Smoking, behavioral factors and familial environment: a population based study with Brazilian adolescents
Tabaquismo, factores comportamentales y ambiente familiar: un estudio basado en la población de adolecentes brasileños
Gabriella L. Arrais-Ribeiro, Marayza A. Clementino, Monalisa da N. Cesarino-Gomes, Ramon T. Firmino, Maria B. Lins Dantas-Siqueira y Ana F. Granville-Garcia
Department, University State of Paraíba, Campina Grande, Paraíba, Brazil. email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Recibido 10 Junio 2012/Enviado para Modificación 3 Julio 2012/Aceptado 5 Agosto 2012
Objective The aim of the present study was to assess the association between smoking and both behavioral and environmental factors among adolescents in the public school system in the city of Campina Grande (northeastern Brazil).
Methods An analytical cross-sectional study was carried out involving 574 schoolchildren between 10 and 19 years, with the use of a structured questionnaire addressing behavioral factors, environmental factors and smoking. The chi-squared test and Fisher's exact test were used for the statistical analysis (5 % level of significance).
Results The prevalence of smoking was de 3.3 %. The lowest age regarding the use of tobacco for the first time was eight years and the age group with the greatest frequency of initiation into this habit was 11 to 14 years (44.3 %). A total of 84.3 % of tobacco users smoked between one and 10 cigarettes per day. Smoking was associated with delays in schooling (p=0.047), gender (p=0.016), alcohol use and frequency of alcohol use (p<0.001) and the relationship with one's father (p=0.014) and mother (p=0.004).
Conclusions Despite the low prevalence, an early initiation into smoking was found, suggesting that educational campaigns should be directed at earlier ages. Alcohol use stood out among the variables studied, suggesting that smoking is influenced by both the use and intensity of this substance.
Key Words: Smoking; students; alcoholism; epidemiology; risk factors (source: MeSH, NLM).
Objetivo El objetivo del presente estudio fue evaluar la asociación entre el tabaquismo, los factores comportamentales y los factores ambientales entre adolescentes de escuelas públicas de Campina Grande- Paraíba.
Métodos El estudio realizado fue de tipo transversal analítico, en el cual participaron 574 adolescentes, entrevistados por medio de un cuestionario estructurado que contenía preguntas relacionadas con factores comportamentales y ambientales y con el tabaquismo. Las pruebas estadísticas utilizadas fueron el Chi-Cuadrado y la prueba exacta de Fisher (5 % nivel de significancia).
Resultados La prevalencia del tabaquismo fue de 3,3 %. La menor edad relacionada con el inicio del uso del cigarro fue de 8 años y el grupo de edad con la mayor frecuencia de inicio fue entre 11 y 14 años (44,3 %). Se estimó que 84,3 % de los fumadores consumía entre 1 a 10 cigarros por día. El tabaquismo fue asociado al fracaso escolar (p=0,047), al sexo (p=0,016), al consumo y frecuencia de uso de alcohol (p<0,001) y a la relación con el padre (p=0,014) y con la madre (p=0,004).
Conclusiones A pesar de la baja prevalencia encontrada, se observó un inicio prematuro en el tabaquismo sugiriendo que las campañas educativas deben ser enfocadas en edades más tempranas. Entre las variables analizadas se destaca el uso de alcohol, lo que también sugiere que el tabaquismo puede ser influenciado tanto por el consumo, como por la intensidad del uso de esta sustancia.
Palabras Clave: Hábito de fumar; estudiantes; alcoholismo; epidemiología; factores de riesgo (fuente: DeCS, BIREME).
Adolescence spans the ages of 10 to 19 years. Individuals in this phase of life undergo numerous physical, cognitive, emotional and social changes. Adolescence is marked by the search for an identity as well as extreme instability, which makes teenagers especially susceptible to experimentation with drugs, including tobacco (1).
Smoking has been associated with more than 50 diseases and currently contributes greatly to the number of avoidable deaths. Despite an overall reduction in smoking in recent decades, smoking among adolescents continues to be a challenge to public health authorities (2,3). Ninety percent of smokers become dependent by the age of 19 years (4). The susceptibility of this age group has made adolescents the target of the tobacco industry through the widespread advertising of tobacco products (5).
A study carried out in the United States reports that 1500 of every 3900 youths who have experimented with cigarettes become habitual smokers and, in 2002, 18 % of adolescents in the tenth grade reported smoking at least once in the previous 30 days (6). A study carried out in the United Kingdom found that 10 % of adolescents reported having smoked cigarettes in the previous week, with this figure rising to 25 % among those aged 16 years or older (7). In developing countries, prevalence values are reported to range from 8 to 22.3 % (5,8) and studies carried out in Brazil report prevalence values ranging from 6.3 to 17.7 % (9,10).
The Framework Convention on Tobacco Control (FCTC) was established by the World Health Organization (WHO) in response to the global tobacco epidemic. This was a landmark for public health and was embraced by all WHO member countries on May 21st, 2003. Brazil signed the FCTC on June 16th, 2003 and it first became effective in the country in February 2005. The FCTC contains chapters designed to protect present and future generations from the devastating health, social, environmental and economic results of tobacco consumption and exposure to tobacco smoke (11). The control of tobacco consumption has since been regarded as an ethical matter and a social responsibility of governments towards their populations (4).
The Global Youth Tobacco Survey is one of the WHO strategies for controlling smoking and has broadened discussion on this issue, as it provides a profile of the population in relation to the early exposure to tobacco and its relationship with environmental and lifestyle factors (12). The determination of the epidemiological profile of tobacco use and the analysis of behaviors, attitudes and associated factors could contribute toward a better understanding of this complex problem and guide the drafting of health programs aimed at the prevention and combating of smoking in adolescence.
The aim of the present study was to assess the association between smoking and behavioral/environmental factors among adolescents at public schools in northeastern Brazil.
A cross-sectional study was carried out involving 574 male and female adolescents between 10 and 19 years of age at public schools in the city of Campina Grande, state of Paraíba, Brazil. The participants were selected from a population of 11,228 students, with the sample corresponding to 5.11% of this population. Campina Grande had approximately 386 thousand inhabitants and is divided into six districts. It is an industrialized city with considerable cultural, social and economic disparities. Mean monthly income per capita is 110 US dollars and the human development index is 0.72 (13).
Two-stage sampling was performed to ensure representativity. Schools were randomly selected from each district of the city in the first stage and schoolchildren were randomly selected from each school in the second stage. The sample size was calculated based on a 5 % margin of error, 95% confidence level and an expected prevalence value of 50 %. A 1.3 correction factor was applied to compensate for the design effect. The minimal sample was estimated to be 496 schoolchildren, to which 20 % was added to compensate for possible losses, totaling 596 schoolchildren.
Adolescents aged 10 to 19 years, enrolled in the schools selected for the study, who authorized (adults) or whose parents/guardians (minors) authorized their participation by signing a statement of informed consent.
Data acquisition was carried out between August and December 2010 by four previously calibrated researchers using a self-administered semi-structured questionnaire previously used by the Brazilian Information Center on Psychotropic Drugs (14). The questions addressed the smoking profile of the sample (smoker, ex-smoker, non-smoker, age at which the subject began smoking and number of cigarettes smoked per day) and associated factors (gender, age group, schooling, work, religion, practice of sports, relationship with parents and parents' profile and alcohol intake).
Alcohol intake was defined based on the following categories:
- Use in lifetime: use at least once in the individual's lifetime;
- Use in previous year: use at least once in the 12 months prior to the interview;
- Use in previous month: use at least once in the 30 days prior to the interview;
- Frequent use: use six or more times in the 30 days prior to the interview;
- Heavy use: use 20 or more times in the 30 days prior to the interview.
A smoker was defined as an individual who smoked any type or amount of tobacco on a daily basis for a period of at least six months at the time of the interview. An ex-smoker was defined as any individual who had been a smoker, but had not smoked any type or amount of tobacco in the previous six months. A non-smoker was defined as any individual who had never smoked or smoked for only a short period or sporadically at any time in life (11).
Contact with the school was initially made to schedule the data acquisition procedure and deliver the statements of informed consent. The reliability of the responses was tested using the "face validation" method on 10 % of the interviewees. For such, the researcher asked the respondents to explain what they understood by each question in their own words (15). None of the interviewees exhibited any difficulty in answering the items on the questionnaire. Test-retest reliability was determined with a seven-day interval between applications of the questionnaire (10% of the interviewees). Agreement between tests was 80 %.
The administration of the questionnaire lasted a period of 10 minutes. After the questionnaires were returned to the researchers, an educational lecture was given on the consequences of smoking.
All data were analyzed using the Statistical Package for Social Sciences (SPSS for Windows, version 18.0, SPSS Inc, Chicago, IL, USA). The chi-squared test and Fisher's exact test were used to determine associations between the variables and smoking, with the level of significance set to 5 % (p<0.05).
This study received approval from the Human Research Ethics Committee of the University State of Paraíba (Brazil), under process number 0253.0.133.000-10, in compliance with Resolution 196/96 of the Brazilian National Health Council.
A total of 574 schoolchildren participated in the present study. Twenty-two individuals refused to participate, corresponding to a loss rate of 3.7 %.
Table 1 displays the characterization of the sample with regard to age, gender and schooling. The majority of the adolescents were between 13 to 15 years (53.8 %), female (53.5 %) and attended elementary school (87.6 %). Nineteen adolescents (3.3 %) were categorized as current smokers.
Eleven (15.7 %) had their first contact with cigarettes between eight and ten years of age and most (84.3 %) smoked between one and 10 cigarettes per day (Table 2).
Gender, delays in schooling (p=0.47) and alcohol use and frequency of alcohol use (p<0.00) were associated with smoking (Table 3).
Relationships with one's father (p=0.01) and mother (p=0.00) were also associated with smoking (Table 4).
Brazil is a large developing country covering 8,512,000 Km2, with 200 million inhabitants. As in other countries, tobacco is the second most frequently consumed drug among adolescents and, together with alcohol, is a gateway substance for the use of illicit drugs (13,16).
A total of 574 schoolchildren participated in the present study and the prevalence of smoking was low (3.3 %), which corroborates findings described in previous studies (10,11), but is lower than the figure found in a large national study employing a similar methodology entitled Tobacco Surveillance in Schoolchildren (2004), which reports a prevalence value of 16 % (range: 9 to 27 %) (12). The prevalence in the present study is also lower than values reported in international studies [19 % (6) and 14.8 % (17)]. While the present study does not offer data that indicate a tendency toward a reduction in the prevalence of smoking among schoolchildren, the comparison with previous studies suggest such a decline in smoking in this population. This may be the reflection of national anti-smoking policies and local actions involving restrictive measures, the prohibition of smoking in closed public and private environments and educational campaigns carried out at schools. Another important factor to consider is that the questionnaire was administered in the school setting, which increases the possibility of under-reporting smoking habits. However, the anonymity ensured by the self-administered questionnaire may have minimized this possibility.
The risk of disease and difficulty quitting are greater when smoking habits are acquired at an early age (18). The lowest age for initiating smoking in the present study was eight years and 44.3 % reported initiating smoking between 11 and 14 years of age. These findings reveal that schoolchildren begin smoking at an early age and underscore the need to intensify educational and prevention programs aimed at younger children. Previous studies report similar results (3,4). A number of factors favor smoking among young Brazilians, such as the low price of cigarettes, which is among the lowest in the world, and the easy access to tobacco products (19). The early starting age of smoking (90 % under 19 years of age) has led the WHO to classify smoking among pediatric diseases, requiring proper diagnosis, treatment and preventive measures (20).
Smoking has been identified as the major risk factor for the development of several diseases such as lung cancer, heart, circulatory, coronary and respiratory diseases, and sexual impotence in men (21). The number of cigarettes smoked per day is directly related to disease and mortality rates among smokers. Consumption of more than 1 pack per day (>20 cigarettes/day) is associated with a 13-fold increase in the risk of developing head and neck cancers, while the consumption of 1 to 20 cigarettes per day has been associated with an increased risk of stomach cancer (22). The majority of adolescents in the present study reported smoking between one and 10 cigarettes per day, which is similar to findings reported in previous studies (5,18). The amount of cigarettes consumed is also related to nicotine addiction. Although it was not within the scope of the present study to analyze the magnitude of this dependence, adolescents are more susceptible. After reaching the brain, nicotine binds to nicotine receptors. Activated receptors then stimulate the release of dopamine, a neurotransmitter associated with addiction (20).
Regarding the associations between smoking, age and school year reported by other authors (11,23), it was not possible to establish these associations in the present study. However, an association was found between delayed schooling and smoking (p=0.04), with a greater risk when students were three or more years behind in their studies (OR=5.25). This behavioral aspect has been related to smoking habits over time and may be related to the socioeconomic and environmental context, such as a lack of familial support (24).
While there has been an tendency toward an increase in smoking among women, who have been targeted by marketing campaigns of the tobacco industry (9), smoking was more prevalent among males in the present study (p=0.01).
It is presumed that practicing a religion places individuals within a group with shared values and norms, in which there is an explicit condemnation of overall drug use (25). However, no statistically significant association was found in the present study between religion and smoking (p=0.08). This finding may have been due to the fact that the participants were only asked whether they had a religion and not whether they practiced the religion. Officially belonging to a particular religion is frequently just a formality not likely to influence behavior (26).
All adolescents surveyed were enrolled in public schools, which denote an underprivileged economic status. Thus, the participants were asked if they held jobs to determine whether buying power exerted an influence over the practice of smoking. However, no significant association was found between these variables (p=0.18), which contrasts findings reported in previous studies (27,28).
The practice of sports is a source of pleasure and contributes toward the physical, emotional and social development of adolescents, helping them maintain a healthy lifestyle (29). The protective aspect of practicing sports likely reflects scenarios and characteristics that promote health as being different from those that facilitate smoking among adolescents (11). Nonetheless, no such association was found in the present investigation (p=0.67), as also reported in previous studies (18,30).
Tobacco and alcohol are two major human vices and the combination of both can have compound effects, such as in cases of cankers of the esophagus (31). In the present study, the majority of smokers also consumed alcohol (p<0.00). The combined use of these drugs has been reported in previous studies (31,32) and suggests a bidirectional relationship between smoking and alcohol use. Moreover, the majority of smokers made frequent or heavy use of alcohol (p<0.00), suggesting that the practice of smoking may be influenced by the intensity of alcohol use.
The presence of parents and brothers who smoke has been positively associated with smoking in adolescence. Likewise, parents' values and familial supervision are reported to be protective factors when not smoking is one of these values (33,34). Analyzing the family environment, having a fair or poor relationship with one's father or mother (p=0.01 and p=0.00, respectively) was associated with smoking. It is possible that the stress produced by strained parental relationships may induce adolescents to smoke. There are also reports in the literature that a strained relationship between one's mother and father and authoritarian attitudes in the household are positively associated with smoking (35,36). However, it was not possible to establish such associations in the present study. Further studies are needed to address this complex issue.
The different definitions used for the measurement of the outcome (smoking among adolescents) and different age groups addressed in the literature constitute methodological limitations. The present study employed the criteria determined by the WHO and used in a large Brazilian national study on monitoring tobacco use (16). Regarding the age group, the entire span of adolescence was included, as individuals in this phase in life are considered to be at greater risk for drug abuse. Another limitation of the present study was the impossibility of calculating odds ratios in many cases due to very low or null frequencies, which rendered a multivariate analysis impossible.
Factors associated with smoking can be modified over time and behavioral patterns may vary from population to population, between individuals and even within a single individual in different phases of life. Thus, the constant monitoring of smoking habits in population-based studies is necessary to the establishment of prevention programs and the assessment of existing programs, as new epidemiological data can challenge the efficacy of public policies. The Brazilian government adhered to the Framework Convention on Tobacco Control in 2005 and has adopted campaigns with a strong appeal toward reducing exposure to smoking (less advertising, the promotion of negative images of cigarettes, an increase in the price of cigarettes, etc.). Another important measure has been the establishment of reference centers for addressing and treating smokers in the public healthcare system, at which smokers can receive guidance and medication to assist them in giving up smoking. While it was not within the scope of the present study to assess the impact of such measures, there has been a clear reduction in smoking among adolescent schoolchildren over the years, which suggests the importance of these public policies aimed at combating tobacco use.
Despite the low prevalence, an early initiation into smoking was found, suggesting that educational campaigns should be directed at younger children. Alcohol use stood out among the variables studied, suggesting that smoking is influenced by both the use and intensity of use of this substance. It is hoped that the findings of the present study can contribute toward guiding public policies aimed at combating smoking.
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