Indoor dampness and molds and development of adult-onset asthma: a population-based incident case-control study

Previous cross-sectional and prevalent case-control studies have suggested increased risk of asthma in adults related to dampness problems and molds in homes. We conducted a population-based incident case-control study to assess the effects of indoor dampness problems and molds at work and at home on development of asthma in adults. We recruited systematically all new cases of asthma during a 2.5-year study period (1997-2000) and randomly selected controls from a source population consisting of adults 21-63 years old living in the Pirkanmaa Hospital district, South Finland. The clinically diagnosed case series consisted of 521 adults with newly diagnosed asthma and the control series of 932 controls, after we excluded 76 (7.5%) controls with a history of asthma. In logistic regression analysis adjusting for confounders, the risk of asthma was related to the presence of visible mold and/or mold odor in the workplace (odds ratio, 1.54; 95% confidence interval, 1.01-2.32) but not to water damage or damp stains alone. We estimated the fraction of asthma attributable to workplace mold exposure to be 35.1% (95% confidence interval, 1.0-56.9%) among the exposed. Present results provide new evidence of the relation between workplace exposure to indoor molds and adult-onset asthma.     

Environmental tobacco smoke, parental atopy, and childhood asthma.

We hypothesized that the joint effect of genetic propensity to asthma and exposure to environmental tobacco smoke on the risk of childhood asthma is greater than expected on the basis of their independent effects. We performed a population-based 4-year cohort study of 2,531 children born in Oslo, Norway. We collected information on the child's health and environmental exposures at birth and when the child was 6, 12, 18, and 24 months and 4 years of age. The outcomes of interest were bronchial obstruction during the first 2 years and asthma at the age of 4 years. Parental atopy was defined as a history of maternal or paternal asthma or hay fever. Exposure to environmental tobacco smoke was defined on the basis of questionnaire information on household smokers at birth. In logistic regression analysis adjusting for confounding, parental atopy alone increased the risk of bronchial obstruction [odds ratio 1.62; 95% confidence interval (CI) 1.10-2.40] and asthma (1.66; 95% CI, 1.08-2.54). In children without parental atopy, there was little effect of exposure to environmental tobacco smoke on bronchial obstruction (1.29; 95% CI, 0.88-1.89) and asthma (0.84; 95% CI, 0.53-1.34). The presence of parental atopy and exposure had a substantial effect both on bronchial obstruction (2.88; 95% CI, 1.91-4.32) and asthma (2.68; 95% CI, 1.70-4.22). The results are consistent with the hypothesized joint effect of parental atopy and exposure to environmental tobacco smoke. This phenomenon--denoted as effect modification of environmental exposure by genetic constitution, or gene by environment interaction--suggests that some genetic markers could indicate susceptibility to environmental factors.     

The associations between childhood asthma and atopy, and parental asthma, hay fever and smoking

Summary. The aim of this analysis was to examine the degree to which a life time prevalence of asthma in a 7-year-old child is statistically associated with atopic conditions of the child, and with parental asthma, hay fever and smoking. In 1968, 8585 children who were born in 1961 and who were attending school in Tasmania were surveyed. This comprised 99% of the eligible population. The prevalence of a history of asthma in the 7-year-olds was 16.2% (males 19.0%, females 13.2%). Multiple logistic regression analysis showed that a history of asthma in a 7-year-old was associated with the child being male (odds ratio [OR] 1.56; 99% confidence interval 1.30–1.86), having a history of hay fever (3.86; 3.12–4.78), eczema (2.04; 1.63–2.55), hives (1.34; 1.09–1.65) or allergy to foods or medicines (1.70; 1.26–2.30), the child's mother or father having a history of asthma (2.63; 2.08–3.31 or 2.52; 1.99–3.19, respectively), and the mother being a smoker (1.26; 1.05–1.51). Parental hay fever and paternal smoking were not independently associated with childhood asthma. The strength of association between childhood asthma and parental asthma was independent of the sex of either the parent or the child, and of atopic conditions in the child. In the 133 children for whom both parents were asthmatic, 65 (49%) had a history of asthma. These findings, based on a population survey, are consistent, not only with a childhood history of asthma being strongly associated with atopy, but also with the existence of strong unmeasured determinants common to family members, the effects of which are not mediated via atopy. The risk for asthma being independent of both the sex of the child and of the parent, is consistent with a genetic aetiology for susceptibility to asthma.     

Maternal alcohol and coffee drinking, parental smoking and childhood leukaemia: a French population-based case-control study

We investigated the role of maternal alcohol and coffee drinking during pregnancy and that of parental smoking in the aetiology of childhood leukaemia. A French, population-based, case-control study was conducted, comparing 472 [407 acute lymphoblastic leukaemia (ALL) and 62 acute myeloblastic leukaemia] cases of childhood acute leukaemia (AL) and 567 population controls, frequency-matched with cases on age, gender and region of residence. Both case and control mothers filled in a comprehensive self-administered standardised questionnaire, eliciting detailed data on maternal alcohol and coffee consumption during pregnancy and parental smoking before, during and after pregnancy. Maternal alcohol consumption of more than 1 drink per day was related to ALL (OR = 2.8 [95% CI 1.8, 5.9]). While maternal coffee consumption was not significantly related to AL (OR = 1.4 [95% CI 0.9, 2.3]), highest intake of coffee (more than 3 cups per day) during pregnancy was associated with AL in children whose mothers were non-smokers (OR = 1.9 [95% CI 1.0, 3.5]). No association with parental smoking, either maternal or paternal, was observed with AL. The present results suggest a possible role of the highest consumption of alcohol by the mother during pregnancy in the aetiology of childhood AL.     

Fertility rates in women with asthma, eczema, and hay fever: a general population-based cohort study

The protective association between having older siblings and the risk of subsequent allergic disease may be due to decreased fertility among women with allergic disease. In this study, the authors compared fertility rates among women with asthma, eczema, or hay fever with those in the general female population. Computerized primary-care data from the United Kingdom were used to conduct a cohort analysis of 491,516 women. General fertility rates and age-specific fertility rates for 1994-2004 were estimated. Using Poisson regression, the authors compared fertility rates among women with asthma, eczema, or hay fever with rates in women without these diagnoses. Fertility rates were 53.0 and 52.3 livebirths per 1,000 person-years in women with and without asthma, respectively. The fertility rate ratio for women with asthma compared with women without asthma was 1.02 (95% confidence interval (CI): 1.00, 1.04) after adjustment for age, smoking, body mass index, and socioeconomic status. Equivalent fertility rate ratios for eczema and hay fever were 1.15 (95% CI: 1.13, 1.17) and 1.08 (95% CI: 1.06, 1.10), respectively. The authors found no evidence that the fertility rates of women with asthma, eczema, or hay fever are lower than those of women in the general population.     

Parental age and risk of childhood cancers: a population-based cohort study from Sweden

BACKGROUND: Frequent germ line cells mutations were previously demonstrated to be associated with aging. This suggests a higher incidence of childhood cancer among children of older parents. A population-based cohort study of parental ages and other prenatal risk factors for five main childhood cancers was performed with the use of a linkage between several national-based registries. METHODS: In total, about 4.3 million children with their parents, born between 1961 and 2000, were included in the study. Multivariate Poisson regression was used to obtain the incidence rate ratios (IRR) and 95% confidence interval (CI). Children <5 years of age and children 5-14 years of age were analysed independently. RESULTS: There was no significant result for children 5-14 years of age. For children <5 years of age, maternal age were associated with elevated risk of retinoblastoma (oldest age group's IRR = 2.39, 95%CI = 1.17-4.85) and leukaemia (oldest age group's IRR = 1.44, 95%CI = 1.01-2.05). Paternal age was significantly associated with leukaemia (oldest age group's IRR = 1.31, 95%CI = 1.04-1.66). For central nervous system cancer, the effect of paternal age was found to be significant (oldest age group's IRR = 1.69, 95%CI = 1.21-2.35) when maternal age was included in the analysis. CONCLUSION: Our findings indicate that advanced parental age might be associated with an increased risk of early childhood cancers.     

Longitudinal,population-based cohort study of prenatal influenza vaccination and influenza infection in childhood

BackgroundInfluenza vaccination is recommended to protect mothers and their infants from influenza infection. Few studies have evaluated the health impacts of in utero exposure to influenza vaccine among children more than six months of age.MethodsWe used probabilistically linked administrative health records to establish a mother–child cohort to evaluate the risk of influenza and acute respiratory infections associated with maternal influenza vaccination. Outcomes were laboratory-confirmed influenza (LCI) and hospitalization for influenza or acute respiratory infection (ARI). Adjusted hazard ratios (aHRs) accounted for child’s Aboriginal status and were weighted by the inverse-probability of treatment.Results14,396 (11.5%) children were born to vaccinated mothers. Maternally vaccinated infants aged < 6 months had lower risk of LCI (aHR: 0.33; 95% CI: 0.13, 0.85), influenza-associated hospitalization (aHR: 0.39; 95% CI: 0.16, 0.94) and ARI-associated hospitalization (aHR: 0.85; 95% CI: 0.77, 0.94) compared to maternally unvaccinated infants. With the exception of an increased risk of LCI among children aged 6 months to < 2 years old following first trimester vaccination (aHR: 2.28; 95% CI: 1.41, 3.69), there were no other differences in the risk of LCI, influenza-associated hospitalization or ARI-associated hospitalization among children aged > 6 months.ConclusionStudy results show that maternal influenza vaccination is effective in preventing influenza in the first six months and had no impact on respiratory infections after two years of age.     

Chlorinated pool attendance, atopy, and the risk of asthma during childhood

The pool chlorine hypothesis postulates that the rise in childhood asthma in the developed world could result at least partly from the increasing exposure of children to toxic gases and aerosols contaminating the air of indoor chlorinated pools. To further assess this hypothesis, we explored the relationships between childhood asthma, atopy, and cumulated pool attendance (CPA). We studied 341 schoolchildren 10-13 years of age who attended at a variable rate the same public pool in Brussels (trichloramine in air, 0.3-0.5 mg/m3). Examination of the children included a questionnaire, an exercise-induced bronchoconstriction (EIB) test, and the measurement of exhaled nitric oxide (eNO) and total and aeroallergen-specific serum IgE. CPA by children (range, 0-1,818 hr) emerged among the most consistent predictors of asthma (doctor diagnosed or screened with the EIB test) and of elevated eNO, ranking immediately after atopy and family history of asthma or hay fever. Although the risk of elevated eNO increased with CPA [odds ratio (OR) = 1.30; 95% confidence interval (CI), 1.10-1.43] independently of total or specific serum IgE, the probability of developing asthma increased with CPA only in children with serum IgE > 100 kIU/L (OR for each 100-hr increase in CPA = 1.79; 95% CI, 1.07-2.72). All these effects were dose related and most strongly linked to pool attendance before 6-7 years of age. Use of indoor chlorinated pools especially by young children interacts with atopic status to promote the development of childhood asthma. These findings further support the hypothesis implicating pool chlorine in the rise of childhood asthma in industrialized countries.     

Childhood asthma in Beijing,China: a population-based case-control study

China is the most populous country in the world. Few studies, however, have been conducted there to investigate the risk factors for childhood asthma. A population-based case-control study was conducted in Shunyi County, People's Republic of China, in January 1999 and March 2001 to investigate the issue. An increased risk of childhood asthma was associated with smoking by relatives in front of the mother while she was pregnant with the child (odds ratio (OR) = 1.3, 95% confidence interval (CI): 1.0, 1.6) and with smoking by relatives in front of the child (OR = 1.4, 95% CI: 1.1, 1.9). The risk increased with the increasing number of smokers and the total minutes of smoking by relatives in front of both the child and the mother while she was pregnant with the child. An increased risk was observed for use of coal for heating (OR = 1.5, 95% CI: 1.1, 1.9). Those who reported using coal for cooking without ventilation also had an increased risk (OR = 2.3, 95% CI: 1.5, 3.5). An increased risk was observed for those who reported having molds or fungi on the ceilings of their houses (OR = 1.8, 95% CI: 1.1, 2.9) or inside the child's room (OR = 1.8, 95% CI: 1.0, 3.2). An increased risk was also found for those having both a dog and a cat as pets (OR = 1.5, 95% CI: 1.0, 2.3) or for finding both cockroaches and rats inside their houses (OR = 1.8, 95% CI: 1.2, 2.8).     

Allergy,atopy, and cancer: a prospective study of the 1981 Busselton cohort

The associations among certain allergic disorders, atopy upon skin-prick testing, and specific cancers were evaluated in a prospective study. Information regarding history of asthma and hay fever was collected by questionnaire from 3,308 cancer-free participants in the 1981 Busselton Health Survey. A subset of 1,005 participants also underwent skin-prick testing. The cohort was followed for a new diagnosis of cancer or death until the end of 1999. Cox proportional hazards regression analysis was used to estimate adjusted hazard ratios (relative risks) for breast, prostate, colorectal, lung, and hematologic cancers and melanoma. Having a skin reaction to house dust mites nearly tripled the risk of prostate cancer (relative risk = 2.90, 95% confidence interval: 1.26, 6.68). History of asthma and hay fever were associated with a trend toward a reduced risk of colorectal cancer and increased risk of leukemia, but these results were not statistically significant. Hay fever was associated with melanoma risk in men but not in women. No association was found between breast and lung cancers and allergic disorders or atopy.     

Occupation and adult-onset asthma among Chinese women in a population-based cohort

BACKGROUND: Exposure to industrial irritants is believed to have contributed to the increasing prevalence of asthma worldwide. We examined the associations between occupation and asthma among women in a case-control study nested in the population-based Shanghai Women's Health Study cohort in China. METHODS: Cases were 1,050 women who reported a physician-diagnosed asthma as adults. Controls were 4,200 women matched to the cases by year of birth and age at diagnosis. Lifetime occupational histories were obtained. Logistic regression was applied to estimate odds ratios (ORs) adjusting for smoking, education, family income, and concurrent chronic bronchitis. RESULTS: Asthma is more prevalent in production industries for metal tools (OR = 2.4; 1.3-4.7), metal products for everyday use (OR = 1.6; 1.1-2.4), ships (OR = 2.6; 1.0-6.8), and clocks (OR = 1.9; 1.0-3.4), and in occupations as farm workers (OR = 4.0; 1.2-13.0), laboratory technicians and analyzers (OR = 2.2; 1.2-3.9), and installation and maintenance workers for weaving and knitting machineries (OR = 2.4; 1.1-5.4). Other associations less commonly reported were identified for electricians (OR = 2.1; 1.1-4.1), performers (OR = 3.2; 1.4-7.4), administrative workers in organizations and enterprises (OR = 1.8; 1.1-2.8), and postal and telecommunication workers (OR = 3.5; 1.6-7.6). CONCLUSIONS: Our findings suggest that occupational exposures contribute to the development of asthma in women.     

Longitudinal study of parental smoking habits and development of asthma in early childhood

Objective

This study examined the association between parental smoking habits and the development of asthma in early childhood by using representative samples.

Methods

The survey subjects included all of the 53,575 babies born in Japan during the periods January 10-17 and July 10-17, 2001. The families of the subjects were asked to complete questionnaires that were delivered by post at 6 months, 1 year 6 months, 2 years 6 months, 3 years 6 months, and 4 years 6 months postpartum. The first survey contained questions regarding the smoking habits of the parents. The second to fifth surveys asked if the child had needed medical attention for the treatment of asthma.

Results

Data from 36,888 subjects (collection rate: 68.9%) were analyzed. The 4-year cumulative incidence of asthma was 12.0%. Maternal indoor smoking significantly increased the risk of asthma development in children, 4-year risk 14.4% vs. 11.7%, risk ratio = 1.24, 95% CI: 1.11 to 1.38. No statistically significant association was found between paternal smoking and asthma development in children.

Conclusions

In order to prevent the development of asthma in early childhood, it is necessary to formulate measures to stop or discourage maternal smoking.     

Drowning in childhood and adolescence: a population-based study.

We present the results of a residence-based study of drownings among Sacramento County, California children and adolescents ages 0-19 years for the years 1974-84. Children ages 1-3 had the highest drowning rates. The majority of drownings in this group, and one-third of all drownings in the study, occurred in residential swimming pools. Males ages 15-19 had a high drowning rate as well; at least 38 per cent of drownings in that age group were alcohol-associated. The implications for preventive efforts are discussed.     

Occupation and asthma: a population-based incident case-control study

The authors assessed the relations between occupation and risk of developing asthma in adulthood in a 1997-2000 population-based incident case-control study of 521 cases and 932 controls in south Finland. The occupations were classified according to potential exposure to asthma-causing inhalants. Asthma risk was increased consistently for both men and women in the chemical (adjusted odds ratio (OR) = 5.69, 95% confidence interval (CI): 1.08, 29.8), rubber and plastic (OR = 2.61, 95% CI: 0.92, 7.42), and wood and paper (OR = 1.72, 95% CI: 0.71, 4.17) industries. Risk in relation to occupation was increased only for men-for bakers and food processors (OR = 8.62, 95% CI: 0.86, 86.5), textile workers (OR = 4.70, 95% CI: 0.29, 77.1), electrical and electronic production workers (OR = 2.83, 95% CI: 0.82, 6.93), laboratory technicians (OR = 1.66, 95% CI: 0.17, 16.6), and storage workers (OR = 1.57, 95% CI: 0.40, 6.19). Of the predominantly men's occupations, metal (OR = 4.52, 95% CI: 2.35, 8.70) and forestry (OR = 6.00, 95% CI: 0.96, 37.5) work were the strongest determinants of asthma. For women, asthma risk increased for waiters (OR = 3.03, 95% CI: 1.10, 8.31), cleaners (OR = 1.42, 95% CI: 0.81, 2.48), and dental workers (OR = 4.74, 95% CI: 0.48, 46.5). Results suggest an increased asthma risk both in traditional industries and forestry and in several nonindustrial occupations.     

Risk factors for asthma deaths: a population-based, case-control study

OBJECTIVES: To investigate risk factors for death from asthma using a case-control study design with two control groups. METHODS: Cases (n = 42) comprised subjects aged 10-59 years who died from asthma. Two control groups were selected: a random sample of asthmatics from the community (n = 132) and age and sex matched patients recently admitted to hospital for asthma (n = 89). We obtained information from proxies of cases and controls, and their general practitioners, by a structured telephone survey. Matched and unmatched logistic regression analyses were used to determine odds ratios for risk factors for asthma deaths. RESULTS: Compared to community controls, important risk factors for asthma deaths included indicators of asthma severity, use of three or more groups of asthma medications, more extensive use of health services for asthma, poor compliance with asthma medications and regularly missing hospital and general practitioner appointments for asthma. Compared to hospital controls, risk factors for asthma deaths were previous visits to emergency department for asthma, knowledge about asthma medications and regularly missing general practitioner appointments. CONCLUSIONS: In this study, severity of asthma, increased health service utilisation and suboptimal asthma self-management were associated with increased risks for asthma death. IMPLICATIONS: People with severe asthma or poorly controlled asthma have a greater risk of dying from their asthma. Both clinicians and non-clinicians managing asthma should regularly assess the appropriateness of management to prevent deaths.     

Trends in childhood and parental asthma prevalence in Merseyside, 1991-1998

OBJECTIVE: To determine changes in childhood and parental asthma prevalence in Merseyside between 1991 and 1998. METHODS: Three standardized cross-sectional respiratory health surveys using a parent-completed questionnaire were completed in 1991 (n = 1171), 1993 (n = 2368) and 1998 (n = 1964) amongst primary school children (5-11 years) attending the same 10 schools. The main outcome measures were prevalence of reported doctor diagnosed asthma, the symptom triad of cough, wheeze and breathlessness (C+W+B+) and parental asthma. RESULTS: Significant changes in prevalence for all respiratory variables occurred between 1991 and 1998, except for the symptom triad C+W+B+. Between 1991 and 1998 the prevalence of reported doctor diagnosed asthma increased from 17.7 to 29.8 per cent (p < 0.001), history of wheezing increased from 22.5 to 29.4 per cent (p < 0.001). The symptom triad of C+W+B+ changed from 9.6 to 9.9 per cent (p = 0.78). Childhood reported hospital admissions for respiratory illness increased from 5.5 to 10.7 per cent (p < 0.001). Paternal asthma increased from 6.5 per cent in 1991, to 8.6 per cent in 1998 (p = 0.031), and maternal asthma almost doubled in the same period from 6.6 to 11.2 per cent (p < 0.001). Children living in poorer areas (Townsend score 8-11) were more likely to have doctor diagnosed asthma (OR = 2.99, 95 per cent CI, 2.06 to 4.33) and C+W+B+ (OR = 2.17, CI 1.13 to 4.18). Childhood obesity was significantly associated with increased risk of both doctor diagnosed asthma (OR = 1.74, 95 per cent CI, 1.29 to 2.37) and C+W+B+ (OR = 1.88, 95 per cent CI, 1.21 to 2.90). CONCLUSION: A rising prevalence of reported doctor diagnosed asthma, but not C+W+B+ was observed during the 1990s in a low socio-economic area of Liverpool. Asthma prevalence was related to socio-economic deprivation and was associated with obesity. The rising prevalence of reported doctor diagnosed asthma is likely to be attributable to several factors, including changes in diagnostic labelling and the distribution of factors related to socio-economic status.