Do fast foods cause asthma, rhinoconjunctivitis and eczema? Global findings from the International Study of Asthma and Allergies in Childhood (ISAAC) phase three

Dietary patterns and asthma prevalence, incidence and control

BACKGROUND

The increased asthma prevalence in westernized societies has been suggested to be related to environment exposures and lifestyle changes, particularly diet. We aimed to explore the association between dietary patterns and asthma prevalence, incidence and control in a nationally representative population.

METHODS

Data from 32,644 adults, 53% female, from the 4th Portuguese National Health Survey were analysed. Prevalence of asthma was 5.3%; 'current asthma', defined by asthma symptoms within previous year, 3.5%; 'current medicated asthma' defined by use of asthma medication within previous year, 3.0%; 'current severe asthma' defined by emergency visit because of asthma within previous year, 1.4%; and 'incident asthma', 0.2%. Dietary patterns (DP) were identified by latent trait models based on dietary intake. Unconditional logistic regression models were performed to analyse association between DP and asthma. Age, gender, education, family income, proxy reporting information, smoking, body mass index and physical activity level were analysed as confounders.

RESULTS

Two of the five identified DP were associated with asthma: 'high fat, sugar and salt' DP (positively correlated with pastry, chocolate and sweet desserts, candies, salty snacks, chips, fruit juices, soft drinks and alcoholic beverages consumption at snacks) was associated with asthma prevalence (OR = 1.13, 95% CI = 1.03, 1.24) and current severe asthma (OR = 1.23, 95% CI = 1.03, 1.48), while 'fish, fruit and vegetables' DP (positively correlated with fish, vegetables and fruit intake at meals) was negatively associated with current (OR = 0.84, 95% CI = 0.73, 0.98), and current medicated asthma (OR = 0.84, 95% CI = 0.72, 0.98), after adjustment for confounders.

CONCLUSION & CLINICAL RELEVANCE

Our results suggest a protective association between 'fish, vegetables and fruit' DP and current asthma and current medicated asthma, and a detrimental association between 'high fat, sugar and salt' DP and severe asthma prevalence, further supporting the rational for diet and lifestyle intervention studies in asthma based on whole dietary patterns and physical activity.

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.

The lipid profile in obese asthmatic children compared to non-obese asthmatic children

BACKGROUND

A relationship between asthma and obesity has been documented in children and adolescents. An alternate day calorie restriction diet has been reported to improve asthma symptoms by decreasing levels of serum cholesterol and triglycerides, reducing markers of oxidative stress and increasing levels of the antioxidant uric acid. Therefore, to investigate the lipid profile in asthmatic children may be important in asthma control treatment.

MATERIALS AND METHODS

One hundred and sixty newly diagnosed persistent asthmatic children were selected to participate in the study. They were divided into four groups based on their body mass index (BMI): Group I normal weight (BMI=20-24.9kg/m(2), n=30); Group II under-weight (BMI<20kg/m(2), n=30); Group III overweight (BMI=25-30kg/m(2), n=25); and Group IV obese (BMI>30kg/m(2), n=25). Fasting blood sugar, fasting insulin, and HbA1c were measured to exclude the possibility of pre-diabetes. Lipid profile measurements included total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), apo-A1, apo-B and triglycerides.

RESULTS

There were no significant differences in the levels of apo-A1, apo-B, triglycerides, cholesterol and LDL in all four groups. Only the level of HDL was higher in GIV>GIII>GII>GI (75.84±13.95, 68.56±15.28, 64.17±13.93, 63.17±14.34mg/dl, respectively). There were no cases of pre-diabetes in any of the four groups.

CONCLUSION

Hypercholesterolaemia and hypertriglyceridaemia were not found in any of the persistent asthmatic children, and thus they are not high risk factors for asthma. Similarly, there were no differences in apo-A1 and apo-B between any of the BMI groups. No differences were found in LDL levels, however HDL levels were increased in all four groups, indicating that allergic sensitisation may have occurred. Controlling body weight and restricting calorie intake may be as important as appropriate pharmacological management in controlling asthma.

Can geodata be used to determine the distribution of fast food outlets in relation to the prevalence and severity of asthma? A novel methodology

RESEARCH QUESTION

Can the distribution of fast food outlets be obtained and effectively used to identify if there is a relationship between the placement of these and the prevalence and severity of asthma, rhinoconjunctivitis and eczema (ARE) in children and adolescents?

METHOD

Fast food restaurant location data was obtained for seven countries. Data from the International Study of Asthma and Allergies in Childhood (ISAAC) was used from 53 centres in the same seven countries. Each ISAAC centre provided a detailed map of the study area. The location of restaurants and ISAAC centres were overlaid using the ArcMap software, and the number of restaurants within each ISAAC centre counted. Bivariate regression analysis was used to compare outlet density with ARE prevalence and severity.

RESULTS

The results from the analyses showed a positive (non-significant) trend on a regression plot between outlet density and ARE severity. This project has shown that it is practical to systematically obtain and map fast food outlets and compare their distribution worldwide with the prevalence and severity of diseases, in this case ARE. The devised methodology has proven to be an efficient way to obtain restaurant distribution data in a form that is manageable and suitable to compare with area based disease prevalences. This project has shown that a larger scale investigation is both feasible and warranted.

Tryptophan Metabolism in Allergic Disorders

Allergic diseases such as asthma and rhinitis, as well the early phase of atopic dermatitis, are characterized by a Th2-skewed immune environment. Th2-type cytokines are upregulated in allergic inflammation, whereas there is downregulation of the Th1-type immune response and related cytokines, such as interferon-x03B3; (IFN-x03B3;). The latter is a strong inducer of indoleamine 2,3-dioxygenase-1 (IDO-1), which degrades the essential amino acid tryptophan, as part of an antiproliferative strategy of immunocompetent cells to halt the growth of infected and malignant cells, and also of T cells - an immunoregulatory intervention to avoid overactivation of the immune system. Raised serum tryptophan concentrations have been reported in patients with pollen allergy compared to healthy blood donors. Moreover, higher baseline tryptophan concentrations have been associated with a poor response to specific immunotherapy. It has been shown that the increase in tryptophan concentrations in patients with pollen allergy only exists outside the pollen season, and not during the season. Interestingly, there is only a minor alteration of the kynurenine to tryptophan ratio (Kyn/Trp, an index of tryptophan breakdown). The reason for the higher tryptophan concentrations in patients with pollen allergy outside the season remains a matter of discussion. To this regard, the specific interaction of nitric oxide (NO∙) with the tryptophan-degrading enzyme IDO-1 could be important, because an enhanced formation of NO∙ has been reported in patients with asthma and allergic rhinitis. Importantly, NO∙ suppresses the activity of the heme enzyme IDO-1, which could explain the higher tryptophan levels. Thus, inhibitors of inducible NO∙ synthase should be reconsidered as candidates for antiallergic therapy out of season that may abrogate the arrest of IDO-1 by decreasing the production of NO∙. Considering its association with the pathophysiology of atopic disease, tryptophan metabolism may play a relevant role in the pathophysiology of allergic disorders.

The Microbiome and Mental Health: Looking Back, Moving Forward with Lessons from Allergic Diseases

Relationships between gastrointestinal viscera and human emotions have been documented by virtually all medical traditions known to date. The focus on this relationship has waxed and waned through the centuries, with noted surges in interest driven by cultural forces. Here we explore some of this history and the emerging trends in experimental and clinical research. In particular, we pay specific attention to how the hygiene hypothesis and emerging research on traditional dietary patterns has helped re-ignite interest in the use of microbes to support mental health. At present, the application of microbes and their structural parts as a means to positively influence mental health is an area filled with promise. However, there are many limitations within this new paradigm shift in neuropsychiatry. Impediments that could block translation of encouraging experimental studies include environmental forces that work toward dysbiosis, perhaps none more important than westernized dietary patterns. On the other hand, it is likely that specific dietary choices may amplify the value of future microbial-based therapeutics. Pre-clinical and clinical research involving microbiota and allergic disorders has predated recent work in psychiatry, an early start that provides valuable lessons. The microbiome is intimately connected to diet, nutrition, and other lifestyle variables; microbial-based psychopharmacology will need to consider this contextual application, otherwise the ceiling of clinical expectations will likely need to be lowered.

Dietary n-3 long chain polyunsaturated fatty acids in allergy prevention and asthma treatment

The rise in non-communicable diseases, such as allergies, in westernized countries links to changes in lifestyle and diet. N-3 long chain polyunsaturated fatty acids (LCPUFA) present in marine oils facilitate a favorable milieu for immune maturation and may contribute to allergy prevention. N-3 LCPUFA can suppress innate and adaptive immune activation and induce epigenetic changes. Murine studies convincingly show protective effects of fish oil, a source of n-3 LCPUFA, in food allergy and asthma models. Observational studies in human indicate that high dietary intake of n-3 LCPUFA and low intake of n-6 PUFA may protect against the development of allergic disease early in life. High n-6 PUFA intake is also associated with an increased asthma risk while n-3 LCPUFA may be protective and reduce symptoms. The quality of the marine oil used has impact on efficacy of allergy prevention and several observations link in particular n-3 LCPUFA DHA to allergy suppression. Randomized controlled trials indicate that optimal timing, duration and dosage of n-3 LC-PUFA is required to exert an allergy protective effect. Supplementation during early pregnancy and lactation has shown promising results regarding allergy prevention. However these findings should be confirmed in a larger cohort. Although clinical trials in asthma patients reveal no consistent clinical benefits of n-3 LCPUFA supplementation on lung function, it can suppress airway inflammation. Future food-pharma approaches may reveal whether adjunct therapy with dietary n-3 LCPUFA can improve allergy prevention or immunotherapy via support of allergen specific oral tolerance induction or contribute to the efficacy of drug therapy for asthma patients.

Association between dietary habits and asthma severity in children

OBJECTIVE

To investigate association between dietary habits and asthma severity in children.

DESIGN

Cross-sectional study.

SETTING

Two teaching hospitals in Brazil.

PARTICIPANTS

Cases (n=268) were children (3-12yr) with persistent asthma and age-matched controls (n=126) were those with intermittent asthma.

MAIN OUTCOME MEASURES

Dietary habits were determined based on food consumption in the past 12 months classified as frequent (≥3 times per week) or infrequent (never or <3 times per week).Nutritional status was classified into two categories according to WHO Child Growth Standards: obese: >2Z-score of BMI-for-age; non-obese: ≤2Z-score of BMI-for-age.

RESULTS

After adjusting for confounding factors, maternal smoking during pregnancy, preterm birth and obesity were significantly associated with persistent asthma, with adjusted ORs (95% CI) of 2.11 (1.08- 4.13), 2.61(1.07-6.35) and 2.89 (1.49-5.61), respectively. No significant association was observed between frequency of consumption of specific foods, food groups, or dietary pattern (pro- or contra-Mediterranean diet) and the severity of asthma.

CONCLUSIONS

This study did not find a significant association between dietary habits and asthma severity in children. Maternal smoking during pregnancy, preterm birth and obesity were independent factors associated with persistent asthma.

Prevalence, severity and risk factors of allergic disorders among people in south India

BACKGROUND

Allergic disorders are not usually life-threatening conditions but they impair the person's ability to function. It thus adversely affects the psychological wellbeing and quality of life. These implications of allergic disorders can be minimized if strategies are planned for its early identification followed by appropriate interventions.

OBJECTIVES

To find out the prevalence and risk factors of allergic disorders.

METHODS

Data was collected by house to house survey among participants aged 18 years and above using a standardized allergy assessment questionnaire.

RESULTS

Mean age of the 400 participants was 42.8±14.7 years. Majority 105(26.2%) were in the age group 36 to 45 years. Majority were females 287(71.7%) and were house wives 217(54.2%). Majority of participants were of upper socio economic class 98(44.7%) out of 219 and majority were from urban areas 326(81.5%). The prevalence of allergy among participants was found to be 115(28.7%). Out of these 115, 37(32.2%) had possibility of allergy, 60(52.2%) had probability of allergy and the rest 18(15.6%) had very high likelihood for allergy. People residing in semi urban areas had increased risk of allergy (p=0.024) than those from urban areas. The prevalence of asthma was 30(7.5%) and skin allergy was 23(5.8%). Most common precipitating factors for allergy were dust exposure 103(25.8%) followed by seasonal changes 71(17.8%). Family history of allergy was associated with allergy among participants (p<0.001). Usage of firewood was associated with symptoms of respiratory allergy among participants (p=0.01).

CONCLUSION

The study revealed some important determinants of allergic disorders which have important implications to frame appropriate prevention and health educational strategies.

Role of Environmental Factors in the Development of Pediatric Eosinophilic Esophagitis

BACKGROUND

Despite accumulating data on the pathogenesis of eosinophilic esophagitis, not much is known about risk factors for the development of the disease. The role of factors such as smoking, breastfeeding, early antibiotic exposure and other factors that have been associated with other allergic diseases has not been well studied in children with eosinophilic esophagitis.

AIM

To explore the role of environmental and medication exposures in the development of pediatric eosinophilic esophagitis.

METHODS

We conducted a cross-sectional case-control study, utilizing a parent and child questionnaire and medical chart review. Urine cotinine levels, measured by high-performance liquid chromatography, were obtained as objective evidence for smoking exposure.

RESULTS

One hundred and two children with eosinophilic esophagitis and 167 controls were recruited. The controls were mainly diagnosed with functional gastrointestinal disorders (33%) and gastroesophageal reflux disease (29%). Food allergy, specifically for peanuts and tree nuts, and allergy to pollen, tree, and grass were significantly higher among eosinophilic esophagitis children. Smoking exposure, both primary and secondary, was not associated with pediatric eosinophilic esophagitis when compared to controls (odds ratio 0.96, 95% confidence interval 0.58-1.59). Furthermore, early smoking exposure in the first year of life was higher among controls. Common accepted risk factors for allergy and atopy, such as breastfeeding practices, antibiotics exposure, animals' exposure, and others, were not found to be associated with eosinophilic esophagitis in our study.

CONCLUSION

Common risk factors in other allergic and atopic conditions were not found to be associated with eosinophilic esophagitis.

Diet, interleukin-17, and childhood asthma in Puerto Ricans

BACKGROUND

Dietary patterns might influence the pathogenesis of asthma in Puerto Ricans, the ethnic group most affected by this disease in the United States.

OBJECTIVE

To examine the association among diet, T-helper cell type 17 cytokines, and asthma in Puerto Rican children.

METHODS

As part of a case-control study of 678 Puerto Rican children 6 to 14 years old in San Juan, participants completed a 75-item questionnaire on the child's food consumption in the prior week. Foods were aggregated into 7 groups: fruits, vegetables, grains, protein foods, dairy, fats, and sweets. Logistic regression was used to evaluate consumption frequency of each group, plasma T-helper cell type 17 cytokine levels, and asthma. Based on this analysis, a food score (range -2 [unhealthy diet: high consumption of dairy products and sweets, low consumption of vegetables and grains] to +2 [healthy diet: high consumption of grains and vegetables, low consumption of dairy and sweets]) was created to identify dietary patterns.

RESULTS

High consumption of grains was associated with lower odds of asthma (adjusted odds ratio [aOR] 0.52, 95% confidence interval [CI] 0.33-0.82), whereas frequent consumption of dairy products (aOR 1.93, 95% CI 1.32-2.84) or sweets (aOR 1.82, 95% CI 1.08-2.72) was associated with higher odds of asthma. A healthier diet (each 1-point increment in food score) was associated with lower levels of interleukin-17F (β = -1.48 pg/mL, 95% CI -1.78 to -1.20) and with 36% decreased odds of asthma (aOR 0.64, 95% CI 0.53-0.77).

CONCLUSION

A healthy diet, with frequent consumption of vegetables and grains and low consumption of dairy products and sweets, was associated with lower levels of interleulin-17F and decreased odds of childhood asthma in Puerto Ricans.

Fast food consumption in pregnancy and subsequent asthma symptoms in young children

BACKGROUND

Recent cross-sectional studies suggested children's current fast food consumption to be related to frequency of asthma and allergies. Maternal prenatal diet has been suspected to contribute to children's asthma and atopic disease risks.

OBJECTIVES

We hypothesized that maternal fast food intake during pregnancy increases offspring's risk for asthmatic symptoms.

METHODS

We conducted a population-based study of 1201 mother/child pairs in Los Angeles, California. Detailed information about prenatal fast food intake and other dietary, lifestyle/environmental factors, and pregnancy was collected shortly after birth; further data were retrieved from birth certificates. Using the International Study of Asthma and Allergies in Childhood core questions, asthma and rhinitis symptoms were assessed, and doctor's diagnoses were recorded in offspring 3.5 years after birth. Poisson regression with robust error variance using a log link function was used to estimate relative risks (RRs). Models were adjusted using covariates or propensity scores.

RESULTS

Maternal prenatal fast food consumption related to increased relative risks of their children for severe, and current asthma symptoms (wheeze last 12 months combined with doctor's diagnosis) in a dose-dependent manner: 'once a month': RR: 0.99 (95% CI: 0.36, 2.75), 'once a week': 1.26 (0.47, 3.34); '3-4 days a week': 2.17 (0.77, 6.12); and 'every day' 4.46 (1.36 14.6) compared to 'never', adjusting for potential confounders (p for trend = 0.0025). There was also suggestion of increased risks for rhinitis symptoms.

CONCLUSIONS

These findings suggest that in utero exposure to frequent fast food through maternal diet may be a risk factor for asthmatic symptoms in young children.

Dietary changes in migrant adolescents with increasing length of stay in Australia and associated risk of wheeze--a retrospective, cross sectional study

BACKGROUND

Recent studies have reported that asthma prevalence increases on migration to Australia. We hypothesised that changes in dietary intake contribute to this phenomenon. The aim of this study was to assess dietary intake in relation to migration status, length of stay in Australia and the association with self-reported wheeze.

METHODS

Students (n = 144) in a multicultural high school in Western Sydney completed the asthma symptoms ISAAC video questionnaire (AVQ3.0), spirometry and allergy skin prick tests. A dietitian administered a'Food Frequency' and 'Food Habits' questionnaire and a dietary history interview.

RESULTS

Students who spoke a language other than English, consumed a traditional or mixed dietary pattern, with lower consumption of saturated fat, compared to students who spoke English only. Saturated fat intake increased and fibre intake decreased with length of time in Australia. Intake of foods high in saturated or trans fatty acids were positively associated with length of stay in Australia. No associations between nutrient intake or whole food intake and self-reported wheeze were observed.

CONCLUSION

As time progressed, dietary intake of immigrant children changed. While this was not associated with the development of wheeze in the students in this cohort, these changes are likely to have negative health consequences.

A Traditional Diet Is Associated with a Reduced Risk of Eczema and Wheeze in Colombian Children

Background: Diet might influence the risk of allergic diseases. Evidence from developing countries with high prevalence of childhood asthma is scant. Methods: Information on wheeze, rhinitis, and eczema was collected from 3209 children aged 6–7 years in 2005, who were taking part in the International Study on Asthma and Allergy in Children (ISAAC) in Colombia. Intake frequency of twelve food groups was assessed. Associations between each food group and current wheeze, rhino-conjunctivitis, and eczema were investigated with multiple logistic regressions, adjusting for potential confounders. Simes’ procedure was used to test for multiple comparisons. Results: 14.9% of children reported wheeze in the last 12 months, 16% rhino-conjunctivitis, and 22% eczema. Eczema was negatively associated with consumption of fresh fruits and pulses three or more times per week (adjusted Odds ratio (aOR): 0.64; 95% Confidence Interval (CI): 0.49 to 0.83; p value = 0.004; and aOR: 0.62, 95% CI: 0.47 to 0.80; p value < 0.001, respectively). Current wheeze was negatively associated with intake of potatoes (aOR: 0.44, 95% CI: 0.31 to 0.62, p value = 0.005), whilst this outcome was positively associated with consumption of fast food (aOR: 1.76, 95% CI: 1.32 to 2.35, p value = 0.001). These associations remained statistically significant after controlling for multiple comparisons. Conclusions: A traditional diet might have a protective effect against eczema and wheeze in Colombian children, whilst intake of fast foods increases this risk.

Evidence that asthma is a developmental origin disease influenced by maternal diet and bacterial metabolites

Asthma is prevalent in Western countries, and recent explanations have evoked the actions of the gut microbiota. Here we show that feeding mice a high-fibre diet yields a distinctive gut microbiota, which increases the levels of the short-chain fatty acid, acetate. High-fibre or acetate-feeding led to marked suppression of allergic airways disease (AAD, a model for human asthma), by enhancing T-regulatory cell numbers and function. Acetate increases acetylation at the Foxp3 promoter, likely through HDAC9 inhibition. Epigenetic effects of fibre/acetate in adult mice led us to examine the influence of maternal intake of fibre/acetate. High-fibre/acetate feeding of pregnant mice imparts on their adult offspring an inability to develop robust AAD. High fibre/acetate suppresses expression of certain genes in the mouse fetal lung linked to both human asthma and mouse AAD. Thus, diet acting on the gut microbiota profoundly influences airway responses, and may represent an approach to prevent asthma, including during pregnancy.

Asthma control in pregnancy is associated with pre-conception dietary patterns

OBJECTIVE

To examine pre-conception dietary patterns in pregnant asthmatic women and to identify associations between maternal diet and asthma control during pregnancy.

DESIGN

Cross-sectional study. Pre-conception food frequency data were collected retrospectively. Asthma control was assessed using the Global Initiative for Asthma guidelines. Dietary patterns were derived using factor analysis. Binary logistic regression analyses were used to test the association between uncontrolled asthma and each dietary pattern (Z-score), with values presented as odds ratio and 95 % confidence interval.

SETTING

Antenatal clinic in a tertiary hospital, Adelaide, Australia, May 2009-July 2013.

SUBJECTS

One hundred and fifty-eight asthmatic pregnant women.

RESULTS

Three dietary patterns were identified: (i) 'high protein/fruit' (strong food group loadings for fish, meat, chicken, fruit); (ii) 'high fat/sugar/takeaway' (takeaway foods, crisps, refined grains); and (iii) 'vegetarian-type' (vegetables, fruit, soya milk, whole grains). A 1 sd increase in score on the high fat/sugar/takeaway pattern was associated with increased likelihood of uncontrolled asthma (adjusted OR=1·54; 95 % CI 1·07, 2·23; P=0·022). Women with uncontrolled asthma (n 115) had higher energy-adjusted intakes of saturated fat, monounsaturated fat, carbohydrate, sugar and fibre compared with women with controlled asthma (n 43, all P≤0·05).

CONCLUSIONS

Pre-pregnancy dietary patterns may influence maternal asthma control. Our work highlights the importance of achieving a healthy diet before pregnancy that is low in saturated fat, sugar and takeaway foods, and therefore higher in lean meats, poultry and fish, as well as fruits, vegetables and whole grains. A healthy dietary pattern should be encouraged in all asthmatic women who are of childbearing age, and should additionally be promoted before pregnancy and beyond.

The gut microbiota and inflammatory noncommunicable diseases: associations and potentials for gut microbiota therapies

Rapid environmental transition and modern lifestyles are likely driving changes in the biodiversity of the human gut microbiota. With clear effects on physiologic, immunologic, and metabolic processes in human health, aberrations in the gut microbiome and intestinal homeostasis have the capacity for multisystem effects. Changes in microbial composition are implicated in the increasing propensity for a broad range of inflammatory diseases, such as allergic disease, asthma, inflammatory bowel disease (IBD), obesity, and associated noncommunicable diseases (NCDs). There are also suggestive implications for neurodevelopment and mental health. These diverse multisystem influences have sparked interest in strategies that might favorably modulate the gut microbiota to reduce the risk of many NCDs. For example, specific prebiotics promote favorable intestinal colonization, and their fermented products have anti-inflammatory properties. Specific probiotics also have immunomodulatory and metabolic effects. However, when evaluated in clinical trials, the effects are variable, preliminary, or limited in magnitude. Fecal microbiota transplantation is another emerging therapy that regulates inflammation in experimental models. In human subjects it has been successfully used in cases of Clostridium difficile infection and IBD, although controlled trials are lacking for IBD. Here we discuss relationships between gut colonization and inflammatory NCDs and gut microbiota modulation strategies for their treatment and prevention.

Urban-rural differences in asthma prevalence among young adolescents: The role of behavioural and environmental factors

BACKGROUND

Asthma prevalence has been reported to be lower in rural areas compared to urban areas, although this has been inconsistent. This study aims to identify the influence of urban-rural residence on asthma prevalence in adolescents in the Republic of Macedonia and to investigate characteristics that may explain observed associations.

METHODS

Following International Study of Asthma and Allergies in Childhood protocol, a national sample of Macedonian urban and rural dwelling adolescents (12-16 years) was recruited in 2006. Self-completed questionnaires were used to collect data on wheeze and asthma as well as personal, environmental and dietary characteristics. Following descriptive and multiple logistic regression analyses, a mediation analysis approach was performed to help explain observed associations.

RESULTS

A lower prevalence of current wheeze and ever-diagnosed asthma was observed in rural compared to urban dwelling adolescents (4.9% vs. 7.2% and 1.2% vs. 1.9%, respectively). After adjustment for potential confounders, the associations, although still protective, were not statistically significant (wheeze: OR=0.74, 95%CI=0.46-1.21; asthma: OR=0.97, 95%CI=0.38-2.46). The associations between urban-rural status with current wheeze and asthma were mediated by region of the country (wheeze 9%; asthma 19%) and by diet (>5% change for both wheeze and asthma). Having a dog resulted in a strengthening of the association between urban-rural status and current wheeze by 11.9%.

CONCLUSIONS

The prevalence of asthma and wheeze was lower in rural dwelling Macedonian adolescents and the association was mediated by the region of the country with diet likely to be part of the reason for this mediating effect.

Lifestyle domains as determinants of wheeze prevalence in urban and rural schoolchildren in Ecuador: cross sectional analysis

BACKGROUND

The acquisition of a modern lifestyle may explain variations in asthma prevalence between urban and rural areas in developing countries. However, the effects of lifestyle on asthma have been investigated as individual factors with little consideration given to the effects of lifestyle as a set of attributes. The aim of the present study was to identify modern lifestyle domains and assess how these domains might explain wheeze prevalence in urban and rural areas.

METHODS

We analysed data from cross-sectional studies of urban and rural schoolchildren in Esmeraldas Province, Ecuador. Variables were grouped as indicators of socioeconomic factors, sedentarism, agricultural activities and household characteristics to represent the main lifestyle features of the study population. We used multiple correspondence analyses to identify common lifestyle domains and cluster analysis to allocate children to each domain. We evaluated associations between domains and recent wheeze by logistic regression.

RESULTS

We identified 2-3 lifestyle domains for each variable group. Although wheeze prevalence was similar in urban (9.4%) and rural (10.3%) schoolchildren, lifestyle domains presented clear associations with wheeze prevalence. Domains relating to home infrastructure (termed transitional, rudimentary, and basic urban) had the strongest overall effect on wheeze prevalence in both urban (rudimentary vs. basic urban, OR = 2.38, 95% CI 1.12-5.05, p = 0.024) and rural areas (transitional vs. basic urban, OR = 2.02, 95% CI 1.1-3.73, p = 0.024; rudimentary vs. basic urban, OR = 1.88, 95% CI 1.02-3.47, p = 0.043). A high level of sedentarism was associated with wheeze in the rural areas only (OR = 1.64, 95% CI 1.23-2.18, p = 0.001).

CONCLUSIONS

We identified lifestyle domains associated with wheeze prevalence, particularly living in substandard housing and a high level of sedentarism. Such factors could be modified through programmes of improved housing and education. The use of lifestyle domains provides an alternative methodology for the evaluation of variations in wheeze prevalence in populations with different levels of development.

Asthma and obesity in children: current evidence and potential systems biology approaches

Both obesity and asthma are highly prevalent, complex diseases modified by multiple factors. Genetic, developmental, lung mechanical, immunological and behavioural factors have all been suggested as playing a causal role between the two entities; however, their complex mechanistic interactions are still poorly understood and evidence of causality in children remains scant. Equally lacking is evidence of effective treatment strategies, despite the fact that imbalances at vulnerable phases in childhood can impact long-term health. This review is targeted at both clinicians frequently faced with the dilemma of how to investigate and treat the obese asthmatic child and researchers interested in the topic. Highlighting the breadth of the spectrum of factors involved, this review collates evidence regarding the investigation and treatment of asthma in obese children, particularly in comparison with current approaches in 'difficult-to-treat' childhood asthma. Finally, the authors propose hypotheses for future research from a systems-based perspective.

Factors associated with asthma in adolescents in the city of Fortaleza, Brazil

OBJECTIVE

Asthma is a chronic inflammatory airway disease. In Brazil, little is known about factors associated with this disease. This study aimed to identify factors associated with asthma in 13- to 14-year-old adolescents in Fortaleza, Ceará, Brazil.

METHODS

It is a cross-sectional population-based study, with a probability sample of 3015 students in 2006-2007. We used the questionnaires about asthma, rhinitis and socio-demographic/environmental factors from the International Study for Asthma and Allergies in Childhood (ISAAC) protocol. Current asthma was defined as physician-diagnosed asthma and wheezing in the previous 12 months. Bivariate analysis was performed between asthma and factors included in the study, using prevalence ratio and Chi-square test. Confidence intervals (95%) and odds ratio (OR) were also calculated. Factors associated with asthma in bivariate analysis were then assessed using logistic regression.

RESULTS

Final sample was composed by 694 adolescents, 179 with asthma. Rhinoconjunctivitis and consumption of stuffed biscuits and fried snacks three or more times per week were independently and positively associated with asthma; consumption of fruits three or more times per week was negatively associated with asthma.

CONCLUSIONS

Dietary factors were the most associated with asthma in this study. Besides rhinoconjunctivitis, consumption of stuffed biscuits and fried snacks (foods with high content of saturated fat) three or more times per week were independently associated with asthma as aggravating factors, while the consumption of fruits three or more times per week was associated with asthma as protective factor. Interventions acting on these factors may decrease the occurrence of asthma in this population.

Dietary habits and prevalence of allergic rhinitis in 6 to 7-year-old schoolchildren in Turkey

BACKGROUND

The prevalence of allergic rhinitis and other allergies has risen worldwide. Dietary habits are considered to be among the potential risk factors. The aim of this study was to evaluate the prevalence of allergic rhinitis and its relationship with dietary habits and other risk factors among 6 to 7-year-old Turkish schoolchildren.

METHODS

In this cross-sectional study, a total of 11483 children aged 6-7 years were surveyed. The prevalence of symptoms of allergic rhinitis was assessed using the ISAAC protocol. Dietary information was collected using a food frequency questionnaire.

RESULTS

Of them, 9875 (50.7% M 49.3% F) questionnaires were appropriately completed. The prevalence rates of lifetime rhinitis, current rhinitis, current rhinoconjunctivitis and physician-diagnosed allergic rhinitis, were 44.3%, 29.2%, 8.5% and 8.1%, respectively. Consumption of rice, and cereals ≥3 times per week showed protective effect on physician-diagnosed allergic rhinitis (aOR = 0.53, 95% CI = 0.32-0.87 and aOR = 0.58, 95% CI = 0.36-0.92). Eating pasta, and chocolates ≥3 times per week showed protective effect on current rhinoconjunctivitis (aOR = 0.45, 95% CI = 0.25-0.79 and aOR = 0.50, 95% CI = 0.29-0.86). Eating lollipops, candies and animal fats ≥3 times per week was positively associated with current rhinoconjunctivitis (aOR = 1.47, 95% CI = 1.00-2.17 and aOR = 2.25, 95% CI = 1.11-4.56). Protective effect of the Mediterranean diet was not significant.

CONCLUSIONS

Frequent consumption of cereals, rice, pasta and chocolates may have beneficial effect on symptoms of rhinoconjunctivitis. Although dietary habits may affect the prevalence of symptoms of current rhinoconjunctivitis, the Mediterranean diet alone may not be protective against rhinoconjunctivitis.

Fruit and vegetable intake and risk of wheezing and asthma: a systematic review and meta-analysis

Major bibliographic databases were searched for studies examining the relationship between fruit and vegetable consumption and the risk of wheezing and asthma. Random-effects models were used to pool study results. Subgroup analyses were conducted by fruit and vegetable categories, study design, and age group. Twelve cohorts, 4 population-based case-control studies, and 26 cross-sectional studies published between January 1990 and July 2013 were identified. For the meta-analysis of adults and children, the relative risk (RR) and confidence intervals (CI) when comparing the highest intake group with the lowest intake group were 0.78 (95%CI, 0.70-0.87) for fruit and 0.86 (95%CI, 0.75-0.98) for vegetables. High intake of fruit and vegetables (RR = 0.76; 95%CI, 0.68-0.86 and RR = 0.83; 95%CI, 0.72-0.96) reduced the risk of childhood wheezing. Total intake of fruit and vegetables had a negative association with risk of asthma in adults and children (RR = 0.54; 95%CI, 0.41-0.69). Consuming fruit and vegetables during pregnancy had no association with the risk of asthma in offspring. High intake of fruit and vegetables may reduce the risk of asthma and wheezing in adults and children.

Trends in the prevalence of asthma

The asthma epidemic of the last few decades may have peaked; studies suggest that the incidence and prevalence of asthma has decreased in some countries in the last few years, although other studies suggest continuing small increases in prevalence. Increasing awareness and changing diagnostic habits make precise evaluation of epidemiologic trends difficult in the absence of a gold-standard test for asthma, and on a global basis uncertainty persists. Trends in prevalence in some populations (eg, immigrants, farming communities) suggest both adverse and beneficial effects of specific environmental factors. Although the effects of indoor allergens, dampness, and mold and of outdoor air pollutants, especially traffic related, have traditionally dominated risk-factor research, more recent epidemiologic and clinical studies have focused on metabolic and nutritional factors, including maternal obesity and vitamin D levels, mode of delivery and its effect on the infant microbiome, fetal and infant growth, the psychosocial environment, and medication use by mother and infant. It is likely that changes in incidence and prevalence are due to multiple factors, each contributing a relatively small effect. Longitudinal studies from pregnancy through childhood to adulthood will yield greater insights into the complex pathways leading to asthma.

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.

Association between environmental factors and current asthma, rhinoconjunctivitis and eczema symptoms in school-aged children from Oropeza Province--Bolivia: a cross-sectional study

BACKGROUND

In recent years, the prevalence of asthma, rhinoconjunctivitis and eczema symptoms in childhood has considerably increased in developing countries including Bolivia, possibly due to changes in lifestyle, environmental and domestic factors. This study aimed to assess the association between environmental factors and asthma, rhinoconjuctivitis and eczema symptoms in school-aged children from Oropeza Province in Chuquisaca, Bolivia.

METHODS

A cross-sectional study was performed in 2340 children attending the fifth grade in 36 randomly selected elementary schools in Oropeza province. The prevalence of symptoms was determined using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Environmental factors were assessed by the ISAAC environmental questionnaire including questions related to exposure to pets, farm animals, indoor and outdoor pollution, presence of disease vectors at home and precarious household conditions. Generalized linear mixed-effects models were adjusted for age, sex and place of living.

RESULTS

Thirty seven percent of children reported that at least one of their parents smoked at home. Wood or coal was used as cooking fuel in 19% of the homes and 29% reported intense truck traffic on the street where they lived. With respect to hygiene conditions, 86% reported exposure to dogs, 59% exposure to cats and 36% regular contact to farm animals. More than one precarious household condition was reported by 8% of children. In the adjusted model exposure to dog (adjusted OR 1.4; CI 95% 1.0-1.9), cat (1.2; 1.0-1.5), farm animals (1.5; 1.2-1.8); intense truck traffic (1.3; 1.0-1.6), parents smoking at home (1.2; 1.0-1.5), presence of disease vectors at home (fourth quartile vs. first quartile: 1.6; 1.2-2.3) and two or more precarious household conditions (1.5; 1.0-2.2) were significantly associated with rhinoconjunctivitis symptoms. The associations were similar for asthma and eczema symptoms; however it did not reach the level of statistical significance for all items.

CONCLUSION

Our results support previous findings reported for poor communities especially in Latin America, showing that lower hygiene conditions did not have protective effect against asthma and rhinoconjunctivitis and eczema symptoms.

Diet and allergic diseases among population aged 0 to 18 years: myth or reality?

Allergic diseases are an important health problem. However, epidemiological studies concerning childhood diet-related allergic diseases are scarce. This review examines published articles dealing with diet, dietary patterns and nutrition in relation with allergic diseases among population aged 0 to 18 years. Studies and trials were identified using MEDLINE/PubMed and Cochrane Database of Systematic Reviews and were limited to those published in English or French from 1992 until 2012. This manuscript also reviews the evidence for maternal diet during pregnancy and diet during early childhood and their association with childhood atopic diseases, taking into account the methodology used to evaluate dietary patterns. The evidence reviewed is derived from large epidemiological studies exploring the effects of different food categories on asthma, atopic dermatitis, and allergic rhinitis in children. Overall, maternal diet during pregnancy and a childhood diet rich in antioxidants and omega-3 fatty acids are considered as healthy diets that could be protective for allergic diseases in childhood.