Month of birth and allergic disease at the age of 10.

The relationship between month of birth and asthma, hay fever and skin sensitization to mixed grass pollen was analysed in a population-based cross-sectional study in Munich and Bavaria 1989-1990 of 6535 10-year-old children. The relative risk of developing atopic disease is calculated by comparing the prevalence in a single month with the prevalence of all other months. A slightly increased risk of developing allergic skin sensitization for grass pollen (n = 1128) was found for February (odds ratio, 1.3, 95% confidence interval 1.0-1.6), May (1.4, 1.1-1.8) and June (1.3, 1.0-1.6). For hay fever (n = 379) an increase was found for May (1.5, 1.0-2.1) and for allergic asthma (n = 277) for August (1.4, 1.0-2.1). A protective effect was observed for certain months of birth; September for allergic sensitization (0.8, 0.6-1.0), October for and November for hay fever (0.6, 0.3-0.9). The occurrence of hay fever and positive prick test is explained by the seasonal variation of atmospheric grass pollen and the peak in August of asthmatic patients by house dust. Date of birth appears therefore to slightly influence the risk of developing an allergic sensitization and allergic diseases.     

Risk factors for asthma at 3.5 and 7 years of age

Background It has been suggested that factors in early life including exposure to allergens and microbes may influence the development of asthma. Objective To identify risk factors for asthma in early childhood. Methods Eight‐hundred and seventy‐one children of European mothers were enrolled at birth, of whom 385 (44.2%) were born small for gestational age (SGA) and 486 were appropriate for gestational age (AGA). Data were collected at birth, 12 months, 3.5 years of age (y) and 7 y. The outcome of interest (current wheeze) was defined as a positive response to the question: ‘Has your child had wheezing or whistling in the chest in the last 12 months?’ Results Participation rate was 85.4% at 1 y, 63.1% at 3.5 y and 68.0% at 7 y. The prevalence of asthma was 23.8% at 3.5 y and 18.1% at 7 y. Antibiotic use in the first year of life and day care in the first year of life were associated with increased risk of wheeze at 7 y [odds ratio (OR)=4.3 95% confidence interval (CI) (1.8–10.1) and OR=2.8 95% CI (1.2–6.5), respectively], but not at 3.5 y. Exposure to dogs was a risk factor for asthma at both ages [OR=2.1 95% CI (1.1–3.8)] as was sleeping on a used cot mattress in the first year of life [OR=1.8 95% CI (1.0–3.2)]. Conclusions There was a significant association between antibiotic use and day care in the first year of life and wheezing at 7 y but not at 3.5 y. This strengthens the argument that these factors increase the risk of asthma. We have also made the novel observation that sleeping on a used mattress in the first year of life is a risk factor for wheezing at 3.5 and 7 y. Capsule summary This prospective study of 871 children made the novel observation that sleeping on a used mattress in the first year of life was a risk factor for wheezing at 3.5 and 7 y.     

Perinatal characteristics and obstetric complications as risk factors for asthma, allergy and eczema at the age of 6 years

BACKGROUND: Considerable effort has been put into identifying early determinants for atopic disorders. Many studies have evaluated the role of fetal development and obstetric complications. However, the results are not unequivocal. STUDY OBJECTIVE: To assess the relationship between perinatal characteristics and obstetric complications, and the presence of reported current asthma, allergy and eczema at the age of 6 years in the framework of a previously conducted study. METHOD: Seven hundred families in the Netherlands with index children born in 1988-1990 were retrospectively selected. Data were extracted from the Municipal Health Service's records of health examinations of these children and their siblings. These examinations were carried out at the age of 6 years. The records contained data on reported atopic disorders and perinatal characteristics. RESULTS: Gestational age was inversely related to the risk of asthma (P for trend: 0.03). Children with low birth weight tended to have a lower risk of any allergy, albeit not significant (P=0.07). However, no link was found between neonatal head circumference and atopic disorders. The ratio of neonatal head circumference to birth weight was positively associated with the risk of atopic disorders, especially with the risk of asthma (odds ratio (OR)=1.87; 95% confidence interval (CI(95%))=[1.11, 3.15]). Vacuum extraction was a risk factor for allergy (OR=1.84, CI(95%)=[1.03, 3.28]), but not for asthma. Induced labour was positively associated with the risk of inhalant allergy (OR=2.22, CI(95%)=[1.09, 4.51]) and, to a lesser extent, asthma (OR=1.72, CI(95%)=[0.95, 3.10]). For caesarean section and forcipal extraction there were no such relationships. CONCLUSIONS: Prematurity is a risk factor for asthma reported at 6 years. A high ratio of head circumference to birth weight is a risk factor for any atopic disorder. Vacuum extraction was associated with a higher risk of allergy, and induced labour is a risk factor for inhalant allergy. All results should be viewed with the possibility of residual confounding.     

The natural course of atopic dermatitis from birth to age 7 years and the association with asthma

BACKGROUND: Atopic dermatitis (AD) is considered to be one of the first manifestations in the atopic march. However, few prospective studies on AD and its association with childhood asthma exist. OBJECTIVE: The aim of this study was to prospectively investigate the natural course of AD to determine factors influencing its prognosis and to analyze the relationship of AD with childhood asthma. METHODS: The Multicenter Allergy Study, a German birth cohort, followed 1314 children from birth to age 7 years. Physical examinations, parental interviews on atopic symptoms and diagnoses, and determination of specific IgE levels were performed regularly. RESULTS: The cumulative prevalence of AD in the first 2 years of life was 21.5%. Of these children with early AD, 43.2% were in complete remission by age 3 years, 38.3% had an intermittent pattern of disease, and 18.7% had symptoms of AD every year. Severity (adjusted cumulative odds ratio, 5.86; 95% CI, 3.04-11.29) and atopic sensitization (adjusted cumulative odds ratio, 2.76; 95% CI, 1.29-5.91) were major determinants of prognosis. Early wheeze and a specific sensitization pattern were significant predictors for wheezing at school age, irrespective of AD. Early AD without these cofactors constituted no increased risk of subsequent wheeze (adjusted odds ratio, 1.11; 95% CI, 0.56-2.20) or bronchial hyperreactivity. CONCLUSION: AD is a common condition in infancy but disappears around age 3 years in a significant proportion of children. The prognosis is mostly determined by the severity and the presence of atopic sensitization. Early AD is associated with asthma at school age, but in many of these asthmatic children, wheezing manifests before or with the onset of AD. Children with AD and wheeze have a marked loss in lung function, suggesting a distinct phenotype rather than a progressive development from AD to asthma.     

Direct and indirect exposure to pets – risk of sensitization and asthma at 4 years in a birth cohort

INTRODUCTION: There are conflicting data on the association between early exposure to pets and allergic diseases. Bias related to retrospective information on pet ownership has been addressed as a reason for distorted study results. OBJECTIVE: To elucidate how early exposure to cat and dog relates to IgE-sensitization and asthma in children at 2 and 4 years of age, in a prospective birth-cohort study. METHODS: Four thousand and eighty-nine families with children born 1994-1996 in predefined areas of Stockholm answered questionnaires on environmental factors and symptoms of allergic disease at birth, one, two and four years of age. Dust samples collected from the mothers' beds at birth were analysed for Fel d 1 and Can f 1 in a subgroup of the cohort. Blood samples taken at four years from 2614 children were analysed for allergen-specific IgE to common airborne allergens. Risk associations were calculated with a multiple logistic regression model, with adjustment for potential confounders. RESULTS: A correlation was seen between allergen levels and reported exposure to cat and dog. Exposure to cat seemed to increase the risk of cat sensitization, OR (odds ratio) 1.44 (95% confidence interval 1.03-2.01), whereas dog exposure did not have any effect on dog sensitization, OR 1.16 (0.79-1.72). Dog ownership was related to a reduced risk of sensitization to other airborne allergens, OR 0.36 (0.15-0.83), and a similar tendency was seen for cat ownership OR 0.63 (0.37-1.07). Early dog ownership seemed to be associated with a lower risk of asthma, OR 0.50 (0.24-1.03), with no corresponding effect after cat ownership, OR 0.88 (0.56-1.38). CONCLUSION: Early exposure to cat seems to increase the risk of sensitization to cat but not of asthma at 4 years of age. Dog ownership, on the other hand, appears to be associated with lowered risk of sensitization to airborne allergens and asthma. Both aetiological relationships and selection effects have to be considered in the interpretation of these findings.     

Low socioeconomic status as a risk factor for asthma, rhinitis and sensitization at 4 years in a birth cohort

BACKGROUND: The relation between socioeconomic status and allergic diseases in childhood is controversial. Some studies have proposed childhood asthma to be more common in families with low socioeconomic status, while sensitization to airborne allergens seems to be more frequent in individuals with higher socioeconomic status in childhood. OBJECTIVE: To assess the relation between socioeconomic status and asthma, rhinitis and sensitization in an unselected prospective birth cohort. METHODS: Four thousand and eighty-nine families with children born 1994-1996 in predefined areas of Stockholm answered questionnaires on environmental factors, socioeconomic status (parental occupation), and symptoms of allergic disease at birth, 1, 2 and 4 years of age. Blood samples taken at 4 years from 2614 children were analysed for specific IgE to common airborne and food allergens. Odds ratios (OR) and 95% confidence intervals (CI) for various outcomes in relation to socioeconomic status were estimated with a multiple logistic regression model, adjusting for potential confounders such as heredity for allergic diseases, maternal smoking, short duration of breastfeeding and house construction. RESULTS: There was a decreasing risk of asthma and rhinitis with increasing socioeconomic status. The OR for asthma was 0.33 (95% CI 0.17-0.66) and for rhinitis 0.50 (0.32-0.79) comparing the highest and the lowest socioeconomic groups, with a tendency to stronger effects in those with heredity for allergic disease. The risk of sensitization to food allergens also decreased with increasing socioeconomic status; OR 0.65 (0.41-1.02) in the highest socioeconomic group (Ptrend=0.03), which was not clearly seen for airborne allergens. CONCLUSION: Asthma, rhinitis and sensitization is more common in lower than in higher socioeconomic groups after adjustment for traditional risk factors. This may be related to additional uncontrolled differences in life style and environmental exposures between the groups, and calls for further studies.     

The Canadian asthma primary prevention study: outcomes at 2 years of age

BACKGROUND: Avoidance of individual risk factors have not been successful in preventing the development of asthma. OBJECTIVE: We sought to determine the effectiveness of a multifaceted intervention program in primary prevention of asthma in high-risk infants. METHODS: We identified 545 high-risk infants on the basis of an immediate family history of asthma. Families were randomized into intervention or control groups. Intervention measures included avoidance of house dust mite, pet allergen, and environmental tobacco smoke. Breast-feeding was encouraged with formula supplementation if necessary, and introduction of solid foods was delayed. RESULTS: At 2 years of age, 19.5% of the children had asthma, and 14.7% had atopy (positive skin test response to one or more common allergens). Significantly fewer children had asthma in the intervention group compared with in the control group (16.3% vs 23.0%), with 60% less persistent asthma at 2 years. There was a 90% reduction for recurrent wheeze in the intervention group compared with that seen in the control group. Exposure to maternal environmental tobacco smoke during pregnancy or the first year was a risk factor for asthma at 2 years of age. A positive skin test response, particularly to food, at 12 months predicted asthma at 2 years. There was no significant difference for atopy between the intervention and control groups, but daycare reduced atopy at 2 years. CONCLUSION: This multifaceted intervention program during a window of opportunity in the first year of life was effective in preventing asthma in high-risk children at 2 years of age. Future studies with this cohort at school age are important.     

Neuropsychologic status at the age 4 years and atopy in a population-based birth cohort

Background:  Mental health has been reported to be associated with allergy, but only a few cohort studies have assessed if neurodevelopment predicts atopy.
Objective:  To investigate if neurobehavioral status of healthy 4-year-old children was associated with specific immunoglobulin E (IgE) at the same age and skin prick test results 2 years later.
Methods:  A population-based birth cohort enrolled 482 children, 422 of them (87%) provided neurobehavioral data, 341 (71%) had specific IgE measured at the age of 4 years; and 395 (82%) had skin prick tests completed at the age of 6 years. Atopy was defined as IgE levels higher than 0.35 kU/l to any of the three tested allergens at the age of 4 or as a positive skin prick test to any of the six tested allergens at the age of 6. McCarthy Scales of Child Abilities and California Preschool Social Competence Scale were the psychometric instruments used.
Results:  Twelve percent of children at the age of 4 and 17% at the age of 6 were atopic. Neurobehavioral scores were negatively associated with 6-year-old atopy after adjustment for socio-demographic and allergic factors, A relative risk of 3.06 (95% CI: 1.30–7.24) was associated with the lowest tertile (scorings ≤90 points) of the general cognitive scale. Similar results were found for verbal abilities, executive functions, and social competence. Asthma, wheezing, rhinitis, and eczema at the age of 6, but not at the age of 4, were associated with neurodevelopment at the age of 4.
Conclusions:  Neuropsychologic functioning and later atopy are negatively associated in preschool age children.