as predictive atopic markers during infancy (elevated serum IgE level; egg, cow's milk, and peanut sensitization; and nasal eosinophils and nasal basophilic cells).

CONCLUSIONS

These findings help to: (1) elucidate the natural history of atopic disease in high-risk children; (2) document the progression of allergy from atopic dermatitis, food allergy, and food sensitization to respiratory allergy and aeroallergen sensitization despite food allergy prevention in infancy; (3) identify allergy predictive markers; and (4) expand our appreciation of the interactions of genetic and environmental factors in the development of atopy.

Risk factors for asthmatic patients requiring intubation. I. Observations in children

There are significant concerns regarding the increased mortality of patients with asthma. Indeed the paradox of improved pharmacotherapy but worsening prognosis has been explored in depth in several studies including observations in epidemiology, access to medical care, and drug toxicity. Because of our ability to track all admissions to a tertiary-care hospital, we attempted to define the demographic data from a population of asthmatic children admitted for asthma in order to identify risk factors for intubation. We performed a retrospective cohort study of all asthma admissions excluding patients with cystic fibrosis. This study included all asthmatics aged 5-12 years admitted over a 10-year period (1984-1994) to the University of California at Davis Medical Center, Sacramento. A total of 300 such asthma admissions were reviewed, involving 135 girls and 165 boys, mean age 7.7 +/- 2.4 years. Of this group, 166 children were black, 70 were Caucasian, 49 were Hispanic, 14 were Asian, and 1 was an American Indian. By National Heart, Lung, and Blood Institute guidelines, this group included 147 mild, 117 moderate, and 36 severe cases. Thirteen children required intubation for their asthma. Significant risk factors identified for children requiring intubation, compared to those who did not require intubation, were secondhand smoke exposure [odds ratio (O.R.) 22.4; 95% confidence interval (C.I.) 7.4, 68.0], psychosocial problems (O.R. 13.5; 95% C.I. 5.1, 36.0), family dysfunction (O.R. 13.0; 95% C.I. 3.9, 43.9), upper respiratory infection (O.R. 10.2; 95% C.I. 3.4, 28.1), little formal education (O.R. 8.7; 95% C.I. 2.4, 31.6), prior asthma emergency room visit in past year (O.R. 7.2; 95% C.I. 1.9, 27.1), prior asthma hospitalization in past year (O.R. 7.1; 95% C.I. 2.2, 22.2), crowding (O.R. 6.9; 95% C.I. 2.5, 19.1), low socioeconomic status (O.R. 6.5; 95% C.I. 2.1, 20.8), steroid-dependent (O.R. 3.8; 95% C.I. 1.2, 12.1), parental history of allergy or asthma (O.R. 3.4; 95% C.I. 1.1, 10.0), and language barrier (O.R. 3.3; 95% C.I. 1.1, 10.6). Nonsignificant mild risk factors included inhaled cromolyn (O.R. 2.7; 95% C.I. 0.7, 10.0), atopy (O.R. 1.9; 95% C.I. 0.6, 5.9), and prior intubation (O.R. 1.6; 95% C.I. 0.2, 13.1). These risk parameters may be important determinants of baseline risk for asthma deaths and their recognition may have a significant impact on preventive measures.

Risk factors for asthmatic patients requiring intubation. II. Observations in teenagers

The asthma mortality rate has increased steadily over the past 15 years in the United States and has only recently shown signs of leveling off. It is widely believed, although unproven, that many asthma deaths may be preventable. We have addressed one critical factor in severe asthma by attempting a definition of risk factors for intubation using demographic data and a retrospective cohort study of hospitalized asthmatic teenagers. This study included all asthmatics aged 13-19 years admitted over a 10-year period (1984-1994) to the University of California Davis Medical Center, Sacramento, California. A total of 143 such asthma admissions were reviewed, involving 68 females and 75 males, mean age 16.4 +/- 2.3 years. Of this group, 85 teenagers were black, 34 were Caucasian, 14 were Hispanic, and 10 were Asian. By National Heart, Lung, and Blood Institute guidelines, there were 42 mild, 85 moderate, and 16 severe cases. Ten of the 143 teenagers studied required intubation for their asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma, allergy, and atopy in three south-east Asian populations

BACKGROUND

Whilst many recent reports have suggested a rise in the prevalence of asthma and allergic disease in Western countries, little is known about the epidemiology of these common conditions in south-east Asia. This study compared the prevalence of asthma and allergic disease amongst secondary school students in three south-east Asian populations--Hong Kong, Kota Kinabalu in Malaysia, and San Bu in China--and investigated the associations with atopy and family history.

METHODS

Secondary school students were given standard questionnaires on respiratory and allergic symptoms for completion by parents with response rates of 89.2% in Hong Kong (611 male, 451 female; mean (SD) age = 13.9 (1.8 years), 87.6% in Kota Kinabalu (134 male, 275 female; 15.5 (2.1) years), and 98.6% in San Bu (492 male, 245 female; 16.4 (1.8) years). Skin tests were performed in a subsample of students to determine atopic status.

RESULTS

The respective prevalence (and 95% CI) for hayfever, eczema, and wheeze or asthma were 15.7% (13.5, 17.9), 20.1% (17.7, 22.5), 11.6% (9.3, 13.9) in Hong Kong, 11.2% (8.2, 14.3), 7.6% (5.0, 10.1), 8.2% (5.5, 10.9) in Kota Kinabalu, and 2.1% (1.2, 3.1), 7.2% (5.4, 9.1), 1.9% (0.7, 3.1) in San Bu. Atopy was common and was present in 49.0-63.9% of subjects in the three populations. Dust mite and cockroach were the commonest allergens that gave positive reactions in 42.8-60.5% and 25.7-35.9% of students respectively. A higher proportion of students in Hong Kong had severe degree of reactivity on skin test than the other two populations. Family history was associated with asthma and allergic symptoms in the three populations conferring a 3-80-fold increase in risk to family members and was a stronger predictor for asthma and allergy than atopy.

CONCLUSIONS

Prevalence of asthma and allergic disease is low compared with Western countries, but considerable differences exist between the three south-east Asian populations despite similar rates of atopy. Asthma and allergic disease are more strongly associated with family history than atopy, which suggests that genetic and environmental factors common to the family, other than aeroallergen sensitisation, are important in the pathogenesis of asthma and allergy in the region.

Appearance of atopic disease in relation to serum IgE antibodies in children followed up from birth for 4 to 15 years

BACKGROUND

Few studies have addressed the relationship between sensitization and the development of atopic disease over many years.

OBJECTIVE

To study the temporal relationship between the appearance of IgE antibodies in serum and atopic disease, we studied 324 children from three different groups, who were followed up prospectively from birth for 4, 12, and 15 years, respectively.

METHODS

Serum samples were obtained at various ages and analyzed for IgE antibodies against egg white, cow's milk, wheat, animal dander, house dust mite, birch and timothy with Phadebas RAST (Kabi Pharmacia Diagnostics AB, Uppsala, Sweden) or Pharmacia CAP system. In addition, a screening test for atopy, the Phadiatop Paediatric test (Kabi Pharmacia Diagnostics AB) was performed. Presence of atopic disease was assessed by means of clinical examination, interviews, and questionnaires.

RESULTS

In 135 children IgE antibodies were detected at least once to at least one allergen. Antibodies to egg white appeared in 46 children before or at 2 years of age: in 57% of them IgE antibodies to inhalants developed within the next 2 years, and in 19 of 25 (76%) IgE antibodies to inhalants developed before or at 12 to 15 years. Antibodies to inhalant allergens appeared in 55 children during the first 4 years of life and in 64 before 12 to 15 years. Among the former 48% and among the latter 32% had previously detectable egg white antibodies. Atopic disease appeared before or at age 4 years in 80% of the 40 children with IgE antibodies against egg white up to 9 months of age and in 69% of the 58 children who had a positive Phadiatop Paediatric test result in infancy.

CONCLUSIONS

IgE antibodies in children are usually associated with current or later topic disease. Sensitization to foods in infants is usually associated with appearance of IgE antibodies to inhalants later in life.

High anti-IgE levels at birth are associated with a reduced allergy prevalence in infants at risk: a prospective study

Development of atopic disease was prospectively studied in 148 children from birth to the age of 18 months and related to serum levels of IgG anti-IgE antibody. Children with a dual heredity of allergy, but remaining healthy, had significantly higher IgG anti-IgE levels at birth than children with a similar predisposition to allergy, who became allergic. Children with increased allergy risk, defined by elevated IgE levels at birth (> = 0.53 kU/l) and with probable allergy symptoms had also significantly higher IgG anti-IgE levels at birth than children of the same risk group, developing definite allergy. Independent of allergy risk, there was a significantly lower prevalence of atopic disease in children with cord serum levels of IgG anti-IgE above 350 AU/l than in children with lower levels. Additionally, we showed that the allergy predictive capacity of IgE levels in cord serum was slightly improved in specificity, sensitivity and efficiency by including not only the family history of allergy, but also cord serum levels of IgG anti-IgE. Our results thus raise the possibility that high levels of IgG anti-IgE protect children of increased allergy risk from early development of atopic disease and reduce the severity of symptoms.

Genetic 'risk' for atopy is associated with delayed postnatal maturation of T-cell competence

Recent in vitro studies suggest that IgE production in adults is co-ordinately regulated by negative signals from gamma IFN-producing CD4+ T-helper-1 (TH-1) and positive signals from IL-4 producing (TH-2) T-cells. Additionally, seroepidemiological evidence has pinpointed infancy as the period of maximum lifetime risk for T-cell sensitization to ubiquitous environmental antigens. The present study sought to elucidate the relationship between these observations, by examination of CD4+ T-cell function in normal children and those genetically at 'high risk' for atopy, spanning the age range (up to 4 years) in which IgE responses to environmental allergens is typically manifest. Immunocompetent T-cell precursor frequencies (determined by cloning at limiting dilution) were markedly reduced in 'high risk' children relative to normals (0.53 +/- 0.29 vs 0.26 +/- 0.19; P = 0.0025). Consistent with reports from other laboratories employing bulk T-cell culture techniques, the gamma IFN producing capacity of CD4+ T-cell clones from both groups of children were markedly reduced relative to adults, and was lowest in the high risk group (P < 0.02). IL-4 production by CD4+ T-cell clones from the normal children was within the adult range, but again was significantly lower in the high risk group (P < 0.00005). This indicates that initial immune responses to environmental allergens in early childhood occur against a background of maturational 'deficiency' in CD4+ T-cell function, and suggests the possibility that variations in the rate of postnatal maturation of T-cell competence may be a contributing factor in the development of differing patterns of immunological responsiveness to environmental allergens.

Prediction and detection of allergy development: influence of genetic and environmental factors

The prevalence of atopic diseases is increasing in northwestern Europe and probably also in the rest of the Western world. Detecting cord blood IgE, in combination with obtaining a family history of atopic disease, seems to be the most valuable method of predicting all forms of atopic disease; however, this will identify only a small proportion of children with subsequent development of atopic disease. Determination of cord blood IgE cannot, without modifications, be recommended as a single test for identifying infants for allergy prevention programs. Skin prick reaction to egg white during the first year of life seems to identify a majority of children in whom allergic disease is going to develop during infancy. Other methods, such as genetic markers of an atopic constitution, eventually may facilitate early identification of infants at risk of atopic disease.

Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function

The relationship between urinary levels of cotinine (U-cotinine) and arsenic (U-As), blood levels of cadmium (B-Cd), blood levels of lead (B-Pb), lung function, and questionnaire data on smoking habits were studied in 107 parents and their 46 children (7-10 y of age). There was a statistically significant relationship between the reported amount of tobacco smoked and U-cotinine levels. Nonsmokers who were married to persons who smoked had three times higher U-cotinine levels than nonsmokers whose spouses did not smoke. There was a significant association between the number of parents who smoked in the family and the U-cotinine levels of children. If only one parent smoked, maternal smoking was of greater importance than paternal smoking. There was also an association between U-cotinine and B-Cd. A study of lung function in the children revealed that vital capacity and functional residual capacity (corrected for sex, age, and height) increased as the number of parents who smoked increased. Therefore, the present study showed that (1) U-cotinine was a useful index of active smoking and environmental tobacco smoke exposure in adults and children, (2) U-cotinine was associated with the blood concentration of cadmium, and (3) environmental tobacco smoke exposure was associated with changes in lung function of children.

Prevalence of atopic disorders among adolescents in Turku, Finland

A study of the prevalence of atopic disorders among 15-16-year-old teenagers was carried out in a coastal urban town in south-western Finland. Altogether, 1712 children were found in that age group, all previously examined by a pediatrician. Each child who had present or previous allergic diseases was invited for a detailed study, a total of 434 (25%) pupils. Of these patients 416 (95.8%) participated in clinical examination and skin testing. The prevalence of atopic diseases was 21% in the studied group; atopic eczema was found in 9.7%, allergic rhinitis in 14% and asthma in 2.5%. Of subjects who had rhinitis, 38% also had atopic eczema, while rhinitis--as the only symptom--was found in 8.8%. Figures obtained from this survey suggest that the prevalence rates of atopic diseases are about the same as found 10 years ago in Finland and they correspond also with other recent reports.

Passive smoking and childhood asthma. Urinary cotinine levels in children with asthma and in referents

Passive exposure to tobacco smoke was assessed in children with asthma (age 3-15) and in referents. There was statistically significantly (P less than 0.0005) higher excretion of the nicotine metabolite, cotinine, in the urine of 49 children with asthma (geometric mean 10 ng/ml) compared with 77 referents (4.8 ng/ml). Maternal smoking was statistically significantly more prevalent among the asthmatics than among the referents (relative risk = RR = 2.6, 95% C1 = 1.2-5.3). In conclusion, the exposure to environmental tobacco smoke in asthmatic children was higher than among healthy children, indicating that passive smoking may be a predisposing and/or aggravating factor for childhood asthma.

In utero exposure to parental smoking, cotinine measurements, and cord blood IgE

The relationship between parental smoking and cord blood IgE has been studied in a survey conducted in 99 unselected newborn infants with a sensitive tests for IgE and cotinine as a biologic marker to validate smoking data. For both cord blood cotinine and maternal urine continine creatinine ratio (CCR), significantly higher levels were observed for smokers compared to nonsmokers. Furthermore, among nonsmokers, passive smokers had significantly higher cotinine levels than true nonsmokers, which demonstrates that cord blood may be used to assess active as well as passive maternal smoking. No association was observed in this study between cord blood IgE and maternal smoking assessed by questionnaire (geometric means of cord blood IgE levels were 0.11 IU/ml for newborn infants of smoking mothers and 0.12 IU/ml for newborn infants of nonsmoking mothers). The same observations were drawn from the analysis of cord blood IgE and cotinine levels, with correlation coefficients of -0.005 for cord blood CCR and 0.003 for maternal CCR. Additional studies are needed to determine whether maternal smoking is causally related to cord blood IgE and by which mechanisms.

Nonpharmacologic means of preventing asthma

Cessation of smoking in the home is one of the most important nonpharmacologic actions to be recommended. There is a highly significant increase in wheezing, coughing, and respiratory infections in children with smoking mothers, and this increase is directly proportional to the number of cigarettes smoked. Cord blood IgE levels are increased in babies whose mothers smoke during pregnancy. Other agents, such as sulpur dioxide and chemical pollutants from industrial processes may play a role in the development or exacerbation, of asthma symptoms and should be avoided. One of the most interesting areas in food allergy is whether breast feeding causes sensitization or induces tolerance in infants to foods ingested by the mother. There is an increase in asthma in second-generation immigrant populations who are exposed, from birth, to the Western style of living which increases their exposure to house dust mite. Several studies have shown that month of birth is important in the development of specific allergies, for example, in the incidence of birch pollen allergy in Scandinavia. The presence of a pet in the home at birth is associated with a greater incidence of allergy to that animal. Our study in asthmatic children has shown a strong association (p less than 0.001) between the presence of allergens in the air in their homes (sampled retrospectively in the month of birth) with a positive skin test to those allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

The impact of allergy and immunology on our expanding industrial environment

In summary, allergists and clinical immunologists have assumed a primary role related to the diagnosis and pathophysiology of a wide range of environmental and occupational diseases associated with our increasingly industrialized environment. Prevention, rather than therapy, is the primary goal in managing many of these conditions. With all such diseases, it is most important to take into account the patient's environment and to record a thorough occupational and environmental history. The concept of environmental agents as causative factors of disease in man dates to antiquity but has assumed considerably greater significance in recent years. In this context, it should be remembered that Hippocrates and Socrates both emphasized that a good physician should strongly consider the patient's environment as an aid in diagnosis. Of equal importance was the recommendation by Bernardo Ramazzini in 1713, that, "in addition to the questions and recommendations of Hippocrates," a careful inquiry into the patient's occupation should be made.

Environmental factors in the first months of life and the possible relationship to later development of hypersensitivity

The results of skin prick test (SPT) with common aeroallergens (in 870 severely asthmatic children, average age at testing 8.1 years) were analysed and compared with the results of a questionnaire about pets and smoking habits in the children's homes during the first 6 months of life. The study indicates a possible correlation between early massive exposure to certain allergens (cat, timothy) and later development of hypersensitivity. No conclusion can be drawn about a possible role of tobacco-smoking.

Defence against allergic sensitization in the healthy lung: the role of inhalation tolerance

Experimental animal studies indicate that under normal steady-state conditions, initial encounters with non-pathogenic antigens (i.e. inert proteins, such as pollens) do not trigger immune responses, but instead activate antigen-specific suppressor T cells which protect against subsequent allergic sensitization by inducing a state of immunological tolerance towards the inhaled antigen. This inhalation tolerance phenomenon appears analogous to the more familiar process of oral tolerance in the gastrointestinal tract, and is proposed to serve as the 'last line of defence' against sensitization to aero-allergens which have evaded other levels of containment in the respiratory tract. It is postulated that this tolerance process plays a similar protective role in man, as the final component of a multi-layer defence system centering upon the respiratory epithelium. Recent findings which indicate that both oral and inhalation tolerance mechanisms are relatively slow to develop postnatally, provides a possible basis for the increased risk of allergic sensitization recognized in infancy.

Passive exposure to cigarette smoke does not increase allergic sensitization in children

The purpose of this study was to learn whether children passively exposed to parental cigarette smoke would be more frequently sensitized to common allergens or would have higher concentrations of allergen-specific IgE. To evaluate this question, we studied two groups of children aged 2 to 17 years. The first group consisted of 100 children selected from a general pediatric group practice. These children were being observed for well-child care, and the only selection criteria were the need for a venous blood sample for a reason unrelated to the study. The second group of 91 patients were consecutively referred, from the same pediatric group, for allergy evaluation because of respiratory tract symptoms. Parental smoking histories were obtained, and total serum IgE, IgD, and IgE specific for cat, dog, mite, ragweed, grass, and cockroach were measured by ELISA. Children of smoking mothers had significantly greater IgD concentrations (p = 0.03) and were more likely to be referred for allergy evaluation (p = 0.0001), but these children did not have increased concentrations of total or allergen-specific IgE. Exposed children were not more likely to be serologically sensitive to any of the allergens tested. We conclude that children passively exposed to cigarette smoke do not produce more IgE to common allergens nor are they more likely to produce IgE to any particular allergen.

Symptoms of bronchial hyperreactivity and asthma in relation to environmental factors

A questionnaire study regarding airway morbidity in children and environmental factors was performed in April 1985. The parents of 5301 children, aged 6 months to 16 years, from different rural areas in mid Sweden were sent a validated questionnaire and 4990 (94%) responded. The cumulative prevalence of bronchial hyperreactivity was 9.7% and of allergic asthma 5.2%. Children living near a paper pulp plant more often had symptoms suggesting bronchial hyperreactivity (124 (13.0%), relative risk 1.3) and allergic asthma (68 (7.1%), relative risk 1.3). In children living in a damp house problem bronchial hyperreactivity was found in 76 (19.0%) (relative risk 1.9) and allergic asthma in 35 (8.7%) of the children (relative risk 1.9). Children living in a damp house with parents who smoked had the highest figures: bronchial hyperreactivity was found in 44 (23.5%) (relative risk 2.8) and allergic asthma in 22 (11.6%) (relative risk 2.5). The results indicate that various moderate environmental pollutants may act synergistically to increase bronchial hyperreactivity and allergy especially in children with a family history of allergy.

Atopic babies with wheezy bronchitis. Follow-up study relating prognosis to sequential IgE values, type of early infant feeding, exposure to parental smoking and incidence of lower respiratory tract infections

Clinical course and sequential IgE values were recorded in a 4-year prospective study of 80 atopic wheezing babies at ages from 6 months to 4-5 years. At final assessment, 68% of the children had been symptom-free for at least 1 year whilst 32% still suffered from wheezing attacks. Total IgE levels from the first visit until final assessment were greater than 2 SD above normal for age in 63% of all children, but no significant correlation could be found between sequential IgE levels and the clinical picture or course of the disease. In all cases IgE levels rose steadily with increasing age, independently of whether wheezing disappeared or persisted. The most significant rise in IgE values occurred between 1 and 2 years of age, and IgE levels at 4 years could be predicted by the value at the age of 2 years (r = 0.97). In the group of children that lost their wheezing tendency there was: a significantly greater number of infants that were breast-fed during at least the first 3 months of life (P less than 0.01), a lower incidence of exposure to parental smoking (P less than 0.01), and a lesser incidence of lower respiratory tract infections (P less than 0.01). Though there was no correlation between increase of IgE levels and type of feeding or exposure to cigarette smoke, statistical data confirms that bottle feeding and parental smoking lead to persistence of wheezing in atopic children.