Sex-related interactive effect of smoking and household pets on asthma incidence

Different effects of smoking on atopic and non-atopic adult-onset asthma

BACKGROUND

Both tobacco smoking and atopy increase the risk of adult-onset asthma. We studied if there are differences in the effects of smoking on the risks of atopic and non-atopic adult-onset asthma, and if gender modifies these effects.

METHODS

The Finnish Environment and Asthma Study (FEAS) includes 521 incident cases of adult-onset asthma and 932 population-based controls, aged 21 to 63 years, recruited from a geographically defined area of Pirkanmaa, South Finland. Asthma was defined based on symptoms and lung function measurements, atopy by IgE antibodies to common aeroallergens and smoking by the study questionnaire.

RESULTS

Altogether 212 cases were atopic, and 251 cases were non-atopic. Regular smoking increased the risk of atopic asthma (adjusted OR 1.24, 95% CI 0.83-1.85), this effect was seen in women (aOR 1.77, 1.06-2.95) but not in men (aOR 0.75, 0.39-1.45). Among regular smokers, the amount smoked was lowest among women with atopic asthma. Recent quitting of smoking was related to increased risk of both atopic (aOR 4.91, 2.26-10.65) and non-atopic (aOR 4.37, 1.87-10.21) asthma. Having quitted smoking over a year ago was related to increased risk of non-atopic asthma (aOR 1.57, 1.08-2.28), mainly in men (aOR 2.03, 1.06-3.88).

CONCLUSIONS

In women, rather small amounts of regular smoking increase the risk of atopic asthma. However, for non-atopic asthma, the smoking induced risk continues for longer after quitting, especially in men. In conclusion, the effects of smoking on the risks of atopic and non-atopic asthma differ, and gender modifies these effects.

Relationships between acrylamide and glycidamide hemoglobin adduct levels and allergy-related outcomes in general US population, NHANES 2005-2006

BACKGROUND

Acrylamide-induced immunotoxicity and allergic dermatitis have been reported in animal experiments and clinical reports, respectively. However, epidemiological evidence from the general population is limited.

OBJECTIVES

The purpose of the present study was to estimate the associations between acrylamide exposure and allergy-related outcomes in the general US population.

METHODS

A total of 6982 subjects were selected from the National Health and Nutrition Examination Survey 2005-2006 (NHANES). Internal exposure was measured by the hemoglobin adducts of acrylamide (HbAA) and its metabolite glycidamide (HbGA). Allergy-related outcomes including asthma, hay fever, allergy, itchy rash, sneeze, wheeze and eczema were obtained by self-administered questionnaires. Allergic sensitization was assessed by the total immunoglobulin E (IgE) levels. The associations of HbAA and HbGA quartiles with allergy-related outcomes were calculated using logistic regression models with multivariable adjustments. Analyses were additionally stratified according to age, gender and serum cotinine levels.

RESULTS

When setting quartile 1 of HbAA as reference, the odds ratios (ORs) [95% confidence intervals (CIs)] of quartile 2 to 4 for eczema were 1.18 (0.79-1.76), 1.14 (0.73-1.78) and 1.58 (1.14-2.18), respectively (p_trend = 0.002). Individuals at the highest quartile of HbGA had significantly elevated likelihoods of itchy rash (OR = 1.37, 95% CI = 1.02-1.83, p_trend = 0.032) and eczema (OR = 1.45, 95% CI = 1.06-1.97, p_trend = 0.044). The stratification analyses indicated various results in different subgroups.

CONCLUSIONS

This study indicated significant associations between HbAA and HbGA levels and the likelihoods of allergy-related outcomes in the general US population, depending on age, gender and smoke exposure status. These findings suggested potential public health concerns for the widespread exposure to acrylamide.

Neighborhood and Individual Socioeconomic Status and Asthma Incidence in African American Women

OBJECTIVE

Individual socioeconomic status (SES) has been associated with asthma incidence but whether neighborhood SES has an influence is unknown. We assessed the contributions of neighborhood socioeconomic status (SES), neighborhood housing density, neighborhood racial composition, and individual SES to the development of adult-onset asthma in Black women, accounting for other known or suspected risk factors.

DESIGN AND PARTICIPANTS

Prospective cohort study conducted among 47,779 African American women followed with biennial health questionnaires from 1995 to 2011.

METHODS AND MAIN OUTCOME MEASURES

Incident asthma was defined as new self-report of doctor-diagnosed asthma with concurrent use of asthma medication. We assessed neighborhood SES, indicated by census variables representing income, education, and wealth, and housing density and % African American population, as well as individual SES, indicated by highest education of participant/spouse. Cox proportional hazards models were used to derive multivariable hazard ratios (HRs) and 95% CIs for the association of individual SES and neighborhood variables with asthma incidence.

RESULTS

During a 16-year follow-up period, 1520 women reported incident asthma. Neighborhood factors were not associated with asthma incidence after control for individual SES, body mass index, and other factors. Compared with college graduates, the multivariable HR for asthma was 1.13 (95% CI 1.00-1.28) for women with some college education and 1.23 (95% CI 1.05-1.44) for women with no more than a high school education.

CONCLUSIONS

Individual SES, but not neighborhood SES or other neighborhood factors, was associated with the incidence of adult-onset asthma in this population of African American women.

Asthma risk factors

BACKGROUND

Bronchial asthma is one of the most common chronic diseases in childhood, with a current prevalence of 6% to 9%, but a prevalence that is increasing at an alarming rate. Asthma is a complex genetic disorder with strong environmental influence. It imposes a growing burden on our society in terms of morbidity, quality of life, and healthcare costs. Despite large-scale efforts, only a few asthma genes have been confirmed, suggesting that the genetic underpinning of asthma is highly complex.

METHODS

A review of the literature was performed regarding atopic and nonatopic asthma risk factors, including environmental risk factors and genetic studies in adults and children.

RESULTS

Several environmental risk factors have been identified to increase the risk of developing asthma such as exposure to air pollution and tobaccos smoke as well as occupational risk factors. In addition atopy, stress, and obesity all can increases the risk for asthma in genetically susceptible persons.

CONCLUSION

Asthma represents a dysfunctional interaction with our genes and the environment to which they are exposed, especially in fetal and early infant life. The increasing prevalence of asthma in all age groups indicate that our living environment and immunity are in imbalance with each other reacting with airway inflammation to the environmental exposures and often non-harmful proteins, such as allergens causing the current "asthma and allergy epidemic." Because of the close relationship between asthma and chronic rhinosinusitis, it is important that otolaryngologists have a good understanding of asthma, the etiologic factors associated with disease, and its evaluation and management.

Active and passive smoking and the incidence of asthma in the Black Women's Health Study

RATIONALE

Evidence linking active or passive smoking to the incidence of adult-onset asthma is inconsistent with both positive and inverse associations being reported. Most previous studies of active smoking have not accounted for passive smoke exposure, which may have introduced bias.

OBJECTIVES

To assess the separate associations of active and passive smoking to the incidence of adult-onset asthma in the U.S. Black Women's Health Study, a prospective cohort of African American women followed since 1995 with mailed biennial questionnaires.

METHODS

Active smoking status was reported at baseline and updated on all follow-up questionnaires. Passive smoke exposure during childhood, adolescence, and adulthood was ascertained in 1997. Asthma cases comprised women who reported doctor-diagnosed asthma with concurrent asthma medication use. Cox regression models were used to derive multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for former and current smoking and for passive smoking among nonsmokers compared with a reference category of never active or passive smokers.

MEASUREMENTS AND MAIN RESULTS

Among 46,182 participants followed from 1995 to 2011, 1,523 reported incident asthma. The multivariable HRs for former active smoking, current active smoking, and passive smoking only were, respectively, 1.36 (95% CI, 1.11-1.67), 1.43 (95% CI, 1.15-1.77), and 1.21 (95% CI, 1.00-1.45), compared with never active/passive smoking.

CONCLUSIONS

In this large population with 16 years of follow-up, active smoking increased the incidence of adult-onset asthma, and passive smoke exposure increased the risk among nonsmokers. Continued efforts to reduce exposure to tobacco smoke may have a beneficial effect on the incidence of adult-onset asthma.

[Influence of tobacco smoking on the risk of developing asthma]

The aim of this general review is to investigate the influence of active and passive smoking on the development of asthma in children and adults. Passive smoking during and after pregnancy facilitates the onset of childhood asthma and wheezing. In particular, smoking during pregnancy is associated with the occurrence of wheezing prior to the age of 4 years. In contrast, the results of studies on the relationship between parental smoking in the post-natal period and the onset of asthma or wheezing are discordant. Exposure to passive smoking during childhood facilitates the occurrence of asthma in adulthood. In adults and adolescents, active smoking appears to be a factor favoring the development of asthma. On the other hand, non-smoking adult subjects without history of asthma exposed to passive smoking have a risk of asthma. The pathophysiological mechanisms by which tobacco smoke is the cause of asthma are still poorly known. Smoking cessation is an essential component in the management of asthmatic subjects who smoke, facilitating the control of the disease.

Indoor air pollution and respiratory health in the elderly

Data on respiratory effects of indoor air pollution in elderly are scanty. The purpose of this review is to summarize current knowledge on adverse respiratory effects of indoor air pollution in individuals aged over 65 years, by presenting existing epidemiological evidence. Using MEDLINE database through PubMed, we identified relevant publications published between 1991 and 2011 in English on respiratory health effects of indoor air pollution in elderly (>65 years). A total of 61 studies were found and after application of the inclusion criteria: (i) epidemiologic studies published in English in peer-reviewed journals between January 1991 and December 2011, (ii) study population with age over or equal 65 years, and (iii) outcome of respiratory symptoms and disease with the exclusion of lung cancer, 33 relevant publications were selected. Most of them showed significant relationships between exposure to major indoor air pollutants and various short-term and long-term respiratory health outcomes such as wheezing, breathlessness, cough, phlegm, asthma, COPD, lung cancer and more rarely lung function decline. The most consistent relationship is found between chronic obstructive pulmonary disease (COPD) and environmental tobacco smoke (ETS). Further studies in the elderly population are needed in order to define causal relationships between exposures to indoor air pollution and underlying mechanisms in this sub-population.

The population attributable fraction of asthma among Canadian children

OBJECTIVE

We calculated the population attributable fraction (PAF) of Canadian childhood asthma due to modifiable environmental exposures, in order to estimate their relative contributions to asthma development based on the current literature.

METHODS

We conducted a systematic review to determine Canadian childhood asthma incidence, Canadian prevalence of exposure to airborne pollutants and indoor allergens, and international estimates of the risk of developing physician-diagnosed asthma (PDA) associated with each exposure. Combining risk estimates by meta-analysis where possible, PAF was calculated by the formula: PAF = Attributable risk *Exposure prevalence* 100%/Asthma incidence.

SYNTHESIS

Age-specific Canadian childhood asthma incidence ranged from 2.8%-6.9%. Canadian exposure prevalences were: PM10 16%, PM2.5 7.1%, NO2 25%, environmental tobacco smoke (ETS) 9.0%, cat 22%, dog 12%, mouse 17%, cockroach 9.8%, dust mite 30%, moisture 14% and mould 33%. Relative risk estimates of PDA were: PM10 1.64, PM2.5 1.44, NO2 1.29, ETS 1.40, mouse 1.23, cockroach 1.96, and spanned 1.00 for cat, dog, dust mites, moisture and mould. PAF estimates for incident asthma among preschool children were: PM10 11%, PM2.5 1.6%, NO2 4.0%, ETS 2.9%, mouse 6.5% and cockroach 13%.

CONCLUSIONS

This systematic review suggests contributions to childhood asthma development from exposure to particulates, NO2, ETS, mouse and cockroach. The associations appeared to be more complex for cat, dog and dust mite allergens and more variable for mould and moisture. Additional prospective, population-based studies of childhood asthma development with objectively-measured exposures are needed to further quantify these associations.

Smoking and asthma: disentangling their mutual influences using a longitudinal approach

BACKGROUND

The association between smoking and asthma remains unclear and has mostly been assessed in cross-sectional studies, with potential selection bias ("healthy smoker effect").

AIMS

Using a longitudinal approach, the aims were to assess whether 1) childhood asthma modifies smoking initiation, 2) active smoking influences asthma incidence in adults and 3) active smoking among subjects with asthma influences the persistence of the disease or the 12-year evolution in lung function in children and adults.

METHODS

Subjects (513 children and 1190 adults) were recruited and followed-up for 12 years in the context of the EGEA study (Epidemiological study on the Genetics and Environment of Asthma).

RESULTS

Childhood asthma was not associated with a decreased probability of starting active smoking (Hazard Ratio, HR = 0.96; 95% confidence interval (CI): 0.72, 1.27). Smoking at baseline was associated with a higher risk for asthma incidence in adulthood (HR = 1.95, 95% CI: 1.00, 3.77). Among subjects with asthma, smoking was unrelated to lung function evolution; however, among children with moderate to severe asthma at inclusion, smoking tended to slow down the lung function growth (P = 0.04).

CONCLUSION

These findings support the hypothesis that childhood asthma does not prevent smoking initiation and confirm that active smoking has a deleterious role on asthma. Altogether this study emphasizes the importance of active smoking as a serious public health problem particularly for children and women.

Smoking and asthma in men and women with normal weight, overweight, and obesity

BACKGROUND

There is a complex interrelationship among smoking, body weight, and asthma. It needs to be clarified whether smoking is related to an increased risk of asthma after taking into account for relative body weight.

OBJECTIVE

To examine the association between cigarette smoking and the prevalence of asthma in Canadian men and women with normal weight, overweight, and obesity.

METHODS

The analysis was based on data from 112,830 Canadians aged 18 years or more who participated in a national survey in 2007-2008. A questionnaire covered the information on prevalent asthma, smoking status, height, weight, and other factors. Logistic regression analysis was used to determine the association between smoking and the prevalence of asthma stratified by sex and body mass index (BMI).

RESULTS

The crude prevalence of asthma was 6.6% for men and 9.3% for women. After adjustment for covariates, the odds ratios (ORs) for current smoking associated with asthma was 1.20 [95% confidence interval (CI): 1.01-1.43] for men with normal weight, 0.98 (95% CI: 0.81, 1.18) for overweight men, and 1.02 (95% CI: 0.80-1.30) for obese men. For women, the corresponding adjusted ORs were 1.41 (95% CI: 1.23-1.62), 1.27 (95% CI: 1.05-1.54), and 1.28 (95% CI: 1.03-1.59), respectively.

CONCLUSION

Current smoking was significantly associated with prevalent asthma in all women regardless of their relative body weight. In men, however, the association was only observed in those with under- or normal weight.

Asthma and cigarette smoking: a review of the empirical literature

The purpose of this review paper is to present and evaluate the empirical literature on the association between asthma and cigarette smoking. The authors conducted a literature search utilizing electronic search engines (i.e., PsycINFO and MEDLINE) to examine databases using the following key word algorithms: smoking OR nicotine OR tobacco AND asthma. Only articles that focused on active tobacco smoking and analyzed groups with asthma patients only were examined in the present review. Overall, empirical evidence suggests that (1) smoking is more prevalent among individuals with asthma than those without; (2) smoking is a risk candidate for the development of asthma; (3) smoking is associated with decreased asthma control and increased risk of mortality and asthma attacks and exacerbations; (4) smokers with and without asthma may have different risk factors for smoking onset as well as different smoking motives and outcome expectancies; and (5) smoking cessation is associated with improvements in lung functioning and asthma symptoms. Future work in this domain of study will lead to clinically relevant health care advances as well as the development of theoretically driven, methodologically diverse lines of research exploring asthma-smoking comorbidity issues.

Gender-related interactive effect of smoking and rural/urban living on asthma prevalence: a longitudinal Canadian NPHS study

The effects of passive smoking on asthma are well documented, however there is limited research conducted to study the relationship of asthma and smoking among adult populations. This article aims to investigate the gender differences when studying the relationship of asthma prevalence and smoking and further explore if rural/urban living affects the relationship over time. The longitudinal National Population Health Survey (NPHS) dataset was used. For analytic purposes five time periods were used. Generalized estimating equation (GEE) approach was used to obtain the odds ratios and 95% confidence intervals. A total of 11,223 participants ranging in age from 18 to 64; 5,382 men and 5,841 women, were included in the baseline time point (1994-1995). Rural/urban living for the present analysis was an effect modifier for the relationship of asthma prevalence and smoking, and this was true only for women. The results showed that female smokers and ex-smokers residing in rural locations were 1.4 times (95% CI: Rural Smokers = 1.02-1.94, and Rural Ex-smokers = 1.02-2.02) more likely to be diagnosed with asthma compared to non-smoking urban women. Results indicate that the combination of living in a rural area and smoking increases the risk of asthma prevalence among women but not among men.

An interdisciplinary analysis of sex and gender in relation to the pathogenesis of bronchial asthma

BACKGROUND

An increasing number of studies confirm that pathogenesis and prevalence of bronchial asthma are age and sex dependent. Detailed physiological mechanisms of the changing sex ratios with age are not fully known, however, the gender (socio-cultural) factors are also imperative. Although multiple factors definitely influence the pathogenesis of asthma, only individual or few combinations of these have been investigated.

METHODS

The terms 'sex', 'gender' and plausible combinations of both were systematically researched in selected databases (Medline, Scopus) or other sources, including publications from January 2000 to June 2007. Generated articles were categorized, either as endogenous or exogenous factors influencing the pathogenesis of asthma, and divided into the following subgroups: genetic, immunological, hormonal, gynaecological, nutritional, and environmental parameters.

RESULTS

An increasing number of studies investigate the influence of sex and gender in the aetiology, therapy and prevention of asthma. While their results are still debatable, others regarding its initiation, perpetuation and cessation have been clarified. Recent insights into interactions at biomolecular and immunological levels greatly contribute to clarifying sex-specific influences. Despite occasional oversimplifications, a trend for explanations considering the complex interplay of different factors can be observed. This work is in line with this trend and offers explanation models from our point of view.

CONCLUSIONS

Some disagreements regarding the patho-physiology, diagnosis, treatment and prevention of asthma still prevail. Nevertheless, in order to better appreciate its complexity, openness to and persistent consideration for interdisciplinary as well as sex- and gender-related factors is required of the medical-research community in future investigations.

Prevalence of asthma among Chinese adolescents living in Canada and in China

BACKGROUND

Studies of the prevalence of asthma among migrating populations may help in identifying environmental risk factors.

METHODS

We analyzed data from Vancouver, Canada, and from Guangzhou, Beijing and Hong Kong, China, collected during phase 3 of the International Study of Asthma and Allergies in Childhood. We subdivided the Vancouver adolescents according to whether they were Chinese immigrants to Canada, Canadian-born Chinese or Canadian-born non-Chinese. We compared the prevalence of asthma and wheezing among Chinese adolescents born in Canada, Chinese adolescents who had immigrated to Canada and Chinese adolescents living in China.

RESULTS

Of 7794 Chinese adolescents who met the inclusion criteria, 3058 were from Guangzhou, 2824 were from Beijing, and 1912 were from Hong Kong. Of 2235 adolescents in Vancouver, Canada, 475 were Chinese immigrants, 617 were Canadian-born Chinese, and 1143 were Canadian-born non-Chinese. The prevalence of current wheezing among boys ranged from 5.9% in Guangzhou to 11.2% in Canadian-born Chinese adolescents. For girls, the range was 4.3% in Guangzhou to 9.8% in Canadian-born Chinese adolescents. The prevalence of ever having had asthma ranged from 6.6% to 16.6% for boys and from 2.9% to 15.0% for girls. Prevalence gradients persisted after adjustment for other environmental variables (odds ratios for ever having had asthma among Canadian-born Chinese compared with native Chinese in Guangzhou: 2.72 [95% confidence interval 1.75-4.23] for boys and 5.50 [95% confidence interval 3.21-9.44] for girls; p < 0.001 for both). Among Chinese adolescents living in Vancouver, the prevalence of ever wheezing increased with duration of residence, from 14.5% among those living in Canada for less than 7 years to 20.9% among those living their entire life in Canada. The same pattern was observed for the prevalence of ever having had asthma, from 7.7% to 15.9%.

INTERPRETATION

Asthma symptoms in Chinese adolescents were lowest among residents of mainland China, were greater for those in Hong Kong and those who had immigrated to Canada, and were highest among those born in Canada. These findings suggest that environmental factors and duration of exposure influence asthma prevalence.

Potential population impact of changes in heroin treatment and smoking prevalence rates: using Population Impact Measures

BACKGROUND

The drug misuse and asthma are major health problems in urban settings. There are effective interventions to reduce cigarette smoking and also to treat heroin use; in the context of European System of Urban Health Indicators Project (EURO-URHIS), we explored the use of Population Impact Measures (PIMs) to describe the potential for increase in methadone use and reduction in cigarette smoking to reduce deaths -from heroin use- and asthma events in examples of urban populations.

METHODS

The two PIMs calculated here are the Number of Events Prevented in your Population (NEPP) and the Population Impact Number of Eliminating (or reducing the prevalence of) a Risk Factor (PIN-ER-t).

RESULTS

Increasing methadone treatment uptake from its current levels to 90% would prevent 21 (95% CI: 11-34) deaths in Manchester City, 218 (95% CI: 114-339) in Greater London and overall 1 243 (95% CI: 641-1953) in England in 1 year. In males 2 (95% CI: -22 to 28), 27 (95% CI: -296 to 363) and 170 (95% CI: -1757 to 2186) and in females 36 (95% CI: 6-70), 0 and 2312 (95% CI: 934-3783) fewer asthma cases per year would have been expected in Manchester City, Greater London and overall in England respectively, if the smoking prevalence is reduced from current levels to 20% in both sexes.

CONCLUSIONS

PIMs provide estimates of absolute risk and benefit to a total population, of potential use to policy-makers since current practice and intervention goals are taken into account.

Opposing trends in the prevalence of health professional-diagnosed asthma by sex: a Canadian National Population Health Survey study

BACKGROUND

The prevalence of asthma is on the rise worldwide, with large variations in prevalence existing between and within countries. Little is known regarding the variation in asthma prevalence in adults living in rural and urban settings.

OBJECTIVES

Using questionnaire data from the Canadian National Population Health Survey, the prevalence of asthma at four time periods (1994/1995 [cycle 1], 1996/1997 [cycle 2], 1998/1999 [cycle 3] and 2000/2001 [cycle 4]) was compared between rural and urban populations stratified by sex, smoking status and age group. Asthma was defined as a positive response to the question: "Do you have asthma diagnosed by a health professional?"

METHODS

To account for the complexity of the survey design, the bootstrap method was used to calculate prevalences and 95% CIs.

RESULTS

Overall, the prevalence of asthma increased from 7.3% (cycle 1) to 7.5% (cycle 4). After stratifying by sex, the asthma prevalence decreased among men, but in women, there was a steady increase. Asthma prevalence increased for both the rural population and the urban population. After stratifying each cycle by sex and location (rural or urban), both rural and urban men showed a decrease in asthma prevalence. On dividing according to age groups (0 to 14 years, 15 to 34 years, 35 to 64 years, and 65 years and older), the prevalence of asthma was greatest in the 15- to 34-year age group of urban and rural women.

CONCLUSIONS

Asthma prevalence increased among rural and urban women. The prevalence of asthma was highest among female smokers and male nonsmokers when stratified by smoking status. Based on these findings, the rate of increase in asthma prevalence is different for men and women.

[Lung function and exposure to tobacco smoke among adolescents]

OBJECTIVE

To study lung function in adolescents in relation to smoking (active and passive smokers) and to investigate the repercussion on spirometric parameters.

PATIENTS AND METHOD

We studied 301 healthy adolescents with no history of bronchial asthma or colds in the month prior to the study. A questionnaire on tobacco exposure was administered and spirometry (Datospir-92) was performed.

RESULTS

There were 165 boys (54.5%) and 136 girls (45.5%) aged between 14 and 20 years old (16.40+/-1.32). A total of 27.2% were non-smokers and were not exposed to tobacco smoke (NS), 31.3% were passive smokers, with household exposure of 10 cigarettes per day during at least the previous year (PS), and 41.5% were current smokers who had been smoking>or=10 cigarettes/day for at least 1 year (CS). Significant differences were found between age and smoking habits (p=0.0001) and between smoking habits and female sex (girls CS: 33.9% vs boys CS: 21.8 %) (p=0.007). A significant association was found between smoking (NS, PS and CS) and spirometric parameters (ANOVA): forced vital capacity (FVC) (p=0.001), forced expiratory volume in 1 second (FEV1) (p=0.0001), FEV1/FVC (p=0.004), peak expiratory flow (PEF) (p=0.0001), midexpiratory flow at 25% of forced vital capacity (MEF25%) (p=0.01), MEF50% (p=0.0001) and MEF25-75% (p=0.0001); CS in relation to NS was as follows: FEV1, PEF, MEF50%, MEF25-50% (p=0.0001) and FVC, FEV1/FVC, MEF25% (p=0.01); CS in relation to PS: FEV1/ FVC (p=0.02), PEF (p=0.004), MEF50% and MEF25-75% (p=0.003), PS in relation to NS: FVC and FEV1 (p=0.02). Significant differences in FVC, FEV1 and MEF25-75% were found in female CS in comparison with boys.

CONCLUSIONS

The CS group showed a significant decrease in spirometric parameters in relation to the NS group. The airway was affected sooner in the female group of smokers than in the male group, even though the intensity and time of exposure were the same in both groups.

Impact of gender on asthma in childhood and adolescence: a GA2LEN review

A number of studies have shown gender differences in the prevalence of wheeze and asthma. The aim of this review was to examine published results on gender differences in childhood and adolescent asthma incidence and prevalence, define current concepts and to identify new research needs. A Medline search was performed with the search words (gender OR sex) AND (child OR childhood OR adolescence) AND (asthma). Articles that reported on absence or presence of gender differences in asthma were included and reviewed, and cross-references were checked. Boys are consistently reported to have more prevalent wheeze and asthma than girls. In adolescence, the pattern changes and onset of wheeze is more prevalent in females than males. Asthma, after childhood, is more severe in females than in males, and is underdiagnosed and undertreated in female adolescents. Possible explanations for this switch around puberty in the gender susceptibility to develop asthma include hormonal changes and gender-specific differences in environmental exposures. This aspect needs consideration of the doctors and allergists who diagnose and treat asthmatic individuals. In conclusion, sex hormones are likely to play an important role in the development and outcome of the allergic immune response and asthma in particular. By obtaining functional data from appropriate models, the exact underlying mechanisms can be unravelled. To examine the effect of gender-specific differences in environmental exposures and changes of asthma prevalence and severity in puberty, larger populations may need to be investigated.

Is there any role for allergen avoidance in the primary prevention of childhood asthma?

In this article we discuss 3 hypotheses to attempt to understand why preventive measures thus far studied with the aim of preventing (or delaying) the development of asthma have shown such disappointing results. The most likely explanation is that the development of a multifactorial disease, such as asthma, is extremely difficult, if not impossible, to prevent by eliminating only one risk factor. In a meta-analysis we investigated the effect of a multifaceted and monofaceted intervention in 10 prospective birth cohorts of a total of 3473 children on a diagnosis of asthma. Multifaceted intervention studies had an odds ratio (OR) of 0.73 (95% CI, 0.55-0.97), whereas the monointervention studies had an OR of 1.22 (95% CI, 0.83-1.78) in patients younger than 5 years and an OR of 0.52 (95% CI, 0.32-0.84) versus 0.93 (95% CI, 0.66-1.31) in patients older than 5 years. We therefore hypothesize that studies with a multifaceted approach will have a much greater chance of being successful than studies using a monofaceted approach, with the latter being unlikely to yield a clinically relevant reduction of asthma.

Sex specificity of asthma associated with objectively measured body mass index and waist circumference: the Humboldt study

STUDY OBJECTIVE

To investigate the possibility of sex specificity for the association of obesity and asthma using objective measures of body mass index (BMI) and waist circumference (WC).

DESIGN

Cross-sectional study of adults (n = 2,057) living in Humboldt, SK, Canada in 2003.

SETTING

A rural community.

MEASUREMENTS

Ever-asthma was defined as lifetime physician-diagnosed asthma, and recent asthma was defined as asthma diagnosed by a physician during the past 12 months. BMI and WC were objectively measured.

RESULTS

Among the participants, 5.6% of men and 10.0% of women reported having ever-asthma, and 2.7% and 6.0% had recent asthma, respectively. Higher levels of both BMI and WC were significantly associated with asthma in women but not in men. The adjusted odds ratios for women with a BMI of at least 30.0 kg/m2 relative to women with a BMI of < 25.0 kg/m2 were 2.06 (95% confidence interval [CI], 1.42 to 4.05) for ever-asthma and 3.47 (95% CI, 1.64 to 7.32) for recent asthma.

CONCLUSIONS

Our study demonstrated that the increased risk of asthma associated with obesity was only significant in women but not in men even when BMI was objectively measured, and this association was robust to the anthropometric measures.

Association of active and passive smoking with allergic disorders in pregnant Japanese women: baseline data from the Osaka Maternal and Child Health Study

BACKGROUND

Evidence remains inconclusive as to whether smoking is a risk factor for allergic disorders in adults.

OBJECTIVE

To investigate the relationship between active and passive smoking exposure and allergic disorders in pregnant Japanese women.

METHODS

This cross-sectional study included 1,002 pregnant women. Participants were classified as having asthma after the age of 18 years if they had used an asthma medication at any time after reaching the age of 18 years. Current atopic eczema and allergic rhinitis (including cedar pollinosis) were defined as being present if participants had received any drug treatment during the previous 12 months. Adjustment was made for age; gestation; parity; family history of asthma, atopic eczema, and allergic rhinitis; indoor domestic pets; family income; education; and the mite antigen level in house dust.

RESULTS

Current smoking, but not environmental tobacco smoke exposure, was independently related to an increased prevalence of asthma after the age of 18 years (adjusted odds ratio [OR], 2.66; 95% confidence interval [CI], 1.30-5.38). A significant positive association of current passive smoking exposure at home (adjusted OR, 1.89; 95% CI, 1.10-3.30) and at work (adjusted OR, 2.50; 95% CI, 1.29-4.76) with the prevalence of current allergic rhinitis was observed, whereas no measurable association with active smoking exposure was found. Neither active nor passive smoking was statistically significantly related to the prevalence of current atopic eczema.

CONCLUSIONS

These findings suggest that active smoking and environmental tobacco smoke exposure may increase the likelihood of asthma and allergic rhinitis, respectively, in pregnant Japanese women.