Trends in children's exposure to second-hand smoke in the INMA-Granada cohort: An evaluation of the Spanish anti-smoking law
Introduction
Over recent decades, a vast array of findings has associated both active and passive smoking with multiple adverse health effects. Young children are not smokers; however, their exposure to second-hand smoke (SHS) is considered a major global public health issue, given the vulnerability of this age group to the health effects of passive smoking. This has been attributed to their higher respiratory rates and less mature immune, nervous, and respiratory systems (Polanska et al., 2006) and it has been reported that SHS is among the leading causes of respiratory morbidity and mortality among infants (Puig et al., 2008). SHS has also been associated with recurrent wheezing, respiratory illnesses, decreased lung function, and asthma (Akinbami et al., 2013), as well as obesity (Lisboa et al., 2012), behavioral disorders (Desrosiers et al., 2013), and kidney and endocrine dysfunction (García-Esquinas et al., 2013) in young children. Indeed, it has been reported that the annual excess mortality in children aged 5 years or younger due to SHS exposure may be higher than that due to all other causes (Florescu et al., 2009). According to the EPA, children’s exposure to SHS in the USA is responsible for: (i) increases in the number of asthma attacks and severity of symptoms in 200,000–1 million children with asthma; (ii) between 150,000 and 300,000 lower respiratory tract infections in children under 18 months of age; and (iii) respiratory tract infections that result in 7500–15,000 hospitalizations each year (EPA, 2011).
Public health authorities have taken various steps to reduce smoke-related diseases. In 2006, Spanish government approved an initial law to prevent smoking in all enclosed workplaces (Law 28/2005), although the degree of restriction depended on the decision of each business owner. This legislation, aimed to protect the health of non-smokers, did not meet expectations. Some studies showed major reductions in the exposure to SHS at the workplace, but no significant changes were observed at home or in leisure spaces (Galán et al., 2007; Jiménez-Ruiz et al., 2008). As a result, the law was amended five years later on January 2 2011, establishing a more severe anti-smoking regime (Law 42/2010, of December 30) and imposing a complete ban on smoking in enclosed public places, on public transport, and in the workplace. The aims of this law were: (i) to protect non-smokers from SHS exposure, (ii) to prevent smoking initiation among young people, and (iii) to promote smoking cessation.
According to the National Health Survey carried out in Spain in 2012, a quarter of the population smoked daily; the prevalence of exposure to SHS in the workplace (2.6%) and in enclosed places and on public transport (2.4%) had markedly decreased; and the household was the most frequent place for exposure to tobacco smoke (17.8%) (National Health Survey, 2011–2012). This is especially relevant to children, given the amount of time they spend in the home.
Although a total ban on smoking at home could be expected to significantly reduce the children's SHS exposure, there appears to be no short-term prospect of this type of legislation in Europe. Most EU member states, including Spain, have implemented complementary strategies to protect children and adolescents, following the Tobacco Products Directive of the EU Commission (2001/37/EC 2001) and the Framework Convention on Tobacco Control (FCTC), which has been ratified by 177 countries. One key aspect of these strategies is to raise the consciousness of citizens about the need for a smoke-free environment in the home (Borland et al., 2006).
Research carried out in countries with an established anti-smoking law has warned that national anti-smoking legislation for workplaces and public places is inadequate to protect children and adolescents from SHS (Akhtar et al., 2007, Protano et al., 2012). Thus, it was reported that the 2006 anti-smoking law in Scotland had no significant effect on the prevalence of smoke-free homes (64.5% vs. 64.3% just before and after smoke-free legislation, respectively) or on the exposure of school students to environmental tobacco smoke (Akhtar et al., 2007).
There has been some research into the effects of the 2010 Spanish anti-smoking law on SHS exposure in adults (Villaverde Royo et al., 2012, Perez-Rios et al., 2014, Sureda et al., 2014; Sánchez-Rodríguez et al., 2015). However, it is also important to establish whether the stricter smoking ban has had an impact on the reduction of exposure in children, by evaluating, for example, the cotinine load in this population. The objectives of the present study were: to assess the impact of the Spanish anti-tobacco legislation (Law 42/2010) on children's exposure to passive smoking exposure by comparing urine cotinine (UC) excretion before and after implementation of the law; and to review how the smoking status of parents and smoking habits at home were related to SHS exposure among boys from the Spanish INMA-Granada cohort evaluated at follow-ups in 2005–2006 and 2011–2012.
Section snippets
Study population and design
The study sample was drawn from the “Environment and Childhood Research Network” (INMA network), a population-based cohort study in different regions of Spain that focuses on prenatal environmental exposures in relation to growth, development, and health from early fetal life until childhood. The INMA study protocol includes medical follow-ups of the children during childhood as well as epidemiological questionnaires and biological sample collections (Guxens et al., 2012).
From October 2000 to
Results
Table 1 summarizes the characteristics of the study population. Out of the 668 families in the prospective birth cohort, 220 (32.9%) and 300 (44.9%) families agreed to participate in the first (2005–2006) and second (2011–2012) follow-ups, respectively. Only families taking part in both follow-ups (n=118) were included in the present study.
According to the questionnaire data, the percentage of children exposed to SHS (considering the presence of at least one cohabitant declaring a smoking habit
Discussion
This prospective study, based on self-reports and an objective biomarker of exposure to second-hand smoke, reveals that the ban on smoking in public places introduced in Spain at the beginning of 2011 (Law 42/2010), was not accompanied by a decrease on SHS exposure in children; i.e. no significant difference in children’s UC levels was observed (8.0 vs. 8.7 ng/mL); furthermore the percentage of children exposed to SHS at home increased from 39.0% in the period 2005–2006 to 50.8% in 2011–2012,
Declaration of interest
The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Contributor statement
All authors meet the criteria for authorship, had read and approved the final manuscript. MFF conceived of the idea and obtained financial support. MFF and FAC wrote the manuscript. CF, RR, RPL, IC, OO and CD were in charge of field activities (recruitment of children in follow-ups, questionnaire and database). AMC performed the urine analyses. FAC and JPA carried out the statistical analysis. NO contributed to writing and revised the final manuscript.
Funding
This research was supported by grants from the Spanish Ministry of Health (CIBERESP and FIS PI11/0610) and from the Andalusia Regional Government and Council of Health (SAS PI-0675-2010). Dr. F. Artacho has the fellowship from the Spanish Ministry of Education (AP2012-2524) and Dr. J.P. Arrebola has a postdoctoral contract from the Council of Health (RH-0092-2013).
Ethical statement
We obtained written informed consent from the parents (mother or father) on behalf of children enrolled in your study. The families registered in the follow-ups signed the informed consent form, which included completion of ad hoc questionnaires. The study followed the guidelines laid down in the Declaration of Helsinki and was approved by the Ethics Committee of San Cecilio University Hospital, Granada, Spain.
Acknowledgments
The authors are indebted to all participants, without whom this work would not have been possible. They are also grateful to Richard Davies for editorial assistance and Rafael Poyatos and Marta Román for technical help.
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