Climate and prevalence of atopic eczema in 6- to 7-year-old school children in Spain. ISAAC phase III

Seasonal Variation of the Burden of Atopic Dermatitis in Finnish Primary Care: A Database Study on Effects of Weather and Air Quality

The burden of atopic dermatitis has been increasing in Finland during recent decades and seems to vary seasonally. The aim was to investigate the effect of season and weather factors on patient numbers of primary care. Data bank information of the Finnish Institute for Health and Welfare was analysed for frequency of atopic dermatitis patients in the primary care of Helsinki during 2018-2023. In addition, the seasonal burden was compared with weather data from the Finnish Meteorological Institute. Patient numbers varied significantly during the year (p = 0.028). There was a recurrent seasonal variation with most atopic dermatitis diagnoses in January, February, March, and November and the least in July and August. A significant inverse association was observed between atopic dermatitis patients and outside temperature (p = 0.004) and UV Index (p = 0.008). Low air quality was associated with a higher burden in primary care (p = 0.013). There was no significant association regarding rain (p = 0.103) or relative air humidity (p = 0.392). The burden of atopic dermatitis in primary care shows a significant seasonal variation. There are specific weather parameters that follow similar patterns and likely comprise important extrinsic pathogenetic factors. It is reasonable to address the changing burden of atopic dermatitis with seasonally directed medical measures, education, and resources.

The impact of meteorological factors on the incidence of infantile atopic dermatitis

BACKGROUND

The role of the climate regarding atopic dermatitis (AD) in infants is still unclear. This study aimed to determine the relationship between meteorological conditions and the incidence of early AD.

METHODS

The study was conducted using a retrospective design. We analyzed children aged 0-24 months with clinically diagnosed AD (n = 603), including infantile eczema (IE, n = 292), in relation to the mean monthly meteorological data in Minsk. The Mantel-Haenszel method was used to study the association between an AD outcome and meteorological variables, stratifying by potential confounders. Seasons of birth were analyzed in children diagnosed with AD before 6 months of age (n = 567) and at 12 months of age (n = 350) from 2005 to 2019.

RESULTS

The incidence rate of IE was negatively associated with air temperature (adjusted incidence rate ratio = 0.75; 95% confidence interval (CI) 0.59-0.94), precipitation (0.74; 95% CI 0.58-0.93), and positively associated with atmospheric pressure (1.31; 95% CI 1.04-1.66). The highest incidence rate of IE was during spring, and the lowest was during summer. Incidences of AD were less frequent among infants born in the spring (18.1% vs. 29.4%, P < 0.001) than among older children. The principal component analysis identified three meteorological combinations where the first one (warm, low humidity) was negatively associated with the incidence rate of AD among children aged 0-24 months (0.77; 95% CI 0.65-0.92), and the third one (rainy, low atmospheric pressure) with IE (0.70; 95% CI 0.54-0.90).

CONCLUSION

Continental seasonal cold-humid weather may influence early AD incidence. Moreover, short-term meteorological factors may play an important role in the onset of IE.

Prevalence of atopic eczema in adolescents from a very low prevalence area (Kosovo): role of wheezing, gender, exercise, and paracetamol

BACKGROUND

The epidemiology of atopic eczema in adolescents in Kosovo is virtually unknown, and the risk factors for the condition in very low-prevalence areas (as it was the case) are not well studied. The objective of the present study was to better know those factors and whether the presence of comorbid wheezing symptoms modifies the factors.

METHODS

The cross-sectional survey, Global Asthma Network-validated questionnaire, which includes questions on eczema symptoms and environmental factors (such as smoking, pet ownership, paracetamol usage, truck traffic, siblings, time spent using screens or watching television, and physical exercise), was administered to adolescents in the following main cities of Kosovo: Ferizaj, Gjakova, Gjilan, Peja, Prishtina, and Prizren. Additionally, height and weight were measured at school.

RESULTS

Prevalence of eczema symptoms ranged from 2.2% in Ferizaj to 5.5% in Gjakova. Severe symptoms were <1% in all cities. Eczema ever ranged from 3.0% in Ferizaj to 6.4% in Prizren. Factors significantly associated with the prevalence of current eczema symptoms in the meta-analysis were males (pooled adjusted odds ratio [aOR] 0.50, 95% Confidence Interval [95% CI] 0.37-0.66); physical exercise (pooled aOR 2.79, 95% CI 1.89-4.10); and paracetamol intake (pooled 1.86, 95% CI 1.32-2.64). The corresponding figures for eczema ever were as follows: pooled aOR: 0.68, 95% CI 0.44-1.06; pooled aOR 2.07, 95% CI 1.48-2.90; and pooled aOR 1.19, 95% CI 0.88-1.60. The associations tended to be higher in the subpopulation with eczema and wheezing comorbidity.

CONCLUSIONS

The prevalence of atopic eczema is very low in Kosovo and is associated with females, physical exercise, and paracetamol intake. These associations are higher when eczema and wheezing are comorbid conditions.

The Role of the Microbiota in the Pathogenesis and Treatment of Atopic Dermatitis-A Literature Review

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a high prevalence worldwide. AD pathogenesis is complex and consists of immune system dysregulation and impaired skin barrier, influenced by genetic and environmental factors. The purpose of the review is to show the complex interplay between atopic dermatitis and the microbiota. Human microbiota plays an important role in AD pathogenesis and the course of the disease. Dysbiosis is an important factor contributing to the development of atopic diseases, including atopic dermatitis. The gut microbiota can influence the composition of the skin microbiota, strengthening the skin barrier and regulating the immune response via the involvement of bacterial metabolites, particularly short-chain fatty acids, in signaling pathways of the gut-skin axis. AD can be modulated by antibiotic intake, dietary adjustments, hygiene, and living conditions. One of the promising strategies for modulating the course of AD is probiotics. This review offers a summary of how the microbiota influences the development and treatment of AD, highlighting aspects that warrant additional investigation.

Physical influences on the skin barrier and pathogenesis of allergy

PURPOSE OF REVIEW

As the incidence of allergic conditions has increased in recent decades, the effects of climate change have been implicated. There is also increased knowledge on the effects of other physical influences, such as scratching and Staphylococcus aureus . The skin barrier is the first line of defense to the external environment, so understanding the ways that these factors influence skin barrier dysfunction is important.

RECENT FINDINGS

Although the impact on environmental exposures has been well studied in asthma and other allergic disorders, there is now more literature on the effects of temperature, air pollution, and detergents on the skin barrier. Factors that cause skin barrier dysfunction include extreme temperatures, air pollution (including greenhouse gases and particulate matter), wildfire smoke, pollen, scratching, S. aureus, and detergents.

SUMMARY

Understanding the ways that external insults affect the skin barrier is important to further understand the mechanisms in order to inform the medical community on treatment and prevention measures for atopic conditions.

The impact of temperature on the skin barrier and atopic dermatitis

Climate change is a global threat to public health and causes or worsens various diseases including atopic dermatitis (AD), allergic, infectious, cardiovascular diseases, physical injuries, and mental disorders. The incidence of allergy, such as AD, has increased over the past several decades, and environmental factors such as climate change have been implicated as a potential mechanism. A substantial amount of literature has been published on the impact of climate factors, including cold and hot temperatures, on the skin barrier and AD. Studies in several countries have found a greater incidence of AD in children born in the colder seasons of fall and winter. The effect of cold and warm temperatures on itch, skin flares, increased outpatient visits, skin barrier dysfunction, development of AD, and asthma exacerbations have been reported. Understanding mechanisms by which changes in temperature influence allergies is critical to the development of measures for the prevention and treatment of allergic disorders, such as AD and asthma. Low and high temperatures induce the production of proinflammatory cytokines and lipid mediators such as interleukin-1β, thymic stromal lymphopoietin, and prostaglandin E2, and cause itch and flares by activation of TRPVs such as TRPV1, TRPV3, and TRPV4. TRPV antagonists may attenuate temperature-mediated itch, skin barrier dysfunction, and exacerbation of AD.

Associations between home environmental factors and childhood eczema and related symptoms in different cities in China

Previous studies have shown significant associations between home environmental factors and childhood eczema. However, few studies have compared how associations differ in different regions. This study investigated associations between home environmental factors and childhood eczema ever, and related symptoms including itchy rash (IR) and being awakened by itchy rash at night (awake by IR) in 4 cities located in different regions of China, based on cross-sectional investigations during 2010-2012. We used two-step analysis to explore the associations between influencing factors and eczema/related symptoms: first, group Least Absolute Shrinkage and Selection Operator (LASSO) was conducted to identify important factors among a list of candidates; then, the associations in total study population and in each city were estimated using logistic regression. We found these home environmental factors to be risk factors for eczema or related symptoms: large residence size, shared room, air cleaner at home, abnormal smell, perceived dry air, visible mold or damp stains, cooking with coal or wood, painted wall, incense, mice, new furniture during pregnancy, abnormal smell at birth, window condensation at birth and environmental tobacco smoke at birth. Environmental protective factors were rural house location and window ventilation. Associations of factors with eczema/related symptoms differed across cities. For example, air conditioning was protective for eczema in Beijing and awakening by IR in Shanghai with ORs of 0.70 (95%CI: 0.52, 0.95) and 0.33 (95%CI: 0.14, 0.81) respectively, but not significant in other cities. Our results have implications for improving home environments to reduce the risk of childhood eczema/related symptoms in different regions of China.

Do temperature changes cause eczema flares? An English cohort study

BACKGROUND

It is unclear if ambient temperature changes affect eczema. It is also unclear if people with worse disease are more susceptible to weather-related flares, or specific types of emollient offer protection.

OBJECTIVES

To investigate the effect of short-term temperature variations on eczema symptoms in children.

METHODS

Data from a UK cohort of 519 children with eczema were combined with data from the Hadley Centre's Integrated Surface Database. Hot and cold weeks were defined by average regional temperature > 75th or < 25th percentile, January 2018 to February 2020. Eczema flares were defined as ≥ 3-point change in Patient-Oriented Eczema Measure (POEM). Random-effects logistic regression models were used to estimate the odds ratios of flares in hot and cold weeks (reference group: temperate weeks).

RESULTS

The baseline mean age was 4.9 years (SD 3.2) and the POEM score was 9.2 (SD 5.5). From the 519 participants, there were 6796 consecutively paired POEMs and 1082 flares. Seasonal variation in POEM scores was observed, suggesting symptoms worsening in winter and improving in summer. Odds ratios of flares were: 1.15 [95% confidence interval (CI) 0.96-1.39, P = 0.14] in cold weeks and 0.85 (95% CI 0.72-1.00, P = 0.05) in hot weeks. The likelihood ratio test showed no evidence of this differing by disease severity (P = 0.53) or emollient type used (P = 0.55).

CONCLUSIONS

Our findings are consistent with previous studies demonstrating either improvements in eczema symptoms or reduced flares in hot weather. Worse disease and different emollient types did not increase susceptibility or provide protection against temperature changes. Further work should investigate the role of sunlight, humidity, pollution and other environmental factors.

Climate and human health: a review of publication trends in the International Journal of Biometeorology

The climate-health nexus is well documented in the field of biometeorology. Since its inception, Biometeorology has in many ways become the umbrella under which much of this collaborative research has been conducted. Whilst a range of review papers have considered the development of biometeorological research and its coverage in this journal, and a few have reviewed the literature on specific diseases, none have focused on the sub-field of climate and health as a whole. Since its first issue in 1957, the International Journal of Biometeorology has published a total of 2183 papers that broadly consider human health and its relationship with climate. In this review, we identify a total of 180 (8.3%, n = 2183) of these papers that specifically focus on the intersection between meteorological variables and specific, named diagnosable diseases, and explore the publication trends thereof. The number of publications on climate and health in the journal increases considerably since 2011. The largest number of publications on the topic was in 2017 (18) followed by 2021 (17). Of the 180 studies conducted, respiratory diseases accounted for 37.2% of the publications, cardiovascular disease 17%, and cerebrovascular disease 11.1%. The literature on climate and health in the journal is dominated by studies from the global North, with a particular focus on Asia and Europe. Only 2.2% and 8.3% of these studies explore empirical evidence from the African continent and South America respectively. These findings highlight the importance of continued research on climate and human health, especially in low- and lower-middle-income countries, the populations of which are more vulnerable to climate-sensitive illnesses.

Season of birth and atopic dermatitis in early infancy: results from the Japan Environment and Children's Study

BACKGROUND

Atopic dermatitis (AD) is reported to be more prevalent in children who were born in autumn than in spring. Here, we investigated how early the association between season of birth and eczema or AD can be observed in the postnatal period. We also examined whether specific prevalence outcomes for infant eczema and AD differed according to sex and maternal history of allergic disease in a large Japanese cohort.

METHODS

Using data of 81,615 infants from the Japan Environment and Children's Study, we examined the associations of birth month or season with four different outcomes-eczema at 1 month, 6 months, and 1 year of age and physician-diagnosed AD up to 1 year of age-using multiple logistic regression analysis. We also analyzed the effect of maternal history of allergic disease on these outcomes stratified by infant sex.

RESULTS

The risk of eczema at 1 month was highest in infants born in July. In contrast, infants born in autumn had higher risks of eczema at 6 months (adjusted odds ratio [aOR], 2.19; 95% confidence interval [CI], 2.10-2.30) and at 1 year (aOR, 1.08; 95% CI, 1.02-1.14) and of physician-diagnosed AD up to 1 year of age (aOR, 1.33; 95% CI, 1.20-1.47) compared with infants born in spring. Eczema and AD were more prevalent in infants with a maternal history of allergic disease, particularly boys.

CONCLUSIONS

Our findings suggest that the prevalence of AD is associated with the season of observation. Eczema is prevalent in infants born in autumn, and this phenomenon was observed in infants as young as 6 months old. The risk associated with being born in autumn was particularly clear in boys with a maternal history of allergic disease.

TRIAL REGISTRATION

UMIN000030786.

Short-term effects of meteorological factors on childhood atopic dermatitis in Lanzhou, China

Atopic dermatitis (AD) is one of the leading burdens of skin disease in children globally. Meteorological factors are involved in the onset and development of AD. Several studies have examined the effects of meteorological factors on AD, but their results are inconsistent, and the understanding of the link between AD and meteorological factors remains inadequate. In this study, a total of 19,702 children aged 0 to 14 visited the outpatient clinic for AD from 2015 to 2019 in Lanzhou, China. A distributed lag nonlinear model (DLNM) applies to evaluate effects of meteorological factors on childhood AD in Lanzhou, China, and further explored age and gender differences. It was found that extremely high or low temperatures, extremely high diurnal temperature range (DTR), extremely low relative humidity (RH), and extremely high wind speed (WS) increased the risk of outpatient visits for childhood AD. Effects of extremely high DTR and extremely high WS were more intense, with maximum cumulative risks of 2.248 (95% CI 1.798, 2.811) and 3.834 (95% CI 3.086, 4.759) at lag 0-21, respectively. Furthermore, the combination of low temperature and low RH can also contribute to the higher risk of childhood AD. For extreme temperatures, children aged 7-14 years were more vulnerable. For extremely low RH, extremely high DTR and WS, boys and children aged 0-3 years were more vulnerable. Public health departments should strengthen publicity and education about how meteorological factors affect childhood AD and develop sex- and age-specific preventative measures.

Have the prevalence of eczema symptoms increased in the Mexican pediatric population? Prevalence and associated factors according to Global Asthma Network Phase I

Background

In children, atopic dermatitis or eczema is the most common inflammatory disease of the skin. According to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase IIIB in Mexico, 5.8% of children and 4.9% of adolescents had eczema symptoms. In 2012, Global Asthma Network (GAN) was established to update the prevalence of eczema and estimate potential factors contributing to its development.

Objective

To estimate the prevalence and associated factors for atopic eczema symptoms and diagnosis in children and adolescents according to GAN Phase I and compare the results with ISAAC Phase IIIB in Mexico.

Methods

A cross-sectional, multicenter survey was conducted in 15 Mexican centers during the period of 2015-2017 using the GAN Phase I questionnaires in children (6-7-year-olds) and adolescents (13-14-year-olds). The prevalences obtained from the GAN Phase I study, were compared with ISAAC Phase IIIB results; a Spearman's correlation analysis was conducted between temperature, relative humidity, and altitude and eczema symptoms, and a logistic regression was performed to predict current eczema symptoms by age group.

Results

A total of 35 777 children and 41 399 adolescents were included. Since ISAAC Phase IIIB, the prevalence of itchy rash in the past 12 months significantly increased in the children's group [6.6% (95% CI 5.7-7.4) vs 7.8 (95% CI 7.5-8.1), p = 0.000] and adolescents' group [5.8% (95% CI 5.0-6.7) vs 6.7% (95% CI 6.5-7.0), p = 0.000].In the adolescents' group, the prevalence of nocturnal awakenings caused by rash symptoms on more than one night per week had a negative correlation between altitude (Spearman's Rho = -0.558, p value = 0.031), and a positive correlation with the average annual temperature (Spearman's Rho = 0.604, p value = 0.017) and annual relative humidity (Spearman's Rho = 0.742, p value = 0.002). The most significant associations in children were the presence of sneezing or runny or blocked nose in the past 12 months [(OR 3.13, 95% CI 2.60-3.77), p = 0.000], the use of paracetamol in the first year of life ([OR 1.52, 95% CI 1.15-2.01), p = 0.003] and the use of antibiotics in the first year of life [(OR 1.30, 95% CI 1.08-1.55) p = 0.004]. Moreover, altitude at 100-1000 m above sea level was associated with current eczema symptoms in adolescents (p = 0.001).

Conclusions

There has been a significant increase in eczema symptoms in both age groups since ISAAC Phase IIIB study. Additionally, eczema symptoms were associated with temperature, relative humidity, asthma, hay fever symptoms, the use of paracetamol and antibiotics.

Eczema, facial erythema, and seborrheic dermatitis symptoms among young adults in China in relation to ambient air pollution, climate, and home environment

A questionnaire survey on dermal symptoms and home environment was performed in eight Chinese cities (40 279 participants). Data on city level temperature, precipitation, PM₁₀ , NO_2, and gross domestic product (GDP) per capita were collected. In total, 2.2% had eczema, 2.4% facial erythema (FE) and 2.6% seborrheic dermatitis symptoms (SD). Higher temperature was associated with eczema (OR = 1.09). Higher GDP per capita was related to less SD. Higher PM₁₀ was related to SD. Suburban living was protective for eczema (OR = 0.77) (vs. urban). Living in old buildings (built before 1991) was related to eczema (OR = 1.42). Living near heavily trafficked roads was related to FE (OR = 1.33) and SD (OR = 1.35). Having new furniture was related to all symptoms (OR = 1.26-1.47). Burning mosquito coils (OR = 1.37-1.57) and incense (OR = 1.33-1.37) were associated with eczema, FE, or SD. Presence of cockroaches and rats/mice was associated with FE or SD (OR = 1.31-1.40). Using air conditioner, daily cleaning and frequently exposing bedding to sunshine were protective (OR = 0.60-0.83). In conclusion, higher temperature, higher PM₁₀ , urban living, living near heavily trafficked roads, old buildings, new furniture, burning mosquito coils and incense, and presence of cockroaches/rats/mice increased the risk of eczema, FE, or SD. Higher GDP, air conditioner, daily cleaning, and exposing bedding to sunshine were protective.

Association between ambient temperature and atopic dermatitis in Lanzhou, China: a time series analysis

Many studies have explored the association between temperature and atopic dermatitis (AD); however, the results are inconsistent. We used a quasi-Poisson function fitted to a distributed lag nonlinear model (DLNM) to evaluate the association between daily average temperature and AD outpatient visits from January 1, 2013, to December 31, 2019, in Lanzhou, China. We found that the exposure-response association curve was inversely "s-shaped," low-temperature effects occurred at a lag of 11 days and then lasted for 10 days, and high-temperature effects occurred on the current day and then significantly decreased. Both low and high ambient temperatures can increase the risk of outpatient visits. Compared with median temperature (12.89°C), the cumulative relative risk (RR) of extreme high temperature and moderate-high temperature were 1.847 (95% confidence interval [CI]: 1.613, 2.114) and 1.447 (95% CI: 1.298, 1.614), respectively, at lag0-7 days, and the cumulative RRs of extremely low temperature and moderate-low temperature were 1.004 (95% CI: 0.904, 1.115) and 1.056 (95% CI: 0.925, 1.205), respectively, at lag0-21 days. Females were more sensitive to high temperatures than males, and high or low temperatures had significant effects on children ≤14 years of age. Graphical abstract.

Environmental Exposure and Childhood Atopic Dermatitis in Shanghai: A Season-Stratified Time-Series Analysis

BACKGROUND

Childhood atopic dermatitis (AD) is an inflammatory skin disease which sometimes predisposes to allergies. Environmental factors (low humidity, irritants, etc.) are prominent causative triggers of AD.

OBJECTIVES

This study aims to explore the effects of both meteorological factors and air pollutants on childhood AD, and the modification effects by season in Shanghai, China.

METHODS

Quasi-Poisson generalized linear regression model, combined with a distributed lag nonlinear model was used to examine the nonlinear and lagged effects of environmental factors on childhood AD from 2009 to 2017 in Shanghai. We also performed a season-stratified analysis to determine the modification effects of environmental exposure by season on childhood AD.

RESULTS

There were 1,043,240 outpatient visits for childhood AD in total, at 3 major pediatric hospitals. Low temperature and relative humidity (RH), and high daily temperature difference (DTD) and air pollutants (i.e., NO2) increased the relative risks (RRs) of outpatient visits for childhood AD in the whole year. In the cold season, an increased risk of outpatient visits for childhood AD was associated with low RH (RR 2.26, 95% CI 1.69-3.02) and high NO2 (1.11, 95% CI 1.06-1.17). In the warm season, outpatient visits for childhood AD were associated with low temperature (3.49, 95% CI 3.22-3.77), low RH (1.89, 95% CI 1.74-2.06), high DTD (1.41, 95% CI 1.31-1.53), and high NO2 (1.05, 95% CI 1.03-1.06).

CONCLUSIONS

This study suggests that environmental exposure may be a key trigger for outpatient visits for childhood AD with apparent seasonal effects. Tailored preventive strategies to avoid environmental triggers of childhood AD should be developed.

The Influence of Sunlight Exposure and Sun Protecting Behaviours on Allergic Outcomes in Early Childhood

The dramatic rise in allergic disease has occurred in tandem with recent environmental changes and increasing indoor lifestyle culture. While multifactorial, one consistent allergy risk factor has been reduced sunlight exposure. However, vitamin D supplementation studies have been disappointing in preventing allergy, raising possible independent effects of ultraviolet (UV) light exposure. The aim of this study was to examine whether UV light exposure influences the development of allergic disease in early childhood. Direct sunlight exposure (290-380 nm) in early infancy was measured via UV dosimeters. Outdoor exposure, sun protective behaviours, and allergy outcomes were assessed over the first 2.5 years of life with clinical assessment appointments at 3, 6, 12 and 30 months of age. Children with eczema had less (p = 0.038) direct UV light exposure between 0-3 months of age (median (IQR) 747 (473-1439) J/m²) than children without eczema (median (IQR) 1204 (1717-1843) J/m²); and less outdoor exposure time (7 min/day) between 11 a.m. and 3 p.m. compared to children without eczema (20 min/day, p = 0.011). These associations were seen independent of vitamin D status, and after adjusting for other potential confounders. Whilst we could not find any associations between direct UV light exposure and other allergic disease outcomes, exposure to UV light appears to be beneficial in reducing the risk of eczema development in early childhood. Further research is required to determine optimal levels of UV light exposure while balancing the potential risks.

Genetic predisposition and environmental factors associated with the development of atopic dermatitis in infancy: a prospective birth cohort study

The influence of environmental factors on atopic dermatitis (AD) has been investigated in many cross-sectional studies. It remains however unclear if they could influence AD development early in life. This prospective birth cohort study aimed to monitor aspects of family lifestyle and child's nutrition within a Caucasian population and to assess its association with AD development over the first 2 years of life. Genetic predisposition was evaluated based on family history and profilaggrin genotyping. Of 149 included children, 36 developed AD. Infants with a family history of atopy developed AD 2.6 times more frequently (30 of 97) than infants without atopic predisposition (6 of 52). Genotyping was carried out on 50% of the children included. Profilaggrin mutations (R501X, 2282del4, R2447X, and S3247X) were infrequent in our population. Lower incidence of AD was observed in infants exposed to a damp housing environment, lower household income, and smoking mothers with a higher but not with a lower education level.Conclusion: Family history of atopy was a significant risk factor for AD regardless of the most common, currently defined, FLG mutations. Humidity at home and passive smoking seem associated with AD development in infancy. What is Known: • Atopic dermatitis (AD) is associated with mutations in various genes of the immune system and the epidermal barrier complex in particular filaggrin (FLG) mutation. • Inherited factors alone cannot explain the rising AD; environmental factors are therefore likely to play a decisive role in this rise but the exact role that these factors may play in increasing AD risk in infancy remains unclear. Moreover, the relationship between environmental factors and AD has been the focus of mostly cross-sectional studies and not prospective studies. What is New: • This prospective birth cohort study demonstrates that family history of atopy is a significant risk factor for AD regardless of the most common, currently defined, FLG mutations. • A lower incidence of AD was observed in infants exposed to a moist housing environment, lower household income, and smoking of mothers with a higher but not with a lower education level.

Effects of climate and air pollution factors on outpatient visits for eczema: a time series analysis

Eczema resulting from external and internal factors accounts for the biggest global burden of disability owing to skin disease. This study aimed to determine an association between environmental factors and outpatient clinic visits for eczema. We collected data on dermatology clinic outpatient visits for eczema between January 2013 and July 2019. Data concerning environmental factors during this period were collated using national air quality network and air monitoring measurement parameters, namely barometric pressure, relative humidity, air temperature, and air pollutant concentrations, such as sulfur dioxide (SO₂) and particulate matter (PM₁₀). A distributed lag nonlinear model was used to investigate the relationship among eczema, environmental factors, and lagged effects. In total, 27,549 outpatient visits for eczema were recorded. In both single-factor and multiple-factor lag models, the effects of a 10-µg/m³ increase in PM₁₀ and SO₂ values had significantly positive effects on the number of daily outpatient visits over a total 5 days of lag after adjusting for temperature, the number of daily outpatient visits increased with 0.87%, 7.65% and 0.69%, 5.34%, respectively. Relative humidity (RR = 1.3870, 95% CI 1.3117-1.4665) and pressure (RR = 1.0394, 95% CI 1.0071-1.0727) had significantly positive effects on the number of daily outpatients in single-factor lag models. However temperature had a significantly negative effect on them in the number of daily outpatients (RR = 0.9686, 95% CI 0.9556-0.9819). Exposure to air pollution exacerbated eczema. Outpatient visits for eczema were found to have strong positive associations with changes in PM₁₀ levels.

Prevalence and Comorbidity of Atopic Dermatitis in Children: A Large-Scale Population Study Based on Real-World Data

This study aimed at exploring atopic dermatitis (AD) prevalence in children and exhaustively analyzing their comorbidity. We conducted a descriptive analysis of their socio-demographic and comorbidity characteristics in the EpiChron Cohort (Aragón, Spain). Adjusted odds ratios (OR) were calculated for each comorbidity using logistic regression models. In total, 33,591 children had a diagnosis of AD, resulting in an overall prevalence of 15.5%. AD prevalence was higher in girls compared to boys, in 3–9-year-olds compared to children of other ages, and in Spanish children compared to those of other nationalities. Multimorbidity was present in 43% of children, with the most frequent chronic comorbidities being asthma (13.1%), psychosocial disorders (7.9%), and visual impairment (7.8%). Many diseases were, regardless of their prevalence, statistically associated with AD. The strongest associations (odds ratio (OR) (95% confidence interval (CI))) were found in asthma (2.10 (2.02–2.17)), allergic rhinitis (2.00 (1.91–2.10)), and irritable bowel syndrome (1.90 (1.56–2.31)). A better understanding of the array of comorbidities associated with AD in children might help improve their clinical management. Future longitudinal studies are encouraged to shed light on the potential underlying pathophysiological mechanisms involved in the identified associations.

The Role of the Environmental Risk Factors in the Pathogenesis and Clinical Outcome of Atopic Dermatitis

Atopic dermatitis (AD) prevalence is rising worldwide. Literature data suggest the incidence of AD in developing countries is gradually getting close to that of developed ones, in which AD affects 20% of the paediatric population. Such an increment, associated with significant variations in prevalence among the various countries, underlines the importance of environmental factors in the disease onset. Among these, great importance is given to hygiene, intestinal microbiota, exposure to bacterial endotoxins, outdoor living with contact to animals, atmospheric pollution, weather, and diet. Genetic (alteration of the skin barrier function) as well as immunologic factors concur with the environmental ones. Only the systematical study of all these elements can best elucidate AD epidemiology.

Optimization of placebo use in clinical trials with systemic treatments for atopic dermatitis: an International Eczema Council survey-based position statement

BACKGROUND

As novel systemic therapeutics for patients with atopic dermatitis (AD) are developed, ethical and methodological concerns regarding placebo-controlled-trials (PCT) have surfaced.

OBJECTIVE

To guide the design and implementation of PCT in AD, focusing on trials with systemic medications.

METHODS

A subgroup of the International Eczema Council (IEC) developed a consensus e-survey, which was disseminated to IEC members.

RESULTS

The response rate was 43/82 (52%). Consensus was reached on 24/27 statements and on 3/11 options from multiple-selection statements, including: performing monotherapy studies in proof-of-concept phases; avoiding concomitant topical corticosteroids or calcineurin inhibitors until a predefined timepoint as rescue (borderline consensus); selection of sites and assessors with recognized expertise in AD clinical trials; clear definition and identification of baseline disease severity; minimizing time and proportion of patients on placebo; using daily emollients with several options provided; instigating open-label extension studies for enrolment after a predefined timepoint; and including outcomes which set a higher bar for disease clearance.

CONCLUSION

Conducting PCT in AD requires balancing several, sometimes opposing principles, including ethics, methodology, regulatory requirements and real-world needs. This paper can provide a framework for conducting PCT with systemic medications for patients with AD.

Impact of Weather Conditions on Atopic Dermatitis Prevalence in Abuja, Nigeria

BACKGROUND

Climatic conditions may trigger subclinical disease in predisposed individuals and also exacerbate eczematous symptoms resulting in persistence or increased frequency of atopic dermatitis (AD) flares. The aim of this study is to assess the impact of tropical weather conditions on the frequency at which atopic dermatitis patients present at the dermatology clinic of a tertiary hospital in Abuja, Nigeria; and, to find out which component of these conditions exerts the most significant effects.

METHODS

Medical records of all new patients seen at the clinic within July 2015 and June 2017 was obtained. Data for monthly temperature, humidity, precipitation, cloud cover and UV index of Abuja during this period was obtained from worldweatheronline. Univariate analyses and multiple regressions were used to assess the associations between monthly prevalence of AD and the above-mentioned meteorological variables.

RESULTS

Patients had a 1.6 times odds (95% CI: 1.03-2.56, p = 0.038) of presenting with AD in the dry season as compared to wet season. Dry season was associated with higher temperatures and UV index and lower precipitation, humidity and cloud cover, p<0.001. Multivariate logistic regression modelling adjusting for precipitation, humidity, cloud cover and age group demonstrated that precipitation (OR = 1.01, 95% CI: 1.00-1.02, p = 0.002), humidity (OR = 1.03, 95% CI:1.01-1.05, p = 0.015) and cloud cover (OR = 0.92, 95% CI: 0.88-1.02, p = 0.002) exert the most significant effects. Also infants had 4.4 times odds of AD than adults (95% CI: 2.04-9.69, p<0.001).

CONCLUSION

Exposure to tropical season meteorological variables can influence the presentation of AD.

Climate change and atopic dermatitis: is there a link?

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease with a growing health concern, because of its high prevalence and associated low quality of life. The etiology of AD is multifactorial with interaction between various factors such as genetic predisposition, immune, and importantly, environmental factors. Since climate change is associated with a profound shift in environmental factors, we suggest that AD is being influenced by climate change. This review highlights the effects of ultraviolet light, temperature, humidity, pollens, air pollutants, and their interaction between them contributing to the epidemiology and pathophysiology of AD.

The effects of particulate matter on atopic dermatitis symptoms are influenced by weather type: Application of spatial synoptic classification (SSC)

The effects of weather and air pollution on atopic dermatitis (AD) flares have not been well investigated. To investigate the effects of particulate matter (PM) on AD symptoms by weather type, a total of 125 young children (76 boys and 49 girls) under 6 years of age with AD living in Seoul, Korea, were enrolled as a panel and followed for 17 months between August 2013 and December 2014. AD symptoms were recorded on a daily basis, including itching, sleep disturbance, erythema, dry skin, oozing, and edema. Daily weather was classified into 7 categories according to spatial synoptic classification (SSC). Personal exposure to PM with an aerodynamic diameter less than 2.5 and 10 μm (PM_2.5 and PM₁₀, respectively) in each individual was estimated with time-weighted average concentrations considering outdoor and indoor levels of PMs and time to spend outdoors or indoors in a day. Generalized linear mixed models were used to analyze the effects of PM_2.5 and PM₁₀ on AD symptoms, controlling for ambient temperature, humidity, age, sex, SCORAD (SCORing of AD) at enrollment, fever, day of week, and topical corticosteroid use. A total of 20,168 person-days of symptom records were collected. The presence of AD symptoms was higher on dry polar (DP) days (45.4%, P < .0001) than on moist tropical (MT) days (37.7%, P < .0001). Overall, the risk of AD symptoms significantly increased with increased exposure to PM_2.5 and PM₁₀. Among the 7 weather types, the risks of AD symptoms caused by PM_2.5 and PM₁₀ exposure were significantly increased on dry moderate (DM) days, while not significant on the other weather types. In addition, lagged effect of PM_2.5 up to 4 days was found on DM days. In conclusion, dry moderate weather type, particulate matters, and their modifying effects should be simultaneously considered for proper management of AD.

Short-term effects of weather and air pollution on atopic dermatitis symptoms in children: A panel study in Korea

INTRODUCTION

The effects of weather and air pollution on the severity and persistence of atopic dermatitis (AD) are important issues that have not been investigated in detail. The objective of our study was to determine the short-term effects of meteorological variables and air pollution on AD symptoms in children.

METHODS

We enrolled 177 AD patients with 5 years or younger from the Seoul Metropolitan Area, Korea, and followed for 17 months between August 2013 and December 2014. Symptoms records of 35,158 person-days, including itching, sleep disturbance, erythema, dry skin, oozing, and edema, were obtained. We estimated the effect of meteorological variables including daily mean temperature, relative humidity (RH), diurnal temperature range (DTR), rainfall and air pollutants including particulate matter with an aerodynamic diameter ≤10 μm (PM10), nitrogen dioxide (NO2), and tropospheric ozone (O3) on AD symptoms using a generalized linear mixed model with adjustment for related confounding factors.

RESULTS

A 5°C increase in outdoor temperature and a 5% increase in outdoor RH was associated with 12.8% (95% confidence intervals (CI): 10.5, 15.2) and 3.3% (95% CI: 1.7, 4.7) decrease in AD symptoms, respectively, on the same day. An increase of rainfall by 5 mm increased AD symptoms by 7.3% (95% CI: 3.6, 11.1) for the days with <40 mm rainfall. The risk of AD symptoms increased by 284.9% (95% CI: 67.6, 784.2) according to a 5°C increase in DTR when it was >14°C. An increase in PM10, NO2, and O3 by 10 units increased the risk of AD symptoms on the same day by 3.2% (95% CI: 1.5, 4.9), 5.0% (95% CI: 1.4, 8.8), and 6.1% (95% CI: 3.2, 9.0), respectively.

CONCLUSION

Exposure to meteorological variables and air pollutants are associated with AD symptoms in young children.

Ambient Air Pollution, Meteorological Factors and Outpatient Visits for Eczema in Shanghai, China: A Time-Series Analysis

Environmental irritants are important risk factors for skin diseases, but little is known about the influence of environmental factors on eczema incidence. In this time-series study, our objective was to examine the associations of environmental factors with outpatient visits for eczema. Daily outpatient visits between 2007 and 2011 (1826 days) were collected from Huashan Hospital in Shanghai, China. We used an overdispersed generalized additive model to investigate the short-term association between environmental factors and outpatient visits for eczema. Daily outpatient visits for eczema were significantly associated with air pollution and meteorological factors. For example, a 10 μg/m³ increase of 7-day (lag 06) average concentrations of PM₁₀ (particulate matter no greater than 10 microns), SO₂, NO₂ was associated with 0.81% (95% confidence intervals (CI) 0.39%, 1.22%), 2.22% (95% CI: 1.27%, 3.16%) and 2.31% (95% CI: 1.17%, 3.45%) increase in outpatient visits for eczema, respectively. A 10 °C elevation of temperature on lag 0 day were associated with 8.44% (95% CI: 4.66%, 12.22%) increase in eczema visits, whereas 10 unit decrease of 7-day average relative humidity were associated with 10.86% (95% CI: 8.83%, 12.89%) increase in eczema visits. This study provided clear evidence of ambient air pollution, high temperature and low relative humidity on increasing the incidence of eczema in Shanghai, China.

Environmental risk factors and their role in the management of atopic dermatitis

INTRODUCTION

The etiology of atopic dermatitis (AD) is multifactorial with interaction between genetics, immune and environmental factors. Areas covered: We review the role of prenatal exposures, irritants and pruritogens, pathogens, climate factors, including temperature, humidity, ultraviolet radiation, outdoor and indoor air pollutants, tobacco smoke exposure, water hardness, urban vs. rural living, diet, breastfeeding, probiotics and prebiotics on AD. Expert commentary: The increased global prevalence of AD cannot be attributed to genetics alone, suggesting that evolving environmental exposures may trigger and/or flare disease in predisposed individuals. There is a complex interplay between different environmental factors, including individual use of personal care products and exposure to climate, pollution, food and other exogenous factors. Understanding these complex risk factors is crucial to developing targeted interventions to prevent the disease in millions. Moreover, patients require counseling on optimal regimens for minimization of exposure to irritants and pruritogens and other harmful exposures.

Ambient humidity and the skin: the impact of air humidity in healthy and diseased states

Humidity, along with other climatic factors such as temperature and ultraviolet radiation, can have an important impact on the skin. Limited data suggest that external humidity influences the water content of the stratum corneum. An online literature search was conducted through Pub-Med using combinations of the following keywords: skin, skin disease, humidity, dermatoses, dermatitis, eczema, and mist. Publications included in this review were limited to (i) studies in humans or animals, (ii) publications showing relevance to the field of dermatology, (iii) studies published in English and (iv) publications discussing humidity as an independent influence on skin function. Studies examining environmental factors as composite influences on skin health are only included where the impact of humidity on the skin is also explored in isolation of other environmental factors. A formal systematic review was not feasible for this topic due to the heterogeneity of the available research. Epidemiological studies indicated an increase in eczema with low internal (indoors) humidity and an increase in eczema with external high humidity. Other studies suggest that symptoms of dry skin appear with low humidity internal air-conditioned environments. Murine studies determined that low humidity caused a number of changes in the skin, including the impairment of the desquamation process. Studies in humans demonstrated a reduction in transepidermal water loss (TEWL) (a measure of the integrity of the skin's barrier function) with low humidity, alterations in the water content in the stratum corneum, decreased skin elasticity and increased roughness. Intervention with a humidifying mist increased the water content of the stratum corneum. Conversely, there is some evidence that low humidity conditions can actually improve the barrier function of the skin. Ambient relative humidity has an impact on a range of parameters involved in skin health but the literature is inconclusive. Further studies are needed to better delineate the interactions that can occur in normal and diseased states. Therapeutic measures might be forthcoming especially for skin diseases such as eczema, which are regarded as being characterized by 'skin dryness'. Further research examining the interaction between different environmental exposures thought to impact the skin, and indeed the interplay between genetic, environmental and immunological influences, are required.

Epidemiology of Frequently Occurring Skin Diseases in Italian Children from 2006 to 2012: A Retrospective, Population-Based Study

BACKGROUND

Recent estimates indicate an increase in the prevalence of skin diseases in children. Few large epidemiologic studies have examined prevalence trends in Europe. This study evaluated the incidence and prevalence of frequently occurring pediatric skin diseases (PSDs) in Italy as seen by family pediatricians (FPs).

METHODS

Data were retrospectively extracted from the Pedianet database (2006-2012) in children ages 0 to 14 years presenting with a skin disease at their FP. The incidence and prevalence estimates were calculated per year and stratified according to sex, age, and geographic area.

RESULTS

A mean of 145,233 children (52.1% male) across five Italian regions were registered with their participating FP for a total of 913,253 person-years of follow-up. The majority of patients were from the northeast (44.6%) and 37.7% were ages 5-9 years. Incidence estimates (new cases/1,000 person-years) for most PSDs increased from 2006 to 2012, the highest being for atopic dermatitis (AD) (14.1 vs 16.5), acute urticaria (10.1 vs 11.6), and contact dermatitis (9.3 vs 10.8), whereas psoriasis remained unchanged over the 7 years (0.61 vs 0.57). In contrast, prevalence estimates (cases/100 patients) increased two to three times for several PSDs, including AD (2.7% vs 8.5%), seborrheic dermatitis (0.5% vs 1.6%), chronic urticaria (0.4% vs 0.8%), and psoriasis (0.09% vs 0.22%). Differences in prevalence according to age range and geographic area were observed for psoriasis, AD, and urticaria.

CONCLUSION

This study provides comprehensive evidence of the increasing prevalence and incidence of PSDs across Italy. Additional causality studies to address this important clinical and psychosocial problem are recommended.

Environmental tobacco smoke and the risk of eczema symptoms among school children in South Africa: a cross-sectional study

OBJECTIVE

The aim of this study was to investigate the association between eczema ever (EE) and current eczema symptoms (ES) in relation to exposure to environmental tobacco smoke (ETS).

DESIGN

A cross-sectional study using the International Study of Asthma and Allergies in Childhood questionnaire.

SETTING

16 schools were randomly selected from two neighbourhoods situated in Ekurhuleni Metropolitan Municipality, Gauteng Province, South Africa.

PARTICIPANTS

From a total population of 3764 school children aged 12-14 years, 3468 completed the questionnaire (92% response rate). A total of 3424 questionnaires were included in the final data analysis.

PRIMARY OUTCOME

The prevalence of EE and current ES was the primary outcome in this study.

RESULTS

Data were analysed using Multilevel Logistic Regression Analysis (MLRA). The likelihood of EE was increased by exposure to ETS at home (OR 1.30 95% CI 1.01 to 1.67) and at school (OR 1.26 95% CI 1.00 to 1.60). The likelihood of EE was lower for males (OR 0.66 95% CI 0.51 to 0.84). The likelihood of ES was increased by ETS at home (OR 1.93 95% CI 1.43 to 2.59) and school (1.44 95% CI 1.09 to 1.90). The likelihood of ES was again lower for males (OR 0.56 95% CI 0.42 to 0.76). Smoking by mother/female guardian increased the likelihood of EE and ES, however, this was not significant in the multivariate analysis.

CONCLUSIONS

Symptoms of eczema were positively associated with exposure to ETS at home and school. The results support the hypothesis that ETS is an important factor in understanding the occurrence of eczema.

Relationship between Acute Phase of Chronic Periodontitis and Meteorological Factors in the Maintenance Phase of Periodontal Treatment: A Pilot Study

The acute phase of chronic periodontitis may occur even in patients during supportive periodontal therapy. However, the details are not fully understood. Since the natural environment, including meteorology affects human health, we hypothesized that weather conditions may affect occurrence of acute phase of chronic periodontitis. The aim of this study was to investigate the relationship between weather conditions and acute phase of chronic periodontitis in patients under supportive periodontal therapy. Patients who were diagnosed with acute phase of chronic periodontitis under supportive periodontal therapy during 2011–2013 were selected for this study. We performed oral examinations and collected questionnaires and meteorological data. Of 369 patients who experienced acute phase of chronic periodontitis, 153 had acute phase of chronic periodontitis without direct-triggered episodes. When using the autoregressive integrated moving average model of time-series analysis, the independent covariant of maximum hourly range of barometric pressure, maximum hourly range of temperature, and maximum daily wind speed were significantly associated with occurrence of acute phase of chronic periodontitis (p < 0.05), and 3.1% of the variations in these occurrence over the study period were explained by these factors. Meteorological variables may predict occurrence of acute phase of chronic periodontitis.

Time-dependent variation in the responses to the web-based ISAAC questionnaire

BACKGROUND

Epidemiologic studies have shown seasonal variations in responses to the written questionnaire for rhinitis symptoms.

OBJECTIVE

To evaluate whether the timing of data collection affected responses to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire in a Web-based study.

METHODS

The Web-based ISAAC questionnaires were completed by parents with children 6 to 12 years old using an online research system. The authors conducted surveys of asthma symptoms every month for 1 year and surveys of rhinitis and eczema symptoms every season throughout 1 entire year.

RESULTS

There was a significant fluctuation in the positive responses to questions about wheezing in the past 12 months (P < .001) but not in the positive responses to questions about exercise-induced wheezing in the past 12 months and asthma ever (P = .75 and P = .15, respectively). The positive responses to questions about rhinitis and allergic rhinoconjunctivitis in the past 12 months and pollinosis ever exhibited significant seasonal variations (P = .002, P < .001, and P < .001, respectively). In contrast, there were no significant variations in positive responses regarding eczema in the past 12 months and eczema ever (P = .33 and P = .55, respectively).

CONCLUSION

There were time-dependent fluctuations in responses to the Web-based questionnaire regarding allergic symptoms. Timing of data collection should be taken into account when evaluating prevalence of asthma and rhinitis in children.

Asthma, respiratory symptoms and lung function in children living near a petrochemical site

Residential proximity to environmental hazards has been related to adverse health outcomes. Respiratory health and allergies in children living near petrochemical sites have not been extensively studied. We evaluated the association between residential proximity to the petrochemical site of Tarragona (Catalonia, Spain) and the prevalence of asthma, respiratory symptoms and lung function in children. Children aged 6-7 (n=2672) and adolescents aged 13-14 (n=2524) residing near two large petrochemical sites and those living in a city with medium vehicular traffic were cross-sectionally compared with children from an area with low vehicular traffic and without industry. The prevalence of symptoms was measured using the International Study of Asthma and Allergies in Childhood written and video questionnaires. Lung function measurements were done in a subsample of 959 adolescents in the four areas. Multivariable analyses were done to estimate the effects of the residential area on symptoms and lung function adjusted for potential confounders. Crude prevalence of symptoms was similar across the studied areas. After adjustment, children and adolescents living near a petrochemical site had a statistically significant higher prevalence of respiratory hospitalizations in the previous year (Prevalence Ratio (PR)=1.49; 95%CI, 1.06-2.09) and of nocturnal cough (PR=1.29; 95%CI 1.05-1.57), respectively. Reduced lung function values among adolescents residing near the petrochemical areas were not observed. Although a higher prevalence of asthma in children and adolescents living near the petrochemical sites could not be demonstrated, as described in other studies, respiratory hospitalizations and nocturnal cough could be related to short-term exposures to pollutants. Other clinical and sub-clinical respiratory health effects in the petrochemical industry areas should be investigated.

Skin symptoms in the construction industry: occurrence and determinants

BACKGROUND

In the construction industry, a relatively high hand eczema prevalence can be expected due to exposure to irritating and allergenic agents.

METHODS

As part of a regular program of voluntary medical examinations, a questionnaire including items on health symptoms and working circumstances is administered to construction industry personnel. We studied 152,200 male workers (response rate 52%). Associations between possible risk factors and self-reported skin symptoms and skin hypersensitivity were assessed using log-binomial regression analysis.

RESULTS

Prevalence of skin symptoms on the hands was 25.4% among construction workers, 14.6% among office personnel. Nuisance due to dust exposure was the most important work-related determinant for skin symptoms [Prevalence Ratio (PR) 1.59, 95% confidence interval (CI): 1.55-1.63]. Cross-sectional findings were supported by longitudinal analyses in a study population subset.

CONCLUSIONS

Skin symptoms are common among construction workers. Nuisance due to dust exposure was associated with higher prevalences of skin symptoms.

Effects of climate changes on skin diseases

Global climate is changing at an extraordinary rate. Climate change (CC) can be caused by several factors including variations in solar radiation, oceanic processes, and also human activities. The degree of this change and its impact on ecological, social, and economical systems have become important matters of debate worldwide, representing CC as one of the greatest challenges of the modern age. Moreover, studies based on observations and predictive models show how CC could affect human health. On the other hand, only a few studies focus on how this change may affect human skin. However, the skin is the most exposed organ to environment; therefore, it is not surprising that cutaneous diseases are inclined to have a high sensitivity to climate. The current review focuses on the effects of CC on skin diseases showing the numerous factors that are contributing to modify the incidence, clinical pattern and natural course of some dermatoses.

New insights into the epidemiology of childhood atopic dermatitis

There is a growing desire to explain the worldwide rise in the prevalence of atopic dermatitis (AD). Trend data on the burden of AD suggest that the picture in the developing world may soon resemble that of wealthier nations, where AD affects over 20% of children. This, combined with significant variations in prevalence within countries, emphasizes the importance of environmental factors. Many hypotheses have been explored, from the modulation of immune priming by hygiene, gut microbiota diversity, and exposure to endotoxins through farm animals to the effects of pollution, climate, and diet. The discovery of the filaggrin skin barrier gene and its importance in AD development and severity has brought the focus on gene-environment interactions and the identification of environmental factors that impact on skin barrier function. This article reviews our current understanding of the epidemiology of AD, with an emphasis on the findings reported in the international literature over the last 5 years.

Impact of ambient humidity on child health: a systematic review

BACKGROUND AND OBJECTIVES

Changes in relative humidity, along with other meteorological factors, accompany ongoing climate change and play a significant role in weather-related health outcomes, particularly among children. The purpose of this review is to improve our understanding of the relationship between ambient humidity and child health, and to propose directions for future research.

METHODS

A comprehensive search of electronic databases (PubMed, Medline, Web of Science, ScienceDirect, OvidSP and EBSCO host) and review of reference lists, to supplement relevant studies, were conducted in March 2013. All identified records were selected based on explicit inclusion criteria. We extracted data from the included studies using a pre-designed data extraction form, and then performed a quality assessment. Various heterogeneities precluded a formal quantitative meta-analysis, therefore, evidence was compiled using descriptive summaries.

RESULTS

Out of a total of 3797 identified records, 37 papers were selected for inclusion in this review. Among the 37 studies, 35% were focused on allergic diseases and 32% on respiratory system diseases. Quality assessment revealed 78% of the studies had reporting quality scores above 70%, and all findings demonstrated that ambient humidity generally plays an important role in the incidence and prevalence of climate-sensitive diseases among children.

CONCLUSIONS

With climate change, there is a significant impact of ambient humidity on child health, especially for climate-sensitive infectious diseases, diarrhoeal diseases, respiratory system diseases, and pediatric allergic diseases. However, some inconsistencies in the direction and magnitude of the effects are observed.

Warm, humid, and high sun exposure climates are associated with poorly controlled eczema: PEER (Pediatric Eczema Elective Registry) cohort, 2004-2012

Anecdotal reports of children experiencing eczema flares during winter and summer months along with global variation in eczema prevalence has fueled speculation that climate may modulate disease activity. The aim of this study was to determine if long-term weather patterns affect the severity and persistence of eczema symptoms in children. We performed a prospective cohort study of U.S. children (N=5,595) enrolled in PEER (Pediatric Eczema Elective Registry) between 2004 and 2012 to evaluate the effect of climate (daily temperature, daily sun exposure, daily humidity) on the severity of eczema symptoms. Odds ratios were calculated for the patient evaluated outcome of disease control. Multivariate logistic regression modeling adjusting for gender, race, income, and topical medication use demonstrated that higher temperature (OR=0·90, 95% CI: 0·87–0·93, p<0·001) and increased sun exposure (OR=0·93, 95% CI: 0·89–0·98, p=0·009) were associated with poorly controlled eczema. Higher humidity (OR=0·90, 95% CI: 0·812–0.997, p=0·04) was also associated with poorly controlled disease, but the statistical significance of this association was lost in our multivariate analysis (p=0.44).

Climatic factors are associated with childhood eczema prevalence in the United States

Atopic dermatitis (AD, atopic eczema) is driven by a complex relationship between genetic predisposition and environmental exposures. We sought to determine the impact of specific climatic factors on the US prevalence of AD. We used a merged analysis of the 2007 National Survey of Children's Health from a representative sample of 91,642 children age 0–17 years and the 2006–2007 National Climate Data Center and Weather Service measurements of relative humidity (%), indoor heating degree days (HDD), clear sky UV indices ozone levels, and outdoor air temperature. As a proxy for AD, we used an affirmative response to the NSCH survey question asking whether the participant’s child has been given a doctor diagnosis of “eczema or any other kind of skin allergy” in the previous 12 months. In multivariate models controlling for sex, race/ethnicity, age and household income, eczema prevalence was significantly lower with highest-quartile mean annual relative humidity (logistic regression, adjusted odds ratio [95% confidence interval]=0.82 [0.71–0.96], P=0.01) and issued UV index (0.73 [0.64–0.84], P<0.0001), and with two other factors associated with increased UV exposure. Eczema prevalence was decreased with highest-quartile air temperature (0.80 [0.70–0.92], P=0.002), but increased with 3^rd–quartile mean annual HDD (1.26 [1.11–1.43], P=0.0003). This study provides evidence of climate influences on the US prevalence of childhood eczema.

Impact of meteorological variation on hospital visits of patients with tree pollen allergy

Background

Climate change could affect allergic diseases, especially due to pollen. However, there has been no epidemiologic study to demonstrate the relationship between meteorological factors, pollen, and allergic patients. We aimed to investigate the association between meteorological variations and hospital visits of patients with tree pollen allergy.

Methods

The study subjects were adult patients who received skin prick tests between April and July from 1999 to 2008. We reviewed the medical records for the test results of 4,715 patients. Patients with tree pollen allergy were defined as those sensitized to more than 1 of 12 tree pollen allergens. We used monthly means of airborne tree pollen counts and meteorological factors: maximum/average/minimum temperature, relative humidity, and precipitation. We analyzed the correlations between meteorological variations, tree pollen counts, and the patient numbers. Multivariable logistic regression analyses were used to investigate the associations between meteorological factors and hospital visits of patients.

Results

The minimum temperature in March was significantly and positively correlated with tree pollen counts in March/April and patient numbers from April through July. Pollen counts in March/April were also correlated with patient numbers from April through July. After adjusting for confounders, including air pollutants, there was a positive association between the minimum temperature in March and hospital visits of patients with tree pollen allergy from April to July(odds ratio, 1.14; 95% CI 1.03 to 1.25).

Conclusions

Higher temperatures could increase tree pollen counts, affecting the symptoms of patients with tree pollen allergy, thereby increasing the number of patients visiting hospitals.

Comparison in asthma and allergy prevalence in the two major cities in Greece: the ISAAC phase II survey

BACKGROUND

Variability in the prevalence of allergic diseases has been detected not only between different countries, but also between cities with similar national and different socio-economic or climatic characteristics. The aim of this study was to determine the prevalence of childhood asthma and allergies and which factors are associated with them, in the two largest Greek cities, Athens and Thessaloniki.

METHODS

Two thousand and twenty-three Greek 9-10-year-old schoolchildren from Athens (Central Greece) and Thessaloniki (North Greece, more humid), were included in ISAAC-II study. All participants followed the ISAAC-II protocol by questionnaire, skin prick testing and flexural dermatitis examination.

RESULTS

Compared with Athens, the prevalence of current wheezing (8.4% vs. 5.7%, p=0.002), lifetime asthma (11.5% vs. 7.7%, p=0.004), atopic current asthma (3.2% vs. 1.6%, p=0.02), allergic rhinitis (8.2% vs. 5.2%, p=0.007), and hay fever (21.7% vs. 12.5%, p<0.001) were higher in Thessaloniki. The overall sensitisation rate was also higher in Thessaloniki than in Athens (25.2% vs. 16%, p<0.001) with more prevalent sensitising due to the perennial allergens (D. pteronyssinus, D. farinae, Alternaria tenuis) and cat dander. Perennial allergens sensitisation was a risk factor for current asthma in both cities.

CONCLUSION

A higher prevalence of asthma symptoms, allergic rhinitis, and sensitisation rate was detected in Greek schoolchildren living in Thessaloniki compared to those in Athens. Allergy to mites and mould was more prevalent in Thessaloniki. The more humid weather of Thessaloniki may be implicated.

Recent perspectives on the global epidemiology of childhood eczema

The International Study of Asthma and Allergies in Childhood (ISAAC) is the largest epidemiological study ever performed and the only truly global allergy study. This review summarises the childhood eczema-related findings from ISAAC and discusses how these fit into our current understanding of eczema aetiology, with particular emphasis on worldwide time trends in eczema prevalence, climatic and dietary risk factors, breastfeeding, the role of skin barrier impairment and allergic sensitisation.