Asthma and lung function in a birth cohort at 6-7 years of age in southern Brazil

Prevalence and impact of asthma in schoolchildren in the city of Caxias do Sul-RS

OBJECTIVE

To analyze the prevalence and impact of asthma in schoolchildren from the city of Caxias do Sul, RS, Brazil.

METHODS

Cross-sectional observational and case-control study with children and adolescents between 7 and 15 years old, from public schools in Caxias do Sul, RS. The study is composed of two phases: Phase I analyzed the prevalence of asthma in the delimited population, investigating 1915 schoolchildren; Phase II quality of life questionnaires, asthma control and classification (for the asthmatic group), physical activity, school performance, pulmonary function tests and anthropometric measures were applied to 266 asthmatics and 288 controls.

RESULTS

The estimated prevalence of asthma was 16.1%. In the comparison between asthmatics and nonasthmatics premature birth (p<0.001) and diagnosis of another chronic disease at birth (p<0.001) were found. Regarding pulmonary function, significant differences were found in the values between groups in FEV₁, FEV₁/FVC and forced expiratory flow in the 25 and 75% (FEF_25-75%), being that asthmatics presented lower values. Among asthmatics, 133 (50.8%) did not have the disease controlled. In the anthropometric variables, significant differences were observed, with higher values in controls, in the the waist-to-height ratio (p=0.009) and in the perception of health (p<0.001). Quality of life is lower in asthmatics in the physical well-being domain (p=0.001) and in the total score (p=0.016). The total school performance score did not present a statistically significant difference between the groups.

CONCLUSION

The prevalence of asthma is similar to that of other industrialized urban centers and may negatively affect some areas of the development of schoolchildren.

Associations of α- and γ-tocopherol during early life with lung function in childhood

BACKGROUND

Tocopherol isoforms may regulate child lung growth and spirometric measures.

OBJECTIVE

Our aim was to determine the extent to which plasma α-tocopherol (α-T) or γ-tocopherol (γ-T) isoform levels in early childhood or in utero are associated with childhood lung function.

METHODS

We included 622 participants in the Project Viva cohort who had lung function at a mid-childhood visit (age 6-10 years). Maternal and child tocopherol isoform levels were measured by HPLC at the second trimester and 3 years of age, respectively. Multivariable linear regression models (adjusted for mid-childhood body mass index z scores, maternal education, smoking in pregnancy, and prenatal particulate matter with diameter of <2.5 micrometers (PM_2.5) particulate exposure) stratified by tertiles of child γ-T level were used to assess the association of α-T levels with FEV₁ and forced vital capacity (FVC) percent predicted. Similarly, models stratified by child α-T tertile evaluated associations of γ-T levels with lung function. We performed similar analyses with maternal second trimester tocopherol isoform levels.

RESULTS

The median maternal second trimester α-T level was 63 μM (interquartile range = 47-82). The median early-childhood level was 25 μM (interquartile range = 20-33 μM). In the lowest tertile of early-childhood γ-T, children with a higher α-T level (per 10 μM) had a higher mid-childhood FEV₁ percent predicted (β = 3.09; 95% CI = 0.58-5.59 and a higher FVC percent predicted (β = 2.77; 95% CI = 0.47-5.06). This protective association of α-T was lost at higher γ-T levels. We did not see any consistent associations of second trimester levels of either α-T or γ-T with mid-childhood FEV₁ or FVC.

CONCLUSION

When γ-T levels were in the lowest tertile, a higher early-childhood α-T level was associated with better lung function at mid-childhood. Second trimester maternal plasma α-T concentration was 3-fold higher than in the adult nonpregnant female population.

Respiratory function in children of asthmatic mothers

OBJECTIVE

To evaluate lung function and clinical manifestations suggestive of asthma in children of mothers with a reported medical diagnosis of asthma.

METHODS

An observational cross-sectional analytical study nested in a cohort of 4,757 pregnant women. A total of 86 six-year-old children were evaluated, born to mothers with a medical diagnosis of asthma before pregnancy. Information was collected regarding clinical symptoms of atopy and respiratory diseases, as well as socioeconomic and exposure variables; the children were submitted to spirometry.

RESULTS

Spirometric alterations were observed in 30.3% of cases, with a prevalence of asthma in those who had an obstructive pattern. 9.3% of the children had a previous medical diagnosis of asthma; however, the established diagnosis based on the presence and frequency of asthma symptoms was 18.6%. Of the 86 participating children, 37.2% had a score of five or more points in the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, which was associated with spirometry alterations (p=0.002). After multiple logistic regression analysis, higher paternal education, higher number of bedrooms in the family's home, and mother who did not have "wheezing" episodes during pregnancy were statistically significant as protective factors for the presence of respiratory disorder detected by spirometry.

CONCLUSIONS

The frequency of spirometry alterations in children of asthmatic mothers was high; the restrictive pattern was more often observed that the obstructive. There was a higher incidence of obstructive test results in those who presented clinical symptoms of asthma, with a higher frequency of clinical diagnosis of asthma than that found in the literature.