Age at bacille Calmette–Guérin vaccination and risk of allergy and asthma

BACKGROUND: It has been proposed that early age at bacille Calmette-Guérin (BCG) vaccination protects against the development of allergy. OBJECTIVE: To study whether early age at BCG vaccination was associated with a decreased risk of atopy, allergic rhinitis, and asthma compared to BCG vaccination at later ages in childhood. METHODS: The occurrence of atopy, allergic rhinitis, and asthma was studied in nearly 2000 women participating in the Danish National Birth Cohort study. Detailed information on age at BCG vaccination (age 0-15 years) was available from school health records. Atopic status was assessed serologically by a specific response to 11 common inhalant allergens using serum samples obtained from the women during the period 1997-2001. Information on allergic rhinitis and asthma was available from telephone interviews. RESULTS: Approximately 85% of the women had been BCG-vaccinated. Age at BCG vaccination was not associated with risk of atopy, allergic rhinitis, or asthma. The odds ratio of atopy, allergic rhinitis, and asthma associated with being vaccinated during the first year of life was 1.05 (95% CI 0.71-1.56), 1.42 (95% CI 0.85-2.36), and 1.71 (95% CI 0.91-3.20), respectively, compared with being vaccinated at the age of 7 years. Adjustment for birth cohort, sibship size, age of the woman's mother at birth, and social class in childhood did not affect the results. CONCLUSION: Our findings suggest that age at BCG vaccination in childhood does not influence the development of allergy or asthma.     

Respiratory illnesses in early life and asthma and atopy in childhood

BACKGROUND: The relation between respiratory illnesses in early life and the development of asthma and atopy in childhood is incompletely understood. OBJECTIVE: We sought to examine the relationship between respiratory illnesses in early life and atopic diseases at school age. METHODS: We performed a prospective birth cohort study of the relationship between respiratory illnesses in the first year of life and asthma, atopy (sensitization to >or=1 allergen), and allergic rhinitis at school age in 440 children with a parental history of atopy. Logistic regression was used to examine the relationship between respiratory illnesses and asthma, atopy, and allergic rhinitis. The relationship between respiratory illnesses in early life and repeated measures of wheezing between the ages of 1 and 7 years was investigated by using a proportional hazards models. RESULTS: Physician-diagnosed croup (adjusted odds ratio [OR], 0.30; 95% CI, 0.12-0.72) and having 2 or more physician-diagnosed ear infections (adjusted OR, 0.58; 95% CI, 0.35-0.98) in the first year of life were inversely associated with atopy at school age. Physician-diagnosed bronchiolitis before age 1 year was significantly associated with asthma at age 7 years (adjusted OR, 2.77; 95% CI, 1.23-6.22). Recurrent nasal catarrh (>or=3 episodes of a runny nose) in the first year of life was associated with allergic rhinitis at age 7 years (adjusted OR, 2.99; 95% CI, 1.03-8.67). CONCLUSION: The relationship between early-life respiratory illnesses and asthma and atopy is complex and likely dependent on the type of infection and immune response it initiates. CLINICAL IMPLICATIONS: Certain respiratory illnesses in early life modify the risk of atopy and asthma at school age.     

Childhood allergic rhinitis predicts asthma incidence and persistence to middle age: a longitudinal study

BACKGROUND: The association between allergic rhinitis and asthma is well documented, but the temporal sequence of this association has not been closely examined. OBJECTIVE: We sought to assess the associations between childhood allergic rhinitis and (1) asthma incidence from preadolescence to middle age and (2) asthma persistence to middle age. METHODS: Data were gathered from the 1968, 1974, and 2004 surveys of the Tasmanian Asthma Study. Cox regression was used to examine the association between childhood allergic rhinitis and asthma incidence in preadolescence, adolescence, and adult life. Binomial regression was used to examine the association between childhood allergic rhinitis and asthma beginning before the age of 7 years and persisting at age 44 years. RESULTS: Childhood allergic rhinitis was associated with a significant 2- to 7-fold increased risk of incident asthma in preadolescence, adolescence, or adult life. Childhood allergic rhinitis was associated with a 3-fold increased risk of childhood asthma persisting compared with remitting by middle age. CONCLUSIONS: Childhood allergic rhinitis increased the likelihood of new-onset asthma after childhood and the likelihood of having persisting asthma from childhood into middle age. CLINICAL IMPLICATIONS: Asthma burden in later life might be reduced by more aggressive treatment of allergic rhinitis in early life.     

Number of offspring and maternal allergy

The consistent association seen between family size and childhood allergy has led to the 'hygiene hypothesis', namely that a lower frequency of infections in early childhood is associated with an increased risk of asthma and hay fever. Maternal atopy, however, is a strong predictor of childhood asthma and hay fever. If maternal atopy is inversely related to the number of siblings then the role of siblings in the development of childhood atopy, the basic tenet of the 'hygiene hypothesis', is challenged. We evaluated the association between number of pregnancies and number of live births with lifetime occurrence of maternal wheeze, asthma, allergic rhinitis, and allergic conjunctivitis in a cross-sectional study in four areas in Italy. A total of 1755 (35-74 year old) nonsmoking women filled a questionnaire on reproductive history as well as on lifetime occurrence of symptoms/diseases. The number of live births was inversely related to lifetime allergic rhinitis (P-value for trend=0.031) and allergic conjunctivitis (P-value for trend=0.011). The odds ratios for those with 4+ children (in comparison with those having 0-1) were: 0.53 (95% CI: 0.27-1.04) and 0.42 (95% CI: 0.22-0.81), respectively. A similar trend was seen for number of pregnancies, although not statistically significant. No association was found between number of pregnancies and number of live births with wheeze or asthma. The results may be interpreted as an indication that maternal atopy influences pregnancy outcomes or that pregnancy itself has an effect on maternal atopy.     

Gestational age and occurrence of atopy at age 31—a prospective birth cohort study in Finland

BACKGROUND: It has been suggested that main risk factors for development of allergic diseases operate already during pregnancy and in early childhood. OBJECTIVE: To study the association between gestational age, birth weight, parity and parental farming with the risk of atopy and asthma in young adults. METHODS: In a prospective birth cohort study, 5192 subjects born in Northern Finland in 1966 were followed up at the age of 31. Skin prick tests were done to three of the most common allergens in Finland and to house dust mite. Data on doctor-diagnosed asthma was obtained from questionnaires. Perinatal data had already been collected during pregnancy. RESULTS: The risk of atopy increased linearly with increasing length of pregnancy among babies born in the 35th weak of gestation or later. Gestational age equal to, or over 40 weeks compared with less than 36 weeks was associated with an increased risk of atopy (multivariate odds ratio 1.65, 95% CI 1.16, 2.34). The association was stronger among farmers' children (P for interaction 0.01). High parity and being a farmer's child (multivariate odds ratio 0.50, 95% CI 0.42-0.60) was associated with decreased risk of atopy. In contrast, no associations were observed for doctor-diagnosed asthma. CONCLUSIONS: The results underline the importance of pregnancy and very early childhood in the development of atopy, and suggest that timing of the environmental exposure is of importance for the immune system. No association was observed for asthma, which may be due to the multifactorial origins of asthma.     

The association between birth size and atopy in young North-European adults

BACKGROUND: There is evidence that atopic disorders may begin in intra-uterine life; however, studies of birth characteristics and atopy show conflicting results. METHODS: We wanted to investigate the association of birth weight and head circumference with serum total or specific IgE, allergic rhinitis or eczema while addressing the influence of demographic and geographical factors. In this historic prospective cohort study, data were collected from birth records for 1683 men and women born in 1947-1973, from six Nordic-Baltic populations participating in the European Community Respiratory Health Survey. Blood tests for the measurement of serum total and specific IgE were available for 1494 subjects. In multiple regression analyses, adjustments were made for birth length, gender, age, study centre, adult body mass index, level of education, parental and adult smoking. RESULTS There was no association of birth weight (n=1230) and head circumference (n=285) with serum total IgE, specific IgE antibodies, allergic rhinitis or eczema. There were neither significant interactions by gender or age, nor heterogeneity between the study centres in the analyses of birth weight and adult atopy. CONCLUSION: Birth size was not associated with atopy among adults in this large Nordic-Baltic population study.     

Mode of delivery and risk of allergic rhinitis and asthma

BACKGROUND: It has been hypothesized that cesarean section might increase the risk of developing allergic disease by depriving the fetus and newborn of exposure to maternal microflora. Furthermore, it has been suggested that complicated modes of delivery might be associated with an increased risk of asthma. OBJECTIVE: The purpose of this investigation was to study whether cesarean section and other complicated modes of delivery are associated with an increased risk of allergic rhinitis or asthma. METHODS: Information on self-reported allergic rhinitis, asthma ever, current asthma, and occupation was obtained from 9722 singleton women born in Denmark during the period 1973-1977 who participated in a national cohort study during the period 1997-2001. For these women, information was available on mode of delivery (spontaneous delivery, cesarean section, vacuum extraction, or other complicated mode of delivery, such as rotation/traction or use of forceps), gestational age, birth weight, and length at birth from the Danish Medical Birth Register. Information on parity and maternal age was obtained from the Danish Civil Registration System. RESULTS: The odds ratios (ORs) of allergic rhinitis were 1.16 (95% CI, 0.90-1.49) for cesarean section and 1.06 (95% CI, 0.85-1.32) for other complicated modes of delivery in comparison with spontaneous delivery. The corresponding ORs of asthma ever were 1.33 (95% CI, 1.02-1.74) and 1.18 (95% CI, 0.94-1.49) for cesarean section and other complicated modes of delivery, respectively, and the ORs of current asthma were 1.22 (95% CI, 0.87-1.73) and 1.26 (95% CI, 0.94-1.68), respectively, in comparison with spontaneous delivery. CONCLUSIONS: Our findings do not support the hypothesis that cesarean section or other complicated modes of delivery are associated with the development of allergic rhinitis. However, there might be a positive association with development of asthma--in particular, for cesarean section--that was not explained by gestational age, birth weight, ponderal index, smallness for gestational age, parity, maternal age, or occupation.     

The association between infant feeding practices and subsequent atopy among children with a family history of asthma

BACKGROUND: Although longer duration of breastfeeding and later introduction of solid foods are both recommended for the prevention of asthma and allergic disease, evidence to support these recommendations is controversial. OBJECTIVE: To examine the relation between infant feeding practices and the risk of asthma and allergic disease at age 5 years. METHODS: A cohort of children with a family history of asthma in Sydney, Australia, was followed from birth to age 5 years. Data on infant feeding practices and on early manifestations of eczema were collected prospectively. The presence of eczema, asthma and atopy (positive allergen skin prick tests) were determined at age 5 years. RESULTS: In 516 children evaluated at age 5 years, there was no significant association between the duration of breastfeeding or timing of introduction of solid foods and protection against asthma or other allergic disease, after adjustment for confounding factors. However, breastfeeding for 6 months or more and introduction of solid foods after 3 months were both associated with an increased risk of atopy at age 5 years (P=0.02 and 0.01, respectively). There was no significant association between the presence of eczema at 4 weeks and at 3 months and continued breastfeeding beyond those times. CONCLUSION: Longer duration of breastfeeding and later introduction of solid foods did not prevent the onset of asthma, eczema or atopy by age 5 years.     

Farming environment and prevalence of atopy at age 31: prospective birth cohort study in Finland

Background Cross‐sectional studies have shown an association between the farming environment and a decreased risk of atopic sensitization, mainly related to contact with farm animals in the childhood. Objective Investigate the association of a farming environment, especially farm animal contact, during infancy, with atopic sensitization and allergic diseases at the age of 31. Methods In a prospective birth cohort study, 5509 subjects born in northern Finland in 1966 were followed up at the age of 31. Prenatal exposure to the farming environment was documented before or at birth. At age 31, information on health status and childhood exposure to pets was collected by a questionnaire and skin prick tests were performed. Results Being born to a family having farm animals decreased the risk of atopic sensitization [odds ratio (OR) 0.67; 95% confidence interval (CI) 0.56–0.80], atopic eczema ever (OR 0.77; 95% CI 0.66–0.91), doctor‐diagnosed asthma ever (OR 0.74; 95% CI 0.55–1.00), allergic rhinitis at age 31 (OR 0.87; 95% CI 0.73–1.03) and allergic conjunctivitis (OR 0.86; 95% CI 0.72–1.02) at age 31. There was a suggestion that the reduced risk of allergic sensitization was particularly evident among the subjects whose mothers worked with farm animals during pregnancy, and that the reduced risk of the above diseases by farm animal exposure was largely explained by the reduced risk of atopy. Having cats and dogs in childhood revealed similar associations as farm animals with atopic sensitization. Conclusion and Clinical Relevance Contact with farm animals in early childhood reduces the risk of atopic sensitization, doctor‐diagnosed asthma and allergic diseases at age 31. Cite this as: J. Lampi, D. Canoy, D. Jarvis, A.‐L. Hartikainen, L. Keski‐Nisula, M.‐R. Järvelin and J. Pekkanen, Clinical & Experimental Allergy, 2011 (41) 987–993.     

Relevance of the hygiene hypothesis to early vs. late onset allergic rhinitis

Introduction The hygiene hypothesis proposes that reduced exposure to infections in early life increases the risk of developing allergic conditions including allergic rhinitis. We examined the association between markers of the hygiene hypothesis and allergic rhinitis that developed before 7 years of age and allergic rhinitis that developed after 7 years of age. Methods The Tasmanian Longitudinal Health Study (TAHS) is a population‐based cohort (n=8583) study of respiratory disease. Participants have been followed from 7 to 44 years of age. Information on potential risk factors, allergies and respiratory symptoms was collected longitudinally. Using multi‐nomial logistic regression, exposure to siblings, infections, tonsillectomy and farm residence during childhood were examined as risk factors for allergic rhinitis that developed before or after 7 years of age. All analyses were adjusted for gender, maternal and paternal atopy, mother's age at participant's birth, paternal socio‐economic status in 1968 and personal socio‐economic status in 2004. Results Greater cumulative exposure to siblings before the age of 2 years was strongly inversely associated with early onset allergic rhinitis (<1 year sib exposure: OR=0.6, 95% CI 0.3–1.0; 1–3 years sib exposure: OR=0.6, 95% CI 0.4–0.9; >3 years sib exposure: OR=0.4, 95% CI 0.3–0.8) less so with later onset allergic rhinitis. The risk of early onset allergic rhinitis decreased with increasing viral infections (OR=0.7, 95% CI 0.5–0.9) during childhood. Having a tonsillectomy before 7 years of age increased the risk of early onset allergic rhinitis (OR=1.7, 95% CI 1.2–2.5). None of these factors was associated with later onset allergic rhinitis. Conclusions Exposures relevant to the hygiene hypothesis were important predictors for the development of early onset but less so for later onset allergic rhinitis. The exact mechanisms by which siblings and infections protect against allergic rhinitis are unclear. The stronger findings for earlier onset allergic rhinitis suggest that family structure and infections have most impact on disease risk in early life. Further research should focus on early onset allergic rhinitis when exploring causal explanations for any sibling effect.     

The use of a feather quilt, childhood asthma and allergic rhinitis: a prospective cohort study

BACKGROUND: Feather bedding has long been considered as a potential source of allergen exposure and thus a potential risk factor for allergic diseases. However, recent cross-sectional studies have reported a higher risk of allergic diseases among users of synthetic bedding compared with feather-bedding users. OBJECTIVE: To explore associations between early life exposure to feather bedding and the risk of developing asthma allergic rhinitis in childhood. METHODS: We assessed the association between early life exposure to feather quilts and the risk of bronchial obstruction during the first 2 years of life and asthma and allergic rhinitis in a prospective 4-year cohort study of 2531 Norwegian children. RESULTS: At the age of 6 months, 24% of the children had a quilt with feathers, decreasing to 20% at the age of 2 years. The adjusted odds ratio for bronchial obstruction 0 to 2 years by exposure to a feather quilt at the age of 6 months was 0.59, 95% confidence interval 0.41 to 0.86, for asthma at the age of 4 years 0.38, 0.23 to 0.64 and for allergic rhinitis at the age of 4 years 0.73, 0.43 to 1.18. CONCLUSION: The use of a feather quilt in early life does not seem to increase the risk of asthma and allergic rhinitis later in childhood.     

Farm environment in childhood prevents the development of allergies

BACKGROUND: A protective effect of infections in early life might explain the firmly reported finding of an inverse association between atopic disorders and large sibships. OBJECTIVE: To study the effect of childhood farm, rural non-farm and urban environment, as well as family size and other factors on the occurrence of asthma, wheezing and atopic disorders up to young adulthood. METHODS: Data on lifetime prevalence of physician-diagnosed asthma, allergic rhinitis and/or allergic conjunctivitis, atopic dermatitis, as well as self-reported episodic wheezing from 10 667 Finnish first-year university students aged 18-24 years were collected by a postal questionnaire. Associations of lifetime prevalence of the diseases with living on a farm, in a rural non-farm and urban environment during childhood were estimated by logistic regression analysis. Adjustment was made for potential confounding by gender, parental atopy, parental education, number of older siblings, day care outside the home and passive smoking. RESULTS: The childhood farm environment independently reduced the risk for physician-diagnosed allergic rhinitis and/or allergic conjunctivitis (adjusted odds ratio 0.63, 95% CI 0.50-0.79, P < 0.001), and for diagnosed asthma and episodic wheezing analysed together (OR 0.71, 95% CI 0.54-0.93, P < 0.05), but not for atopic dermatitis during lifetime. Urban childhood environment did not show independent increased risk when compared with rural non-farm residence. The inverse association of sibship size with the occurrence of allergic rhinitis and/or allergic conjunctivitis was found among subjects with one (OR 0.86, 95% CI 0.77-0.96, P < 0.01) or at least four older siblings (OR 0.47, 95% CI 0.26-0.84, P < 0.05). CONCLUSION: Childhood farm environment seems to have a protective effect against allergic rhinitis and/or conjunctivitis, and more weakly against asthma and wheezing irrespective of family size. Environmental exposure to immune modulating agents, such as environmental mycobacteria and actinomycetes, favouring manifestation of a nonatopic phenotype could explain the finding.     

Relationship between childhood atopy and wheeze: what mediates wheezing in atopic phenotypes?

BACKGROUND: The nature of the relationship between childhood wheeze and atopy remains uncertain. OBJECTIVE: To characterize childhood wheeze among atopic phenotypes in a longitudinal birth cohort study. METHODS: A whole population birth cohort (N = 1,456) was recruited in 1989. Children were seen at birth and at 1, 2, 4, and 10 years of age to obtain information on asthma and allergic disease development and relevant risk factors for these states. Skin prick testing at ages 4 (n = 980) and 10 (n = 1,036) years was used to define atopic phenotypes. Wheezing in these states was characterized, and logistic regression was used to identify independent risk factors for wheeze onset in different atopic phenotypes. RESULTS: Wheeze ever occurred in 37% of never atopics, 38% of early childhood atopics, 65% of chronic childhood atopics, and 52% of delayed childhood atopics. Chronic childhood atopics had significant wheezing morbidity and bronchial hyperresponsiveness. Their wheezing was associated with male sex, early eczema, family history of eczema, and early tobacco exposure. Never atopic wheeze was related to maternal asthma, parental smoking, and respiratory tract infections. Exclusive breastfeeding protected against early childhood atopic wheeze. Maternal asthma, family history of urticaria, and dog ownership increased delayed childhood atopic wheeze. CONCLUSIONS: In many respects, chronic childhood atopy is the atopic phenotype associated with the most significant forms of childhood wheezing. In such children, heritable drive, allergens, and synergy with other environmental triggers seem to be crucial determinants of wheeze onset. Where such sensitization is absent, numerous environmental factors plus genetic predisposition may assume importance for wheezing.     

The effect of infectious burden on the prevalence of atopy and respiratory allergies in Iceland, Estonia, and Sweden

BACKGROUND: Epidemiologic reports on the effect of microbe exposure on the development of atopy and allergic asthma are inconsistent. OBJECTIVES: The study investigates the association between serologic markers of infections and occurrence of atopy, allergic asthma, and rhinitis among adults in Iceland, Sweden, and Estonia. METHODS: Individuals (n = 1249; mean age, 42 years) from Iceland, Sweden, and Estonia underwent a structured interview and blood sampling. Specific IgE was measured against 4 allergens, and IgG antibodies were measured against Helicobacter pylori, Toxoplasmosis gondii, hepatitis A virus, herpes simplex virus 1, Chlamydia pneumoniae, EBV, and cytomegalovirus. RESULTS: Nonatopic subjects more often had positive serology for Helicobacter pylori, herpes simplex virus 1, Chlamydia pneumoniae, and cytomegalovirus. Having a low number (相似文献   

Recurrent childhood upper respiratory tract infections do not reduce the risk of adult atopic disease

BACKGROUND: Children of large families and those attending day care are at increased risk of respiratory tract infections, which in turn may protect against the development of allergic disease. Longitudinal studies investigating these associations beyond childhood are, however, scarce. OBJECTIVE: To investigate the association between childhood recurrent upper respiratory tract infections (URTI) and asthma, allergic rhinitis (AR) and eczema in adulthood. METHODS: A birth cohort of 1055 members followed prospectively from the ages of 2 to 21 years. Detailed information on URTI between the ages of 2 and 4 years was collected at 3 monthly intervals in a standardized interview. At the age of 8 years, a parental questionnaire regarding URTI between the ages of 4 and 8 years was used. The incidence of asthma and atopic disease at the age of 21 years was determined using a standardized questionnaire. RESULTS: Of the original cohort, 693 (66%) members completed the questionnaire. Children who experienced recurrent URTI before the age of 2 years, between the ages of 2-4 years and between ages of 4 and 8 years were not less likely to have asthma at 21 years of age than children who did not experience recurrent URTI, relative risk (RR) 0.97 (95% confidence interval (CI) 0.65-1.46), RR 1.45 (CI 0.95-2.21) and RR 1.51 (CI 0.97-2.36), respectively. Neither were recurrent URTI associated with a decreased risk of AR, nor eczema at the age of 21 years. CONCLUSIONS: Recurrent URTI in childhood did not reduce the risk of atopic disease in young adulthood.     

Lower prevalence of reported asthma in adolescents with symptoms of rhinitis that received neonatal BCG

BACKGROUND: BCG is a vaccine used against tuberculosis and leprosy and is an immunostimulant that primes T(H)1 lymphocytes to produce cytokines that antagonize atopy both in animal models and in man. Considering that atopy is the main risk factor for asthma, one can hypothesize that vaccination inducing T(H)1 responses, such as BCG, can be protective against asthma. METHODS: OBJECTIVE: To estimate the association between neonatal BCG vaccination and prevalence of asthma among adolescents. STUDY DESIGN: Cross-sectional study with schoolchildren aged 12-16 years. The presence of a scar compatible with BCG was used as a surrogate of neonatal vaccination. A self administered structured questionnaire was prepared based on that used by the International Study of Asthma and Allergies in Childhood. The prevalence of asthma was categorized according to the report of lifetime wheeze, lifetime asthma, lifetime asthma among those referring allergy and among those referring allergy and sneezing. RESULTS: Neonatal BCG vaccination was not associated with the overall prevalence of reported wheezing or asthma. However, in the subgroup reporting current allergy and sneezing, neonatal BCG was associated with a 37% reduction of prevalence of lifetime asthma. CONCLUSIONS: In the population we surveyed, neonatal BCG scar was associated with a reduction in the risk of asthma only in individuals with a past history suggestive of allergic rhinitis.     

Antenatal determinants of neonatal immune responses to allergens

BACKGROUND: The environmental factors responsible for recent increases in the prevalence of asthma and atopic disease have been assumed to act after birth. Their possible effects on fetal immune development in utero have not been investigated systematically, although sensitization to allergens may occur before birth. OBJECTIVE: This prospective study determined whether the risk factors for asthma and atopic disease, namely family history of atopic disease, maternal smoking, birth order, or maternal dietary intake of antioxidant vitamins, exert antenatal effects on the fetal immune system that may predispose to childhood atopy. METHODS: The T helper (Th) cell proliferative responses of cord blood mononuclear cells (CBMC) from a sample of 223 neonates, representative of children born to a cohort of 2000 pregnant women, were measured and related to family, maternal and environmental factors associated with the pregnancy. RESULTS: The magnitude of CBMC-proliferative responses to allergens increased significantly in association with a family history of atopic disease or maternal smoking, and decreased significantly with increasing birth order and high maternal dietary intake of vitamin E. The epidemiological association between birth order and atopy may therefore be a consequence of antenatal influences rather than of protective effects of childhood infections. The association between maternal intake of vitamin E and CBMC responsiveness suggests that diet during pregnancy may influence the fetal immune system in such a way as to modulate the risk of childhood atopy. CONCLUSION: These results provide a new insight into the aetiology of atopic disease by demonstrating that the maternal environmental risk factors for atopy, diet, birth order and smoking, influence the development of the fetal immune system. This raises the prospect of preventative public health interventions during pregnancy.     

Rhinitis as an independent risk factor for adult-onset asthma

BACKGROUND: For many years, the association between asthma and rhinitis has primarily been attributed to a common allergic background. Recently, it has been suggested that asthma and rhinitis are associated in the absence of atopy. The nature of this association is not well known. OBJECTIVE: The purpose of this study, which was performed in a large, longitudinal community population, was to determine the extent to which rhinitis is an independent risk factor for adult-onset asthma. METHODS: We carried out a nested case-control study from the longitudinal cohort of the Tucson Epidemiologic Study of Obstructive Lung Diseases. One hundred seventy-three incident patients with physician-confirmed asthma were compared with 2177 subjects who reported no asthma or shortness of breath with wheezing. Potential risk factors, including the presence of rhinitis, were assessed before the onset of asthma (patients) or before the last completed survey (control subjects). RESULTS: Rhinitis was a significant risk factor for asthma (crude odds ratio, 4.13; 95% confidence interval, 2.88-5.92). After adjustment for years of follow-up, age, sex, atopic status, smoking status, and presence of chronic obstructive pulmonary disease, the magnitude of the association was reduced but still highly significant (adjusted odds ratio, 3.21; 95% confidence interval, 2.19-4.71). After stratification, rhinitis increased the risk of development of asthma by about 3 times both among atopic and nonatopic patients and by more than 5 times among patients in the highest IgE tertile. Patients with rhinitis with persistent and severe nasal symptoms and a personal history of physician-confirmed sinusitis had an additional increased risk of asthma development. CONCLUSION: We conclude that rhinitis is a significant risk factor for adult-onset asthma in both atopic and nonatopic subjects. The nature of the association between rhinitis and asthma is open to interpretation.     

Parental allergic disease before and after child birth poses similar risk for childhood allergies

Whether the strength of associations between parental and child allergic diseases differs by whether the first onset of the parental disease is before or after a child's birth has never been examined and is the aim of this study. Yearly childhood asthma, allergic rhinitis, and eczema diagnoses were longitudinally regressed against the effect of a parental disease (pre‐ vs post‐child birth) of the same type separately for each parent using generalized estimation equations. Both a maternal and paternal history of asthma were associated with childhood asthma prevalence up to 15 years of age. Effect estimates were similar for parental asthma with first onset before and after the birth of the child. The results for allergic rhinitis and eczema were less consistent. Parental allergic diseases with first onsets before and after the birth of a child both pose risks to childhood allergic disease in the offspring, especially for asthma.     

New pregnancies and loss of allergy

BACKGROUND: Inverse associations between allergic disease and sibship have been consistently described and are frequently explained by purported lower rates of early infection among children from small families. Alternative explanations include the possibility that pregnancy itself determines maternal atopic status. OBJECTIVE: To test the hypothesis that atopy defined by skin prick test (SPT) declines with increasing numbers of pregnancies. METHODS: At enrollment to a birth cohort, mothers were skin prick tested to three common allergens. Seven years later these women underwent a second SPT and provided information on their reproductive histories. At both visits, information on allergic disease was also sought. RESULTS: Twenty five (15%) women who were initially atopic were no longer so at the second visit; loss of hayfever symptoms was reported by 33 (29%) women. Women with higher numbers of intervening pregnancies were more likely to 'lose' their atopy (P=0.05) and symptoms of hayfever (P=0.02); this was not true for asthma. The findings could not be accounted for by maternal age. CONCLUSION: Successive pregnancies may in part determine a mother's atopic state. Since maternal atopy is a risk factor for childhood atopic disease, this process may affect the atopic state of successive children. These findings suggest an alternative explanation for the sibship effect in allergic disease.