Serious childhood respiratory infections and asthma in adult life. A population based study. ECRHS Italy. European Community Respiratory Health Survey

Neuronal control of breathing: sex and stress hormones

There is a growing public awareness that hormones can have a significant impact on most biological systems, including the control of breathing. This review will focus on the actions of two broad classes of hormones on the neuronal control of breathing: sex hormones and stress hormones. The majority of these hormones are steroids; a striking feature is that both groups are derived from cholesterol. Stress hormones also include many peptides which are produced primarily within the paraventricular nucleus of the hypothalamus (PVN) and secreted into the brain or into the circulatory system. In this article we will first review and discuss the role of sex hormones in respiratory control throughout life, emphasizing how natural fluctuations in hormones are reflected in ventilatory metrics and how disruption of their endogenous cycle can predispose to respiratory disease. These effects may be mediated directly by sex hormone receptors or indirectly by neurotransmitter systems. Next, we will discuss the origins of hypothalamic stress hormones and their relationship with the respiratory control system. This relationship is 2-fold: (i) via direct anatomical connections to brainstem respiratory control centers, and (ii) via steroid hormones released from the adrenal gland in response to signals from the pituitary gland. Finally, the impact of stress on the development of neural circuits involved in breathing is evaluated in animal models, and the consequences of early stress on respiratory health and disease is discussed.

Childhood infections and the risk of asthma: a longitudinal study over 37 years

BACKGROUND

Few studies have examined common childhood infections and adult asthma. We examined associations between childhood infectious diseases, childhood pneumonia, and current, persisting, and incident asthma to middle age.

METHODS

We analyzed data from the Tasmanian Longitudinal Health Study (TAHS). A history of pneumonia was ascertained from their parents when the TAHS participants were 7 years old. Measles, rubella, mumps, chickenpox, diphtheria, and pertussis were identified from school medical records. Associations with current, persisting, or incident asthma were examined using regression techniques.

RESULTS

Greater infectious diseases load was negatively associated with persisting asthma at all ages. Individually, pertussis (adjusted OR [aOR], 0.53; 95% CI, 0.28-1.00) was negatively associated with asthma persisting to age 13 years, chickenpox (aOR, 0.58; 95% CI, 0.38-0.88) was negatively associated with asthma persisting to age 32 years, and rubella was negatively associated with asthma persisting to ages 32 (aOR, 0.61; 95% CI, 0.31-0.96) and 44 years (aOR 0.53; 95% CI, 0.35-0.82). Pertussis was associated with preadolescent incident asthma (adjusted hazard ratio [aHR], 1.80; 95% CI, 1.10-2.96), whereas measles was associated with adolescent incident asthma (aHR, 1.66; 1.06-2.56). Childhood pneumonia was associated with current asthma at ages 7 (aOR, 3.12; 95% CI, 2.61-3.75) and 13 years (aOR, 1.32; 95% CI, 1.00-1.75), an association stronger in those without than those with eczema (aOR, 3.46; 95% CI, 2.83-4.24 vs aOR, 2.08; 95% CI, 1.38-3.12).

CONCLUSIONS

Overall, childhood infectious diseases protected against asthma persisting in later life, but pertussis and measles were associated with new-onset asthma after childhood. Measles and pertussis immunization might lead to a reduction in incident asthma in later life.

Prevalence of self-reported asthma in urban and rural areas of Turkey

BACKGROUND AND PURPOSE

The risk factors for asthma in rural and urban population of Turkey are not well known. In this study we examined the effects of risk factors on the prevalence of asthma in adults living in rural and urban areas using data from a representative sample.

METHODS

Parents and grandparents of students from 20 randomly selected primary schools in urban and rural areas of Kirikkale, Turkey, were asked about respiratory diseases using the respiratory questionnaire, which were returned to us by their children.

RESULTS

Out of 13,225 parents and grandparents of primary school students 12,270 returned the questionnaires, for an overall response rate of 92.7%. The prevalence of asthma was more common in adults living in rural areas than in urban areas (10.8% vs. 6.2%, p < .0001, respectively). Asthma was more prevalent in women exposed to biomass smoke than those who were not exposed to it in rural areas (14.8% vs. 6.6%, p = .0001, respectively). Frequent childhood respiratory infections were more common in adults living in rural areas than in urban areas (18.2% vs. 10.9%, p < .0001, respectively). Exposure to biomass smoke and frequent childhood respiratory infections were associated with an increased risk of asthma, after adjusting for possible confounding factors in the logistic model for rural subjects. Chronic rhinitis (p = .0001) and frequent childhood respiratory infections (p = .0001) were associated with an increased risk of asthma, after adjusting for possible confounding factors in the logistic model for urban subjects.

CONCLUSIONS

The prevalence of asthma in adults living in the rural areas of the Kirikkale Region in Central Turkey was significantly higher than that in the urban population. Exposure to biomass smoke and childhood respiratory infections were more common in adults living in rural areas. The higher rate of asthma in adults living in rural areas may be due to a higher frequency of childhood respiratory infections and exposure to biomass smoke.

Chronic airway diseases in adult life and childhood infections

BACKGROUND

Respiratory disorders in childhood may predispose to pulmonary disease in late adult life.

OBJECTIVES

The aim of this study was to evaluate the relationship between their effects in adult life and the characteristics of the respiratory system in childhood.

METHODS

A total of 10,224 parents and grandparents of students from 14 randomly selected primary schools in the city center were asked to answer questionnaires given to their children. 9,853 of 10,224 persons (the overall response rate was 96.3%) were eligible for analysis. In the questionnaire subjects were asked about respiratory system-related symptoms and characteristics.

RESULTS

Chronic cough [14.3 vs. 4.7%, OR 3.4 (2.6-4.4), p < 0.001], chronic bronchitis [35.3 vs. 11.8%, OR 4.0 (3.4-4.8), p < 0.001] and asthma [34.2 vs. 5.1%, OR 9.6 (8.0-11.5), p < 0.001] in the childhood respiratory infection group were more common than in the control group. Childhood respiratory infections were associated with an increased risk of asthma (OR 5.6, p < 0.001), chronic bronchitis (OR 2.3, p < 0.001) and chronic cough (OR 1.5, p < 0.001), after adjusting for possible confounding factors. In addition, the presence of dampness or visible mould, wall-to-wall carpets, pets at home and parents' smoking during childhood were associated with an increased risk of frequent childhood respiratory infections.

CONCLUSION

These results indicated that frequent respiratory infections during childhood might play an important role in the occurrence of chronic airway diseases in adult life. The removing of risk factors for frequent childhood respiratory infections may reduce the subsequent risk of chronic airway disease in late adult life.

The relation of adult bronchial responsiveness to serious childhood respiratory illness in the ECRHS

BACKGROUND

Respiratory symptoms in adulthood have been found to be associated with childhood respiratory infection, but few studies have analyzed adult bronchial responsiveness (BHR) with adequate adjustment for known risk factors.

OBJECTIVE

To estimate the relation of BHR with serious childhood respiratory infections in a large population study.

METHODS

The European Community Respiratory Health Survey (ECRHS) was a cross-sectional population-based survey in 34 centers. Data on serious respiratory infections before the age of 5 years and possible confounders were obtained from a questionnaire administered in the clinic. Blood samples were taken for measurement of total immunoglobulin E (IgE) and specific IgE to four common allergens, and spirometry and bronchial challenge with methacholine were performed. A continuous measure of BHR was analyzed by multiple regression, in 11,282 participants, in relation to serious respiratory infection and other potential risk factors, adjusted for center and major determinants of adult BHR.

RESULTS

Those reporting a serious childhood respiratory infection had greater BHR, by an amount corresponding to approximately 0.23 doubling doses (95% confidence interval 0.02-0.44) of the amount of methacholine causing a 20% fall (PD(20)) in forced expiratory volume in 1s (FEV(1)). All childhood factors explained less than 0.3% of variation in BHR in addition to over 20% by factors measured in adulthood. The relation of BHR to BMI was confined to smokers.

CONCLUSIONS

We found an effect of serious childhood respiratory infection on adult BHR, but this was small in comparison to relations of BHR to IgE-sensitization and airway caliber.

The influence of childhood infections and vaccination on the development of atopy: A systematic review of the direct epidemiological evidence

BACKGROUND

The 'hygiene hypothesis' has been used to justify a belief common among homeopaths, that the suppression of childhood infections and immunisation may lead to the development of chronic atopic diseases.

OBJECTIVES

To analyse the influence of childhood infections and immunisation on the development of atopy.

METHODS

Qualitative systematic review of direct epidemiological evidence (Medline 1993-2004) concerning the influence of childhood infections and immunisation on the development of atopy and discussion based on homeopathy.

CONCLUSIONS

(1) Childhood infections do not protect against atopy; on the contrary, they increase the risk of allergic diseases, in agreement to Hahnemann's observations, which included epidemic diseases among the factors capable of stimulating the development of chronic diseases. (2) Vaccination is not a risk factor for atopy, notwithstanding the allergenic effect of some vaccines.

Infections and atopic disorders in childhood and organochlorine exposure

The authors investigated whether organochlorine exposure is associated with prevalence of otitis media, pneumonia, pertussis, asthma, and increased immunoglobulin E levels in children. Organochlorine concentrations and histories of infection and atopic manifestation were available for 343 children, and immunoglobulin E levels were available for 340 children. The authors applied logistic and linear regressions and controlled for confounders. In general, the prevalence of infections in children was not related to organochlorine exposure. However, for the combined effect of dichlorodiphenyldichloroethene with polychlorinated biphenyls or hexachlorobenzene, a significantly increased relative risk (odds ratios = 3.70 and 2.38, respectively) was found for otitis media. Exposure to dichlorodiphenyldichloroethene resulted in a significantly higher odds ratio for asthma (odds ratio = 3.71; 95% confidence interval = 1.10, 12.56) and in immunoglobulin E concentrations above 200 kU/l (odds ratio = 2.28; 95% confidence interval = 1.20, 4.31). This is the first study in which dichlorodiphenyldichloroethene has been identified as a substantial risk factor for asthma and for increased immunoglobulin E blood levels.

The European Community Respiratory Health Survey: what are the main results so far? European Community Respiratory Health Survey II

The European Community Respiratory Health Survey (ECRHS) was the first study to assess the geographical variation in asthma and allergy in adults using the same instruments and definitions. The database of the ECRHS includes information from approximately 140,000 individuals from 22 countries. The aim of this review is to summarize the results of the ECRHS to date. The ECRHS has shown that there are large geographical differences in the prevalence of asthma, atopy and bronchial responsiveness, with high prevalence rates in English speaking countries and low prevalence rates in the Mediterranean region and Eastern Europe. Analyses of risk factors have highlighted the importance of occupational exposure for asthma in adulthood. The association between sensitization to individual allergens and bronchial responsiveness was strongest for indoor allergens (mite and cat). Analysis of treatment practices has confirmed that the treatment of asthma varies widely between countries and that asthma is often undertreated. In conclusion, the European Community Respiratory Health Survey has shown that the prevalence of asthma varies widely. The fact that the geographical pattern is consistent with the distribution of atopy and bronchial responsiveness supports the conclusion that the geographical variations in the prevalence of asthma are true and most likely due to environmental factors.

Efficacy of a polyvalent bacterial lysate in children with recurrent respiratory tract infections

Respiratory tract infections (RTIs) are the most frequent infections in humans, particularly in children. In addition to intervention, increasing interest is focusing on immunomodulatory therapy for recurrent RTIs, which indicate a reduced defense capacity of the respiratory mucosa. LW 50020, an oral immunomodulator that contains the antigens of seven bacteria common in RTIs, has reduced the number, duration, and severity of RTIs in children and adults. This 56-week placebo-controlled, double-blind study in 188 children investigated whether the efficacy of the standard schedule (immunization cycle + one booster cycle) would be enhanced by additional booster cycles. Efficacy and safety over the long term were also assessed. The rate of infection was reduced by 50% with the standard schedule and could not be further decreased by two consecutive booster cycles. With both schedules, this reduction was sustained during a 28-week treatment-free observation period that followed the 28-week treatment period. The number of adverse drug reactions was low, and all were transient, expected, and nonserious. These results confirm that LW 50020 is an effective and safe strategy for RTIs.