Gender, environmental tobacco smoke, and pulmonary function in rural children and adolescents: the Humboldt study

Do sex and gender modify the association between green space and physical health? A systematic review

A growing literature shows that green space can have protective effects on human health. As a marginalized group, women often have worse life outcomes than men, including disparities in some health outcomes. Given their marginalization, women might have "more to gain" than men from living near green spaces. Yet, limited research has deliberately studied whether green space-health associations are stronger for women or men. We conducted a systematic review to synthesize empirical evidence on whether sex or gender modifies the protective associations between green space and seven physical health outcomes (cardiovascular disease, cancer, diabetes, general physical health, non-malignant respiratory disease, mortality, and obesity-related health outcomes). After searching five databases, we identified 62 articles (including 81 relevant analyses) examining whether such effect modification existed. We classified analyses based on whether green space-health were stronger for women, no sex/gender differences were detected, or such associations were stronger for men. Most analyses found that green space-physical health associations were stronger for women than for men when considering study results across all selected health outcomes. Also, women showed stronger protective associations with green space than men for obesity-related outcomes and mortality. Additionally, the protective green space-health associations were slightly stronger among women for green land cover (greenness, NDVI) than for public green space (parks), and women were also favored over men when green space was measured very close to one's home (0-500 m). Further, the green space-health associations were stronger for women than for men in Europe and North America, but not in other continents. As many government agencies and nongovernmental organizations worldwide work to advance gender equity, our review shows that green space could help reduce some gender-based health disparities. More robust empirical studies (e.g., experimental) are needed to contribute to this body of evidence.

Concentration of noxious gases inside and outside residential apartments across different settlements in Port Harcourt metropolis, Nigeria

The proliferation of harmful gases is a major global problem caused by anthropogenic activities. This study hypothesized that the emission of noxious gases varies seasonally in indoor and outdoor environments. Air samples were collected from 40 georeferenced residential areas ( N = 40) in Port Harcourt using Aeroqual 500 monitor to measure six gases: CH4, CO, NH4, NO2, O3, and SO2. Samples were collected at different times, locations, and seasons. The analysis of variance (ANOVA) indicates a significant difference in concentration between gases, times, and locations at p < 0.001. But the interaction effect shows that times and seasons significantly affect noxious gas concentration compared to location. In general, the concentration of CO was the highest, while that of O3 was the lowest. The order of concentration is CO > SO2 > NO2 > CH4 > NH4 > O3. The concentrations of NO2 and SO2 were higher than the WHO limit, while CO, CH4, NH, and O3 were below the WHO limit. Furthermore, CO concentration was highest in the morning, while NO2 and SO2 concentrations were highest in the evening. For seasons, the CH4, NH4, NO2, and SO2 were higher during the dry season, while CO concentration was higher during the wet season. Pollutant levels should be regularly monitored to help provide exposure advisory to city dwellers on the impact of atmospheric pollution on their health.

Early smoke exposure is associated with asthma and lung function deficits in adolescents

OBJECTIVE

Early life tobacco smoke exposure may influence asthma, lung function and lung function growth into adolescence. We aimed to determine the associations between perinatal smoke exposure and asthma and lung function up to 18 years of age.

METHODS

We prospectively recorded perinatal parental smoking and measured respiratory outcomes at 12 and 18 years in the Melbourne Atopy Cohort Study (MACS), a longitudinal birth cohort. Multiple logistic regression was used to analyse the associations between perinatal smoke exposure and asthma at 12 (n = 370) and 18 years (n = 411). Multiple linear regression was used to investigate the relationship between perinatal smoking and: lung function (12 and 18 years) and lung function growth (between 12 and 18 years).

RESULTS

At 18 years, girls exposed to parental smoking during the perinatal period had increased odds of asthma (OR: 3.45, 95%CI: 1.36, 8.77), reduced pre-bronchodilator Forced expiratory volume in one-second (FEV₁) (-272 ml/s; -438, -107); FEV₁/ forced vital capacity (FVC) (-0.038; -0.065, -0.010); mid expiratory flow (MEF_25-75) (-430 ml/s; -798, -61), and reduced post-bronchodilator FEV₁/FVC (-0.028, -0.053, -0.004). No associations were found for boys (pre-bronchodilator FEV₁ 26ml/s; -202, 255; FEV₁/FVC 0.018; -0.013, 0.049).

CONCLUSIONS

Perinatal smoke may affect risk of asthma, reduce lung function and lung function growth in adolescence. Girls appear to be more susceptible than boys.

Pulmonary effects of active smoking and secondhand smoke exposure among adolescent students in Juárez, Mexico

BACKGROUND

Youth smoking trends among Latin American countries, including Mexico, are on the rise. Notably, although the high prevalence of smoking in teens has been well documented in the literature, few studies have evaluated the impact of smoking and secondhand smoke (SHS) exposure on their respiratory system.

OBJECTIVE

To investigate the effects of smoking and SHS exposure on the respiratory health and lung function among eighth-grade students in Juárez, Mexico.

METHODS

A cross-sectional study was undertaken on a sample of convenience. The study outcomes centered on evaluating 300 students' lung function by spirometry (forced expiratory volume in 1 second [FEV1], forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC], and forced mid-expiratory flow rate [FEF25%-75%]) and their respiratory health (smoking behavior and SHS exposure) by their self-reported responses to a standardized respiratory questionnaire. The study outcomes were compared among three distinct groups: 1) nonsmokers/nonexposed to SHS; 2) nonsmokers/exposed to SHS; and 3) smokers.

RESULTS

The majority of the study participants were 14 years old (85%), females (54%), who attended eighth grade in a public school setting (56%). Approximately, half reported being of low socioeconomic status (49%) and nonsmokers/exposed to SHS (49%). The lung function parameters of smokers were found to be lower (FEV1 =62.88±10.25; FEV1/FVC =83.50±14.15; and FEF25%-75% =66.35±12.55) than those recorded for the nonsmokers/exposed to SHS (FEV1 =69.41±11.35; FEV1/FVC =88.75±15.75; and FEF25%-75% =78.90±14.65) and significantly reduced when compared to the nonsmokers/nonexposed to SHS (FEV1 =79.14±13.61; FEV1/FVC =94.88±21.88; and FEF25%-75% =87.36±17.02) (P<0.001). Similarly, respiratory complaints were more prevalent among smokers and those exposed to SHS when compared to nonsmokers/nonexposed to SHS.

CONCLUSION

Our findings suggest that initiation of cigarette smoking and, to a lesser extent, exposure to SHS in adolescence leads to increased respiratory symptoms and reduction of pulmonary function test values. Public health initiatives that aim to prevent smoking initiation, assist in cessation, and lessen SHS exposure of adolescents need to be school-based and employed as early as middle school.

Unraveling the relationship between aeroallergen sensitization, gender, second-hand smoke exposure, and impaired lung function

BACKGROUND

Contradictory findings on the differential effects of second-hand smoke (SHS) on lung function in girls and boys may result from masked relationships between host and environmental factors. Allergic sensitization may augment the relationship between SHS and decreased lung function, although its role in relation to the inconsistent gender differences in children has not been elucidated.

HYPOTHESIS

We hypothesize that there will be differences between boys and girls related to early-life allergic sensitization and exposure to SHS on pulmonary function later in childhood.

METHODS

Participants in this study (n = 486) were drawn from the Cincinnati Childhood Allergy and Air Pollution (CCAAPS) birth cohort study consisting of 46% girls. Allergic sensitization was assessed by skin prick test (SPT) to 15 aeroallergens at ages 2, 4, and 7, while pulmonary function and asthma diagnosis occurred at age 7. SHS exposure was measured by hair cotinine at ages 2 and/or 4. Gender differences of SHS exposure on pulmonary function among children with positive SPTs at ages 2, 4, and 7 as well as first- and higher-order interactions were examined by multiple linear regression. Interactions significant in the multivariate models were also examined via stratification. Comparisons within and between stratified groups were assessed by examining the slope of the parameter estimates/beta coefficients and associated p-values and confidence intervals.

RESULTS

Increased cotinine levels were significantly associated with decreases in FEV(1) (-0.03 l, p < 0.05), peak expiratory flow (-0.07 l/s, p < 0.05), and FEF (25-75%) (-0.06 l/s, p < 0.01). The interaction between cotinine and sensitization at age 2 was borderline significant (p = 0.10) in the FEF(25-75%) model and showed an exposure response effect according to the number of positive SPTs at age 2; zero (-0.06 l/s, p < 0.01), one (-0.09 l/s, p < 0.05), or two or more positive SPTs (-0.30 l/s, p < 0.01). Despite increased polysensitization among boys, the association between cotinine and FEF(25-75%) among girls, with two or more positive SPTs at age 2, showed the greatest deficits in FEF(25-75%) (-0.34 l/s vs. -0.05 l/s and -0.06 l/s for non-sensitized girls and boys, respectively. Girls with two or more positive SPTs showed a twofold greater decrease in FEF(25-5%) (-0.34 l/s; 95% CI: -0.55, -0.13) compared to boys with the same degree of allergic sensitization (-0.18 l/s; 95% CI: -0.41, 0.06), although this difference was not statistically significant.

CONCLUSIONS

Reductions in lung function were observed among children exposed to SHS, and the number of aeroallergen-positive SPTs at age 2 modifies this relationship. Girls experiencing early childhood allergic sensitization and high SHS exposure are at greater risk of decreased lung function later in childhood compared to non-sensitized girls and boys and demonstrate greater deficits compared to boys with similar degrees of sensitization.

Nasal epithelium integrity, environmental stressors, and allergic sensitization: a biomarker study in adolescents

Changes in the airways epithelium caused by environmental insults might play a role in the development of allergic rhinitis. We measured albumin and Clara cell protein (CC16) in the nasal lavage fluid (NALF) from 474 adolescents (263 girls and 211 boys). The NALF CC16/albumin ratio, integrating the permeability and cellular integrity of the nasal epithelium, decreased mostly with time spent in chlorinated pools. In boys, a lower CC16/albumin ratio in NALF was associated with an increased risk of house dust mite sensitization. The results suggest that the CC16/albumin ratio in NALF can be used to detect nasal epithelium alterations linked to allergic sensitization.

[Environmental tobacco smoke exposure in children and its relationship with the severity of asthma]

INTRODUCTION

Environmental tobacco smoke (ETS) exposure produces serious respiratory problems in childhood. The aim of the study was to evaluate if environmental tobacco smoke affects the severity of asthma in asthmatic children.

MATERIAL AND METHODS

A prospective, multicentre study was conducted on asthmatic children and their parents in 2007-2008, using an exposure questionnaire, pulmonary function, level of cotinine in urine, and evaluation of the severity of asthma according to GEMA guide. The characteristics of the sample are summarised using the appropriate statistical tools, and the comparisons were made using the Pearson chi2 test, Mann-Whitney U test or Studentĭs t, according to the variable and number of groups compared.

RESULTS

Four hundred and eighty four households in 7 Autonomous Communities were included. The population included, 61% male children with asthma, 56% with a smoking caregiver in their home, 34% fathers, 31% mothers and 17% both. Home exposure was 37%, with 11% daily and 94% passive smokers since birth. There was 20% with exposure during whole period of pregnancy of 5±1 cigarettes/day. Children exposed to 6±1 cigarettes/day, 27%, up to 10 cigarettes/day, and 10% to more than 10. Severity of asthma during the survey was worse among those exposed (episodic-occasional 47%, episodic-frequent 35% and persistent-moderate 18% versus 59%, 25% and 16%, respectively, P=.040). Severity of asthma in the last year was worse in those exposed (episodic - occasional 22%, episodic - frequent 37% and persistent - moderate 50% versus 38%, 28% and 25% respectively, P=.037). The spirometry was abnormal in 64% of the exposed against to 36% in the non-exposed for FEV(1) (P=.003, 63% vs 38% for FVC (P=.038), and 54% vs 46% for the PEF (P=.050). The cotinine was higher in exposed: 51 (0-524) ng/ml vs 27 (0-116) ng/ml (P=.032). A relationship was observed between cotinine and level of exposure: 120 (0-590) ng/ml for >10 cigarettes/day as opposed to 44 (0-103) ng/ml ≤10 cigarettes/day (P=.035), which corroborates the consistency of the data collected.

CONCLUSIONS

The exposure of children with asthma to environmental tobacco smoke has a highly negative effect on the severity of their asthma.

Gender-specific differences in effects of prenatal and postnatal environmental tobacco smoke exposure on respiratory symptoms in 23,474 children with and without allergic predisposition: results from 25 districts of northeast China

To assess the interaction of environmental tobacco smoke (ETS) exposure and allergic predisposition regarding respiratory health among Chinese children, a sample of 23,474 children (6-13 years old) was studied from 25 districts in Liaoning province, China. The results showed that children without allergic predisposition were more susceptible to ETS than children with allergic predisposition. Among children without allergic predisposition, ETS exposure was associated with more respiratory symptoms and diseases in boys than in girls; In utero ETS exposure was associated with history of asthma (OR, 1.86; 95% CI, 1.44-2.40) and current asthma (OR, 2.25; 95% CI, 1.48-3.44) only among boys without allergic predisposition. Among children with allergic predisposition, more associations between ETS exposure and respiratory symptoms and diseases were detected in girls. In conclusion, ETS exposure was more evident in boys without family atopy history and more associations were detected in girls with family atopy history.

Asthma, the sex difference

PURPOSE OF REVIEW

asthma is a common chronic disease with significant clinical impact worldwide. Sex-related disparities in asthma epidemiology and morbidity exist but debate continues regarding the mechanisms for these differences. There is a need to review the recent findings for asthma care providers and to highlight areas in need of additional research.

RECENT FINDINGS

recent data illustrate striking sex-related differences in asthma epidemiology and disease expression. Studies show an increased incidence of asthma in women. Data demonstrate that asthmatic women have a poorer quality of life and increased utilization of healthcare compared to their male counterparts despite similar medical treatment and baseline pulmonary function. Research continues to explore hypotheses for these differences including the potential influences of the female sex hormones, altered perception of airflow obstruction, increased bronchial hyper-responsiveness, and medication compliance and technique. However, no single explanation has been able to fully explain the disparities.

SUMMARY

women are more likely to be diagnosed with asthma and suffer greater morbidity than men. The physiologic mechanisms for these differences are not well understood. Understanding sex-related differences in asthma and providing patients with education geared toward these disparities are important in establishing effective, individualized asthma management strategies for all patients.

A growing role for gender analysis in air pollution epidemiology

Epidemiologic studies of air pollution effects on respiratory health report significant modification by sex, although results are not uniform. Importantly, it remains unclear whether modifications are attributable to socially derived gendered exposures, to sex-linked physiological differences, or to some interplay thereof. Gender analysis, which aims to disaggregate social from biological differences between males and females, may help to elucidate these possible sources of effect modification. Studies of children suggest stronger effects among boys in early life and among girls in later childhood. The qualitative review describes possible sources of difference in air pollution response between women and men, which may vary by life stage, coexposures, hormonal status, or other factors. The sources of observed effect modifications remain unclear, although gender analytic approaches may help to disentangle gender and sex differences in pollution response. A framework for incorporating gender analysis into environmental epidemiology is offered, along with several potentially useful methods from gender analysis.

Tobacco use and cessation among women: research and treatment-related issues

The prevalence of tobacco use in women has increased over the past century. This has resulted in dramatic increases in smoking-related lung diseases, such as chronic obstructive pulmonary disease (COPD) and lung cancer. There is growing literature suggesting that women may be more susceptible than men to the effects of tobacco and to the development of COPD. Women may also have specific barriers that interfere with smoking cessation. This article addresses possible differences in lung function decline and nicotine metabolism in women compared to men. Differences in COPD between the sexes are discussed. Finally, barriers to smoking cessation in women are presented.

Overcoming heterogeneity in pediatric asthma: tobacco smoke and asthma characteristics within phenotypic clusters in an African American cohort

OBJECTIVE

Asthma in children and adolescents is a heterogeneous syndrome comprised of multiple subgroups with variable disease expression and response to environmental exposures. The goal of this study was to define homogeneous phenotypic clusters within a cohort of children and adolescents with asthma and to determine overall and within-cluster associations between environmental tobacco smoke (ETS) exposure and asthma characteristics.

METHODS

A combined hierarchical/k-means cluster analysis of principal component variables was used to define phenotypic clusters within a cohort of 6- to 20-year-old urban and largely minority subjects.

RESULTS

Among the 154 subjects, phenotypic cluster analysis defined three independent clusters (Cluster 1 [n = 57]; Cluster 2 [n = 33]; Cluster 3 [n = 58]). A small fourth cluster (n = 6) was excluded. Patients in Cluster 1 were predominantly males, with a relative abundance of neutrophils in their nasal washes. Patients in Cluster 2 were predominantly females with high body mass index percentiles and later-onset asthma. Patients in Cluster 3 had higher eosinophil counts in their nasal washes and lower Asthma Control Test (ACT) scores. Within-cluster regression analysis revealed several significant associations between ETS exposure and phenotypic characteristics that were not present in the overall cohort. ETS exposure was associated with a significant increase in nasal wash neutrophils (beta coefficient = 0.73 [95% confidence interval, CI: 0.11 to 1.35]; p = .023) and a significant decrease in ACT score (-5.17 [-8.42 to -1.93]; p = .003) within Cluster 1 and a significant reduction in the bronchodilator-induced % change in forced expiratory volume in one second (FEV(1)) (-36.32 [-62.18 to -10.46]; p = .009) within Cluster 3.

CONCLUSIONS

Clustering techniques defined more homogeneous subgroups, allowing for the detection of otherwise undetectable associations between environmental tobacco smoke exposure and asthma characteristics.

Correlates of smoking among adolescents with asthma

AIMS AND OBJECTIVE

This study examined the correlates of smoking among asthmatic adolescents to gain a better understanding of who is at particular risk.

BACKGROUND

Smoking is especially harmful to individuals with asthma. However, smoking is surprisingly prevalent among asthmatic individuals, with prevalence rates similar to or higher than those of the general adult or adolescent populations. Despite this notable finding, there has been little research about factors (i.e. biophysical, psychosocial and behavioural) influencing asthmatic adolescents' tobacco use patterns.

DESIGN

A Canadian provincial cross-sectional survey.

METHOD

The study about adolescents' tobacco use and health status was conducted in secondary schools in 2004, 608 asthmatic adolescents participated. Demographic factors, biophysical (body mass index and physical health), psychosocial factors (parents' and peers' smoking, environmental tobacco smoke exposure and depression) and behavioural factors (marijuana use, alcohol use and exercise frequency) were explored. Multinomial logistic regression analyses were conducted to identify risk factors associated with tobacco use.

RESULTS AND CONCLUSIONS

Of the 608 asthmatic adolescents, 17.4% currently smoked and 12.0% formerly smoked. Girls, compared with boys, were more likely to smoke (OR: 3.34, 95% CI: 1.62-6.96) after adjusting for differences in the other demographic, biophysical, psychosocial and behavioural factors. Asthmatic girls who had relatively higher body mass index, were in the higher school grades, used marijuana or alcohol, had minor to severe depressive symptoms, had environmental tobacco smoke exposure in their homes and had friends who smoked or were currently more likely to smoke. The former smokers had similar risk factors including higher body mass index, environmental tobacco smoke exposure at home, friends who smoked and marijuana use.

RELEVANCE TO CLINICAL PRACTICE

Despite their health condition, asthmatic adolescents continue currently or formerly to smoke. Gender appropriate prevention and cessation interventions for asthmatic adolescents may need to address important psychosocial and environmental factors that increase the risk of these adolescents initiating and maintaining tobacco use.

Cigarette smoke alters tissue inhibitor of metalloproteinase 1 and matrix metalloproteinase 9 levels in the basolateral secretions of human asthmatic bronchial epithelium in vitro

BACKGROUND

Asthma, a major cause of chronic lung disease worldwide, has increased in prevalence in all age and ethnic groups, particularly in urban areas where cigarette smoking is common. Cigarette smoke (CS) significantly impacts the development of asthma and is strongly associated with increased asthma-related morbidity.

PURPOSE

To evaluate bioinformatic analyses predicting that CS would alter expression of tissue inhibitor of metalloproteinase (TIMP) 1 and matrix metalloproteinase (MMP) 9 in asthmatic epithelium.

METHODS

Primary differentiated normal (n = 4) and asthmatic (n = 4) human respiratory epithelia on collagen-coated Transwells at air-liquid interface were exposed for 1 hour to CS condensate (CSC) or hydrogen peroxide (H2O2). Tissue inhibitor of metalloproteinase 1 and MMP-9 protein levels were measured at 24 hours by enzyme-linked immunosorbent assay in cell lysates and in apical and basolateral secretions.

RESULTS

Tissue inhibitor of metalloproteinase 1 and MMP-9 levels in the apical secretions of normal and asthmatic epithelia were unchanged after exposure to CSC and H2O2. However, CSC increased TIMP-1 levels in the basolateral secretions of both normal and asthmatic epithelia, but decreased MMP-9 levels only in asthmatic basolateral secretions, resulting in a 2.5-fold lower MMP-9/TIMP-1 ratio that corresponded to decreased MMP-9 activity in CS-exposed asthmatic basolateral secretions.

CONCLUSIONS

These data validate our prior bioinformatic analyses predicting that TIMP-1 plays a role in the stress response to CS and indicate that asthmatics exposed to CS may be more susceptible to MMP-9-mediated airway remodeling. This is in agreement with the current paradigm that a reduction in the MMP-9/TIMP-1 ratio is a milieu that favors subepithelial airway remodeling in chronic asthma.

Delineation of a gene network underlying the pulmonary response to oxidative stress in asthma

Cigarette smoke exposure induces a respiratory epithelial response that is mediated in part by oxidative stress. The contribution of oxidative stress to cigarette smoke-induced responses in asthmatic respiratory epithelium is not well understood. We sought to increase this understanding by employing data integration and systems biology approaches to publicly available microarray data deposited over the last several years. In this study, we analyzed 14 publicly available asthma- or tobacco-relevant data series and found 4 (2 mice and 2 human) that fulfilled adequate signal/noise thresholds using unsupervised clustering and F test statistics. Using significance filters and a 4-way Venn diagram approach, we identified 26 overlapping genes in the epithelial transcriptional stress response to cigarette smoke and asthma. This test set corresponded to a 26-member gene/protein network containing 18 members that were highly regulated in a fifth data series of direct lung oxidative stress. Of those network members, 2 stood out (ie, tissue inhibitor of metalloproteinase 1 and thrombospondin 1) owing to central location within the network and marked up-regulation sustained at later times in response to oxidative stress. These analyses identified key relationships and primary hypothetical targets for future studies of cigarette smoke-induced oxidative stress in asthma.

Delineation of a gene network underlying the pulmonary response to oxidative stress in asthma

Cigarette smoke exposure induces a respiratory epithelial response that is mediated in part by oxidative stress. The contribution of oxidative stress to cigarette smoke-induced responses in asthmatic respiratory epithelium is not well understood. We sought to increase this understanding by employing data integration and systems biology approaches to publicly available microarray data deposited over the last several years. In this study, we analyzed 14 publicly available asthma- or tobacco-relevant data series and found 4 (2 mice and 2 human) that fulfilled adequate signal/noise thresholds using unsupervised clustering and F test statistics. Using significance filters and a 4-way Venn diagram approach, we identified 26 overlapping genes in the epithelial transcriptional stress response to cigarette smoke and asthma. This test set corresponded to a 26-member gene/protein network containing 18 members that were highly regulated in a fifth data series of direct lung oxidative stress. Of those network members, 2 stood out (ie, tissue inhibitor of metalloproteinase 1 and thrombospondin 1) owing to central location within the network and marked up-regulation sustained at later times in response to oxidative stress. These analyses identified key relationships and primary hypothetical targets for future studies of cigarette smoke-induced oxidative stress in asthma.

A growing role for gender analysis in air pollution epidemiology

OBJECTIVE

Epidemiologic studies of air pollution effects on respiratory health report significant modification by sex, although results are not uniform. Importantly, it remains unclear whether modifications are attributable to socially derived gendered exposures, to sex-linked physiological differences, or to some interplay thereof. Gender analysis, which aims to disaggregate social from biological differences between males and females, may help to elucidate these possible sources of effect modification.

DATA SOURCES AND DATA EXTRACTION

A PubMed literature search was performed in July 2009, using the terms "respiratory" and any of "sex" or "gender" or "men and women" or "boys and girls" and either "PM2.5" (particulate matter <or= 2.5 microm in aerodynamic diameter) or "NO2" (nitrogen dioxide). I reviewed the identified studies, and others cited therein, to summarize current evidence of effect modification, with attention to authors' interpretation of observed differences. Owing to broad differences in exposure mixes, outcomes, and analytic techniques, with few studies examining any given combination thereof, meta-analysis was not deemed appropriate at this time.

DATA SYNTHESIS

More studies of adults report stronger effects among women, particularly for older persons or where using residential exposure assessment. Studies of children suggest stronger effects among boys in early life and among girls in later childhood.

CONCLUSIONS

The qualitative review describes possible sources of difference in air pollution response between women and men, which may vary by life stage, coexposures, hormonal status, or other factors. The sources of observed effect modifications remain unclear, although gender analytic approaches may help to disentangle gender and sex differences in pollution response. A framework for incorporating gender analysis into environmental epidemiology is offered, along with several potentially useful methods from gender analysis.

MYLK polymorphism associated with blood eosinophil level among asthmatic patients in a Korean population

The myosin light chain kinase (MYLK) gene encodes both smooth muscle and nonmuscle cell isoforms. Recently, polymorphisms in MYLK have been reported to be associated with several diseases. To examine the genetic effects of polymorphisms on the risk of asthma and related phenotypes, we scrutinized MYLK by re-sequencing/genotyping and statistical analysis in Korean population (n = 1,015). Seventeen common polymorphisms located in or near exons, having pairwise r ( 2 ) values less than 0.25, were genotyped. Our statistical analysis did not replicate the associations with the risk of asthma and log-transformed total IgE levels observed among African descendant populations. However, two SNPs in intron 16 (+89872C > G and +92263T >C), which were in tight LD (|D'| = 0.99), revealed significant association with log-transformed blood eosinophil level even after correction multiple testing (P = 0.002/P( corr )= 0.01 and P = 0.002/P( corr ) = 0.01, respectively). The log-transformed blood eosinophil levels were higher in individuals bearing the minor alleles for +89872C > G and +92263T > C, than in those bearing other allele. In additional subgroup analysis, the genetic effects of both SNPs were much more apparent among asthmatic patients and atopic asthma patients. Among atopic asthma patients, the log-transformed blood eosinophil levels were proportionally increased by gene-dose dependent manner of in both +89872C > G and +92263T > C (P = 0.0002 and P = 0.00007, respectively). These findings suggest that MYLK polymorphisms might be among the genetic factors underlying differential increases of blood eosinophil levels among asthmatic patients. Further biological and/or functional studies are needed to confirm our results.

[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.

Housing characteristics, home environmental factors and respiratory health in 14,729 Chinese children

BACKGROUND

Very few studies have assessed the relative impact of housing characteristics and home environmental factors on asthma and asthma-related symptoms in Chinese children who have lower rates of asthma. To our knowledge few studies have assessed respiratory symptoms and allergies in this context.

METHODS

To assess the effects of housing characteristics, pet keeping, home decorations and other indoor environmental factors on respiratory health of Chinese children. We studied a population of 14,729 children (1-13 years old) from 12 districts in Liaoning province, Northeast China. Information on respiratory health, housing characteristics, and environmental pollutions were obtained by a standard questionnaire from the American Thoracic Society.

RESULTS

Housing conditions, house adjacent to traffic or not, house with or without pollution source nearby, pet keeping, presence of pests and mold/water damage in the home, home decorations and exposure to environmental tobacco smoke (ETS) were associated with doctor-diagnosed asthma and asthma-related symptoms both in boys and girls. The vulnerability towards exposure to housing conditions and environmental factors differed between males and females. Among boys, the risk of respiratory morbidity appeared to be reduced in households with larger surface areas and more rooms; use of a ventilation device was strongly protective against persistent phlegm (OR=0.68; 95%CI: 0.48, 0.96). Asthma-related symptoms were more associated with different pets among girls than among boys. The presence of a cat in the household was associated with doctor-diagnosed asthma (OR=1.89; 95% CI, 1.11-3.20), current wheeze (OR=2.64; 95% CI, 1.52-4.59), persistent cough (OR=1.84; 95% CI, 1.18-2.87) and persistent phlegm (OR=2.17; 95% CI, 1.21-3.87) only among girls.

CONCLUSION

Living within the vicinity of a source of pollution, traffic, pet keeping, home decorations, pests, mold and ETS are important determinants of children's respiratory health in China.

Tobacco smoke exposure and tracking of lung function into adult life

Maternal smoking during pregnancy leads to abnormal lung function in infancy that tracks through to later childhood and continues into adult life. This is associated with transient wheezing illnesses through early childhood. Both social and physiological factors are likely to predispose those exposed to passive smoke to become active smokers. Adult smokers demonstrate an increased decline of lung function with age. The effects of passive smoke exposure vary with genetic factors, gender, race and exposure to other pollutants. Exposure to environmental tobacco smoke and subsequent active smoking both aggravate symptoms and have a negative effect on lung function in those with asthma.

Effects of environmental tobacco smoke on respiratory health of boys and girls from kindergarten: results from 15 districts of northern China

The effects of childhood environmental tobacco smoke (ETS) exposure on respiratory symptoms were investigated in 6053 kindergarten-aged children residing in 15 districts of northern China. Responses to a self-administered questionnaire completed by parents of children from 30 kindergartens were used to ascertain children with persistent cough, persistent phlegm, asthma symptom, current asthma, wheeze and wheeze without asthma. In first 2 years ETS exposure and current ETS exposure were associated with increased prevalence of persistent cough, persistent phlegm, wheeze and wheeze without asthma. Among boys, ETS exposure was associated with more respiratory symptoms and diseases than in girls. ETS exposure during pregnancy was associated with asthma symptom [odds ratio (OR), 3.00; 95% confidence interval (CI): 1.28-7.03], current asthma (OR, 3.38; 95% CI: 1.25-9.14), persistent cough (OR, 1.64; 95% CI: 1.13-2.37), persistent phlegm (OR, 1.74; 95% CI: 1.01-3.01), wheeze (OR, 1.75; 95% CI: 1.15-2.68), and wheeze without asthma (OR, 1.46; 95% CI: 1.01-2.37) only among boys. In boys, the adjusted ORs for increased risk of asthma symptom and current asthma for household exposures (> or =10 cigarettes smoked per day vs. none smoked) during workday were 2.04 (95% CI: 1.01-3.89) and 2.76 (95% CI: 1.06-9.58), respectively. We conclude that ETS exposure increases the occurrence of respiratory symptoms and diseases during childhood. Boys may be more susceptible to ETS than girls.

PRACTICAL IMPLICATIONS

Environmental tobacco smoke (ETS) is a highly prevalent respiratory irritant. In agreement with previous cross-sectional studies, our study indicates that exposure to ETS may increase the occurrence of respiratory symptoms and diseases in children, and the association of ETS exposure and respiratory health of children increased in strength with number of cigarettes smoked inside the house per day during workday and day-off. Boys may be more susceptible to ETS than girls. These findings support the view that measures should be taken to reduce ETS exposure for children.