Validation of the Chinese translated version of ISAAC core questions for atopic eczema

Prenatal and postnatal early life exposure to greenness and particulate matter of different size fractions in relation to childhood rhinitis - A multi-center study in China

The impact of early life exposure to residential greenness on childhood rhinitis and its interaction with particulate matter (PM) of different size fractions remain inconsistent. Herein, we recruited 40,486 preschool children from randomly selected daycare centers in 7 cities in China from 2019 to 2020, and estimated exposure to residential greenness by the normalized difference vegetation index (NDVI) with a 500 m buffer. Exposure to ambient PM (PM1, PM2.5, and PM10) was evaluated using a satellite-based prediction model (daily, at a resolution of 1 km × 1 km). By mixed-effect logistic regression, NDVI values during pregnancy, in the first (0-1 year old) and the second (1-2 years old) year of life were negatively associated with lifetime rhinitis (LR) and current rhinitis (CR) (P < 0.001). PM in the same time windows was associated with increased risks of LR and CR in children, with smaller size fraction of PM showing greater associations. The negative associations between prenatal and postnatal NDVI and LR and CR in preschool children remained robust after adjusting for concomitant exposure to PM, whereas the associations of postnatal NDVI and rhinitis showed significant interactions with PM. At lower levels of PM, postnatal NDVI remained negatively associated with rhinitis and was partly mediated by PM (10.0-40.9 %), while at higher levels of PM, the negative associations disappeared or even turned positive. The cut-off levels of PM were identified for each size fraction of PM. In conclusion, prenatal exposure to greenness had robust impacts in lowering the risk of childhood rhinitis, while postnatal exposure to greenness depended on the co-exposure levels to PM. This study revealed the complex interplay of greenness and PM on rhinitis in children. The exposure time window in prenatal or postnatal period and postnatal concomitant PM levels played important roles in influencing the associations between greenness, PM and rhinitis.

Improved ambient air quality is associated with decreased prevalence of childhood asthma and infancy shortly after weaning is a sensitive exposure window

BACKGROUND

The urban ambient air quality has been largely improved in the past decade. It is unknown whether childhood asthma prevalence is still increasing in ever top-ranking city of Shanghai, whether the improved air quality is beneficial for children's asthma and what time window of exposure plays critical roles.

METHODS

Using a repeat cross-sectional design, we analyzed the association between early life exposure to particles and wheezing/asthma in each individual and combined surveys in 2011 and 2019, respectively, in 11,825 preschool children in Shanghai.

RESULTS

A significantly lower prevalence of doctor-diagnosed asthma (DDA) (6.6% vs. 10.5%, p < 0.001) and wheezing (10.5% vs. 23.2%, p < 0.001) was observed in 2019 compared to 2011. Exposure to fine particulate matter (PM2.5), coarse particles (PM2.5-10) and inhalable particles (PM10) was decreased in 2019 by 6.3%, 35.4%, and 44.7% in uterus and 24.3%, 20.2%, and 31.8% in infancy, respectively. Multilevel log-binomial regression analysis showed exposure in infancy had independent association with wheezing/DDA adjusting for exposure in uterus. For each interquartile range (IQR) increase of infancy PM2.5, PM2.5-10 and PM10 exposure, the odds ratios were 1.39 (95% confidence interval (CI): 1.24-1.56), 1.51 (95% CI:1.15-1.98) and 1.53 (95% CI:1.27-1.85) for DDA, respectively. The distributed lag non-linear model showed the sensitive exposure window (SEW) was 5.5-11 months after birth. Stratified analysis showed the SEWs were at or shortly after weaning, but only in those with <6 months of exclusive breastfeeding.

CONCLUSIONS

Improved ambient PM benefits in decreasing childhood asthma prevalence. We firstly reported the finding of SEW to PM at or closely after weaning on childhood asthma.

Impact of environmental characteristics on children's gut microbiota - A pilot study in assessing the role of indoor microbiome and metabolites

BACKGROUND

A diverse and balanced human gut microbiota is crucial for maintaining normal human physiological functions. However, the impact of indoor microbiome and metabolites on gut microbiota is not well understood.

METHODS

A self-administered questionnaire was used to collect information on more than 40 personal and environmental characteristics and dietary habits from 56 children in Shanghai, China. Shotgun metagenomics and untargeted liquid chromatography-mass spectrometry (LC-MS) were used to characterize the indoor microbiome and metabolomic/chemical exposure in children's living rooms. PacBio full-length 16 S rRNA sequencing was used to characterize children's gut microbiota. Associations between environmental characteristics and gut microbiota diversity/composition were assessed using PERMANOVA and regression.

RESULTS

In total, 6247 and 318 indoor and gut microbial species and 1442 indoor metabolites were characterized. Age of children (R2 = 0.033, p = 0.008), age start kindergarten (R2 = 0.029, p = 0.03), living adjacent to heavy traffic (R2 = 0.031, p = 0.01) and drinking soft drinks (R2 = 0.028, p = 0.04) significantly impacted overall gut microbial composition, consistent with previous studies. Having pets/plants and frequent vegetable intake were positively associated with gut microbiota diversity and the Gut Microbiome Health Index (GMHI), while frequent juice and fries intake decreased gut microbiota diversity (p < 0.05). The abundance of indoor Clostridia and Bacilli was positively associated with gut microbial diversity and GMHI (p < 0.01). Total indoor indole derivatives and 6 indole metabolites (L-tryptophan, indole, 3-methylindole, indole-3-acetate, 5-hydroxy-L-tryptophan and indolelactic acid, p < 0.05) were positively associated with the abundance of total protective gut bacteria, suggesting a potential role in promoting gut health. Neural network analysis revealed that these indole derivatives were derived from indoor microorganisms.

CONCLUSIONS

The study is the first to report associations between indoor microbiome/metabolites and gut microbiota, highlighting the potential role of indoor microbiome in shaping human gut microbiota.

Poultry exposure and environmental protection against asthma in rural children

BACKGROUND

Asthma is one of the most common chronic diseases in childhood, and the prevalence has been increasing over the past few decades. One of the most consistent epidemiological findings is that children living in a farming or rural environment are protected from development of asthma and allergies, but the protective factors in rural China are not clear.

METHODS

A community-based, cross-sectional epidemiological study was performed in a total of 17,587 children aged 5-8 years, 3435 from Hong Kong (urban) and 14,152 from Conghua (rural county in southern China). Asthma and allergic symptoms as well as environmental exposures were ascertained by using a standardized and validated questionnaire.

RESULTS

The prevalence of current wheeze was significantly lower in rural Conghua than that of urban Hong Kong (1.7% vs. 7.7%, p < 0.001). A lower rate of asthma ever was also reported in rural children compared with their urban counterparts (2.5% vs. 5.3%, p < 0.001). After adjusting for confounding factors, exposure to agricultural farming (adjusted odds ratio 0.74, 95% confidence interval: 0.56-0.97) and poultry (0.75, 0.59-0.96) were the most important factors associated with the asthma-protective effect in the rural area. Further propensity score-adjusted analysis indicated that such protection conferred by living in the rural environment was mainly attributable to poultry exposure.

CONCLUSIONS

We confirmed that the prevalence of asthma and atopic disorders was significantly lower in rural children when compared with their urban peers. Exposure to poultry and agricultural farming are the most important factors associated with asthma protection in the rural area.

Prenatal pyrethroid exposure and lung function among school-aged children

BACKGROUND

Previous epidemiological evidence mainly focused on the adverse effects of prenatal exposure to pyrethroid insecticides (PYRs) on respiratory health during childhood. It remains unclear whether the PYR exposures can also impact on children's lung function.

OBJECTIVES

To explore the potential effects of prenatal PYR exposures on lung function in a population of Chinese children.

METHODS

This study included 233 mother-child dyads from the Laizhou Wan Birth Cohort (LWBC), Shandong province, northern China, between September 2010 and December 2013. Three metabolites of PYRs [3-phenoxybenzoic acid (3-PBA), and cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-DCCA and trans-DCCA)] were measured using gas chromatography-mass spectrometry (GC-MS) in maternal urine samples collected at recruitment. Lung function was assessed with spirometry in children aged 6-8 years. Multivariable linear regression and generalized linear models (GLMs) assessed the associations of prenatal PYR exposures with lung function in children.

RESULTS

Among the PYR metabolites, 3-PBA (81.5%) were most frequently detected, followed by trans-DCCA (55.4%) and cis-DCCA (21.9%). The 3-PBA concentration was associated with a 1% decrease in FEV₁/FVC in the highest quartiles of exposure compared to the lowest quartile, with a potential dose response association (p-trend = 0.085). Our findings provide a suggestive effect modification by sex, with girls being more susceptible than the boys (p-trend = 0.011). However, there were no associations between the trans-DCCA concentration and lung function parameters.

CONCLUSION

Prenatal 3-PBA concentrations were associated with a modest decrease in FEV₁/FVC among school-aged children, and the association was slightly more pronounced for the girls than for the boys.

Time-trends for eczema prevalences among children and adults from 1985 to 2015 in China: a systematic review

Background

Several studies have reported that childhood prevalence of eczema has been increasing worldwide. However, none study quantitatively evaluated prevalence trends of eczema among children and adults in the last 30 years in China.

Methods and Findings

Via a systematic review of literature databases in English and Chinese, we summarized all studies reporting eczema prevalences from 1985 to 2015 in China as well as diagramed prevalence and eczematous population trends against year for different age groups. A total of 93 studies and 17 studies (16 for children and one for adults) were selected for qualitative and quantitative synthesis, respectively. Childhood lifetime-ever eczema prevalences ranged from 10.0% to 30.0%. Prevalences among 3-12-year-olds children showed increasing trends in most specific cities, but national lifetime-ever eczema prevalences among 13-14-year-olds children decreased from 10.6% in 2001 to 8.6% in 2009 in mainland China. We estimated that about 1.5 million children aged 13-14-year-olds in 2009 and 15.5 million children aged 3-6-year-olds in 2012 had lifetime-ever eczema in mainland China. Similar studies were too few to ascertain time-trends of eczema prevalence among adults. About 39.4, 20.0, and 11.6 million adults aged 15-86-year-olds in 2010 had contact dermatitis, seborrheic dermatitis, and atopic dermatitis in the mainland China, respectively.

Conclusions

The burden of eczema became heavier in young children, whereas perhaps had been reduced in adolescent in China. More studies for eczema prevalence in adults are warranted.

Maternal exposure to PM2.5/BC during pregnancy predisposes children to allergic rhinitis which varies by regions and exclusive breastfeeding

BACKGROUND

Increasing prevalence of childhood allergic rhinitis(AR) needs a deeper understanding on the potential adverse effects of early life exposure to air pollution.

OBJECTIVES

The main aim was to evaluate the effects of maternal exposure to PM_2.5 and chemical constituents during pregnancy on preschool children's AR, and further to explore the modification effects of regions and exclusive breastfeeding.

METHODS

A multi-center population-based study was performed in 6 cities from 3 regions of China in 2011-2012. Maternal exposure to ambient PM_2.5 and main chemical constituents(BC, OM, SO₄^2-, NO₃^-, NH₄⁺) during pregnancy was assessed and a longitudinal prospective analysis was applied on preschool children's AR. The modification effects of regions and exclusive breastfeeding were investigated.

RESULTS

A total of 8.8% and 9.8% of children reported doctor-diagnosed allergic rhinitis(DDAR) and current hay fever, respectively, and 48.6% had less than 6 months of exclusive breastfeeding. The means of PM_2.5 during pregnancy were 52.7 μg/m³, 70.3 μg/m³ and 76.4 μg/m³ in the east, north and central south of China, respectively. Multilevel log-binomial model regression showed that each interquartile range(IQR) increase of PM_2.5 during pregnancy was associated with an average increase in prevalence ratio (PR) of DDAR by 1.43(95% confidence interval(CI): 1.11, 1.84) and current hay fever by 1.79(95% CI: 1.26, 2.55), respectively. Among chemical constituents, black carbon (BC) had the strongest associations. Across 3 regions, the eastern cities had the highest associations, followed by those in the central south and the north. For those equal to or longer than 6 months of exclusive breastfeeding, the associations were significantly reduced.

CONCLUSIONS

Children in east of China had the highest risks of developing AR per unit increase of maternal exposure to PM_2.5 during pregnancy, especially BC constituent. Remarkable decline was found in association with an increase in breastfeeding for ≥6 months, in particular in east of China.

Association between prenatal exposure to metal mixtures and early childhood allergic diseases

The association between prenatal exposure to the metal mixture and allergic diseases is poorly understood. We aimed to explore the individual effect and the combined effect of prenatal exposure to vanadium (V), chromium (Cr), nickel (Ni), arsenic (As), cadmium (Cd), thallium (Tl), and lead (Pb) on early childhood allergic diseases based on a birth cohort study that included 628 mother-infant pairs. Metals were measured in maternal urine samples collected in the first, second, and third trimesters. Children were prospectively followed up at age 4 years to collect information on allergic rhinitis, wheeze, and eczema status. By applying logistic regression models, weighted quantile sum (WQS) regression, and Bayesian kernel machine regression (BKMR), the different statistical analyses revealed urinary metals were only associated with early childhood allergic rhinitis. The averaged prenatal As exposure was significantly associated with an increased OR for allergic rhinitis in both single-metal (OR = 2.04, 95% CI: 1.35, 3.07) and multiple-metal logistic regression models (OR = 1.78, 95% CI: 1.15, 2.78). The WQS index of mixed metal exposure was positively associated with allergic rhinitis (OR = 1.66, 95% CI: 1.26, 2.19), and As and Tl had the largest weights in the WQS index (weighted 0.51 and 0.29, respectively). The BKMR analysis also showed the overall effect of the metal mixture was significantly associated with allergic rhinitis when all the metals were at their 55th percentile or above, compared to their 50th percentile. The effect of As and Tl on the risk of allergic rhinitis was significant when all of the other metals were fixed at the specific percentiles. Our findings suggest that prenatal co-exposure to higher levels of the seven metals increases the risk of allergic rhinitis in children, and As and Tl may contribute most to the combined risk.

Pediatric allergy and immunology in China

Over the past 30 years, China has enjoyed rapid economic development along with urbanization at a massive scale that the world has not experienced before. Such development has also been associated with a rapid rise in the prevalence of allergic disorders. Because of the large childhood population in the country, the burden of childhood allergic disorders has become one of the major challenges in the healthcare system. Among the Chinese centers participating in the International Study of Asthma and Allergies in Childhood, the data clearly showed a continuing rise in the prevalence of asthma, allergic rhinitis, and atopic eczema. However, the discipline of pediatric allergy in mainland China is still in its infancy due to the lack of formal training program and subspecialty certification. Clinicians and researchers are increasingly interested in providing better care for patients with allergies by establishing pediatric allergy centers in different regions of the country. Many of them have also participated in national or international collaborative projects hoping to answer the various research questions related to the discipline of pediatric allergy and immunology. It is our hope that the research findings from China will not only improve the quality of care of affected children within this country but also the millions of patients with allergies worldwide.

Childhood exposure to phthalates and pulmonary function

Phthalate exposure is related to the development of allergic diseases; however, studies regarding its effect on lung function are limited. Our study aims to identify an association between phthalate exposure at different ages and lung function in children at age 9 by conducting a cohort study. The Taiwan Birth Panel Study (TBPS) was established from April 2004 to January 2005. Urine samples were collected from children in the TBPS cohort at ages 2, 5, and 9years. Urinary phthalate metabolite concentrations were measured via ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry. Questionnaires, lung function tests and serum IgE levels were obtained from children at the age of 9. Multiple linear regressions adjusted for confounding factors were applied to investigate the associations between phthalate exposure at different ages and lung function at age 9. Our results demonstrate that in children with allergic diseases, a per log unit increase in the urinary phthalate metabolite mono-ethyl phthalate (MEP) concentration at age 9 was associated with a decreasing forced expiratory volume in 1 sec (FEV1) (β=-25.22; 95% CI: -47.53 to -2.91 per log ml/ln-μg/g cr) and forced vital capacity (FVC) (β=-32.3; 95% CI: -63.51 to -1.09 per log ml/ln-μg/g cr). For children with high serum IgE levels (>100kU/L) at age 9, the urinary MEP concentrations at the same age were negatively associated with the FEV1 (β=-30.4; 95% CI: -56.8 to -4.0 per log ml/ln-μg/g cr), FVC (β=-47.6; 95% CI: -84.2 to -11.0 per log ml/ln-μg/g cr) and peak expiratory flow (PEF) (β=-102.4; 95% CI: 180.2 to -24.7 per log ml/ln-μg/g cr). Phthalate exposure at ages 2 and 5 had little effect on lung function at age 9. Our study suggests that concurrent exposure to phthalates, such as MEP, is negatively associated with lung function in children. Further investigation is required to elaborate on this correlation.

Prenatal exposure to perfluoroalkyl and polyfluoroalkyl substances and childhood atopic dermatitis: a prospective birth cohort study

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been reported to suppress immune function. However, previous studies on prenatal exposure to PFASs and allergic disorders in offspring provided inconsistent results. We aimed to examine the association between prenatal exposure to PFASs and childhood atopic dermatitis (AD) in offspring up to 24 months of age.

METHODS

A prospective birth cohort study involving 1056 pregnant women was conducted in two hospitals in Shanghai from 2012 to 2015. Prenatal information was collected by an interview with the women and from medical records. Fetal umbilical cord blood was collected at birth. Cord blood plasma PFASs were measured. Children were followed at 6, 12 and 24 months and information on the development of AD was recorded. AD was diagnosed by 2 dermatologists independently based on the questionnaires. Multiple logistic regression was used to compute odds ratio (OR) and corresponding 95% confidence interval (CI) for the association between AD and each PFASs, adjusting for potential confounders.

RESULTS

A total of 687 children completed a 2-year follow-up visit and had PFASs measurement. AD was diagnosed in 173 (25.2%) children during the first 24 months. In female children, a log-unit increase in perfluorooctanoic acid (PFOA) was associated with a 2.1-fold increase in AD risk (AOR 2.07, 95% CI 1.13-3.80) after adjusting for potential confounders. The corresponding risk was 2.22 (1.07-4.58) for perfluorononanoic acid (PFNA). The highest PFOA quartile was significantly associated with AD (2.52, 1.12-5.68) compared with the lowest quartile. The highest quartile of PFNA, perfluorodecanoic acid (PFDA) and perfluorohexane sulfonic acid (PFHxS) were associated with AD with AOR (95% CI) being 2.14 (0.97-4.74), 2.14 (1.00-4.57), and 2.30 (1.03-5.15), respectively. Additionally, the second quartile of perfluorododecanoic acid (PFDoA) was associated with a 3.2-fold increase in AD risk (3.24, 1.44-7.27). However, no significant associations were found in male children.

CONCLUSIONS

Prenatal exposure to PFOA, PFDA, PFDoA and PFHxS significantly increased the risk of childhood AD in female children during the first 24 months of life. In addition, the associations between AD with prenatal exposure to PFNA were close to statistical significance.

Breastfeeding and timing of first dietary introduction in relation to childhood asthma, allergies, and airway diseases: A cross-sectional study

OBJECTIVES

We investigated associations of breastfeeding (BF) durations and patterns and of timing of other dietary introductions with prevalence of asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema among preschool children.

METHODS

During April 2011-April 2012, we conducted a cross-sectional study in 72 kindergartens from five districts of Shanghai, China and obtained 13,335 questionnaires of children 4-6-years-old. We used multiple logistic regression models to evaluate the target associations.

RESULTS

Compared to children who were never BF, children who were exclusively breastfed 3-6 months had the lowest risk of asthma (adjusted odds ratio and 95% confidence interval: 0.81, 0.72-0.91) and wheeze (0.93, 0.87-0.99); and exclusive BF >6 months was significantly associated with a reduced risk of hay fever (0.93, 0.89-0.97), rhinitis (0.97, 0.94-0.99), pneumonia (0.97, 0.94-0.99), and eczema (0.96, 0.93-0.99). No significant associations were found between time when fruits or vegetables were introduced and the studied diseases. Associations were independent of the child's sex and parent's ownership of the current residence. Longer duration BF was only significantly protective when there was no family history of atopy.

CONCLUSIONS

This study suggests that heredity, but not sex and socioeconomic status, may negatively impact the effect of BF on childhood airway and allergic diseases. Our findings support China's national recommendation that mothers provide exclusive BF for the first four months, and continue partial BF for more than 6 months.

The first 2-year home environment in relation to the new onset and remission of asthmatic and allergic symptoms in 4246 preschool children

The home environment can influence childhood allergies and respiratory health but there is little information on associations between early life exposure at home and new onset and remission of the asthmatic or allergic symptoms in preschool children. A questionnaire survey was performed in a random cluster sample of 4246 preschool children in Urumqi, China. Information on the home environment (perceptions of odors and indicators of pollution sources) and children's health (wheeze, rhinitis and eczema) was collected for the first 2 years of life and the last year (before answering the questionnaire) from one of the parents or another guardian of the child. Associations between the home environment the first 2 years of life and new onset and remission of childhood symptoms were analyzed by multiple logistic regression. Home environment factors reported for the first 2 years of life were consistently positively associated with new onset of symptoms and negatively associated with remission of symptoms. Visible mold (OR 1.46, 95% CI 1.12-1.90), moldy odor (OR 2.15, 95% CI 1.45-3.18), air dryness (OR 1.31, 95% CI 1.08-1.59), stuffy odor (OR 1.25, 95% CI 1.01-1.54) and parental smoking (OR 1.36, 95% CI 1.13-1.65) were associated with new onset of symptoms. These factors were negatively associated with the remission of symptoms. In conclusion, mold contamination at home (moldy odor/visible mold), poor indoor air quality (stuffy odor, air dryness) and exposure to environmental tobacco smoke (ETS) in the first 2 years of life can increase the incidence of asthmatic and allergic symptoms and decrease the remission from these symptoms in preschool children.

Various diagnostic criteria for atopic dermatitis (AD): A proposal of Reliable Estimation of Atopic Dermatitis in Childhood (REACH) criteria, a novel questionnaire-based diagnostic tool for AD

Atopic dermatitis (AD) is a heterogeneous disease that manifests with a wide variety of clinical symptoms and signs. Due to the lack of definitive biomarkers for AD, it is very difficult to set up standard diagnostic criteria for AD which cover the entire spectrum of AD patients. Various instruments have been proposed for AD diagnosis, and they can be classified into a hospital setting or a community setting. From the preventive medicine viewpoint, questionnaire-based diagnostic criteria in a community setting are important to detect and manage childhood AD patients properly. In this article, various diagnostic criteria for AD in hospital and community settings will be reviewed. Additionally, the Reliable Estimation of Atopic Dermatitis in Childhood (REACH), a new full questionnaire-based diagnostic tool for childhood AD, will be reviewed.

Fetal Growth, Obesity, and Atopic Disorders in Adolescence: a Retrospective Birth Cohort Study

BACKGROUND

Developmental status at birth and subsequent obesity have been implicated in the development of childhood atopic dermatitis (AD) and allergic rhinitis (AR).

METHODS

The current study analysed the cohort data of 74 688 junior high school students from a national retrospective birth cohort study in Taiwan. A random 10% sample was selected from singleton livebirths with complete data on the analytical variables of interest. Atopic disorders, including AD and AR, were assessed by questionnaires (International Study of Asthma and Allergies in Childhood). Logistic regression analyses were applied with adjustments for related risk factors.

RESULTS

Among subjects mainly 13-15 years of age, the estimated prevalence was 7.6% for AD and 22.4% for AR. While the role of fetal growth in allergic disorders was less evident, the risk of developing AD and AR were both influenced by a combination of fetal growth status and adolescent body mass index (BMI). Compared with those with normal fetal growth and school-aged BMI, the risk of developing AD increased 64% among adolescents with both restricted fetal growth and high BMI (odds ratio 1.64, 95% confidence interval 1.37, 1.97). The risk for this combination was higher than that for either restricted fetal growth or high BMI alone. Nevertheless, the overall interaction between BMI and fetal growth status on atopic disorders did not reach statistical significance.

CONCLUSIONS

Excessive weight gain could be an important risk factor related to developing atopic dermatitis and allergic rhinitis during adolescence, especially among infants born small for gestational age.

Association of atopic dermatitis with being overweight and obese: a systematic review and metaanalysis

BACKGROUND

Previous studies found conflicting results about whether atopic dermatitis (AD) is associated with overweight/obesity.

OBJECTIVE

We sought to examine the relationship between AD and overweight/obesity by performing a systematic review and metaanalysis.

METHODS

Observational studies of the relationship between AD and overweight/obesity were selected from PubMed, Embase, and the Cochrane Library. The quality of evidence was assessed using the Newcastle-Ottawa Scale. Fixed and random effects metaanalyses were performed to estimate pooled odds ratios (ORs). Sensitivity analyses were performed that compared results by location of study, study quality, and between studies in children and adults.

RESULTS

In total, 30 studies were included for review. Patients who were overweight (Cochrane-Mantel-Haenszel [CMH] OR, 1.27 [95% confidence interval {CI}: 1.19-1.36]; random effects OR, 1.23 [95% CI: 1.11-1.41]), obese (CMH OR, 1.68 [95% CI: 1.54-1.84]; random effects OR, 1.47 [95% CI: 1.21-1.79]), or overweight/obese (CMH OR, 1.42 [95% CI: 1.34-1.50]; random effects OR, 1.31 [95% CI: 1.16-1.48]) had higher odds of AD than normal weight patients. In sensitivity analyses, children who were overweight (random effects OR, 1.24 [95% CI: 1.08-1.43]), obese (random effects OR, 1.44 [95% CI: 1.12-1.86]), or overweight/obese (random effects OR, 1.32 [95% CI: 1.15-1.51]) and adults who were obese (random effects OR, 1.56 [95% CI: 1.24-1.95]) or overweight/obese (random effects OR, 1.29 [95% CI: 1.05-1.59]) had higher odds of AD. The association remained significant in North America and Asia but not Europe.

LIMITATIONS

Most studies were cross-sectional.

CONCLUSIONS

Overweight/obesity in North America and Asia is associated with an increased prevalence of AD.

Early life phthalate exposure and atopic disorders in children: a prospective birth cohort study

The role of phthalate exposure at different stages in the immune system and atopic disorders is not well-known. This study aims to evaluate the effects of prenatal and postnatal phthalate exposures on immunoglobulin E (IgE) levels and atopic dermatitis (AD) in children by objective biomarkers. We conducted a prospective Taiwan Birth Panel cohort study with 483 mother/infant pairs. Finally, 161 urine specimens at 3rd trimester of pregnancy, 219 urine specimens from children at age 2, and 192 urine specimens at age 5 were analyzed after excluding missing data and loss to follow-up. Urine monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), and mono-(2-ethylhexyl) phthalate (MEHP) at 3rd trimester of pregnancy and at ages 2 and 5 were measured by ultra-performance liquid chromatography coupled with tandem mass spectrometry. At ages 2 and 5, information on the development of AD and serum total IgE was collected. The association between urine phthalate metabolite levels at different stages and serum IgE and AD was evaluated by multivariate linear regression and logistic regression. Urine phthalate metabolite levels were higher at age 2 than those at pregnancy and age 5. At each period, urine MBP levels were higher than MEP, MEHP, and MBzP. MEHP levels at age 2 positively correlated with serum IgE levels (per ln-unit: β=0.191, p=0.02). Analyses stratified by gender revealed that MEHP levels positively correlated with serum IgE levels only in boys (per ln-unit: β=0.256, p=0.03). When dividing into quartiles, urine MBzP levels at age 2 had a significant association with AD. We found no statistically significant association of other phthalate metabolites with IgE and AD. Early life phthalate exposure may increase the risk of allergic sensitization and atopic disorders.

Foetal exposure to maternal passive smoking is associated with childhood asthma, allergic rhinitis, and eczema

Objective. We examined the hypothesis that foetal exposure to maternal passive smoking is associated with childhood asthma, allergic rhinitis, and eczema. Methods. The study was a population-based cross-sectional survey of Hong Kong Chinese children aged ≤14 years carried out in 2005 to 2006. Results. Foetal exposure to maternal passive smoking was significantly associated with wheeze ever (OR 2.05; 95% CI 1.58–2.67), current wheeze (OR 2.06; 95% CI 1.48–2.86), allergic rhinitis ever (OR 1.22; 95% CI 1.09–1.37), and eczema ever (OR 1.61; 95% CI 1.38–1.87). Foetal exposure to maternal active smoking was significantly associated with asthma ever (OR 2.10; 95% CI 1.14–3.84), wheeze ever (OR 2.46; 95% CI 1.27–4.78), and current wheeze (OR 2.74; 95% CI 1.24–6.01) but not with allergic rhinitis ever (OR 1.01; 95% CI 0.70–1.46) or eczema ever (OR 1.38; 95% CI 0.87–2.18). The dose response relationship between wheeze ever and current wheeze with increasing exposure, from no exposure to maternal passive smoking and then to maternal active smoking, further supports causality. Conclusion. There is significant association between foetal exposure to maternal passive smoking and maternal active smoking with childhood asthma and related atopic illnesses. Further studies are warranted to explore the potential causal relationship.

Prevalence of atopic dermatitis in Korea: analysis by using national statistics

We attempted to investigate the prevalence of atopic dermatitis (AD) in Korea by using national statistics. Data on AD patients who received medical service at least once a year from 2003 through 2008 were collected from health insurance research team of National Health Insurance Corporation. Data of estimated populations during the same period were obtained from the Statistics Korea. In 2008, the prevalence of AD was 26.5% in aged 12-23 months and decreased substantially to 7.6% at age 6 yr, 3.4% at age 12 yr and to 2.4% at age 18 yr. In males, the prevalence was higher than females until 2 yr of age, while the opposite was shown in children aged 2 yr or older. In children aged less than 24 months, the prevalence of AD has increased from 19.8% to 23.8% between the years 2003 and 2008, while the prevalence showed no increase in the older age group. In conclusion, the prevalence of AD in 2008 peaked during infancy up to 26.5% and decreased thereafter. Our findings also suggest that increasing prevalence of AD in children less than 24 months might be responsible for the recent increase in the prevalence of AD in Korean children.

The effect of prenatal perfluorinated chemicals exposures on pediatric atopy

BACKGROUND

The role of perfluorinated compounds (PFCs) in the immune system and allergic diseases is not well-known. This study examined the effects of pre-natal exposure to PFCs on immunoglobulin E (IgE) levels and atopic dermatitis (AD).

METHODS

In Taiwan Birth Panel cohort study, newborns with cord blood and peri-natal factors (i.e. birth body weight, weeks of gestation, and type of delivery) gathered at birth were evaluated. At the age of 2 years, information on the development of AD, environmental exposures, and serum total IgE were collected. The AD and non-AD children were compared for the concentration of cord blood serum PFCs measured by Ultra-performance liquid chromatography/triple-quadrupole mass (UPLC-MS/MS). Correlations among cord blood IgE, serum total IgE at 2 years of age, and cord blood PFC levels were made.

RESULTS

Of 244 children who completed the follow-up and specimen collections, 43 (17.6%) developed AD. Concentrations of cord blood serum perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonic acid (PFHxS) were median (range) 1.71 (0.75-17.40), 5.50 (0.11-48.36), 2.30 (0.38-63.87), and 0.035 (0.035-0.420)ng/mL, respectively. PFOA and PFOS levels positively correlated with cord blood IgE levels (per ln-unit: β=0.134 KU/l, p=0.047 for PFOA; β=0.161 KU/l, p=0.017 for PFOS). Analyses stratified by gender revealed that PFOA and PFOS levels positively correlated with cord blood IgE levels only in boys (per ln-unit: β=0.206 KU/l, p=0.025 for PFOA; β=0.175 KU/l, p=0.053 for PFOS). When dividing cord blood serum PFCs into quartiles in the fully adjusted models, AD had no significant association with PFOS.

CONCLUSIONS

Pre-natal PFOA and PFOS exposures positively correlated with cord blood IgE levels.

Point and period prevalences of eczema in rural and urban schoolchildren in Ghana, Gabon and Rwanda

BACKGROUND

Eczema is a growing problem in Africa, particularly amongst children.

OBJECTIVES

To investigate the point-prevalences of eczema by physical examination in schoolchildren living in rural and urban areas and with different socioeconomic backgrounds in Ghana, Gabon and Rwanda. In Ghana period-prevalences were also estimated by questionnaire and compared with the point-prevalences.

METHODS

In total, 4839 schoolchildren in Ghana, Gabon and Rwanda were seen by at least one dermatologist. The point-prevalences of eczema were estimated on the basis of physical examination. Period-prevalences were measured in Ghana with questionnaire based-interviews adapted from the International Study of Asthma and Allergies in Childhood (ISAAC).

RESULTS

The point-prevalences were 1.5% and 1.6% in the two Ghanaian studies; 4% in Gabon and 0.8% in Rwanda. The period-prevalences were 2.6% and 4.4% in the two Ghanaian studies. The prevalences of eczema were not significantly different when comparing the urban and rural groups as well as the different socioeconomic levels. The sensitivity and positive predictive value to identify eczema cases based on the questionnaires compared to the diagnoses by physical examination were only 33% and 22% in the first Ghanaian study and 10% and 4% in the second Ghanaian study respectively.

CONCLUSIONS

The point-prevalences of eczema in the three African countries studied were low compared with industrialized countries. Physical examination by a dermatologist is still the gold standard to identify eczema cases because the sensitivity and the positive predictive value to identify eczema cases with questionnaires were low in the two Ghanaian studies.

Validation of epidemiological tools for eczema diagnosis in Brazilian children: the ISAAC's and UK Working Party's criteria

Background

Instruments for field diagnosis of eczema are increasingly used, and it is essential to understand specific limitations to make best use of their strengths. Our objective was to assess the validity of ISAAC and UK Working Party criteria for field diagnosis of eczema in children.

Methods

We performed a cohort study in urban Brazil. Parents/guardians of 1,419 children answered ISAAC phase II questionnaire. Children were examined for skin lesions (UKWP protocol). Two dermatologists examined most cases of eczema (according to ISAAC or UKWP), and a sample without eczema.

Results

Agreement between repeat questionnaires on the filter question was poor (kappa = 0.4). Agreement between the 2 dermatologists was fair (kappa = 0.6). False positive reports included scabies in 39% of ISAAC cases and 33% of UKWP cases. Sensitivity and PPV were low (ISAAC: 37.1% and 16.1%; UKWP: 28.6% and 23.8%). Specificity and NPV were high (ISAAC: 90.0% and 96.6%; UKWP: 95.3% and 96.2%). One-year prevalence of eczema was 11.3% (ISAAC), 5.9% (UKWP) and 4.9% (adjusted dermatologist diagnosis). Point prevalence of scabies (alone or not) was 43%, 33% and 18%, in eczemas according to ISAAC, to UKWP and to dermatologists. The reasons why children with eczema were not identified by ISAAC or UKWP were wrongly denying dry skin, itchy rash or personal history of atopic diseases. A limitation is that questionnaire was already validated in Brazil, but not field tested in this specific setting.

Conclusions

Studies using UKWP or ISAAC criteria should include a validation arm, to contribute to the understanding of potential limitations of their use in different contexts and to explore solutions. We list specific recommendations.

Validation of the Finnish ISAAC questionnaire on asthma against anti-asthmatic medication reimbursement database in 5-year-old children

BACKGROUND

Valid identification of childhood asthma at the population level for epidemiological purposes remains a challenge. We aimed at validating the Finnish version of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire based on parental-reported childhood asthma.

MATERIALS AND METHODS

The ISAAC questionnaire has been validated against anti-asthmatic medication reimbursement data of the Finnish Social Insurance Institution, being the gold standard, among 2236 5-year-old consecutively born children (1996-2004) carrying human leukocyte antigen (HLA)-conferred susceptibility to type 1 diabetes. Two combined questionnaire questions (any wheezing symptom or use of asthma medication during the preceding 12 months plus ever asthma; any wheezing symptom or use of asthma medication during the preceding 12 months plus ever doctor-diagnosed asthma) were validated against valid reimbursement with purchase of at least one anti-asthmatic medication during a 12-month period. The validity of the questionnaire was estimated as the sensitivity, specificity, positive predictive value, negative predictive value, and Youden's index.

RESULTS

The sensitivity 0.98 [95% confidence interval (CI) = 0.92-0.99]; specificity 0.98 (95% CI = 0.97-0.98); negative predictive value 1.00 (95% CI = 1.00-1.00); and Youden's index 0.96 (95% CI = 0.96-0.96) were the same for each of the two sets of combined questions. The positive predictive value for the first combined question was 0.63 (95% CI = 0.55-0.71), while it was 0.64 (95% CI = 0.57-0.72) for the second combined question.

CONCLUSION

The Finnish ISAAC questionnaire was highly valid and is an acceptable instrument for the survey of the prevalence of parental-reported childhood asthma for epidemiological purposes.

Atopic eczema or atopiform dermatitis

Age period prevalence of atopic eczema (AE), a very common skin disease, has increased during the past decennia. This expansion seems to be ending in wealthy countries, while an increase is observed in developing nations, for which there is no firm explanation. Recent steps in understanding AE are the detection of skin barrier related filaggrin null mutations in approximately 25% of patients and the recognition of IL-31 as a molecule possibly involved in the itch (pruritus). Also interesting are the recognition of thymus and activation-regulated chemokine (TARC) and proliferating-inducing ligand (APRIL), as being associated with AE severity and activity. Immunocentric and corneocentric views on pathogenesis (the inside-outside paradigm) and the diagnostic entity atopiform dermatitis (AFD) are discussed here. We emphasize that diagnosing AE is not simple but challenging. We accentuate that a diagnosis of AE is only possible when there is allergen-specific IgE. Advice as to the need for elimination of allergens and adjustment of lifestyle are only proficient in patients having atopy and true AE, not in those having AFD.

How well do questionnaires perform compared with physical examination in detecting flexural eczema? Findings from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two

BACKGROUND

Questionnaires are widely used in epidemiological studies to measure eczema symptom prevalence, but there are concerns regarding their accuracy if used as a diagnostic tool.

OBJECTIVES

To compare the performance of a validated eczema symptom questionnaire and a standardized skin examination protocol employed in the second phase of the International Study of Asthma and Allergies in Childhood (ISAAC).

METHODS

A total of 30,358 schoolchildren aged 8-12 years from 18 countries were examined for flexural eczema. Parents also completed an eczema symptom questionnaire. We compared prevalence estimates at the population level based on the questionnaire vs. physical examination. We also compared the skin examination and the ISAAC questionnaire in making a diagnosis of flexural eczema.

RESULTS

The point prevalences for flexural eczema at centre level based on a single examination were lower than the questionnaire-based 12-month period prevalences (mean centre prevalence 3.9% vs. 9.4%). Correlation between prevalences of both outcome measures was high (r = 0.77, P < 0.001). At the individual level, questionnaire-derived symptoms of 'persistent flexural eczema in the past 12 months' missed < 10% of cases of flexural eczema detected on physical examination. However, between 33% and 100% of questionnaire-based symptoms of 'persistent flexural eczema in the past 12 months' were not confirmed on examination.

CONCLUSIONS

ISAAC questionnaire-derived symptom prevalences are sufficiently precise for comparisons between populations. Where diagnostic precision at the individual level is important, questionnaires should be validated and potentially modified in those populations beforehand, or a standardized skin examination protocol should be used.

Effect of gestational smoke exposure on atopic dermatitis in the offspring

The adverse impact of smoking on respiratory diseases and birth outcomes in children is well-known. However, the influence of smoke exposure including environmental tobacco smoke (ETS) and maternal smoking during pregnancy on atopic dermatitis (AD) is not clear. The purpose of this study was to evaluate the effect of gestational smoke exposure on the development of AD in the offspring on the basis of the maternal and cord blood cotinine. We recruited 261 mother and newborn pairs in 2004. Cord blood and information on perinatal factors of children were gathered at birth. At 2 yr of age, information about development of AD and environmental exposures were collected. We compared AD with non-AD children for the concentration of cotinine in cord and maternal blood measured by high performance liquid chromatography-mass spectrometry. Multiple logistic regressions were performed to estimate the relationship of cotinine levels and AD. About 150 mother and child pairs completed the follow-up study and specimen collection with 38 (25.3%) children developing AD. Two (1.3%) out of 150 mothers smoked during pregnancy, while 38 (25.3%) mothers reported having ETS exposure. Cotinine levels in cord blood and maternal blood were highly correlated (r = 0.71, p < 0.001). The risk of AD was found to increase with maternal and cord blood cotinine levels in a dose-response manner (p for trend = 0.01). Children exposed to high levels (>75th percentile) had a significantly increased risk of AD. Smoke exposure during pregnancy might increase the risk of AD in children. Avoidance of prenatal smoke exposure may be warranted for early prevention.

The Shanghai Women's Asthma and Allergy Study: objectives, design, and recruitment results

The Shanghai Women's Asthma and Allergy Study is the first population-based incidence study designed to assess the associations of dietary antioxidant intake and measures of oxidative stress and antioxidant enzyme activity with development of adult-onset asthma and allergic rhinitis. A total of 65,732 participants in the Shanghai Women's Health Study, an ongoing cohort study in seven districts of Shanghai, People's Republic of China, were recruited to the Shanghai Women's Asthma and Allergy Study from 2003 to 2007. Dietary intake was assessed in the parent study by using a validated and quantitative food frequency questionnaire at baseline recruitment and at the first biennial follow-up survey. Blood and urine samples were collected to measure baseline oxidative stress, antioxidant enzyme activity, and nutrient levels at the baseline survey. Incident asthma and allergic rhinitis were assessed by using a modification of the International Study of Asthma and Allergies in Childhood questionnaire during the biennial in-person survey of the Shanghai Women's Health Study. Diagnosis of asthma was confirmed by either methacholine challenge testing or test of reversibility to beta-agonists. Dietary antioxidant intake, plasma antioxidants, antioxidant enzymes, and urinary isoprostanes, a marker of oxidative stress, were measured prior to disease onset. This paper describes the study objectives, design, population demographics, and recruitment results.

Diagnostic criteria for atopic dermatitis: a systematic review

BACKGROUND

Atopic dermatitis (AD) has a wide spectrum of dermatological manifestations and despite various validated sets of diagnostic criteria that have been developed over the past decades, there is disagreement about its definition. Nevertheless, clinical studies require valid diagnostic criteria for reliable and reproducible results.

OBJECTIVE

To summarize the evidence concerning the validity of diagnostic criteria for AD.

METHODS

All data sources were identified through searches on Medline, Embase and Cochrane databases. The Quality Assessment of Diagnostic Accuracy tool (QUADAS) was used. Results are presented in a receiver operating characteristic (ROC) plot.

RESULTS

Out of the 20 articles that met the criteria, 27 validation studies were identified. In two studies concerning Hanifin and Rajka diagnostic criteria sensitivity and specificity ranged from 87.9% to 96.0% and from 77.6% to 93.8%, respectively. Nineteen validation studies of the U.K. diagnostic criteria showed sensitivity and specificity ranging from 10% to 100% and 89.3% to 99.1%, respectively. Three validation studies concerning the Schultz-Larsen criteria showed sensitivity from 88% to 94.4% and specificity from 77.6% to 95.9%. In one article concerning the criteria of Diepgen, the sensitivity ranged from 83.0% to 87.7% and the specificity from 83.9% to 87.0%. One article studied the Kang and Tian criteria and reported 95.5% sensitivity and 100% specificity. One article validating the International Study of Asthma and Allergies in Childhood (ISAAC) criteria showed a positive and negative predictive value of 48.8% and 91.1%, respectively.

CONCLUSION

With this systematic review of the existing sets of diagnostic criteria for AD a varying number of validation studies with varying methodological quality was found. The U.K. diagnostic criteria are the most extensively validated. However, improvement of methodological design for validation studies and uniformity in well-validated and applicable diagnostic criteria are needed to improve future intervention studies and to compare study results.

Symptoms of asthma and atopic disorders in preschool children: prevalence and risk factors

BACKGROUND

Published epidemiological data suggested that asthma and allergies may be increasing in preschool children. Identification of the risk factors is important for planning possible early intervention to prevent asthma. This study was designed to measure the prevalence of, and risk factors for, asthma and atopic disorders in preschool children from Hong Kong.

METHODS

Children aged 2-6 years living in Hong Kong were recruited through the local nurseries and kindergartens for this study to ascertain the presence of symptoms of asthma and various possible risk factors. The parental questionnaire was developed based on the International Study of Asthma and Allergies in Childhood questionnaire.

RESULTS

A total of 3089 children (1506 boys) from 14 nurseries and kindergartens participated in this study. The prevalence of wheeze ever and current wheeze were 16.7% and 9.3%. Two hundred and thirty-four subjects were born in mainland China and migrated to Hong Kong subsequently. When compared with children born and raised in Hong Kong, children born in mainland China had significantly lower prevalence of current wheeze (3.4% vs. 9.6%, P<0.01). Two environmental factors in the first year of life were associated with wheezing attacks within the last 12 months. They were the use of foam pillow (Odds ratio: 1.45; 95% Confidence interval: 1.04-2.00) and the use of gas as cooking fuel (1.68; 1.03-2.75). Frequent use of paracetamol was also associated with wheezing attack in the past 12 months.

CONCLUSIONS

This study confirms the high prevalence of symptoms of atopic disorders in preschool children from Hong Kong. Early environmental exposure factors are important determinants of subsequent development of asthma symptoms in the preschool years. Further studies are needed to evaluate the possible pathogenetic role of the identified risk factors.

Allergic disorders in African countries: linking immunology to accurate phenotype

Identification and characterization of risk and protective factors for allergy is important for developing strategies for prevention or treatment. The prevalence of allergy is clearly higher in affluent countries than in developing countries like, e.g. Africa. Especially in urban areas of developing countries, allergy is however on the increase. In Africa, we have the unique opportunity to investigate risk and protective factors and the influence of urbanization and westernization, i.e. almost to take a look at Europe, Australia or the USA as they were before their allergy epidemics. Moreover, migrants from developing to affluent countries experiencing an increased burden of allergy provide new insights into risk and protective factors. Allergen exposure, diet and infections are the major exogenous influences playing a role as risk and protective factors. Depending on the nature, timing, chronicity and level of exposure, each of them can promote or inhibit allergy. Perhaps with the exception of infections, availability of data from Africa on their role in the development of allergy is limited. Detailed epidemiological studies in rural and urban Africa combined with basic immunological research are needed to unravel mechanisms of increase in allergy and of protection. The maturation of the immune system at young age under influence of exogenous factors results in differences in T-cell-skewing (Th1/Th2/Treg) and humoral responses. It is essential to perform studies from a 'non-Eurocentric' angle (e.g. local allergens, locally validated questionnaires and diagnostic procedures). Such studies will provide the affluent countries with new leads to combat the allergy epidemic and more importantly help prevent it in Africa.

Childhood asthma under the north face of Mount Everest

We assessed prevalences of symptoms of asthma, allergic rhinitis, and atopic eczema and their associations with environmental exposures among school children living in high altitude and rural Tibet. After watching an asthma symptom video, 2.8% of the children reported ever wheezing at rest and 1.4% ever severe wheezing. Residential dampness problems were the only environmental exposure that was clearly associated with children's symptoms (odds ratios 1.3 to 2.5), even if several other exposures were common. The low symptom prevalences are in accordance with the hypothesis that the western lifestyle in some way increases the risk of asthma.

Asthma, eczema, and reports on pollen and cat allergy among pupils in Shanxi province, China

OBJECTIVES

To study self-reported asthma, eczema, and pollen and furry pet allergy among pupils (9-20 years) in Shanxi province, China, in relation to dietary and environmental factors.

METHODS

A standardised questionnaire was distributed to pupils in two primary and two secondary schools, one in Taiyuan city (3.0 milj. inhabitants), the others in Qingxu county, a rural area 30 km outside Taiyuan. Totally, 2,116 pupils (90%) participated.

RESULTS

Fifty percent were girls, 61% had been growing up on the countryside, 18% lived in Taiyuan now, 1.7% had ever had asthma, 0.8% had doctor's diagnosed asthma, 1.4% pollen allergy, 1.7% cat allergy, and 0% had dog allergy. Multiple logistic regression was applied, controlling for age, gender, diet, indoor exposures, rural childhood, and current urban residency. Girls had less eczema (OR = 0.51; 95%CI 0.28-0.92). Pupils in the city had more eczema (OR = 5.05; 95% CI 1.11-23.3). Those with a rural childhood had less asthma (OR = 0.17; 95% CI 0.05-0.60), eczema (OR = 0.15; 95% CI 0.13-0.66) and pollen/cat allergy (OR = 0.50; 95%CI 0.25-0.99). None of the indoor variables was related to asthma or allergy. Children with frequent fruit consumption had less asthma (OR = 0.40; 95% CI 0.19-0.82) and pollen/cat allergy (OR = 0.49; 95% CI 0.29-0.84). Those with frequent fish consumption had less asthma (OR = 0.32; 95% CI 0.11-0.97). Those with frequent hamburgers consumption had more asthma (OR = 2.05; 95% CI 1.09-3.87) and eczema (OR = 1.85; 95% CI 1.12-3.04).

CONCLUSION

Asthma, eczema, and pollen or pet allergy was uncommon, compared with western countries and other areas in China. Pupils with a rural childhood had less asthma and allergy, which is consistent with the "hygiene hypothesis". Fruit and fish consumption may reduce, and fast food consumption may increase the risk for asthma. Finally, the higher prevalence of asthma and eczema among younger children, born in the 1990s, indicates a cohort effect similar to that observed in western countries.

Validation of the International Study of Asthma and Allergies in Children (ISAAC) and U.K. criteria for atopic eczema in Ethiopian children

BACKGROUND

Reliable diagnostic criteria for atopic eczema (AE) are essential in order to make international comparisons and to identify possible disease risk factors. Little is known about the prevalence of atopic eczema and validity of diagnostic criteria for AE in developing countries where English is not the first language.

OBJECTIVES

We sought to determine the prevalence of AE in an area of urban and rural Ethiopia, and to compare the predictive values of different questionnaire and examination methods for diagnosing AE in this population.

METHODS

We conducted a cross-sectional survey of 7915 children aged 1-5 years living in and around the town of Jimma in southwest Ethiopia. AE prevalence was assessed in two ways: (i) by using the International Study for Asthma and Allergies in Childhood (ISAAC) questionnaire, and (ii) using the U.K. refinement of Hanifin and Rajka's diagnostic criteria. All possible cases identified by screening questions and random samples of controls were then examined by an experienced local paediatrician, who acted as a reference standard to determine the predictive value of the criteria used to diagnose AE.

RESULTS

The overall 1-year period prevalence of AE according to ISAAC and U.K. criteria was 4.4%[95% confidence interval (CI) 3.95-4.85] and 1.8% (95% CI 1.5-2.1), respectively. Corresponding point prevalence estimates (symptoms in the last week) were 1.8% for ISAAC and 1.3% for the U.K. criteria. The positive predictive values of the ISAAC and U.K. criteria questions for AE symptoms still reported to be present (in the last week) at the doctor's examination were 48.8% and 55.5%, respectively. Corresponding negative predictive values were 90.5% and 90.1%, respectively. The sign of visible flexural dermatitis (a component of the U.K. criteria) when used alone had positive and negative predictive values of 57% and 91%, respectively.

CONCLUSIONS

Neither the ISAAC nor U.K. criteria performed especially well in predicting cases of AE in this survey. Possible reasons include problems with questionnaire translation, cultural conceptions of terminology, asking parents rather than the child about symptoms, the transient nature of AE signs, and differences in what a doctor perceives to constitute a typical case of AE. The results do not preclude the use of standardized diagnostic criteria alongside a doctor's examination in future surveys of Ethiopian children, and knowledge of the criteria's limited predictive value should help to interpret study findings that have employed such criteria. Consideration should be given to adopting the sign of visible flexural dermatitis as a standard for estimating the point prevalence of AE throughout the world because it is less susceptible to problems with translation and interpretation.

Socioeconomic status and prevalence of allergic rhinitis and atopic eczema symptoms in young adolescents

Environmental factors are known to influence the development of allergic rhinitis and atopic eczema in genetically susceptible individuals. Socioeconomic status (SES) may be an important indicator of risk for these conditions. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase 1 written questionnaire was used to determine the prevalence and severity of allergic rhinoconjunctivitis and atopic eczema symptoms in 4947 pupils aged 13-14 years attending 30 schools in socioeconomically diverse areas of Cape Town. Home addresses were used to stratify participants into five SES bands. Relationships between symptom prevalence and severity, and SES, recent urbanization and upward socioeconomic mobility were examined. Logistic regression was used to generate odds ratios (OR) and 95% confidence intervals (CI) in order to assess overall trends by SES. The prevalences of self-reported allergic rhinitis symptoms and recurrent itchy rash in the past year were 33.2% and 11.9% respectively. Girls had a significantly higher prevalence of all symptoms than boys. The prevalence of allergic rhinitis symptoms increased from lowest to highest SES (overall OR for rhinitis symptoms in past year = 1.16, 95% CI 1.11-1.21). There was no significant trend in reported eczema symptoms by SES other than for the question, 'Have you ever had eczema' (OR = 0.88, 95% CI 0.83-0.93). Longer period of urbanization was weakly associated only with recurrent itchy skin rash (OR = 1.05, 95% CI 1.01-1.09). 'Socially mobile' pupils, i.e. those resident in the lowest SES areas but attending highest SES schools showed significantly higher prevalences of eczema and some rhinitis symptoms than pupils attending lowest SES schools. These findings may reflect differences in reporting related to language, culture and access to medical care rather than real differences in prevalence.

Increasing prevalence of allergic rhinitis but not asthma among children in Hong Kong from 1995 to 2001 (Phase 3 International Study of Asthma and Allergies in Childhood)

There is a worldwide belief that the prevalence of asthma and other allergic diseases is increasing but the measures used in many studies are susceptible to systematic errors. We examined the trend of asthma, allergic rhinitis and eczema prevalence in school children aged 6-7 years in Hong Kong from 1995 to 2001 using standardized ISAAC methodology. There were 4448 and 3618 children participating in 2001 and 1995, respectively. The prevalence of life-time rhinitis (42.4% vs. 38.9%, p < 0.01), current rhinitis (37.4% vs. 35.1%, p < 0.03), current rhinoconjunctivitis (17.2 vs. 13.6%, p < 0.01) and life-time eczema (30.7% vs. 28.1%, p = 0.01) increased significantly. There was no significant change in prevalence of life-time asthma, life-time wheeze and current wheeze albeit a significant increase in severe asthma symptoms. We investigated a number of potential risk factors including sex, family history of atopy, sibship size, birth weight, respiratory tract infections, pet ownership and exposure to tobacco smoke. However, the increases in prevalence of rhinitis and eczema could not be entirely explained by the change of prevalence of these risk factors. The odds ratio OR for the study period remained significantly associated with current rhinitis (OR 1.31, 95% confidence intervals CI 1.17-1.46), current rhinoconjunctivitis (OR 1.63, 95% CI 1.41-1.87) and life-time eczema (OR 1.30, 95% CI 1.16-1.45) after adjustment for these confounding variables using logistic regression model. Further study is warranted to elucidate the factors contributing to the observable change in the prevalence of rhinitis in our population.

Validation of a self-administered questionnaire in Chinese in the assessment of eczema severity

The purpose of this study was to validate the Chinese version of the Nottingham Eczema Severity Score (NESS) in determining the severity of atopic dermatitis (AD). Each parent or patient filled out a questionnaire in Chinese based on the NESS. A physician then repeated the NESS independently. Finally, the severity of AD was evaluated according to the Scoring Atopic Dermatitis (SCORAD) scale. The NESSs, severity grades, and SCORAD were analyzed for agreement and correlation. The severity grading agreed with the physician's grading in 38 of 52 parents (73%) and in 16 of 18 children (89%) who self-evaluated the severity of their AD. The weighted kappa (95% confidence interval [CI]) for parents with children less than 10 years old, parents with children > or =10 years old, and patients who self-evaluated their AD were 0.79 (0.66-0.91), 0.85 (0.69-1.00), and 0.74 (0.36-1.00), respectively. The R2 for the NESS by parents, the NESS by patients, and the SCORAD scores was 42.1%, 47.5%, and 49.8%, respectively. When compared with the parents, the older children who self-evaluated their AD showed a better correlation of the NESS with the SCORAD index. The self-administered questionnaire appears to be useful in assessing AD severity in Chinese children.

ISAAC-based asthma and atopic symptoms among Ha Noi school children

Childhood asthma and atopy prevalence patterns in the developing world are only beginning to be defined. No such information exists for Vietnam. Estimates would assist in anticipating health service needs as well as add to the growing database on global patterns of atopy. To estimate the prevalence of atopic symptoms in school children in Ha Noi, Vietnam, a cross-sectional survey was conducted of children aged 5- to 11-years-old in two schools using the parent self-administered International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. The response rate was 66.4% (969 responses). The overall prevalence of selected symptoms were: 'ever wheezed' 24.9%, 'wheezed in past 12 months' 14.9%, 'ever had asthma' 12.1%, 'doctor-diagnosed asthma' 13.9%, 'ever experienced allergic rhinitis (AR) symptoms' 34.9%, 'AR-conjunctivitis symptoms in past 12 months' 10.7%, 'ever had hay fever' 7.8%, 'doctor-diagnosed hay fever' 11.2%, 'ever had eczema' 3.3% and 'doctor-diagnosed eczema' 3.2%. Kappa statistics demonstrated high within symptom category consistency for 'ever had asthma/doctor-diagnosed asthma' (0.728) and 'ever had eczema/doctor-diagnosed eczema' (0.906). Age and gender adjusted odds ratios (OR) were also consistently significant across wheeze and allergic rhinitis symptom categories [highest OR = 10.10 (95% CI 6.23-16.35) between allergic rhinoconjunctivitis and wheeze in past 12 months]. There is a high prevalence of ISAAC-based symptoms in school children in Ha Noi, Vietnam, often above global averages. The high level of association between atopic symptoms suggests some degree of reliability and validity. Childhood atopy symptom prevalence in Vietnam is more similar to that in developed countries rather than developing countries.