Understanding the dynamics of asthma symptoms between childhood and adolescence using latent transition analysis.

OBJECTIVES: Asthma patterns in childhood are important predictors of unwanted outcomes in adolescence. We aimed to define asthma phenotypes in childhood and adolescence and evaluate the transitions between these phenotypes and factors potentially associated with the transitions. METHODS: Baseline (1445 children), first round (1363 children/early adolescents) and second round (1206 adolescents) data from the SCAALA Project in Salvador, Brazil, were used. Phenotypes were defined by latent class analysis at three time points. Transitions between phenotypes were described and the effects of factors associated with transition probabilities estimated using latent transition analysis. RESULTS: The "asymptomatic" and "symptomatic" phenotypes were identified. Approximately 5-6% of asymptomatic children in childhood/later childhood and early adolescence became symptomatic later in time. Maternal common mental disorders were identified as important risk factor for unhealthy states. CONCLUSIONS: Asthma manifestations are characterized by frequent movements, especially between childhood and adolescence. Our study, by simultaneously defining disease subtypes, and examining the transitions and their potential predictors, highlights the importance of longitudinal studies to advance the understanding of the effects of social, environmental and biological mechanisms underlying asthma trajectories over time.

Measuring the level of social support using latent class analysis.

Different instruments have been used to measure social support in epidemiological studies of which the most widely used is the Medical Outcomes Study Social Support Scale (SSS-MOS). However, these studies lack measures of the level of social support on health risks. We used latent class analysis (LCA) to distinguish subgroups with different levels of perceived social support and tested the consistency of these subgroups by their associations with the prevalence of Common Mental Disorders (CMD). This is a cross-sectional study of 1013 mothers living in the city of Salvador, Brazil in which psychosocial data were collected through home visits using the SSS-MOS and the Self Reporting Questionnaire-20. For each dimension of social support analysed here, we selected models with two classes using LCA. Multivariate logistic regression models were used to estimate the association between participants' perceived social support and the prevalence of CMD to verify the consistency of the groups defined by LCA. There was a clear difference in the reporting of perceived social support between those classified as high or low using LCA. The probability of perceiving several types of social support was lower in the subgroup classified as low level of social support (13.7-59.8%), and it was much higher in the group classified as high level of social support (84.3-98%). A greater prevalence of CMD was found among mothers with lower levels of social support. LCA seems to be a useful tool to improve measurement of perceived social support by separation into two levels in which the lower level is associated with an increased prevalence of CMD.

Fatores associados à incidência de maloclusão na dentição decídua em crianças de uma coorte hospitalar pública do nordeste brasileiro / Factors associated with the incidence of malocclusion in the deciduous dentition of children in a public hospital cohort from Northeast Brazil

Estimar a incidência de maloclusão na dentição decídua e fatores associados na primeira infância. Métodos: estudo longitudinal com crianças nascidas na cidade de Feira de Santana, Bahia, acompanhadas por 36 meses. Taxas de incidência de maloclusão e razões de densidade de incidência (RDI), com correspondentes intervalos de 95 por cento de confiança, foram obtidas para avaliar associação entre maloclusão e fatores associados. Modelos de regressão de Poisson foram ajustados para controle de confundimento. Resultados: verificou-se que 34,4 por cento das crianças apresentaram maloclusão leve e 23,3 por cento maloclusão moderada ou grave, totalizando 57,8 por cento com algum grau de maloclusão aos três anos de idade. A taxa global de incidência de maloclusão foi de 27,2 casos por 100 crianças-ano. As crianças que sugaram chupeta ou dedo apresentaram risco de maloclusão maior quando comparadas com as crianças que não desenvolveram tais hábitos de sucção (RDI=1,99; IC95 por cento= 1,26 - 3,26). Crianças que não foram amamentadas de forma exclusiva ou predominante por período igual a quatro meses tiveram um risco de maloclusão 1,5 vezes maior (IC95 por cento= 0,99 - 2,25) quando comparadas com as crianças que mamaram de forma exclusiva ou predominante por este período. Conclusões: alerta-se profissionais de saúde para a necessidade de estímulo ao aleitamento materno e medidas para prevenir as maloclusões na primeira infância...

To estimate the incidence of malocclusion in deciduous dentition and the factors associated with it in early infancy. Methods: a longitudinal study was carried out with children born in the city of Feira de Santana, Bahia, who were accompanied for 36 months. Incidence rates for malocclusion and incidence density ratios (IDR), with corresponding 95 percent confidence intervals, were obtained to assess the association between malocclusion and associated factors. Poisson regression models were adjusted to control for confounders. Results: it was found that 34.4 percent of the children had mild malocclusion and 23.3 percent moderate or serious malocclusion, giving a total of 57.8 percent with some degree of malocclusion at three years of age. The overall incidence rate for malocclusion was 27.2 cases per 100 children per year. Children who used a pacifier or sucked their thumb had a higher risk of malocclusion than those who did not develop such sucking habits (IDR=1.99; CI95 percent= 1.26 - 3.26). Children who were not exclusively or predominantly breastfed for a period offour months had a 1.5-fold greater risk of malocculsion (CI95 percent= 0.99 - 2.25) compared to children who were exclusively or predominantly breastfed during this period. Conclusion: health workers are alerted to the need to encourage maternal breastfeeding and measures to prevent malocclusion in early infancy...