Comparison of allergic diseases, symptoms and respiratory infections between Finnish and Russian school children

Contributions of the early-life microbiome to childhood atopy and asthma development

The rapid rise in atopy and asthma in industrialized nations has led to the identification of early life environmental factors that promote these conditions and spurred research into how such exposures may mediate the trajectory to childhood disease development. Over the past decade, the human microbiome has emerged as a key determinant of human health. This is largely due to the increasing appreciation for the myriad of non-mutually exclusive mechanisms by which microbes tune and train host immunity. Microbiomes, particularly those in early life, are shaped by extrinsic and intrinsic factors, including many of the exposures known to influence allergy and asthma risk. This has led to the over-arching hypothesis that such exposures mediate their effect on childhood atopy and asthma by altering the functions and metabolic productivity of microbiomes that shape immune function during this critical developmental period. The capacity to study microbiomes at the genetic and molecular level in humans from the pre-natal period into childhood with well-defined clinical outcomes, offers an unprecedented opportunity to identify early-life and inter-generational determinants of atopy and asthma outcomes. Moreover, such studies provide an integrative microbiome research framework that can be applied to other chronic inflammatory conditions. This review attempts to capture key studies in the field that offer insights into the developmental origins of childhood atopy and asthma, providing novel insights into microbial mediators of maladaptive immunity and chronic inflammatory disease in childhood.

Altered retinal nerve fiber layer thickness in children with allergic conjunctivitis: the Nanjing eye study

Background

So far, few data are available on the relationship between allergic conjunctivitis (AC) and ocular fundus. Whether retinal parameters change in patients with AC remains unknown. In this study, we investigated the influence of AC on retinal thickness and vessel density among 7-years-old school-age children.

Methods

This large population-based study is part of the Nanjing Eye Study (NES). Comprehensive examinations including anthropometric parameters, refraction, ocular biometric parameters, intraocular pressure and retinal parameters were conducted on each child. Retinal thickness and vessel density were assessed using the optical coherence tomography angiography. Information on AC was obtained from a comprehensive questionnaire.

Results

A total of 739 children (mean age ± SD: 7.40 ± 0.29 years) had complete eye examination and questionnaire data we needed. Ninety-four children (12.7%) had AC, among which, 5 children had the history of corticosteroid use and were excluded from the final analysis. Spherical equivalent, axial length, body mass index and birth weight were correlated with retinal parameters. After adjusting for sex, age, spherical equivalent, axial length, body mass index, birth weight and premature history, children with AC had thinner retinal nerve fiber layer thickness for average (117.39 versus 120.97 μm, p = 0.007), temporal (80.73 versus 84.34 μm, p = 0.001), nasal (98.82 versus 102.18 μm, p = 0.049) and inferior (152.68 versus 157.06 μm, p = 0.034) quadrants than the control group.

Conclusions

Children with AC tended to have thinner retinal nerve fiber layer thickness. More attention is needed to fundus condition of children with AC.

Supplementary information

The online version contains supplementary material available at 10.1186/s12886-022-02399-7.

Pathogen Control in the Built Environment: A Probiotic-Based System as a Remedy for the Spread of Antibiotic Resistance

The high and sometimes inappropriate use of disinfectants and antibiotics has led to alarming levels of Antimicrobial Resistance (AMR) and to high water and hearth pollution, which today represent major threats for public health. Furthermore, the current SARS-CoV-2 pandemic has deeply influenced our sanitization habits, imposing the massive use of chemical disinfectants potentially exacerbating both concerns. Moreover, super-sanitation can profoundly influence the environmental microbiome, potentially resulting counterproductive when trying to stably eliminate pathogens. Instead, environmentally friendly procedures based on microbiome balance principles, similar to what applied to living organisms, may be more effective, and probiotic-based eco-friendly sanitation has been consistently reported to provide stable reduction of both pathogens and AMR in treated-environments, compared to chemical disinfectants. Here, we summarize the results of the studies performed in healthcare settings, suggesting that such an approach may be applied successfully also to non-healthcare environments, including the domestic ones, based on its effectiveness, safety, and negligible environmental impact.

Modern urbanization has reshaped the bacterial microbiome profiles of house dust in domestic environments

Background

The prevalence of allergy and other common chronic diseases is higher in developed than developing countries, and higher in urban than rural regions. Urbanization through its modification of environmental microbiomes may play a predominant role in the development of these conditions. However, no studies have been conducted to compare the microbiome in house dust among areas with different urbanization levels.

Methods

House dust from Xinxiang rural area (XR, n = 74), Xinxiang urban area (XU, n = 33), and Zhengzhou urban area (ZU, n = 32) in central China, and from Australia (AU, n = 58 [with pets AUP, n = 15, without pets AUNP, n = 43]) were collected during a summer season in China and Australia. High-throughput sequencing of 16S rDNA was employed to profile house dust bacterial communities.

Results

Settled dust collected in China was dominant with 2 bacterial phyla: Proteobacteria and Actinobacteria, while floor dust collected in Australia had a higher proportion of phylum Proteobacteria, Firmicutes, and Actinobacteria. XR dust samples presented higher bacterial richness and diversity compared with XU or ZU samples. Urbanization level (r² = 0.741 P < 0.001) had a significant correlation with the distribution of house dust bacterial community. At the genus level, there was a positive correlation (r coefficient > 0.5) between urbanization level and bacterial genera Streptococcus, Bartonella, Staphylococcus, Pseudomonas, Acinetobacter, Bacteroides, Corynebacterium_1,and Enhydrobacter and a negative correlation (r coefficient < −0.5) with Rhodanobacter.

Conclusion

There was a significant difference in house dust microbiota among different urbanization areas. The areas with a lower urbanization level presented higher dust-borne bacterial richness and diversity. Modern urbanization has a significant influence on the bacterial microbiome profiles of indoor dust.

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.

Prospective study confirms that bronchiolitis in early infancy increases the risk of reduced lung function at 10-13 years of age

AIM

This study evaluated children hospitalised for bronchiolitis at less than six months of age to see if they had reduced lung function in early adolescence.

METHODS

We have prospectively followed 166 children hospitalised for infant bronchiolitis in 2001-2004 at Tampere University Hospital, Finland. At 10-13 years of age, flow-volume spirometry was measured in 89 cases and 108 controls without infant bronchiolitis from the local population register. Parameters of flow-volume spirometry before and after bronchodilation were analysed.

RESULTS

Forced expiratory volume in one second/forced vital capacity (FEV1/FVC) after bronchodilation was lower in cases than controls. FEV1 was pathological - under the 5th percentile of the national references - in 25% of cases and 12% of controls (p = 0.020) before bronchodilation and in 18% of cases and 5% of controls (p = 0.003) after bronchodilation. FEV1/FVC was pathological in 25% of cases and 13% of controls (p = 0.034) before bronchodilation. Logistic regression, adjusted for current asthma and maternal smoking, showed that infant bronchiolitis was associated with pathological FEV1 before (odds ratio 2.4) and after (odds ratio 4.4) bronchodilation. The result was similar for positive respiratory syncytial virus cases.

CONCLUSION

Reduced FEV1 after bronchodilation was found in early adolescence after infant bronchiolitis, suggesting irreversible bronchial obstruction.

Risk factors for asthma after infant bronchiolitis

BACKGROUND

Five studies carried out after bronchiolitis at less than 24 months of age, with a follow-up of more than 10 years, reported that atopic dermatitis, family asthma, early-life exposure to tobacco smoke and rhinovirus aetiology were early-life risk factors for later asthma. This study evaluated the long-term outcome at 11-13 years of age of children who were hospitalized for bronchiolitis in early infancy.

METHODS

We previously prospectively followed 166 children hospitalized for bronchiolitis at less than 6 months of age until 5-7 years of age. The current study included a structured questionnaire, parental interviews, clinical examinations and bronchodilation test of 138 of those children at 11-13 years of age.

RESULTS

Respiratory syncytial virus caused 66% of the bronchiolitis cases, and nearly half of the patients were exposed to tobacco smoke in early life. Doctor-diagnosed asthma was present in 13% of the former bronchiolitis patients at 11-13 years of age. Maternal asthma was the only independently significant risk factor in early life (adjusted OR 3.45, 95% CI 1.07-11.74), as was allergic rhinitis at 5-7 years of age (adjusted OR 4.06, 95% CI 1.35-12.25).

CONCLUSIONS

After bronchiolitis at less than 6 months of age, the risk of doctor-diagnosed asthma at 11-13 years was about twice that of the general Finnish population. Maternal asthma was the only independently significant early-life risk factor for current asthma at 11-13 years of age.

Toll-like receptor 1 and 10 gene polymorphisms are linked to postbronchiolitis asthma in adolescence

AIM

Toll-like receptors (TLR) are innate immunity molecules and our previous studies found that TLR1 gene polymorphism was associated with postbronchiolitis asthma at one to six years of age, as was TLR10 at five to seven years of age. This study examined any associations at 11-13 years of age.

METHODS

This prospective follow-up study was part of an ongoing evaluation of children admitted to Tampere University Hospital, Finland, for bronchiolitis in 2001-2004 at less than six months of age. We evaluated the association of TLR1 rs5743618 and TLR10 rs4129009 polymorphisms with asthma and asthma medication in 125 children aged 11-13 years.

RESULTS

Associations were measured as adjusted odd ratios (aOR) with 95% confidence intervals (95% CI). The variant TLR1 rs5743618 (aOR 4.04, 95% CI 0.99-13.01) and TLR10 rs4129009 (aOR 7.02, 95% CI 1.56-31.53) genotypes increased the risk of needing inhaled corticosteroids (ICSs) at 11-13 years of age. The variant TLR10 genotype (aOR 7.69, 95% CI 1.35-43.95) increased the risk of persistent asthma continuing from five to seven years of age until 11-13 years of age. The results were similar when the combined genotypes were analysed. [Correction added on 3 October 2017, after online publication: The data in the variant TRL1 rs5743618 genotype were incorrect and have been corrected in this version.] CONCLUSION: Polymorphisms in both the TLR1 and TLR10 genes may increase the risk of asthma at 11-13 years after infant bronchiolitis.

Towards evidence-based vitamin D supplementation in infants: vitamin D intervention in infants (VIDI) - study design and methods of a randomised controlled double-blinded intervention study

BACKGROUND

Vitamin D is important for bone mass accrual during growth. Additionally, it is considered a requirement for a multitude of processes associated with, for example, the development of immunity. Many countries apply vitamin D supplementation strategies in infants, but the guidelines are not based on scientific evidence and aim at prevention of rickets. It remains unclear whether the recommended doses are sufficient for the wide array of other effects of vitamin D. The VIDI trial performed in Finland is the first large randomised controlled study for evaluation of the effects of different vitamin D supplemental doses in infancy on: 1. bone strength 2. infections and immunity 3. allergy, atopy and asthma 4. cognitive development 5. genetic regulation of mineral homeostasis METHODS/DESIGN: VIDI, a randomised controlled double-blinded single-centre intervention study is conducted in infants from the age of 2 weeks to 24 months. Participants, recruited at Helsinki Maternity Hospital, are randomised to receive daily either 10 μg (400 IU) or 30 μg (1 200 IU) of vitamin D3 supplementation. Both groups are assessed at 6 months of age for calcium homeostasis, and at 12 and 24 months of age for parameters associated with bone strength, growth, developmental milestones, infections, immunity, atopy-related diseases, and genetic factors involved in these functions.

DISCUSSION

The study enables evaluation of short and long term effects of supplemental vitamin D on growth, immune functions and skeletal and developmental parameters in infants, and the effects of genetic factors therein. The results enable institution of evidence-based guidelines for vitamin D supplementation in infancy.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01723852 , registration date 6.11.2012.

No simple answers for the Finnish and Russian Karelia allergy contrast: Methylation of CD14 gene

BACKGROUND

Finnish and Russian Karelian children have a highly contrasting occurrence of asthma and allergy. In these two environments, we studied associations between total serum immunoglobulin E (IgE) with methylation levels in cluster of differentiation 14 (CD14).

METHODS

Five hundred Finnish and Russian Karelian children were included in four groups: Finnish children with high IgE (n = 126) and low IgE (n = 124) as well as Russian children with high IgE (n = 125) and low IgE (n = 125). DNA was extracted from whole blood cells and pyrosequenced. Three CpG sites were selected in the promoter region of CD14.

RESULTS

Methylation levels in two of the three CpG sites were higher in the Finnish compared to Russian Karelian children. In the promoter area of CD14, the Finnish compared to Russian children with low IgE had a significant (p < 0.0001) increase in methylation levels at the Amp5Site 2. Likewise, the Finnish compared to Russian children with high IgE had a significant (p = 0.003) increase in methylation levels at the Amp5Site 3. In Russian children with low vs. high IgE, there were significant differences in methylation levels, but this was not the case on the Finnish side. In the regression analysis, adding the methylation variation of CD14 to the model did not explain the higher asthma and allergy risk in the Finnish children.

CONCLUSIONS

The methylation levels in the promoter region of CD14 gene were higher in the Finnish compared to Russian Karelian children. However, the methylation variation of this candidate gene did not explain the asthma and allergy contrast between these two areas.

High sensitization to house-dust mites in patients with allergic rhinitis in the eastern Black Sea region of Turkey: A retrospective study

OBJECTIVES

Identification of the most common aeroallergens to which patients are sensitized in a specific area is important in the diagnosis and treatment of allergic rhinitis (AR). We determined the distribution of aeroallergens, detected by skin-prick tests (SPT), in adult patients with AR in the Eastern Black Sea region of Turkey and compared the results with the other regions of Turkey and in the world.

METHODS

The medical records of SPT performed on 1457 patients with symptoms of AR (with regard to the Allergic Rhinitis and its Impact on Asthma 2008 guidelines) between March 2010 and March 2013 were analyzed retrospectively. SPT were carried out with the same panel, which included grass; weeds; trees; mold; epidermal mixtures; and with two house-dust mite (HDM) extracts, Dermatophagoides pteronyssinus and Dermatophagoides farinae.

RESULTS

In 1229 of 1457 patients (84.4%), there were positive reactions for at least one aeroallergen on the SPT. The most common aeroallergen was the HDM D. pteronyssinus (84% [n = 1033]) followed by D. farinae (78.2% [n = 962]). Grass pollen sensitivity (70.8% [n = 871]) was higher than tree or weed pollen sensitivity in this region.

CONCLUSIONS

The most common aeroallergens in AR are HDMs of D. pteronyssinus and D. farinae in the Eastern Black Sea region in Turkey. Our study may help in developing environmental control strategies for AR.

Changes in atopy prevalence and sibship effect in rural population at all ages

BACKGROUND

We examined the associations of family size and birth order with atopy prevalence in rural Poland at two time periods.

METHODS

Two cross-sectional surveys were conducted in the same villages and a small town of lower Silesia at an interval of 9 years. In 2003, 1700 (88% of eligible individuals), and in 2012, 1730 (86%) inhabitants aged 5 years or more completed a questionnaire and had a skin prick test for atopy.

RESULTS

There was an inverse association between family size and atopy in the village population in 2003; the prevalence of atopy was the highest for those with no siblings (15.2%) and decreased to 5.4% for those with three and more siblings (OR = 0.22; 0.07-0.66). In contrast, there was little or no such protective effect in the town population where the prevalence of atopy was much higher (7.3% in the villages, 20.0% in the town). Nine years later, the prevalence of atopy had increased in the village to be similar to that in the town (19.6% and 19.9% respectively), and the protective effects of family size and birth order in the villages were much weaker (OR = 0.64; 95% CI 0.33-1.27 for three or more siblings). Both protective effects were strongest among children.

CONCLUSIONS

The protective effects of family size and birth order on atopy were much stronger in children than in adults and among those living in a village. They largely disappeared with the steep increase in atopy prevalence at all ages; this followed environmental changes on the village farms.

Helicobacter pylori neutrophil-activating protein: a potential Treg modulator suppressing allergic asthma?

The ultimate aim of the immune system is to eliminate pathogens without being harmful to the host. But what if eliminating the pathogen in itself is discomforting for the host? One such emerging case is of Helicobacter pylori. Modern medicine, infantile vaccination, and ultra-hygienic conditions have led to progressive disappearance of H. pylori in different parts of the world. However, the adversities caused by H. pylori's absence are much larger than those caused by its presence. Asthma is rising as an epidemic in last few decades and several reports suggest an inverse-relationship between H. pylori's persistence and early-life onset asthma. Regulatory T cells play an important role in both the cases. This is further supported by experiments on mouse-models. Hence, need of the hour is to discern the relationship between H. pylori and its host and eliminating its negative impacts without disturbing our indigenous microbiota. To resolve whether H. pylori is a pathogen or an amphibiont is another important side. This review explores the biological basis of H. pylori-induced priming of immune system offering resistance to childhood-onset asthma. HP-NAP-Tregs interaction has been predicted using molecular docking and dynamic simulation.

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.

Allergic diseases and respiratory symptoms in urban and rural children in Grodno Region (Belarus)

BACKGROUND

Because of the unknown frequency of asthma and other common allergic diseases in children living in Belarus, we conducted a population-based respiratory health survey. The objective of the study was to estimate the prevalence of allergic diseases and major allergic symptoms in children of the Grodno Region (Western Belarus) and to examine their familial and environmental correlates.

METHODS

The cross-sectional study was conducted in 2010 and included 2606 urban and 2422 rural children aged 6-16 years. Physician-diagnosed respiratory diseases and symptoms were ascertained using the ISAAC questionnaire completed by the parents. Both family and environmental factors were examined for their association with respiratory health outcomes including asthma and spastic bronchitis. Descriptive statistics and multiple logistic regression analysis were used to test associations.

RESULTS

The prevalence of asthma, atopic eczema and allergic rhinitis was 1.39%, 10.25%, and 3.84%, respectively. Spastic bronchitis was reported for 6.74% of children. Chronic respiratory symptoms occurring in the past 12 months and suggestive of asthma included chest wheeze (9.71%) attacks of dyspnea at rest (1.77%), symptoms of hay fever (2.45%) attacks of sneezing and nasal congestion without a cold (6.78%), and recurrent itchy rash (13.48%). All diseases except for asthma and spastic bronchitis as well as symptoms of hay fever, congested nose and itchy rash were more frequent in urban than in rural children (p < 0.05). Results of multivariate logistic analysis confirmed associations (p < 0.05) between asthma and parental asthma (OR = 4.82) and dampness in home (OR = 2.12) after adjustment for age, gender and place of residence. Spastic bronchitis in children who did not have a concurrent diagnosis of asthma was related (p < 0.05) to parental asthma (OR = 2.18), dampness in the home (OR = 1.68) and less use of coal-based heating (OR = 0.64). Allergic rhinitis and atopic eczema were associated (p < 0.05) with parental asthma (OR = 5.07 and OR = 1.91, respectively), dampness (OR = 2.33 and OR = 1.51, respectively), lower parental education (OR = 0.74 and OR = 0.68, respectively) and household density (OR = 0.84 and OR = 0.92), respectively.

CONCLUSIONS

The findings show a low prevalence of allergic diseases and symptoms in children of Western Belarus, following similar East-West gradients described in the literature. All allergic disorders except asthma were less frequent in the rural population. A very low prevalence of childhood asthma and the possibility of underdiagosis of the disease in the surveyed population deserve further investigation.

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.

Does diversity of environmental microbial exposure matter for the occurrence of allergy and asthma?

This review describes the recent literature on microbial exposures and protective effects for asthma and atopy. Certain microorganism-associated molecular patterns have been identified as agents that might influence the development of the immune system, which in turn leads to protective effects for asthma and atopy. Endotoxins from gram-negative bacteria were the first agents associated with a reduced risk for asthma and atopy. In later studies, β(1→3)glucans, extracellular polysaccharides, and muramic acid from, respectively, molds and gram-positive bacteria were associated with a reduced risk of allergy and asthma separately in rural and urban populations. These results already suggested that not just one but several independent microbial signals from gram-negative and gram-positive bacteria, as well as molds, might play a role in explaining the protective effects. Recently, the diversity of microbial exposure has been associated with such a reduced risk in farmers' children. Surprisingly, the diversity of both fungal and bacterial exposure seemed to have protective effects. These results open new areas of research and create complex challenges. Methodological issues, such as environmental exposure characterization and assessment and elucidation of potential underlying mechanisms, are discussed because these aspects have a major influence on how microbial diversity can be studied in future studies in relation to protective effects for asthma and atopy.

Prevalence and diversity of allergic rhinitis in regions of the world beyond Europe and North America

BACKGROUND

There is comparatively little information in the public domain on the diversity in prevalence and triggers/factors associated with allergic rhinitis (AR) or allergic rhinoconjunctivitis (AR/C) in countries beyond western-Europe and North America.

OBJECTIVE

To review the prevalence and the sensitizing agents/triggers and factors associated with AR/C in several countries in Africa, the Asia-Pacific region, Australia, Eastern Europe, Latin America, Middle East and Turkey.

METHODS

Articles published in English in peer-reviewed journals were assessed and selected for further review, following an extensive literature search using the Medline database.

RESULTS

This review demonstrated that prevalence of AR and AR/C in these regions has predominantly been investigated in children; with studies indicating wide inter- and intra-regional variations ranging from 2.9% AR and 3.8% AR/C in 10-18-years-old children from one region in Turkey to 54.1% AR and 39.2% AR/C in 13-14-years-old children in one region in Nigeria. Moreover, the prevalence of AR and AR/C has increased markedly over the last decade particularly in some of the more affluent African countries, China-Taiwan and several Middle East countries, likely as a consequence of improved living standards leading to increased exposure to multiple traditional and non-traditional sensitizing agents and risk factors similar to those noted in western-Europe and North America.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings suggest that the greater diversity in prevalence of AR or AR/C in populations in these regions is in contrast to the lower diversity of AR or AR/C in the 'western populations (USA and Europe), which tend to be more uniform. This review provides a comprehensive database of the important allergens and triggers which are likely to influence the prevalence of allergic rhinitis in these diverse regions, where the prevalence of allergic rhinitis is increasing and its adverse impact on the quality of life of affected individuals is increasingly recognised.

Vernal keratoconjunctivitis in school children in Rwanda and its association with socio-economic status: a population-based survey

Vernal keratoconjunctivitis (VKC) is an allergic eye disease and an important cause of hospital referral among children in Africa and Asia. Hospital-based studies have suggested a role for parasites in its pathogenesis. To determine the prevalence and risk factors for VKC in Central Africa, we conducted a nested population-based case control study in Rwanda, involving randomly selected primary schools from different environments (rural/urban) and climate. A prevalence of VKC of 4.0% (95% confidence interval 3.3-4.7%) was found among 3,041 children studied (participation rate 94.7%). The intestinal parasitic burden was not related to VKC. Besides hot dry climate (odds ratio [OR] = 1.5, P = 0.05) and male gender (OR = 1.7, P = 0.005), multivariate analysis identified higher economic status as a risk for VKC (OR = 1.4, P = 0.005). The effect on VKC of higher economic status appears not to act through differences in parasitic intestinal load.

Disparity of innate immunity-related gene effects on asthma and allergy on Karelia

BACKGROUND

We investigated the interactive effects of 11 innate immunity-related genes (IL10, IL12b, IL8, TLR2, TLR4, CD14, IFNGR, CC16, IFNg, CMA1, and TGFB) and four IgE response genes (IL4, IL13, IL4RA, and STAT6) with 'Western' or 'Eastern' environments/lifestyles on asthma and allergy in Karelian children.

METHODS

Karelian children (412 Finnish and 446 Russian) were recruited and assessed for a range of allergic conditions, with 24 single-nucleotide polymorphisms genotyped in 15 genes.

RESULTS

The genotype-phenotype relationships differed in Finnish and Russian Karelian children. The interaction between polymorphisms and the variable representing 'Western' and 'Eastern' environments/ lifestyles was significant for IL10-1082 (p = 0.0083) on current rhinitis, IL12b 6408 on current conjunctivitis (p = 0.016) and atopy (p = 0.034), IL8 781 on atopic eczema (p = 0.0096), CD14 -550 on current rhinitis (p = 0.022), IFNgR1 -56 on atopic eczema(p = 0.038), and STAT6 2964 on current itchy rash (p = 0.037) and total serum IgE (p = 0.042). In addition, the G allele of IL13 130 was associated with a lower level of total serum IgE in Finnish (p = 0.003) and Russian (p = 0.01) children and overall (pooling the two populations together, p = 0.00006). After adjusting for multiple tests, the association between IL13 130 and IgE and the interactive effects of IL10-1082 on current rhinitis and IL8 781 on atopic eczema were significant by controlling a false-positive rate of 0.05 and 0.10, respectively.

CONCLUSIONS

Living in an Eastern vs. Western environment was associated with a different genetic profile associated with asthma and allergy in the Karelian populations.

The Rotterdam Study: 2012 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.

The Shanghai Changfeng Study: a community-based prospective cohort study of chronic diseases among middle-aged and elderly: objectives and design

The Shanghai Changfeng Study is a community-based prospective cohort study of chronic diseases ongoing since February 2009 in Shanghai, China. The study focuses on multiple chronic diseases, including obesity and metabolic syndrome, diabetes, osteoporosis, liver diseases, cardiovascular diseases and neurologic diseases. 15,000 subjects of 40 years or over are planned to be recruited. The rationale, objectives and design of this study are described in this paper.

The Generation R Study: design and cohort update 2010

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health during fetal life, childhood and adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioural and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9,778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. General follow-up rates until the age of 4 years exceed 75%. Data collection in mothers, fathers and preschool children included questionnaires, detailed physical and ultrasound examinations, behavioural observations, and biological samples. A genome wide association screen is available in the participating children. Regular detailed hands on assessment are performed from the age of 5 years onwards. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

The epidemiology of ocular and nasal allergy in the United States, 1988-1994

BACKGROUND

Allergies give rise to the fifth-leading group of chronic diseases. However, the specific prevalence of ocular allergy is poorly described.

OBJECTIVE

We sought to provide a more accurate representation of the epidemiology of ocular allergy in the United States.

METHODS

The National Health And Nutrition Examination Survey III performed in the United States from 1988-1994 was the source for the data collected. Items from the questionnaire regarding ocular and nasal allergy symptoms in relation to skin prick testing were stratified by age, race, region, and sex.

RESULTS

The sample size is 20,010: 1,285 (6.4%) reported ocular symptoms, 3,294 (16.5%) reported nasal symptoms, 5,944 (29.7%) reported both ocular and nasal symptoms, and 9.487 (47.4%) were asymptomatic. Forty percent of the population reported at least 1 occurrence of ocular symptoms in the past 12 months. Those 50 years and older have a higher frequency of isolated ocular symptoms (P < .001). There is an increase in the frequency of symptoms in those younger than 50 years in the populations of subjects with ocular and nasal symptoms combined and isolated nasal symptoms (P < .001). Ocular symptoms are more frequent than nasal symptoms in relation to animals (P < .001), household dust (P < .001), and pollen (P < .001).

CONCLUSION

This analysis provides the first representation of the epidemiology of ocular allergy in the United States. Up to 40% of the population, the highest reported to date, have experienced ocular symptoms at least once in their lifetime, with a peak of symptoms in the months of June and July.

Global variations in prevalence of eczema symptoms in children from ISAAC Phase Three

BACKGROUND

In 1999, The International Study of Asthma and Allergies in Childhood (ISAAC) Phase One reported the prevalence of eczema symptoms in 715,033 children from 154 centers in 56 countries by using standardized epidemiologic tools.

OBJECTIVE

To update the world map of eczema prevalence after 5 to 10 years (ISAAC Phase Three) and include additional data from over 100 new centers.

METHODS

Cross-sectional surveys using the ISAAC questionnaire on eczema symptoms were completed by adolescents 13 to 14 years old and by parents of children 6 to 7 years old. Current eczema was defined as an itchy flexural rash in the past 12 months and was considered severe eczema if associated with 1 or more nights per week of sleep disturbance.

RESULTS

For the age group 6 to 7 years, data on 385,853 participants from 143 centers in 60 countries showed that the prevalence of current eczema ranged from 0.9% in India to 22.5% in Ecuador, with new data showing high values in Asia and Latin America. For the age group 13 to 14 years, data on 663,256 participants from 230 centers in 96 countries showed prevalence values ranging from 0.2% in China to 24.6% in Columbia with the highest values in Africa and Latin America. Current eczema was lower for boys than girls (odds ratio, 0.94 and 0.72 at ages 6 to 7 years and 13 to 14 years, respectively).

CONCLUSION

ISAAC Phase Three provides comprehensive global data on the prevalence of eczema symptoms that is essential for public health planning. New data reveal that eczema is a disease of developing as well as developed countries.

Opposite gene by environment interactions in Karelia for CD14 and CC16 single nucleotide polymorphisms and allergy

BACKGROUND

Finnish Karelians have a higher prevalence of allergic disease than Russian Karelians. As both populations are generally from the same ethnic group, the Karelian population offers a unique opportunity to analyse genetic and allergic disease interactions between 'Western' and 'Eastern' environments.

OBJECTIVES

We investigated associations between allergic diseases and CD14 and CC16 polymorphisms in Finnish vs Russian Karelian women.

METHODS

Adult female Karelians (330 Finnish and 274 Russian) were recruited, examined for a range of symptoms and conditions including rhinitis, itchy rash, asthma and atopy and genotyped for CD14 C-159T and CC16 A38G.

RESULTS

For both CD14 C-159T and CC16 A38G, the risk allele for atopic phenotypes in Finnish Karelia was the protective allele in Russian Karelia. For CD14 C-159T, an interactive effect on ever itchy rash (P(interaction) = 0.004), itchy rash <12 mo (P(interaction) = 0.001) and dry cough at night in the past 12 months (<12 months) (P(interaction) = 0.011) was found; the risk allele was C in Russians and T in Finns. For CC16 A38G, an interaction was significant for ever rhinitis (P(interaction) = 0.006), rhinitis <12 mo (P(interaction) = 0.004), and marginally significant for ever hayfever (P(interaction) = 0.07), allergic eye symptoms <12 mo (P(interaction) = 0.09); their risk allele was G in Russians and A in Finns.

CONCLUSION

An Eastern vs Western environment appears to exert an effect via opposite alleles on risk of allergic diseases in adult women.

The Rotterdam Study: 2010 objectives and design update

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.