Serum 25-hydroxyvitamin D deficiency is associated with atopy, and sex may be an effect modifier of its association with asthma in teenagers from northeast Brazil.

OBJECTIVE: Sufficient vitamin D (25-hydroxyvitamin D [25(OH)D]) serum levels are associated with decreased asthma symptoms. Our aim was to investigate associations between vitamin D and atopy, asthma, asthma severity, and asthma phenotypes in Brazilian teenagers. METHODS: This cross-sectional study involved 942 individuals (11-19 years old) engaged in an asthma cohort. The ISAAC questionnaire was employed to diagnosis asthma and asthma severity. Serum allergen-specific immunoglobulin E (sIgE) was measured by ImmunoCap and serum 25(OH)D was measured by ELISA. We calculated the correlation between sIgE and 25(OH)D. We used multivariate logistic regression analysis to assess associations of interest. RESULTS: We found that 25(OH)D deficiency was positively associated with atopy (OR 1.45, confidence interval [CI] 1.05-2.00) and high levels of this vitamin negatively correlated with sIgE to Dermatophagoides pteronyssinus (r = -0.11, p = 0.019). The average 25(OH)D serum level was 27.0 ± 9.5 ng/ml; 366 individuals (38.8%) had a sufficient level. There was no association between 25(OH)D and asthma, asthma severity or asthma phenotypes in the population. However, sex was a possible effect modifier of the association between vitamin D and asthma: insufficiency in asthmatic women (86%) was higher than in asthmatic men (42%), and there was an association between insufficient vitamin D levels and greater asthma risk only in women (OR = 3.06, 95% CI 1.16-8.07). CONCLUSION: We have shown that vitamin D deficiency was associated with greater risk of atopy in both sexes and vitamin D insufficiency was associated with asthma only in women. There was no association between vitamin D levels and asthma phenotypes or asthma severity.

African biogeographical ancestry, atopic and non-atopic asthma and atopy: A study in Latin American children.

BACKGROUND: Genetic variants underlying African ancestry have been suggested be implicated in the ethnic-racial inequalities reported for asthma and allergies. OBJECTIVES: To investigate the association between individual African ancestry and asthma symptoms, atopic and non-atopic asthma, and atopy in children. METHODS: A cross-sectional study encompassing 1190 individuals was conducted. African biogeographic ancestry was estimated using 370 539 genome-wide SNPs. Serum levels of specific IgE were measured, and skin prick test (SPT) performed for the most common local aeroallergens. Information on asthma symptoms was obtained by applying the International Study of Allergy and Asthma in Childhood questionnaire. The associations between the proportion of individual African ancestry and the outcomes investigated were analyzed through multivariate models adjusted for socio-environmental variables, infections markers, and psychosocial factors. RESULTS: Each 20% increase in the proportion of African ancestry was negatively associated with SPT reactivity (OR: 0.79, 95%CI: 0.66-0.96) and positively associated with asthma symptoms in non-atopic individuals (OR: 1.40, 95%CI: 1.03-1.89). We estimated that socioeconomic status and number of infections mediated 28.4% of the effect of African ancestry on SPT reactivity, while 20.2% of the effect on non-atopic asthma was explained by socioeconomic status and behavioral problems in children. CONCLUSIONS: The negative association observed between African ancestry and atopy is most probably explained by unobserved environmental or social factors that covariate with ancestry. For non-atopic asthma, in turn, putative genetic variants of risk underlying African ancestry may play some role.

Multiobjective grammar-based genetic programming applied to the study of asthma and allergy epidemiology.

BACKGROUND: Asthma and allergies prevalence increased in recent decades, being a serious global health problem. They are complex diseases with strong contextual influence, so that the use of advanced machine learning tools such as genetic programming could be important for the understanding the causal mechanisms explaining those conditions. Here, we applied a multiobjective grammar-based genetic programming (MGGP) to a dataset composed by 1047 subjects. The dataset contains information on the environmental, psychosocial, socioeconomics, nutritional and infectious factors collected from participating children. The objective of this work is to generate models that explain the occurrence of asthma, and two markers of allergy: presence of IgE antibody against common allergens, and skin prick test positivity for common allergens (SPT). RESULTS: The average of the accuracies of the models for asthma higher in MGGP than C4.5. IgE were higher in MGGP than in both, logistic regression and C4.5. MGGP had levels of accuracy similar to RF, but unlike RF, MGGP was able to generate models that were easy to interpret. CONCLUSIONS: MGGP has shown that infections, psychosocial, nutritional, hygiene, and socioeconomic factors may be related in such an intricate way, that could be hardly detected using traditional regression based epidemiological techniques. The algorithm MGGP was implemented in c ++ and is available on repository: http://bitbucket.org/ciml-ufjf/ciml-lib .

Screening for common mental disorders using the SRQ-20 in Brazil: what are the alternative strategies for analysis?

Objective: To analyze the prevalence of common mental disorders (CMD) assessed with the Self Reporting Questionnaire (SRQ-20), using the established cutoff point, and comparing it with the results of a joint correspondence factor analysis (CFA) and cluster analysis and of a latent class analysis (LCA). Methods: A cross-sectional study was carried out in an urban sample of 1,095 women aged 19 to 55 years. Joint CFA-cluster analysis and LCA were used. Results: We found a high prevalence of CMD, regardless of classification method (37.6% when using the cutoff point; 44.4% and 52% for LCA and joint CFA-cluster, respectively). The alternative analysis strategies describe the cases more efficiently when compared to the traditional cutoff method, especially regarding more severe symptoms. Both alternative strategies also provide a description of the SRQ-20 dimensions in their particularities, which may be useful for the planning and implementation of specific actions in a given population. Conclusion: The SRQ-20 cutoff point seems to underestimate the magnitude of CMD among women. The alternative methods of analysis presented herein highlight the different possibilities of using this important instrument of screening for mental health.

Screening for common mental disorders using the SRQ-20 in Brazil: what are the alternative strategies for analysis?

Objective: To analyze the prevalence of common mental disorders (CMD) assessed with the Self Reporting Questionnaire (SRQ-20), using the established cutoff point, and comparing it with the results of a joint correspondence factor analysis (CFA) and cluster analysis and of a latent class analysis (LCA). Methods: A cross-sectional study was carried out in an urban sample of 1,095 women aged 19 to 55 years. Joint CFA-cluster analysis and LCA were used. Results: We found a high prevalence of CMD, regardless of classification method (37.6% when using the cutoff point; 44.4% and 52% for LCA and joint CFA-cluster, respectively). The alternative analysis strategies describe the cases more efficiently when compared to the traditional cutoff method, especially regarding more severe symptoms. Both alternative strategies also provide a description of the SRQ-20 dimensions in their particularities, which may be useful for the planning and implementation of specific actions in a given population. Conclusion: The SRQ-20 cutoff point seems to underestimate the magnitude of CMD among women. The alternative methods of analysis presented herein highlight the different possibilities of using this important instrument of screening for mental health.

The effect of internalization and other psychologic factors on the remission and severity of wheeze in children.

BACKGROUND: Asthma prevalence in Latin America is high and continues to increase. There is evidence that the psychologic characteristics of the child are associated with greater asthma morbidity. This study aimed to investigate the independent effect of internalizing/externalizing problems on two asthma/wheeze outcomes: (i) remission and (ii) progression to severity on Latin American children with mild asthma symptoms at baseline. METHODS: This was a prospective study in a cohort of 371 asthmatic children living in a poor urban area in Salvador, Brazil. The psychologic characteristics of the child were assessed using the Child Behavior Checklist (CBCL), and wheezing was defined using the ISAAC questionnaire at the start and end of follow-up. A multiple logistic regression model with random effects was used to examine the association between the psychologic components and both outcomes. RESULTS: Remission of symptoms of wheeze was observed among 229 (61.73%) children. Remission was 56% lower among children with internalizing problems (OR = 0.54, 95% CI 0.33-0.87, p = 0.01). In addition, we found that 19 (8.76%) of the children acquired severe symptoms during follow-up and there was strong evidence of the effect of internalizing problems in increasing the risk of progression to severe wheeze symptoms (OR = 4.03, 95% CI 1.39-11.70, p = 0.01). CONCLUSIONS: Children with internalizing problems but not externalizing had less remission of wheezing, and a higher risk of acquiring severe symptoms. These results highlight the importance of psychologic care for children with asthma, to improve the prognosis of this condition.

Behavior problems and prevalence of asthma symptoms among Brazilian children.

OBJECTIVE: Asthma is the most common chronic disease in childhood and has been designated a public health problem due to the increase in its prevalence in recent decades, the amount of health service expenditure it absorbs and an absence of consensus about its etiology. The relationships among psychosocial factors and the occurrence, symptomatology, and severity of asthma have recently been considered. There is still controversy about the association between asthma and a child's mental health, since the pathways through which this relationship is established are complex and not well researched. This study aims to investigate whether behavior problems are associated with the prevalence of asthma symptoms in a large urban center in Latin America. METHODS: It is a cross-section study of 869 children between 6 and 12 years old, residents of Salvador, Brazil. The International Study of Allergy and Asthma in Childhood (ISAAC) instrument was used to evaluate prevalence of asthma symptoms. The Child Behavior Checklist (CBCL) was employed to evaluate behavioral problems. RESULTS: 19.26% (n=212) of the children presented symptoms of asthma. 35% were classified as having clinical behavioral problems. Poisson's robust regression model demonstrated a statistically significant association between the presence of behavioral problems and asthma symptoms occurrence (PR: 1.43; 95% CI: 1.10-1.85). CONCLUSION: These results suggest an association between behavioral problems and pediatric asthma, and support the inclusion of mental health care in the provision of services for asthma morbidity.