J Pediatr (Rio J). 2016;92(3):260---267
www.jped.com.br
ORIGINAL ARTICLE
Influence of passive smoking on learning in elementary school夽 Juliana Gomes Jorge a,∗ , Clóvis Botelho b , Ageo Mário Cândido Silva c , Gisele Pedroso Moi d a
Universidade Federal de Mato Grosso (UFMT), Cuiabá, MT, Brazil School of Medicine, Universidade Federal de Mato Grosso (UFMT), Cuiabá, MT, Brazil c Instituto de Saúde Coletiva, Universidade Federal de Mato Grosso (UFMT), Cuiabá, MT, Brazil d Centro Universitário de Várzea Grande (UNIVAG), Várzea Grande, MT, Brazil b
Received 28 November 2014; accepted 26 August 2015 Available online 6 February 2016
KEYWORDS Smoking; Tobacco smoke pollution; Learning disorders; Children
PALAVRAS-CHAVE Tabagismo; Poluic ¸ão por fumac ¸a de tabaco;
Abstract Objective: To analyze the association between household smoking and the development of learning in elementary schoolchildren. Methods: Cross-sectional study with 785 students from the 2nd to the 5th year of elementary school. Students were evaluated by the School Literacy Screening Protocol to identify the presence of learning disabilities. Mothers/guardians were interviewed at home through a validated questionnaire. Descriptive and bivariate analysis, as well as multivariate Poisson regression, were performed. Results: In the final model, the variables associated with learning difficulties were current smoking at the household in the presence of the child (PR = 6.10, 95% CI: 4.56 to 8.16), maternal passive smoking during pregnancy (PR = 1.46, 95% CI: 1.07 to 2.01), students attending the 2nd and 3rd years of Elementary School (PR = 1.44, 95% CI: 1.10 to 1.90), and being children of mothers with only elementary level education (PR = 1.36, 95% CI: 1.04 to 1.79). Conclusion: The study demonstrated an association between passive exposure to tobacco smoke and learning difficulties at school. © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.
Influência do tabagismo passivo na aprendizagem de escolares Resumo Objetivo: Analisar a associac ¸ão entre o tabagismo domiciliar e o desenvolvimento da aprendizagem em escolares do ensino fundamental.
夽 Please cite this article as: Jorge JG, Botelho C, Silva AM, Moi GP. Influence of passive smoking on learning in elementary school. J Pediatr (Rio J). 2016;92:260---7. ∗ Corresponding author. E-mail:
[email protected] (J.G. Jorge).
http://dx.doi.org/10.1016/j.jped.2015.08.010 0021-7557/© 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.
Passive smoking and learning
Transtornos de Aprendizagem; Crianc ¸as
261 Métodos: Estudo transversal, com 785 escolares do 2◦ ao 5◦ ano do ensino fundamental. Os alunos foram avaliados por meio do Protocolo de Triagem de Letramento Escolar, visando identificar a presenc ¸a de dificuldades de aprendizagem. As mães/responsáveis foram entrevistadas no domicílio por meio de questionário validado. Foram realizadas análises descritiva, bivariada e regressão múltipla de Poisson. Resultado: No modelo final, as variáveis associadas às dificuldades de aprendizagem foram tabagismo atual domiciliar na presenc ¸a do filho (RP = 6,10; IC 95% 4,56---8,16), tabagismo passivo materno durante a gestac ¸ão (RP = 1,46; IC 95% 1,07---2,01), alunos pertencerem ao 2◦ e 3◦ ano do ensino fundamental (RP = 1,44; IC 95% 1,10---1,90) e serem filhos de mães com apenas o nível fundamental de escolaridade (RP = 1,36; IC 95% 1,04---1,79). Conclusão: o estudo evidenciou associac ¸ão entre a exposic ¸ão passiva ao tabaco e as dificuldades de aprendizagem nos escolares. © 2016 Sociedade Brasileira de Pediatria. Publicado por Elsevier Editora Ltda. Todos os direitos reservados.
Introduction The development of reading and writing by the child results from the interaction between biological characteristics and multiple family sociocultural factors.1 One of the main negative influences in this process is the exposure of children to cigarette smoke, due to its interference with several physiological processes and cognitive functions related to learning.2---4 In Brazil and other countries with high prevalence of smoking,5 this exposure is a major public health problem. Household tobacco smoke is the most common air pollutant inside homes; its concentration may vary depending on the number of smokers in the household and the number of cigarettes smoked by those individuals. Intense exposure to this type of air pollution can lead to intellectual disability and cognitive impairment in children, as well as result in other deleterious effects related to maternal and child health, such as miscarriage, low birth weight, and prematurity.6 Maternal smoking during pregnancy can lead to premature placental maturation and reduce its nutritional capacity, causing changes in fetal growth. Carbon monoxide and nicotine present in cigarette smoke are rapidly absorbed by the placenta, affecting the mental, intellectual, and behavioral development of these children, in addition to other complications described in literature.7---9 The mechanisms through which tobacco acts on cognitive function have yet to be fully understood. Exposure to tobacco smoke can lead to fetal hypoxia due to increased blood carbon monoxide concentrations, resulting in several neurotoxic effects on the child’s neuropsychomotor development.10 Therefore, children born to mothers who smoke during pregnancy and who are constantly exposed to environmental tobacco smoke, especially in early childhood, are at increased risk of experiencing alterations in their intellectual capacities, mental disorders, and hearing loss,6 in addition to a greater probability of having learning difficulties.2 There is a growing interest in the search for understanding the multiple factors that affect growth and neuropsychomotor development of children, considering the
high prevalence of learning disabilities at school age. It is also important to implement public policies to recognize the deleterious effects of concomitant passive and active smoking of adults and children, both in external environments and in family homes. Thus, the aim of this study was to analyze the association between household smoking and the learning development of schoolchildren attending elementary school.
Methods A cross-sectional study was carried out with 785 students from seven municipal and state urban public schools in the municipality of Campo Verde. Campo Verde is located in the Southeast region of the state of Mato Grosso, and has an area of 4795 km2 , an altitude of 736 m above sea level, and a population of 31,000 inhabitants; it has the highest agricultural GDP of Brazil due to the large production of soybeans, cotton, corn, sorghum, sunflower, and poultry.11 Sample selection was carried out by simple random sampling of students based on the data provided by the Municipal Education Secretariat of Campo Verde, which, in the year 2012, had 1732 students attending the first years of elementary school (2nd to 5th grades), distributed in seven schools. To calculate the sample size, the number of schools and the proportion of students enrolled at the different grades of elementary school were considered. A prevalence of 15% of smoking adults was estimated,12 95% confidence interval, statistical power of 80%, expected outcome frequency in the unexposed individuals of 9.0%, with a ratio of four unexposed to one exposed individual and a detectable prevalence ratio of 2.0. The final sample comprised 718 schoolchildren, plus 10% for expected losses (72), totaling 790 participants. As inclusion criteria, children who were regular students of these schools were selected. Students with mental, hearing, visual disabilities, and psychiatric disorders pre-identified by specialized health services of the municipal Brazilian Unified Health System (Sistema Único de Saúde [SUS]) and reported to the special education team of the Municipal Education Secretariat, were excluded from the study. There was a loss of five participants due to the refusal of the students’ parents/guardians to participate.
262 Data collection occurred in two stages: in the first, the students participated of the School Literacy Screening Protocol13 for the assessment of learning difficulties, applied by the main researcher in their own school. This protocol consists of ten questions about performing tasks such as pairing letters, words and numbers, serial letter identification, words and numbers, naming of letters and words, writing name and surname, writing letters and words, word dictation, reading words, reading sentences, and phrasal cloze test (five sentences were shown with a blank in each and a support chart, to be used to complete these sentences; the student completed them so that they made sense). The maximum score that a student could achieve was 30 points and the minimum, zero points. Subsequently, the students who had a performance above the score median were considered as having ‘‘normal learning status’’ and, up to the median (20.5), as ‘‘altered status’’ for learning development. At the second stage, information was collected on the schoolchildren’s households from every child’s mother or guardian. These data were used to characterize the status of exposure to maternal smoking and the child’s through the Fagerström14 questionnaire, adapted15 and validated16 for the Portuguese language. At this stage eight undergraduate students assisted, from the School of Education of Faculdade Cândido Rondon in Campo Verde, previously trained for this activity. The information on the children’s passive smoking and associated factors were obtained by applying a questionnaire divided into seven parts: the first and the second parts contained questions related to identification data of the child and mother. The third part contained questions related to gestational data of the student, such as: prenatal care, type of delivery, gestational age and weight at birth, and maternal consumption habits such as alcohol, tobacco, drugs, and medication. The fourth part was related to sociodemographic information, including ownership of assets, paternal education, family income, number of household members, and economic class according to the Brazilian Association of Research Companies (Associac ¸ão Brasileira de Empresas de Pesquisas [ABEP]).17 The fifth and the sixth part contained questions related to smoking: past or current smoking history of the mother, father, or other members of the household and tobacco use inside the household. The seventh and last part was related to factors associated with learning difficulties. Data were double entered using the Epi-Info 7.0 software (Epi InfoTM , GA, USA) and by using the Data Compare application, which belongs to the same program; the typing errors were detected and corrected. The bivariate analysis identified the gross associations through the chi-squared test for a prevalence ratio with 95% confidence interval using the Mantel---Haenszel method or Fisher’s exact test, when indicated. Possible interactions and confounding factors were examined through stratified analysis, using as stratification variables those that the literature reports as important. Poisson multiple regression analysis was performed in blocks (block 1 --- sociodemographic variables of the students; block 2 --- maternal sociodemographic variables; block 3 --- gestational variables; block 4 --- type of maternal smoking), including in each block all variables with a p-value
