Association between body mass index and asthma among Japanese adults: risk within the normal weight range

Self-reported prevalence of asthma and its associated factors among adult rural population in Bangladesh: a cross-sectional study using WHO PEN protocol

OBJECTIVE

For over a decade, the prevalence of asthma remained unchanged at around 7% in Bangladesh. Although asthma causes significant morbidity among both children and adults, updates on epidemiological data are limited on the prevalence in Bangladesh. This study attempted to determine the prevalence of asthma, and its modifiable and non-modifiable lifestyle predictors in a rural population of Bangladesh.

METHOD

This study was part of a cross-sectional study that applied the WHO Package of Essential Noncommunicable Disease Interventions via census in a rural area of Bangladesh, where self-reported data on asthma were recorded. Data on anthropometric measurement, sociodemographic characteristics and behavioural risk factors were collected following the standard protocol described in the WHO STEP-wise approach to surveillance (STEPS) questionnaire. Analysis included descriptive statistics to assess the prevalence of asthma and its risk factors, and binary logistic regression to determine contributing factors.

RESULT

The overall prevalence of asthma was 4.2%. Asthma was predominant among people above 60 years (8.4%). Higher asthma was noted among males (4.6%), self-employed (5.1%), with a family history of asthma (9.1%), with comorbidities besides asthma (7.8%) and underweight (6.0%) compared with their counterparts. The OR of having asthma was 1.89, 1.93, 1.32, 1.50, 2.60, 0.67, 0.67 and 0.78 if a respondent was 45 years old or more, married, underweight, ever smoker, with a family history of asthma, housewife, employed and consumed red meat, respectively, while considering all other variables constant, compared with their counterparts.

CONCLUSION

The study emphasised asthma to be a public health concern in Bangladesh, although it seems to have decreased over the last decade. Among others, red meat intake and nutritional status were strongly associated with asthma, and the linkage among these is still a grey area that needs further exploration.

Effects of obesity on CC16 and their potential role in overweight/obese asthma

Introduction

Club cell secretory protein-16 (CC16) is a major anti-inflammatory protein expressed in the airway; however, the potential role of CC16 on overweight/obese asthma has not been assessed. In this study, we examined whether obesity reduces airway/circulatory CC16 levels using experimental and epidemiological studies. Then, we explored the mediatory role of CC16 in the relationship of overweight/obesity with clinical asthma measures.

Methods

Circulating CC16 levels were assessed by ELISA in three independent human populations, including two groups of healthy and general populations and asthma patients. The percentage of cells expressing club markers in obese vs. non-obese mice and human airways was determined by immunohistochemistry. A causal mediation analysis was conducted to determine whether circulatory CC16 acted as a mediator between overweight/obesity and clinical asthma measures.

Results

BMI was significantly and monotonously associated with reduced circulating CC16 levels in all populations. The percentage of CC16-expressing cells was reduced in the small airways of both mice and humans with obesity. Finally, mediation analysis revealed significant contributions of circulatory CC16 in the association between BMI and clinical asthma measures; 21.8% of its total effect in BMI’s association with airway hyperresponsiveness of healthy subjects (p = 0.09), 26.4% with asthma severity (p = 0.030), and 23% with the required dose of inhaled corticosteroid (p = 0.042). In logistic regression analysis, 1-SD decrease in serum CC16 levels of asthma patients was associated with 87% increased odds for high dose ICS requirement (p < 0.001).

Conclusions

We demonstrate that airway/circulating CC16, which is inversely associated with BMI, may mediate development and severity in overweight/obese asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02038-1.

Impact of lifetime body mass index trajectories on the incidence and persistence of adult asthma

BACKGROUND

High body mass index trajectories from childhood to adulthood are associated with development of some chronic diseases, but whether such trajectories influence adult asthma has not been investigated to date. Therefore, we investigated associations between body mass index trajectories from childhood to middle age (5-43 years) and incidence, persistence, and relapse of asthma from ages 43 to 53 years.

METHODS

In the Tasmanian Longitudinal Health Study (n= 4194), weight and height were recorded at 8-time points between 5 and 43 years. body mass index trajectories were developed using group-based trajectory modelling. Associations between body mass index trajectories and asthma incidence, persistence, and relapse from 43 to 53 years; bronchial hyper-responsiveness at 50 years; and bronchodilator responsiveness at 53 years were modelled using multiple logistic and linear regression.

RESULTS

Five distinct body mass index trajectories were identified: average, low, high, child high-decreasing, and child average-increasing. Compared to the average trajectory, child average-increasing and high trajectories were associated with increased risk of incident asthma (OR=2.6; 95%CI 1.1, 6.6 and OR=4.4; 1.7, 11.4, respectively) and bronchial hyper-responsiveness in middle age (OR= 2.9; 1.1, 7.5 and OR= 3.5;1.1, 11.4, respectively). No associations were observed for asthma persistence or relapse.

CONCLUSION

Participants with child average-increasing and high body mass index trajectories from childhood to middle age were at higher risk of incident adult asthma. Thus, encouraging individuals to maintain normal body mass index over the life course may help reduce the burden of adult asthma.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

Investigating genetically mimicked effects of statins via HMGCR inhibition on immune-related diseases in men and women using Mendelian randomization

Statins have been suggested as a potential treatment for immune-related diseases. Conversely, statins might trigger auto-immune conditions. To clarify the role of statins in allergic diseases and auto-immune diseases, we conducted a Mendelian randomization (MR) study. Using established genetic instruments to mimic statins via 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibition, we assessed the effects of statins on asthma, eczema, allergic rhinitis, rheumatoid arthritis (RA), psoriasis, type 1 diabetes, systemic lupus erythematosus (SLE), multiple sclerosis (MS), Crohn's disease and ulcerative colitis in the largest available genome wide association studies (GWAS). Genetically mimicked effects of statins via HMGCR inhibition were not associated with any immune-related diseases in either study after correcting for multiple testing; however, they were positively associated with the risk of asthma in East Asians (odds ratio (OR) 2.05 per standard deviation (SD) decrease in low-density lipoprotein cholesterol (LDL-C), 95% confidence interval (CI) 1.20 to 3.52, p value 0.009). These associations did not differ by sex and were robust to sensitivity analysis. These findings suggested that genetically mimicked effects of statins via HMGCR inhibition have little effect on allergic diseases or auto-immune diseases. However, we cannot exclude the possibility that genetically mimicked effects of statins via HMGCR inhibition might increase the risk of asthma in East Asians.

Alterations of lung microbial communities in obese allergic asthma and metabolic potential

In recent years, there has been a rapid increase in microbiome studies to explore microbial alterations causing disease status and unveil disease pathogenesis derived from microbiome environmental modifications. Convincing evidence of lung microbial changes involving asthma has been collected; however, whether lung microbial changes under obesity leads to severe asthma in a state of allergen exposure has not been studied sufficiently. Here, we measured bacterial alterations in the lung of an allergen mouse model induced by a high fat diet (HFD) by using 16S rRNA gene sequencing. A total of 33 pathogen‑free 3‑week‑old male C57BL/6 mice were used, and they divided randomly into two groups. The Chow diet (n = 16) and high fat diet (n = 17) was administrated for 70 days. Mice were sensitized with PBS or Dermatophagoides pteronyssinus extract (Der.p), and concentration levels of total IgE and Der.p-IgE in the blood were measured to quantify immune responses. Although there were no meaningful differences in bacterial species richness in the HFD mouse group, momentous changes of bacterial diversity in the HFD mouse group were identified after the mouse group was exposed to allergens. At a genus level, the fluctuations of taxonomic relative abundances in several bacteria such as Ralstonia, Lactobacillus, Bradyrhizobium, Gaiella, PAC001932_g, Pseudolabrys, and Staphylococcus were conspicuously observed in the HFD mouse group exposed to allergens. Also, we predicted metabolic signatures occurring under microbial alterations in the Chow group versus the Chow group exposed to allergens, as well as in the HFD mouse group versus the HFD group exposed to allergens. We then compared their similarities and differences. Metabolic functions associated with macrophages such as propanoate metabolism, butanoate metabolism, and glycine-serine-threonine metabolism were identified in the HFD group versus the Chow group. These results provide new insights into the understanding of a microbiome community of obese allergic asthma, and shed light on the functional roles of lung microbiota inducing the pathogenesis of severe asthma.

Knowledge, practice pattern and attitude toward asthma management amongst physicians from Nepal, Malaysia, Lebanon, Myanmar and Morocco

OBJECTIVE

This survey aimed to understand the physicians' practice pattern and challenges faced while treating their patients with asthma in five countries-Malaysia, Nepal, Myanmar, Morocco and Lebanon.

METHODS

Questionnaire-based data was gathered from internal medicine doctors (209), general practitioners (206), chest physicians (152) and pediatricians (58) from 232 locations from across the five countries.

RESULTS

Of the 816 physicians, 374 physicians encountered at least 5 asthma patients daily. Approximately, 38% physicians always used spirometry for diagnosis and only 12% physicians always recommended Peak flow meter (PFM) for home-monitoring. Salmeterol/fluticasone (71%) followed by formoterol/budesonide (38%) were the most preferred ICS/long-acting beta₂-agonists (LABA); Salbutamol (78%) was the most preferred reliever medication. 60% physicians said >40% of their patients were apprehensive to use inhalers. 72% physicians preferred a pressurized metered-dose inhaler (pMDI) to a dry powder inhaler (DPI) with only a third of them using a spacer with the pMDI. 71% physicians believed that using similar device for controller and reliever can be beneficial to patients. Skipping medicines in absence of symptoms (64%), incorrect inhaler technique (48%) and high cost of medication (49%) were considered as major reasons for non-adherence by most physicians. Incorrect inhaler technique (66%) and nonadherence (59%) were considered the most common causes of poor asthma control.

CONCLUSIONS

There are opportunities to improve the use of diagnostic and monitoring tools for asthma. Non-adherence, incorrect inhaler technique and cost remain a challenge to achieve good asthma control. Asthma education, including correct demonstration of inhaler, can potentially help to improve inhaler adherence.

Association between Body Mass Index and Prevalence of Asthma in Korean Adults

We evaluated the association between body mass index (BMI) and the prevalence of asthma. Using data from the 2015 Korean Community Health Survey, 214,971 participants aged between 19 and 106 years were included in this study. Asthma was defined based on the self-report of physician diagnosis. BMI was classified as underweight (<18.5 kg/m²), normal weight (18.5 kg/m²≤BMI<23.0 kg/m²), overweight (23.0 kg/m²≤ BMI<27.4 kg/m²), and obese (≥27.5 kg/m²) based on the BMI categories for Asians by the World Health Organization. Multiple logistic regression analysis was performed with sampling weights to evaluate the association between BMI and asthma after adjusting for age, educational level, income, type of residential area, smoking status, alcohol consumption, physical activity, hypertension, and diabetes. In men, BMI had an inverted J-shaped association with the prevalence of asthma, with an odds ratio of 1.88 (95% confidence interval [CI]: 1.89-2.24) for underweight and 1.12 (95% CIs: 0.97-1.29) for obesity. In women, BMI had a J-shaped association with the prevalence of asthma, with an odds ratio of 1.05 (95% CIs: 0.91-1.22) for underweight and 2.29 (95% CIs: 2.06-2.56) for obesity. In conclusion, in a nationally representative sample of Korean adults, the association between BMI and the prevalence of asthma varied between the sexes. This suggests that malnutrition and obesity are involved in the pathophysiology of asthma.

Obesity and severe asthma

Obesity is an important global health issue for both children and adults. Obesity increases the prevalence and incidence of asthma and also increases the risk for severe asthma. Here we describe the features of severe asthma phenotypes for which obesity is a defining characteristic, including steroid resistance, airway inflammation, and co-morbidities. We also review current concepts regarding the mechanistic basis for the impact of obesity in severe asthma, including possible roles for vitamin D deficiency, systemic inflammation, and the microbiome. Finally, we describe data indicating a role for diet, weight loss, and exercise in the treatment of severe asthma with obesity. Better understanding of the mechanistic basis for the role of obesity in severe asthma could lead to new therapeutic options for this population.

Severe asthma in Japan

The characteristic phenotype of severe asthma in Japan seems to be distilled into the following two features: low incidence of obesity and high prevalence of patients with type 2 inflammation. Only 5-7% of Japanese severe asthma patients had a body mass index (BMI) ≥30 kg/m², and more than 80% of patients with severe asthma exhibited type 2 inflammation. Although the relationship between obesity and non-type 2 inflammation is complex, the low incidence of obesity might explain the prevalence of type 2 inflammation. Some asthma cohorts in Japan have investigated the roles of type 2 biomarkers extensively, including periostin, to identify a severe phenotype, suggesting the utility of combining biomarkers to identify an exacerbation-prone subgroup. Although the prevalence of severe asthma is comparable to Western countries, the rate of asthma death and disease burden seems to be lower in Japan. These trends might be due to the system of public health insurance for the whole nation, leading to good access to hospital and asthma specialists due to the geographically narrow country. In this review article, we will discuss the definition, epidemiology, comorbidities, biomarkers, specific phenotype, and current treatment for severe asthma in Japan.

Obesity-associated severe asthma in an adult Japanese population

BACKGROUND

Severe asthma is increasingly being recognized as an important public health issue. Obesity has been identified as a risk factor for poor asthma control and for worsening of asthma severity. However, most studies investigating obese patients with asthma have been performed in Western countries. Reports on the characteristics of obese Japanese individuals with severe asthma are lacking. Herein, we investigated the clinical characteristics of patients with obesity-associated severe asthma in a Japanese population and the association between obesity and poor asthma control.

METHODS

We conducted a retrospective observational study of adult patients with severe asthma. Patients were classified into two groups based on the definition of obesity recommended by the Japan Society for the Study of Obesity: obese (OB) group (body mass index [BMI] ≥25 kg/m²) and non-obese (NOB) group (BMI <25 kg/m²). The two groups were compared. The characteristics of obesity and the metabolic functions are known to differ between males and females; therefore, we analyzed male-only and female-only cohorts separately.

RESULTS

A total of 492 patients were enrolled. Age, smoking history in terms of number of pack-years, daily controller medications use, and spirometric data were not significantly different between the OB and NOB groups in either cohort. In the female cohort, the annual exacerbation ratio and the percentage of frequent exacerbators were significantly higher in the OB group compared to the NOB group. A multivariate logistic regression analysis showed that obesity was independently associated with frequent asthma exacerbations in the female cohort.

CONCLUSIONS

Our study revealed that obesity, defined as a BMI ≥25 kg/m², was independently associated with poor asthma control (including acute exacerbations) in adult Japanese females with severe asthma.

Contrasting associations of maternal smoking and pre-pregnancy BMI with wheeze and eczema in children

BACKGROUND

Childhood allergies are dynamic and associated with environmental factors. The influence of prenatal maternal smoking and obesity on childhood allergies and their comorbidities remains unclear, especially in prospective cohorts with serial longitudinal observations.

OBJECTIVE

We examined time trends in the prevalence and comorbidity of childhood allergies, including wheeze, eczema, and rhinoconjunctivitis, using a large-scale, population-based birth cohort in Japan, and assessed the effects of prenatal maternal smoking and BMI on the risk of childhood allergies.

METHODS

Parents completed the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires about symptoms of allergies and their risk factors at age 1, 2, 4, and 7 years. Complete data from all pre- and postnatal questionnaires at age 1, 2, 4, and 7 were available for 3296 mother-child pairs.

RESULTS

We observed significant overlap of childhood allergies at 1, 2, 4, and 7 years. Maternal serum cotinine during pregnancy was associated with increased risk of wheezing in the children at age 1, 2, and 4 but disappeared at age 7. In contrast, maternal cotinine levels were inversely associated with the prevalence of eczema in children at age 7. We additionally observed that maternal pre-pregnancy BMI, not children's BMI, had a positive association with wheeze and an inverse association with eczema in 7-year-old children, respectively. We did not find any association of examined maternal factors and rhinoconjunctivitis.

CONCLUSIONS

We demonstrated contrasting association of prenatal maternal smoking and high BMI with postnatal wheeze and eczema. For precise assessment of allergy-associated risk factors, we need to contrast risk factors for different allergic diseases since focusing solely on one allergic disease may result in misleading information on the role of different risk factors.

Asthma and its related socioeconomic factors: The Shiraz Adult Respiratory Disease Study 2015

OBJECTIVE

This study aimed to explore the association between the prevalence of asthma and the socioeconomic factors using data from the Shiraz Adult Respiratory Disease Study, 2015(SARDS).

METHODS

The SARDS was conducted from June to October 2015 among adult subjects of the general population of Shiraz, Iran. Current asthma was defined as the presence of at least 1 of the following factors in the preceding 12 months: (1) being awakened by an attack of shortness of breath, coughing, or chest tightness without any identifiable cause; (2) having an asthma attack; (3) currently using medication for asthma; or (4) having wheezing or whistling in the chest not associated with a cold or the flu. Information on individual socioeconomic status was derived from self-reported education level, occupation, income, and residence location. A value of P < .05 was considered statistically significant.

RESULTS

A total of 4582 respondents aged 20-60 years were included in the analysis. The overall prevalence of adult asthma was 7.8%. The prevalence of asthma was higher significantly among female and subjects with higher body mass index, allergic rhinitis, smokers, jobless, and individuals who live in suburban areas. In the adjusted logistic regression model, being jobless (odds ratio [OR], 2.256; 95% confidence interval [CI], 1.123-4.535) and living in a suburban area (OR, 1.735; 95% CI, 1.058-2.845) were the most significant socioeconomic predictive factors for adult current asthma.

CONCLUSIONS

It can be concluded that lower socioeconomic status is associated with higher adult current asthma prevalence. Target interventions are necessary to reduce disparities in healthcare systems.

Asthma Phenotypes in Japanese Adults - Their Associations with the CCL5 ADRB2 Genotypes

BACKGROUND

Cluster analyses were previously performed to identify asthma phenotypes underlying asthma syndrome. Although a large number of patients with asthma develop the disease later in life, these previous cluster analyses focused mainly patients with younger-onset asthma.

METHODS

Cluster analysis examined the existence of distinct phenotypes of late-onset asthma in Japanese patients with adult asthma. We then associated genotypes at the CCL5, TSLP, IL4, and ADRB2 genes with the clusters of asthma identified.

RESULTS

Using the 8 variables of age, sex, age at onset of the disease, smoking status, total serum IgE, %FEV1, FEV1/FVC, and specific IgE responsiveness to common inhaled allergens, two-step cluster analysis of 880 Japanese adult asthma patients identified 6 phenotypes: cluster A (n = 155): older age at onset, no airflow obstruction; cluster B (n = 170): childhood onset, normal-to-mild airflow obstruction; cluster C (n = 119): childhood onset, the longest disease duration, and moderate-to-severe airflow obstruction; cluster D (n = 108): older age at onset, severe airflow obstruction; cluster E (n = 130): middle-age at onset, no airflow obstruction; and cluster F (n = 198): older age at onset, mild-to-moderate airflow obstruction. The CCL5-28C>G genotype was significantly associated with clusters A, B and D (OR 1.65, p = 0.0021; 1.67, 0.018; and 1.74, 0.011, respectively). The ADRB2 Arg16Gly genotype was also associated with clusters B and D (OR 0.47, p = 0.0004; and 0.63, 0.034, respectively).

CONCLUSIONS

The current cluster analysis identified meaningful adult asthma phenotypes linked to the functional CCL5 and ADRB2 genotypes. Genetic and phenotypic data have the potential to elucidate the pheno- typic heterogeneity and pathophysiology of asthma.

Exploring the origins of asthma: Lessons from twin studies

This thesis explores the contribution of twin studies, particularly those studies originating from the Danish Twin Registry, to the understanding of the aetiology of asthma. First, it is explored how twin studies have established the contribution of genetic and environmental factors to the variation in the susceptibility to asthma, and to the variation in several aspects of the clinical expression of the disease such as its age at onset, its symptomatology, its intermediate phenotypes, and its relationship with other atopic diseases. Next, it is explored how twin studies have corroborated theories explaining asthma's recent increase in prevalence, and last, how these fit with the explanations of the epidemiological trends in other common chronic diseases of modernity.

Epidemiology of adult asthma in Asia: toward a better understanding

Asia is the world's most dynamic area. Asthma is a major chronic disease in Asia, like other continents. However, unlike childhood asthma, the epidemiological burden of asthma in Asian adults has been unclear. Here we reviewed the currently available literatures on the epidemiology of adult asthma in the Asian community populations. Adult asthma prevalence was generally lower in Asian than in Europe, but the increasing trends suggested the disease burden to rise in the near future. However, for better understanding, it may be essential to prepare for the Asian multinational network for the standardization and collaboration of research.

Association between obesity and asthma in the elderly population: potential roles of abdominal subcutaneous adiposity and sarcopenia

BACKGROUND

Obesity is a significant risk factor for asthma; however, the association of asthma with obesity has rarely been studied in the elderly population. The role of central obesity has been suggested as a link between the 2 entities but has not been comprehensively studied in elderly populations.

OBJECTIVE

To investigate the mechanisms of association between obesity and asthma in the elderly population.

METHODS

This cross-sectional analysis included 994 participants (aged ≥65 years) in the Korean Longitudinal Study on Health and Aging. Asthma was defined by using questionnaires. Spirometry and chest radiography were performed to exclude asthma-mimicking conditions. Measurements of abdominal subcutaneous and visceral fat were calculated by computed tomography of the abdomen, and regional body compositions were measured by dual energy X-ray absorptiometry. Biochemical parameters were also measured.

RESULTS

The prevalence of asthma was 5.4%. The study population had a mean body mass index (BMI) of 24.0. Multivariate logistic regression tests revealed that the risk of asthma increased in proportion to an increase in BMI or abdominal subcutaneous adiposity. However, no association was found with visceral adiposity, serum adiponectin levels, or serum vitamin D levels. The dual energy X-ray absorptiometry-measured appendicular fat-free mass index was inversely related to asthma among patients with a BMI of 25.0 or greater.

CONCLUSION

Our findings suggest that the relationships between obesity and asthma in the elderly population may be mediated by factors such as abdominal subcutaneous adiposity and sarcopenia. These associations warrant further investigations to identify their potential roles.

Association of serum levels of polychlorinated biphenyls with IL-8 mRNA expression in blood samples from asthmatic and non-asthmatic Japanese children

BACKGROUND

One of the suggested health outcomes of PCB exposure is childhood asthma.

OBJECTIVES

This study was conducted to find health relevant biomarkers providing the molecular epidemiological evidence for the positive relationship between exposure to PCBs and childhood asthma.

METHODS

Blood samples from fifteen asthmatic children as well as an equal number of non-asthmatic children (average 2 year old) were collected, and were analyzed for PCBs and their select marker expression by using qRT-PCR.

RESULTS

Among biomarkers examined IL-8 expression was significantly correlated to serum levels of PCB #163+164 (P=0.022), #170 (P=0.046), #177 (P=0.022), #178 (P=0.022) and #180+193 (P=0.046) in a dose-dependent manner, which was found only among asthmatic children. In contrast, COX-2 correlations to individual congener levels were recognized only among control subjects, not among asthmatic subjects.

CONCLUSION

Serum concentrations of PCB#163+164, #170, #177, #178 and #180+193 correlate significantly with IL-8 mRNA expressions among asthmatic children.

The prevalence of rhinitis and its association with smoking and obesity in a nationwide survey of Japanese adults

BACKGROUND

Rhinitis is a common disease, and its prevalence is increasing worldwide. Several studies have provided evidence of a strong association between asthma and rhinitis. Although smoking and obesity have been extensively analyzed as risk factors of asthma, associations with rhinitis are less clear.

OBJECTIVE

The aims of our study were (i) to evaluate the prevalence of rhinitis using the European Community Respiratory Health Survey (ECRHS) questionnaire in Japanese adults and (ii) to evaluate the associations of smoking and body mass index (BMI) with rhinitis.

METHODS

Following our study conducted in 2006-2007 to determine the prevalence of asthma using the ECRHS questionnaire, our present analysis evaluates the prevalence of rhinitis and its association with smoking and BMI in Japanese adults 20-79 years of age (N = 22819). We classified the subjects (20-44 or 45-79 years) into four groups as having (i) neither rhinitis nor asthma; (ii) rhinitis without asthma; (iii) asthma without rhinitis; or (iv) rhinitis with asthma. We then evaluated associations with smoking and BMI in each group.

RESULTS

The overall age-adjusted prevalence of rhinitis was 35.1% in men and 39.3% in women. A higher prevalence was observed in the younger population than in the older population. Active smoking and obesity were positively associated with asthma without rhinitis. In contrast, particularly in the 20- to 44-year age-group, active smoking and obesity were negatively associated with rhinitis without asthma.

CONCLUSION

The results of the present study suggest that smoking and obesity may have different effects on the development of rhinitis and asthma.