Migration to a western country increases asthma symptoms but not eosinophilic airway inflammation

The effects of the DASH dietary pattern on clinical outcomes and quality of life in adults with uncontrolled asthma: Design and methods of the ALOHA Trial

BACKGROUND

Poor diet quality is an important risk factor for increased asthma prevalence and poor asthma control. To address the question of whether adults with asthma can benefit from following a healthy diet, this trial will test the efficacy and mechanisms of action of a behavioral intervention promoting the Dietary Approaches to Stop Hypertension (DASH) dietary pattern with sodium reduction among patients with uncontrolled asthma.

METHODS

In this 2-arm randomized clinical trial, 320 racially/ethnically and socioeconomically diverse adults with uncontrolled asthma on standard controller therapy will be randomized to either a control or an intervention group and assessed at baseline, 3, 6 and 12 months. Control and intervention participants will receive education on lung health, asthma, and other general health topics; additionally, the intervention group will receive DASH behavioral counseling over 12 months. The primary hypothesis is that the DASH behavioral intervention, compared with the education-only control, will lead to significantly more participants with minimum clinically important improvement (responders) in asthma-specific quality of life at 12 months. Secondary hypotheses will test the intervention effects on other asthma (e.g., asthma control, lung function) and non-asthma outcomes (e.g., quality of life). Additionally, therapeutic (e.g., short chain fatty acids, cytokines) and nutritional biomarkers (e.g., dietary inflammatory index, carotenoids) will be assessed to understand the mechanisms of the intervention effect.

CONCLUSION

This trial can substantially advance asthma care by providing rigorous evidence on the benefits of a behavioral dietary intervention and mechanistic insights into the role of diet quality in asthma.

CLINICALTRIALS

gov #: NCT05251402.

Prevalence of asthma and allergic symptoms in Suzhou, China: Trends by domestic migrant status

Rapid urbanization in developing countries, with significant rural-to-urban and between-urban areas migration, presents a natural epidemiological model to better understand population-level trends in asthma and allergy prevalance without confounding by genetic factors. This cross-sectional study, conducted November 2014 to January 2015 in Suzhou, China, investigated differences in asthma and allergic symptoms between domestic migrant residents and long-term residents and their children. Using multivariate logistic regression, the odds ratios for children in migrant families compared to those in long-term resident families in Suzhou for doctor-diagnosed asthma, pneumonia, rhinitis, and eczema were 0.56 (95% CI: 0.42.0.73), 0.60 (95% CI: 0.49, 0.72), 0.63 (95% CI:0.52, 0.77), and 0.73 (95% CI: 0.60, 0.89), respectively. While there was a lower prevalence of asthma and allergic symptoms for domestic migrants (children and parents) compared to the local population in Suzhou, migrant children had a higher asthma rate than their parents. This follows the trend of increasing asthma rates for children in the urban local population, suggesting an environmental component. Parental migration plays a role in both parental and children's health but further investigations are needed to determine how these results may be shaped by early life exposures, lifestyle differences, and other environmental factors.

Lower Prevalence of Atopic Dermatitis and Allergic Sensitization among Children and Adolescents with a Two-Sided Migrant Background

In industrialized countries atopic diseases have been reported to be less likely in children and adolescents with a migrant background compared to non-migrants. This paper aimed at both examining and comparing prevalence of asthma, allergic rhinoconjunctivitis and atopic dermatitis and allergic sensitization to specific IgE antibodies in children and adolescents with and without a migrant background. Using data of the population-based German Health Interview and Examination Survey for children and adolescents (KiGGS; n = 17,450; 0–17 years), lifetime and 12-month prevalence of atopic diseases and point prevalence of 20 common allergic sensitizations were investigated among migrants compared to non-migrants. Multiple regression models were used to estimate the association of atopic disease and allergic sensitization with migrant background. In multivariate analyses with substantial adjustment we found atopic dermatitis about one-third less often (OR 0.73, 0.57–0.93) in participants with a two-sided migrant background. Statistically significant associations between allergic sensitizations and a two-sided migrant background remained for birch (OR 0.73, 0.58–0.90), soybean (OR 0.72, 0.54–0.96), peanut (OR 0.69, 0.53–0.90), rice (OR 0.64, 0.48–0.87), potato (OR 0.64, 0.48–0.85), and horse dander (OR 0.58, 0.40–0.85). Environmental factors and living conditions might be responsible for the observed differences.

Pulmonary Disease and Age at Immigration among Hispanics. Results from the Hispanic Community Health Study/Study of Latinos

RATIONALE

Asthma has been reported to be more prevalent among Hispanics of Puerto Rican heritage than among other Hispanics and among Hispanics born in the United States or who immigrated as children than among those who came as adults; however, direct comparisons across Hispanic groups are lacking.

OBJECTIVES

To test whether asthma is more prevalent among Hispanics of Puerto Rican heritage than among other Hispanic groups, whether asthma is associated with age of immigration, and whether chronic obstructive pulmonary disease varies by heritage in a large, population-based cohort of Hispanics in the United States.

METHODS

The Hispanic Community Health Study/Study of Latinos researchers recruited a population-based probability sample of 16,415 Hispanics/Latinos, 18-74 years of age, in New York City, Chicago, Miami, and San Diego. Participants self-reported Puerto Rican, Cuban, Dominican, Mexican, Central American, or South American heritage; birthplace; and, if relevant, age at immigration. A respiratory questionnaire and standardized spirometry were performed with post-bronchodilator measures for those with airflow limitation.

MEASUREMENTS AND MAIN RESULTS

The prevalence of physician-diagnosed asthma among Puerto Ricans (36.5%; 95% confidence interval, 33.6-39.5%) was higher than among other Hispanics (odds ratio, 3.9; 95% confidence interval, 3.3-4.6). Hispanics who were born in the mainland United States or had immigrated as children had a higher asthma prevalence than those who had immigrated as adults (19.6, 19.4, and 14.1%, respectively; P < 0.001). Current asthma, bronchodilator responsiveness, and wheeze followed similar patterns. Chronic obstructive pulmonary disease prevalence was higher among Puerto Ricans (14.1%) and Cubans (9.8%) than among other Hispanics (<6.0%), but it did not vary across Hispanic heritages after adjustment for smoking and prior asthma (P = 0.22), by country of birth, or by age at immigration.

CONCLUSIONS

Asthma was more prevalent among Puerto Ricans, other Hispanics born in the United States, and those who had immigrated as children than among other Hispanics. In contrast, the higher prevalence of chronic obstructive pulmonary disease among Puerto Ricans and Cubans was largely reflective of differential smoking patterns and asthma.

Changes in Expression of Genes Regulating Airway Inflammation Following a High-Fat Mixed Meal in Asthmatics

Consumption of a high fat meal can increase neutrophilic airway inflammation in asthma subjects. This study investigates the molecular mechanisms driving airway neutrophilia following a high fat meal in asthmatics. Subjects with asthma (n = 11) and healthy controls (n = 8) consumed a high-fat/energy meal, containing total energy (TE) of 3846 kJ and 48 g of total fat (20.5 g saturated). Sputum was induced at 0 and 4 h, and gene expression was examined by microarray and quantitative real-time PCR (qPCR). Following the high fat dietary challenge, 168 entities were significantly differentially expressed greater than >1.5 fold in subjects with asthma, whereas, in healthy controls, only 14 entities were differentially expressed. Of the 168 genes that were changed in asthma, several biological processes were overrepresented, with 25 genes involved in "immune system processes". qPCR confirmed that S100P, S100A16, MAL and MUC1 were significantly increased in the asthma group post-meal. We also observed a strong correlation and a moderate correlation between the change in NLRP12 and S100A16 gene expression at 4 h compared to baseline, and the change in total and saturated non-esterified plasma fatty acid levels at 2 h compared to baseline. In summary, our data identifies differences in inflammatory gene expression that may contribute to increased airway neutrophilia following a high fat meal in subjects with asthma and may provide useful therapeutic targets for immunomodulation. This may be particularly relevant to obese asthmatics, who are habitually consuming diets with a high fat content.

Allergy associations with the adult fecal microbiota: Analysis of the American Gut Project

BACKGROUND

Alteration of the gut microbial population (dysbiosis) may increase the risk for allergies and other conditions. This study sought to clarify the relationship of dysbiosis with allergies in adults.

METHODS

Publicly available American Gut Project questionnaire and fecal 16S rRNA sequence data were analyzed. Fecal microbiota richness (number of observed species) and composition (UniFrac) were used to compare adults with versus without allergy to foods (peanuts, tree nuts, shellfish, other) and non-foods (drug, bee sting, dander, asthma, seasonal, eczema). Logistic and Poisson regression models adjusted for potential confounders. Odds ratios and 95% confidence intervals (CI) were calculated for lowest vs highest richness tertile. Taxonomy associations considered 122 non-redundant taxa (of 2379 total taxa) with ≥ 0.1% mean abundance.

RESULTS

Self-reported allergy prevalence among the 1879 participants (mean age, 45.5 years; 46.9% male) was 81.5%, ranging from 2.5% for peanuts to 40.5% for seasonal. Fecal microbiota richness was markedly lower with total allergies (P = 10(-9)) and five particular allergies (P ≤ 10(-4)). Richness odds ratios were 1.7 (CI 1.3-2.2) with seasonal, 1.8 (CI 1.3-2.5) with drug, and 7.8 (CI 2.3-26.5) with peanut allergy. These allergic participants also had markedly altered microbial community composition (unweighted UniFrac, P = 10(-4) to 10(-7)). Total food and non-food allergies were significantly associated with 7 and 9 altered taxa, respectively. The dysbiosis was most marked with nut and seasonal allergies, driven by higher Bacteroidales and reduced Clostridiales taxa.

INTERPRETATION

American adults with allergies, especially to nuts and seasonal pollen, have low diversity, reduced Clostridiales, and increased Bacteroidales in their gut microbiota. This dysbiosis might be targeted to improve treatment or prevention of allergy.

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.

Pollen-derived adenosine is a necessary cofactor for ragweed allergy

BACKGROUND

Ragweed (Ambrosia artemisiifolia) is a strong elicitor of allergic airway inflammation with worldwide increasing prevalence. Various components of ragweed pollen are thought to play a role in the development of allergic responses. The aim of this study was to identify critical factors for allergenicity of ragweed pollen in a physiological model of allergic airway inflammation.

METHODS

Aqueous ragweed pollen extract, the low molecular weight fraction or the major allergen Amb a 1 was instilled intranasally on 1-11 consecutive days, and allergic airway inflammation was evaluated by bronchoalveolar lavage, lung histology, serology, gene expression in lung tissue, and measurement of lung function. Pollen-derived adenosine was removed from the extract enzymatically to analyze its role in ragweed-induced allergy. Migration of human neutrophils and eosinophils toward supernatants of ragweed-stimulated bronchial epithelial cells was analyzed.

RESULTS

Instillation of ragweed pollen extract, but not of the major allergen or the low molecular weight fraction, induced specific IgG1 , pulmonary infiltration with inflammatory cells, a Th2-associated cytokine signature in pulmonary tissue, and impaired lung function. Adenosine aggravated ragweed-induced allergic lung inflammation. In vitro, human neutrophils and eosinophils migrated toward supernatants of bronchial epithelial cells stimulated with ragweed extract only if adenosine was present.

CONCLUSIONS

Pollen-derived adenosine is a critical factor in ragweed-pollen-induced allergic airway inflammation. Future studies aim at therapeutic strategies to control these allergen-independent pathways.

Association between birthplace and current asthma: the role of environment and acculturation

OBJECTIVES

We evaluated associations between current asthma and birthplace among major racial/ethnic groups in the United States.

METHODS

We used multivariate logistic regression methods to analyze data on 102,524 children and adolescents and 255,156 adults in the National Health Interview Survey (2001-2009).

RESULTS

We found significantly higher prevalence (P < .05) of current asthma among children and adolescents (9.3% vs 5.1%) and adults (7.6% vs 4.7%) born in the 50 states and Washington, DC (US-born), than among those born elsewhere. These differences were among all age groups of non-Hispanic Whites, non-Hispanic Blacks, and Hispanics (excluding Puerto Ricans) and among Chinese adults. Non-US-born adults with 10 or more years of residency in the United States had higher odds of current asthma (odds ratio = 1.55; 95% confidence interval = 1.25, 1.93) than did those who arrived more recently. Findings suggested a similar trend among non-US-born children.

CONCLUSIONS

Current asthma status was positively associated with being born in the United States and with duration of residency in the United States. Among other contributing factors, changes in environment and acculturation may explain some of the differences in asthma prevalence.

Hydatid Cyst Protoscolices Induce Cell Death in WEHI-164 Fibrosarcoma Cells and Inhibit the Proliferation of Baby Hamster Kidney Fibroblasts In Vitro

Both in vitro and in vivo models have demonstrated that some parasites can interfere with tumor cell growth. The present study investigates the anticancer activity of hydatid cyst protoscolices on WEHI-164 fibrosarcoma cells and baby hamster kidney (BHK) fibroblast cells in vitro. Those above two cell types were treated with live hydatid cyst protoscolices or left untreated for control groups. After 48 h, lactate dehydrogenase (LDH) and cell counts were assayed for both treated cells and control groups. Following treatment with hydatid cyst protoscolices, cell proliferation of both cell types was inhibited, and lysis of fibrosarcoma cells increased. Based on these results, it appears that hydatid cyst protoscolices have strong anticancer activity, and additional studies are needed to further clarify the mechanisms of this activity.

Potential role of antioxidant food supplements, preservatives and colorants in the pathogenesis of allergy and asthma

A significant increase in the incidence of allergy and asthma has been observed during the past decades. The background of this phenomenon has not been well explained, but changes in lifestyle and habits are heavily discussed as contributing factors. Among these is a too clean environment, which may predispose individuals to increased sensitivity to allergic responses. Also the increase in dietary supplements including preservatives and colorants may contribute to this. In vitro, we and others have shown in freshly isolated human peripheral blood mononuclear cells that antioxidant compounds like vitamins C and E as well as food preservatives and colorants exert significant suppressive effects on the Th1 immune activation cascade. The effects observed may be based on the interaction of antioxidant compounds with proinflammatory cascades involving important signal transduction elements such as nuclear factor-κB. Although only obtained in vitro, these results show an anti-inflammatory property of compounds which could shift the Th1-Th2-type immune balance towards Th2-type immunity. This review article discusses the potential role of increased use of antioxidant food supplements as well as preservatives and colorants in the increase in allergy and asthma in the Western world.

Lessons for primary prevention of asthma: foreign-born children have less association of SES and pests with asthma diagnosis

There are no proven interventions for primary prevention of asthma. As asthma prevalence varies globally, comparing asthma in native and foreign-born children might provide insights. We pooled data from five cross sectional asthma surveys (N = 962). Place of birth was associated with asthma (OR = 3.4, P < 0.001). In children not born in the US, lower socio-economic status had no significant effect on asthma (OR = 0.71, P = 0.53), while for children born in the US, the effect was significant (OR = 2.1, P = 0.001). The odds ratio for exposure to household pests was significant (OR = 1.6, P < 0.008) for children born in the US but was non-significant for children born outside the US (OR = 0.29, P = 0.11). Our findings are consistent with foreign-born children experiencing protective factors or US born children experiencing detrimental environmental exposures.

Housing environments and child health conditions among recent Mexican immigrant families: a population-based study

The influx of immigrants to urban areas throughout the United States has raised concerns about accessibility of safe, affordable housing and the health consequences of poor-quality housing, particularly among immigrant children. We conducted a population-based study of home environmental conditions among recently immigrated Mexican families (weighted n = 473), generally of low socioeconomic status, and the health conditions of their children, in an urban industrial area north of Denver, Colorado. The majority of recent immigrants had low socioeconomic status; virtually all had household incomes below the Colorado median ($50,841). Approximately one quarter of homes were overcrowded. Adverse environmental conditions were present across recent immigrant homes. These conditions include dampness or mold (44%), pests (28%), and minimal to no ventilation potential (26%), all of which are associated with asthma and atopic diseases. At least one of these three environmental hazards was found in 67% of homes; multiple hazards were present in 27% of homes. Children of recent immigrant families had active symptoms within the past 12 months suggestive of asthma (4%) and atopic disorders (10%); however, fewer than 2% had been diagnosed with these conditions. The prevalence of asthma and atopic symptoms among Mexican immigrant children, albeit lower than in other low income and minority communities, is partially explained by housing conditions. Many of the conditions identified (e.g., pest infestation, mold resulting from plumbing leaks, and lack of exhaust fans) are amenable to low cost interventions. Solutions to address unhealthy housing conditions among recent immigrants must be multi-faceted and include strategies that target household-level improvements and access to health care.

Incidence of respiratory and allergic symptoms in Italian and immigrant children

BACKGROUND

Immigration usually implies a complete change of the environment where one lives. Hence, studies on immigrants may help to disentangle genetic and environmental determinants of disease. We investigated whether the incidence of allergic and respiratory symptoms differed for Italian and immigrant children living in one area of Northern Italy.

METHODS

In December 2006, all the children (3-14 years) living in the Viadana district were surveyed through a parental questionnaire (response rate = 99%, n = 3854). Retrospective incidences of several symptoms were compared across different ethnic groups.

RESULTS

Parental asthma, allergic rhinitis and eczema were less frequent in immigrant children than in Italian children. Wheezing and eczema incidences were lower in children born to foreign parents (especially if born abroad, incidence rate ratio (IRR) = 0.47, 95% CI: 0.26-0.82 and IRR = 0.43, 95% CI: 0.23-0.83, respectively), with respect to Italian children, while the occurrence of nasal allergies was similar among the ethnic groups. The greatest incidence of persistent cough/phlegm was observed in children born in Italy to foreign parents (IRR = 1.98, 95% CI: 1.06-3.71) and in children whose parents had chronic bronchitis (IRR = 2.57, 95% CI: 1.52-4.33).

CONCLUSIONS

Considering the distribution of parental atopic diseases and the low disease prevalence in the immigrants' countries of origin, we suggest that nasal allergies may be more sensitive than wheezing or eczema to the change in the environment related to migration. Genetic or environmental factors clustered into families seem to have a role on chronic bronchitis.

Pneumococcal vaccines for allergic airways diseases

BACKGROUND

Asthma is a common global health problem. Environmental exposures such as bacteria may protect against asthma development.

OBJECTIVE

This review aims to examine the possible protective role of pneumococcal infection and vaccination in asthma.

METHODS

A review of known experimental biology and human epidemiology relating to asthma and pneumococcal infection was performed.

RESULTS

Pneumococcal infection can modulate components of allergic airways disease such as airways hyperresponsiveness and airway eosinophilia. Exposure to killed pneumococcus can reproduce these effects and the mechanism may involve control by T regulatory cells.

CONCLUSIONS

Pneumococcal immunoregulatory therapy is a potentially important approach to asthma management that requires further evaluation in well-designed research studies.

Prevalence of asthma among Chinese adolescents living in Canada and in China

BACKGROUND

Studies of the prevalence of asthma among migrating populations may help in identifying environmental risk factors.

METHODS

We analyzed data from Vancouver, Canada, and from Guangzhou, Beijing and Hong Kong, China, collected during phase 3 of the International Study of Asthma and Allergies in Childhood. We subdivided the Vancouver adolescents according to whether they were Chinese immigrants to Canada, Canadian-born Chinese or Canadian-born non-Chinese. We compared the prevalence of asthma and wheezing among Chinese adolescents born in Canada, Chinese adolescents who had immigrated to Canada and Chinese adolescents living in China.

RESULTS

Of 7794 Chinese adolescents who met the inclusion criteria, 3058 were from Guangzhou, 2824 were from Beijing, and 1912 were from Hong Kong. Of 2235 adolescents in Vancouver, Canada, 475 were Chinese immigrants, 617 were Canadian-born Chinese, and 1143 were Canadian-born non-Chinese. The prevalence of current wheezing among boys ranged from 5.9% in Guangzhou to 11.2% in Canadian-born Chinese adolescents. For girls, the range was 4.3% in Guangzhou to 9.8% in Canadian-born Chinese adolescents. The prevalence of ever having had asthma ranged from 6.6% to 16.6% for boys and from 2.9% to 15.0% for girls. Prevalence gradients persisted after adjustment for other environmental variables (odds ratios for ever having had asthma among Canadian-born Chinese compared with native Chinese in Guangzhou: 2.72 [95% confidence interval 1.75-4.23] for boys and 5.50 [95% confidence interval 3.21-9.44] for girls; p < 0.001 for both). Among Chinese adolescents living in Vancouver, the prevalence of ever wheezing increased with duration of residence, from 14.5% among those living in Canada for less than 7 years to 20.9% among those living their entire life in Canada. The same pattern was observed for the prevalence of ever having had asthma, from 7.7% to 15.9%.

INTERPRETATION

Asthma symptoms in Chinese adolescents were lowest among residents of mainland China, were greater for those in Hong Kong and those who had immigrated to Canada, and were highest among those born in Canada. These findings suggest that environmental factors and duration of exposure influence asthma prevalence.

Prevalence of asthma in a large group of Israeli adolescents: influence of country of birth and age at migration

BACKGROUND

The occurrence of asthma has geographic variations and is lower in developing compared with industrialized countries. Both environmental and genetic factors may influence its prevalence. We aimed to evaluate the importance and effect of immigration (country of birth and age at immigration to Israel) on the prevalence of asthma in a large group of Israeli adolescents.

METHODS

Computerized medical records of 17-year-old adolescents, who underwent routine examination before military recruitment, were studied. The sample comprised both native-born Israelis (NBI) and immigrants from Ethiopia, the Former Soviet Union (FSU), and Western countries (WC). Asthma was defined as clinical symptoms and signs compatible with the disease accompanied by abnormal spirometry or documented chronic use of inhaled steroids.

RESULTS

Our cohort consisted of 1 466 654 adolescents, including 1 317 556 (89.8%) NBI and 149 098 (10.2%) immigrants. The prevalence of asthma at age 17 was higher in NBI compared with Ethiopian immigrants [4.7% (61 921) vs 2.6% (418), respectively, P < 0.0005], lower compared with immigrants from WC [5.6% (2177), P < 0.0005], and similar to immigrants from the FSU. Further analysis of the association between age at immigration and the risk for developing asthma showed that the younger immigrants from the FSU and Ethiopia arrived to Israel, the higher their prevalence of asthma at the age of 17 was.

CONCLUSIONS

Both environmental and genetic factors seem to influence the prevalence of asthma in 17-year-old adolescents. However, the higher risk for developing asthma associated with young age of immigration points toward an environmental predominance.

Hygiene hypothesis: Innate immunity, malaria and multiple sclerosis

The establishment of new hygienic conditions plays a role in the appearance of autoimmunity in "westernalised" countries. Consistently, but still unconvincingly, several epidemiological and immunogenetic evidences link the disappearance of malaria with the increase of multiple sclerosis (MS) in Sardinia, insular Italy. To this purpose, we have made an attempt to build a relationship between malaria disappearance and MS under the light of the hygiene hypothesis. This relationship has taken into account the MS frequency increase soon after malaria eradication in Sardinia, the present malaria endemism in Africa, the innate immune system activity here represented by Chitotriosidase (Chit), an hydrolytic enzyme produced by macrophages, and an unproductive polymorphism of Chit gene (CHIT1) as a measure of the genetic weight of Plasmodium-related immunity in these populations. Data were derived from both experimental results specifically designed for this study and other data obtained from the available literature. The experimental and the hystorical-epidemiological findings concur to indicate that whilst in Africa CHIT1 mutation is rare and MS incidence is very low due to unmodified parasitic influence and hygienic conditions, in Sardinia a relationships between CHIT1 mutation, plasma Chit activity and MS prevalence rate is detected, even to a higher extent compared to Sicily, area at former lower rate of malaria endemy. Upon such a basis, we have found convincing argumentations that, at least in part, MS has increased over the last four decades in Sardinia also because of the eradication of malaria, 50 years ago. This infectious disease that run for centuries in Sardinia, besides well documented enzyme deficiencies and red cell pathologies, have left an abnormal macrophage reactivity against Plasmodium falciparum. As a result, some Sardinian individuals secrete abnormally high levels of mediators of the innate immunity, relics of former protective anti-malaria infection, in response to new environmental factors. Therefore, MS, an immune-conditioned pathology of the central nervous system has been subject to an unexplained epidemiological increase in the last few decades in Sardinia because cells of the innate immune system, immuno-genetically selected over the centuries in response to widespread P. falciparum malaria, have kept the tendency to over-respond to triggering factors even after the disappearance of malaria. This hypothesis may have an influence in re-directing clinicians toward a innate immunity-based rather than an antigen specific-based new MS therapies.

Associations of physician-diagnosed asthma with country of residence in the first year of life and other immigration-related factors: Chicago asthma school study

BACKGROUND

Among Mexican Americans in the United States, US-born children have higher rates of asthma than their Mexico-born peers.

OBJECTIVE

To evaluate the associations of immigration-related variables with physician-diagnosed asthma in a sample of Mexican American children.

METHODS

We analyzed data from the ongoing Chicago Asthma School Study, a population-based cross-sectional study, for 10,106 Mexican American schoolchildren in Chicago, Illinois.

RESULTS

Mexican American children who lived in the United States in the first year of life were more likely to have physician-diagnosed asthma than their peers who lived in Mexico in the first year of life, independent of age, sex, income, language, and country of birth (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.09-2.94). The risk of asthma in US-born children was higher (but not significantly) than that observed in Mexico-born children after accounting for covariates, including country of residence in the first year of life (OR, 1.37; 95% CI, 0.86-2.18). Long-term immigrants (lived in the United States for 10 years) had an increased risk of asthma compared with short-term immigrants (lived in the United States for <10 years), independent of country of residence in the first year of life (OR, 1.93; 95% CI, 1.00-3.73).

CONCLUSION

These findings confirm the importance of early childhood exposures and environmental factors that are modified with migration and acculturation in asthma development.

A biopsychosocial approach to examining tobacco-related health disparities among racially classified social groups

AIMS

To articulate a broader, multi-causal model that incorporates psychosocial and environmental factors that can differ systematically across racially classified social groups (RCSGs) and impact biological pathways related to the development of tobacco-related diseases.

METHODS

This paper is built upon a review of the existing scientific literature on selected biopsychosocial factors (diet/nutrition, obesity, alcoholic intake, psychosocial stress, occupational/environmental exposures and exposure to other diseases and illnesses) and tobacco use in examining the biological contributions to differences in tobacco-related health outcomes among RCSGs.

FINDINGS

Recent work has focused on RCSG genetic variations as a possible explanation for differences in tobacco-related health disparities. It is argued in this paper that, given the genetic heterogeneity 'within' RCSGs, it is unlikely that across RCSG genetic variations are likely to be the major source of differences impacting biological pathways in tobacco-related health outcomes. The evidence shows that results, even at the level of within-population genetic variations, have been limited and often inconsistent. A conceptual framework is proposed to account for biological pathways related to the development of tobacco-related diseases.

CONCLUSIONS

Determinants of tobacco-related health disparities are not understood clearly. The contribution of biological factors may be important. Current efforts to determine biological differences in tobacco use and related diseases among RCSGs have focused primarily on genetic variations. However, this approach has limitations. An alternative biopsychosocial framework that examines the potential biological mechanisms through which life experiences and behavior might affect tobacco use and health outcomes in these population groups is needed, including those of life-style (e.g. diet/nutrition, obesity, physical exercise, alcohol consumption), psychosocial (e.g. stress and coping), occupational/environmental exposures and the presence of other diseases/illnesses.

Risk for psychiatric disorder among immigrants and their US-born descendants: evidence from the National Comorbidity Survey Replication

Although previous research has consistently documented that immigrants to the United States have better mental health than US natives, little is known about why this difference occurs. DSM-IV anxiety, mood, impulse control, and substance use disorders were assessed in a nationally representative survey of the US household population, the National Comorbidity Survey Replication. Differences in risk for disorder between immigrants (N = 299) and 5124 natives (N = 5124) were examined using discrete time survival models. Differences were estimated by generation, age of immigration, and duration of residence in the United States. Immigrants had lower lifetime risk of disorder than natives (OR = 0.7; 95% CI, 0.5-0.9). Risk was equally large for natives who were children of immigrants as for natives of subsequent generations. For mood and impulse control disorders, risk equal to that of natives was also found among immigrants who arrived in the United States as children (12 years of age or younger). Immigrants had lower risk than natives prior to arrival in the United States, but there was a trend toward equalization of risk with longer duration of residence in the United States. Differences in risk for disorder emerge within a single generation following immigration, consistent with a strong effect of environmental factors on changes in risk among immigrant populations. This pattern is consistent with either of two causal processes, one involving early socialization in the United States and the other involving postmigration experiences among immigrants who arrive in the United States as adults.

Allergic disorders in African countries: linking immunology to accurate phenotype

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

Prevalence of symptoms of childhood asthma, allergic rhinoconjunctivitis and eczema in the Pacific: the International Study of Asthma and Allergies in Childhood (ISAAC)

The International Study of Asthma and Allergies in Childhood (ISAAC) has provided valuable information regarding international prevalence patterns and potential risk factors for asthma, allergic rhinoconjunctivitis and eczema. However, the only Pacific countries that participated in ISAAC Phase I were Australia and New Zealand, and these included only a small number of Pacific children. Phase III has involved not only repeating the Phase I survey to examine time trends, but also to include centres and countries which are of interest but did not participate in Phase I. The ISAAC Phase III study was therefore conducted in the Pacific (in French Polynesia, New Caledonia, Tonga, Fiji Islands, Samoa, Cook Islands, Tokelau Islands and Niue). The overall prevalence rates of current symptoms (in the last 12 months) were 9.9% for asthma, 16.4% for allergic rhinoconjunctivitis and 10.7% for atopic eczema. The prevalence of current wheezing (9.9%) was generally much lower than that has been observed in Pacific children in New Zealand (31%), but there was considerable variation between the various Pacific centres: Tokelau Islands (19.7%), Tonga (16.2%), Niue (12.7%), French Polynesia (11.3%), Cook Islands (10.6%), Fiji Islands (10.4%), New Caledonia (8.2%) and Samoa (5.8%). The reasons for these differences in prevalence across the Pacific are unclear and require further research. The finding that prevalence levels are generally considerably lower than those in Pacific children in New Zealand adds to previous evidence that children who migrate experience an altered risk of asthma as a result of exposure to a new environment during childhood.

Prevalence of respiratory symptoms in migrant children to Italy: the results of SIDRIA-2 study

BACKGROUND

Epidemiological studies have documented large international variations in the prevalence of asthma, and 'westernization' seems to play an important role in the development of the disease. The aims of this study were to compare the prevalence of respiratory symptoms in migrant and nonmigrant children resident in Italy, and to examine the effect of length of time living in Italy.

METHODS

Data were collected in a large cross-sectional study (SIDRIA-2) performed in 12 Italian centres, using standardized parental questionnaires. For the 29 305 subjects included in the analysis (6-7 and 13-14 years old), information about place of birth and parental nationality was available.

RESULTS

There were 1012 children (3%) born outside of Italy, mainly in East Europe. Lifetime asthma and current wheeze were generally significantly less common among children born abroad than among children born in Italy (lifetime asthma: 5.4% and 9.7% respectively, P < 0.001; current wheeze: 5.2% and 6.9%, respectively, P = 0.04). Lower risks for lifetime asthma (prevalence odds ratio, POR = 0.39; 95% CI: 0.23-0.66) and current wheeze (POR = 0.72; 95% CI: 0.47-1.10) were found for children who had lived in Italy <5 years, while migrant children who had lived in Italy for 5 years or more had risks very similar to Italian children.

CONCLUSIONS

Migrant children have a lower prevalence of asthma symptoms than children born in Italy. Prevalence increased with the number of years of living in Italy, suggesting that exposure to environmental factors may play an important role in the development of asthma in childhood.

Risk factors for asthma and allergy associated with urban migration: background and methodology of a cross-sectional study in Afro-Ecuadorian school children in Northeastern Ecuador (Esmeraldas-SCAALA Study)

Background

Asthma and allergic diseases are becoming increasingly frequent in children in urban centres of Latin America although the prevalence of allergic disease is still low in rural areas. Understanding better why the prevalence of asthma is greater in urban migrant populations and the role of risk factors such as life style and environmental exposures, may be key to understand what is behind this trend.

Methods/design

The Esmeraldas-SCAALA (Social Changes, Asthma and Allergy in Latin America) study consists of cross-sectional and nested case-control studies of school children in rural and urban areas of Esmeraldas Province in Ecuador. The cross-sectional study will investigate risk factors for atopy and allergic disease in rural and migrant urban Afro-Ecuadorian school children and the nested case-control study will examine environmental, biologic and social risk factors for asthma among asthma cases and non-asthmatic controls from the cross-sectional study. Data will be collected through standardised questionnaires, skin prick testing to relevant aeroallergen extracts, stool examinations for parasites, blood sampling (for measurement of IgE, interleukins and other immunological parameters), anthropometric measurements for assessment of nutritional status, exercise testing for assessment of exercise-induced bronchospasm and dust sampling for measurement of household endotoxin and allergen levels.

Discussion

The information will be used to identify the factors associated with an increased risk of asthma and allergies in migrant and urbanizing populations, to improve the understanding of the causes of the increase in asthma prevalence and to identify potentially modifiable factors to inform the design of prevention programmes to reduce the risk of allergy in urban populations in Latin America.

Asthma prevalence in Hispanic and Asian American ethnic subgroups: results from the California Healthy Kids Survey

OBJECTIVES

Asthma prevalence for different ethnic groups in the United States, beyond white, black and Hispanic, is seldom reported. We compared the prevalence of asthma diagnosis among various Hispanic and Asian American ethnic subgroups using data collected from the school-based California Healthy Kids Survey.

METHODS

The California Healthy Kids Survey was administered to 462 147 public school students in the seventh, ninth, and 11th grades throughout California during the 2001-2002 and 2002-2003 school years. Prevalence of lifetime asthma diagnosis was calculated for 11 Asian American Pacific Islander subgroups and 8 Hispanic subgroups.

RESULTS

Asthma prevalence among Hispanic subgroups ranged from 13.2% for Mexican American students to 22.8% for Puerto Rican students and 23.0% among Cuban American students. Lifetime asthma diagnosis among the 11 Asian American Pacific Islander subgroups ranged from 10.9% among Korean American students to 23.8% among Filipino American students.

CONCLUSIONS

The survey revealed substantial variation in asthma prevalence between the different Hispanic and Asian American Pacific Islander subgroups and that Pacific Islanders, Filipinos, Cubans, and Puerto Ricans are at elevated risk for asthma. Differences in the distributions of characteristics related to country of birth, residential history, generational status, and/or degree of acculturation might account for much of the observed differences in asthma prevalence between ethnic subgroups. Previous asthma prevalence estimates for Asians or Hispanics are in part a function of the particular ethnic composition of the population under investigation. We suggest that asthma studies that include a substantial number of Asian Pacific Islander and Hispanic persons use a more detailed categorization of race/ethnicity.

Associations of acculturation and country of birth with asthma and wheezing in Mexican American youths

BACKGROUND

Mexican Americans have lower rates of asthma than other ethnic groups in the United States.

OBJECTIVE

To examine the relationship between country of birth and acculturation with asthma and wheezing among Mexican American youths.

METHODS

We used Chi-squared statistics and logistic regression analyses to determine the associations of country of birth and acculturation with asthma and wheezing among 1,770 Mexican Americans age 12-19 years who participated in the National Health and Nutrition Examination Survey 1999-2002.

RESULTS

Mexican American adolescents born in the United States and those with high acculturation levels reported significantly higher prevalence rates of asthma, wheezing, and hay fever than their peers with low acculturation levels and born in Mexico. In multivariate analyses, youths with a high acculturation level had a higher risk of asthma than those with a low acculturation level independent of country of birth. Highly acculturated youths born in the US had a higher risk for wheezing compared with less acculturated US-born or Mexico-born participants after adjusting for confounding variables. In contrast, associations of asthma and wheezing with country of birth were not significant after controlling for acculturation. CONCLUSIONS. Our findings showed that both acculturation and country of birth were linked with the risk of asthma and wheezing, with acculturation having stronger effects than country of birth, among Mexican American youths. These findings may imply that factors modified by immigration and acculturation could influence the risk of asthma and wheezing. Identification of such factors could help in the design of asthma prevention programs.

Atopy and asthma in migrants

Atopy and asthma result from the effects of environmental factors on genetically susceptible persons, and different prevalence rates have been documented worldwide. In developed and industrialized countries a higher prevalence of atopy and asthma is observed as compared with undeveloped and less affluent countries. Migration involves exposure to a new set of pollutants and allergens. In addition, it involves several socioeconomic and cultural issues such as housing conditions, diet and accessibility to medical services, all of which are likely to affect migrants' health. Migration studies provide information on the role of environmental factors in the development of atopy and asthma. Immigration to allergy-prevalent countries causes more allergies and asthma in immigrants as compared to the prevalence of atopy in their countries of origin. The increase in allergy and asthma is usually not related to ethnicity, but in certain populations may play an important role. Studies on migrants support the notion that lifestyle and environmental factors in western industrialized countries facilitate atopy and asthma. The effect is time-dependent. Acquiring allergy is influenced by the age at the time of immigration. Migrants, in general, are more prone to the development of allergies than the local population. Low hygiene prior to immigration does not seem to protect against the development of atopy or asthma. Vaccinations do not affect the development of atopy or asthma in the general population and in migrants. Migrants should be aware of the potential of developing allergies and/or asthma. Strategies for primary prevention in high-risk atopic individuals and secondary prevention guidelines should be developed both for populations in developing countries as well as for immigrants from such countries to atopy-prevalent developed countries.

Country of birth as a risk factor for asthma among Mexican Americans

In the United States, among Hispanics, Mexican Americans have the lowest rate of asthma. However, this population includes Mexican Americans born in the United States and in Mexico, and risk factors that might impact the prevalence of asthma differ between these groups. To determine the prevalence of and risk factors for asthma among U.S.- and Mexican-born Mexican Americans, we analyzed data from two U.S. surveys that included 4,574 persons who self-reported their ethnicity as Mexican American from the Third National Health and Nutrition Examination Survey (NHANES III) 1998-1994 and 12,980 persons who self-reported their ethnicity as Mexican American from National Health Interview Survey (NHIS) 1997-2001. U.S.-born Mexican Americans were more likely than Mexican-born Mexican Americans to report ever having asthma in both the NHANES III (7% [SE 0.5] vs. 3% [SE 0.3], p < 0.001) and NHIS surveys (8.1% [0.4] vs. 2.5% [0.2], p < 0.001). In a multivariate regression model controlling for multiple demographic variables and health care, the risk for asthma was higher among U.S.-born Mexicans in NHANES III (odds ratio 2.1, 95% confidence interval 1.4-3.3) and NHIS (odds ratio 2.7, 95% confidence interval 1.6-5.5). In conclusion, the prevalence of asthma was higher in U.S.-born than in Mexican-born Mexican Americans. This finding highlights the importance of environmental exposures in developing asthma in a migratory population.

Genetic research and health disparities

Alleviating health disparities in the United States is a goal with broad support. Medical research undertaken to achieve this goal typically adopts the well-established perspective that racial discrimination and poverty are the major contributors to unequal health status. However, the suggestion is increasingly made that genetic research also has a significant role to play in alleviating this problem, which likely overstates the importance of genetics as a factor in health disparities. Overemphasis on genetics as a major explanatory factor in health disparities could lead researchers to miss factors that contribute to disparities more substantially and may also reinforce racial stereotyping, which may contribute to disparities in the first place. Arguments that promote genetics research as a way to help alleviate health disparities are augmented by several factors, including research funding initiatives and the distinct demographic patterns of health disparities in the United States.

An “eye” in the gut: the appendix as a sentinel sensory organ of the immune intelligence network

Neural systems are the traditional model of intelligence. Their complex interconnected network of wired neurons acquires, processes, and responds to environmental cues. We propose that the immune system is a parallel system of intelligence in which the gut, including the appendix, plays a prominent role in data acquisition. The immune system is essentially a virtual unwired network of interacting cells that acquires, processes, and responds to environmental data. The data is typically acquired by antigen-presenting cells (APCs) that gather antigenic information from the environment. The APCs chemically digest large antigens and deconstruct them into smaller data packets for sampling by other cells. The gut performs the same function on a larger scale. Morsels of environmental content that enter the gut are sequentially deconstructed by physical and chemical digestion. In addition to providing nutrients, the componentized contents offer environmental data to APCs in mucosa-associated lymphoid tissues (MALT) that relay the sampled information to the immune intelligence network. In this framework, positioning of the appendix immediately after the ileocecal valve is strategic: it is ideally positioned to sample environmental data in its maximally deconstructed state after small bowel digestion. For single-celled organisms, digestion of the environment has been the primary way to sample the surroundings. Prior to the emergence of complex sensory systems such as the eye, even multi-cellular organisms may have relied heavily on digestion to acquire environmental information. While the relative value of immune intelligence has diminished since the emergence of neural intelligence, organisms still use information from both systems in integrated fashion to respond appropriately to ecologic opportunities and challenges. Appendicitis may represent a momentary maladaptation in the evolutionary transition of sensory leadership from the gut to the eye. Relationships between immune dysfunctions and cognition are explored.