|Year : 2016 | Volume
| Issue : 2 | Page : 119-124
Prevalence and pattern of secondhand smoking in Abia State, Nigeria
Ugochukwu U Onyeonoro1, Andrew U Ukegbu1, Innocent I Chukwuonye2, Okechukwu O Madukwe3, Moses O Akhimien3, Okechukwu S Ogah4
1 Department of Community Medicine, Federal Medical Center, Umuahia, Abia State, Nigeria
2 Department of Medicine, Division of Nephrology, Federal Medical Center, Umuahia, Abia State, Nigeria
3 Department of Public Health, Ministry of Health, Nnamdi Azikiwe Secretariat, Umuahia, Abia State, Nigeria
4 Department of Medicine, Division of Cardiovascular Medicine, University College Hospital, Ibadan, Oyo State, Nigeria
|Date of Web Publication||4-Aug-2016|
Okechukwu S Ogah
Department of Medicine, Division of Cardiovascular Medicine, University College Hospital, Ibadan, Oyo State
Source of Support: None, Conflict of Interest: None
Background: Several studies have reported the burden of smoking and associated risk factors. However, only a few studies have explored the prevalence, pattern of exposure, and risk factors associated with exposure to secondhand smoke (SHS) in Sub-Saharan Africa and particularly Nigeria.
Objective: This study was, therefore, aimed at ascertaining the prevalence and risk factors of exposure to SHS in Abia State, Nigeria.
Methods: Data of 2787 respondents selected using multi-staged cluster sampling technique were analyzed. Prevalence of exposure to SHS at home and public places was calculated for each sociodemographic and economic group.
Results: Exposure to tobacco smoke was more common in respondents who were young, males, unmarried or used alcohol. Females were less frequently and intensely exposed to SHS both at home and public places than males. Predictors of SHS at home were gender, odds ratio (OR) =1.85 (95% confidence interval [CI] 1.20-2.83) and use of alcohol OR = 2.06 (95% CI 1.04-4.09); and in public places were age OR = 1.55 (95% CI 1.10-2.20), gender OR = 2.73 (95% CI 1.96-3.81), and use of alcohol OR = 2.55 (95% CI 1.51-4.28).
Conclusions: The findings of study provide basis for designing tobacco control interventions to address exposure to SHS at home and public places.
Keywords: Abia State, cigarette, Nigeria, passive, secondhand, smoking
|How to cite this article:|
Onyeonoro UU, Ukegbu AU, Chukwuonye II, Madukwe OO, Akhimien MO, Ogah OS. Prevalence and pattern of secondhand smoking in Abia State, Nigeria. Nig J Cardiol 2016;13:119-24
|How to cite this URL:|
Onyeonoro UU, Ukegbu AU, Chukwuonye II, Madukwe OO, Akhimien MO, Ogah OS. Prevalence and pattern of secondhand smoking in Abia State, Nigeria. Nig J Cardiol [serial online] 2016 [cited 2020 Oct 27];13:119-24. Available from: https://www.nigjcardiol.org/text.asp?2016/13/2/119/187710
| Introduction|| |
Secondhand smoke (SHS) or passive smoke is the combination of smoke emitted from the burning end of a cigarette or from other tobacco products and smoke exhaled by other smokers. , Several negative health effects have been associated with smoking; however, these effects are not restricted to smokers only. ,
Secondhand smoking increases the risk of death in both adults and children. Globally 600,000 deaths are attributable to SHS in each year. ,, In the United States alone an estimated 53,000 nonsmokers die each year from exposure to SHS, thereby making it the third leading cause of preventable death. ,
SHS has also been associated with increased morbidity in adults and children. The risk of lung cancer in nonsmokers exposed to SHS is increased by between 20% and 30%; and the risk of heart disease, by 30%. ,, Children exposed to SHS are at particular risk of developing more respiratory symptoms such as coughing and wheezing, worsening of asthma, middle ear disease, neurobehavioral impairment, and cardiovascular disease in adulthood.  SHS during pregnancy is also associated with low birth weight and has been reported to be a risk factor for mortality and morbidity among infants. 
Several studies have been conducted both on the burden of tobacco use and associated risk factors. ,,, On the other hand, data on prevalence and risk factors of SHS exposure including sociodemographic groups at greatest risk for exposure in Sub-Saharan Africa are limited. In Nigeria, studies on the prevalence of SHS and associated factors are few and have focused on selected target populations. 
This study, however, is focused on the general adult population (aged 18 years and above) in both urban and rural communities.
Prevalence, pattern, determinants, and implications of SHS in a given population are correlated with prevalence and pattern of tobacco use and the robustness of tobacco control measures in place. , Therefore, understanding of prevalence, pattern, and risk factors of SHS is important in developing appropriate, integrated, and comprehensive interventions for reduction of the burden of SHS. Article 20 of the WHO Framework Convention on Tobacco Control addresses the need for availability of data to guide tobacco control-related goal setting, and development of appropriate programs and interventions and surveillance.  Hence, the findings of this survey will provide baseline data for evaluating subsequent tobacco control-related interventions both in the state and the country. The objective of this study, therefore, is to ascertain prevalence and determinants of SHS exposure in Abia State, Southeastern Nigeria. Identifying the determinants of exposure to SHS will help identify the sociodemographic group at greater risk as well as enable the development of group-specific interventions.
| Materials and methods|| |
The study was carried out in Abia State, Southeastern Nigeria with an estimated population of 3,152,691 people. The design was cross-sectional, using the WHO STEP-wise approach to surveillance in adult men and women aged 18 and above. Making provision for design effect, age-sex estimates as well as nonresponse rate the minimum calculated sample size for the study was 2880. A multistage-stratified cluster sampling technique was used to select the study participants. Abia State is traditionally divided into three senatorial zones Abia North, Abia Central, and Abia South. One rural and one urban local government area (LGA) were randomly selected from each senatorial zone. They were Ohafia and Isuikwuato/Bende for Abia North, Umuahia North and Ikwuano for Abia Central and Aba South and Ukwa East for Abia South Senatorial Zones. In each LGA, four enumeration areas (EAs) were randomly selected from the listing of all the EAs. Furthermore, households in each selected EA were listed such that not more than two eligible participants of either sex were selected from each household. Using the EA map and starting from a prominent landmark in the community (e.g., church, school, police station, etc.), trained interviewers proceeded from household to household; interviewing eligible respondents until a minimum of 120 respondents were interviewed in the community. Only subjects who gave consent after explanation of the study procedure, risks, and benefits were included in the study.
A modified WHO STEP-wise approach surveillance questionnaire was used for data collection. The questionnaire was administered by two teams of trained health workers. Each team comprised six interviewers and a supervisor and covered three LGAs. Using the questionnaire, responses were elicited from the respondents by the interviewers. Data collected from them included sociodemographic parameters such as gender, age, use of alcohol, use and exposure to tobacco either at home or public places, duration of exposure to smoke in a typical day and frequency of exposure in a week. Others include a personal history and family history of chronic noncommunicable diseases. In addition, anthropometry and blood pressure measurements were done for all respondents and half of them had their blood sugar measured.
Data collected were analyzed using SPSS version 17.0 (SPSS Inc., Chicago, IL, USA 2005). Descriptive and frequency statistics were used to determine the general characteristics of the study population and the prevalence of SHS. Duration (frequency) and intensity were estimated based on number of days/week and number of hours in a typical day exposed to SHS, respectively (following the date of interview). Chi-square test was used to determine association between frequency and intensity of SHS and selected characteristics of the respondents. The value of P < 0.05 was considered statistically significant. Multivariate logistic regression was used to estimate the odds of exposure to SHS at home and public places. Explanatory variables associated with the outcome-exposure to SHS were selected based on findings of previous studies, and they included age, marital status, annual income, gender, educational status, locality, occupation, and alcohol use. The quantitative variables - age and income were categorized into two - <35 years and ≥35 years and <100,000 and ≥N100,000, respectively. Collinearity among the selected variables was tested using the Chi-squared test. Starting with a null model, variables were imputed into the model using a forward selection approach. The significance of odds ratio (OR) was measured using 95% confidence interval. Ethical approval for the study was obtained from the Abia State Ministry of Health Ethics Review Committee.
| Results|| |
A total of 2999 survey participants were recruited, 13 of them did not consent to be interviewed, 12 respondents failed to provide satisfactory responses to this section of the questionnaire, and 187 (6.2%) were smokers hence were excluded from the analysis. Consequently, findings of 2787 respondents were analyzed. The mean age was 42.0 ± 18.2 years and a greater proportion of them were females (55.3%) and in marital relationship (58.5%). The majority of them were either unskilled laborers (36.8%) - artisans and traders or unemployed (29.0%) including students. About 65% of them had at least secondary education, 53.4% of them reside in the rural areas, and 53% were currently using alcohol [Table 1].
|Table 1: Sociodemographic and economic characteristics of the respondents |
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The rate of exposure of SHS at home and public places was 7.7% and 16.4%, respectively. Younger people (<35 years) were more exposed to SHS than older people aged ≥35 both at home (10.0% vs. 8.4%) and in public places (21.5% vs. 16.2%). The proportion of males (26.0%) exposed to outdoor smoking is more than twice the proportion of females (12.2%). Among the occupational groups, semi-skilled workers were most exposed to passive smoke both at home and in public places. However, professionals (17.3%) and skilled workers (10.3%) were more likely to be exposed to tobacco smoke outside their homes than at home (4.0%), respectively. Similarly, individuals with higher education were more exposed to passive smoking in public places (19.7%) than at home (16.6%) [Table 2].
|Table 2: Prevalence of exposure to secondhand smoke at home and public places by sociodemographic characteristics |
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People in the rural communities were more exposed to SHS than urban residents particularly in public places. While respondents with low-income (10.5%) were more exposed to tobacco smoke at home than high-income earners (9.0%), in contrast, high-income earners (23.2%) were more exposed in public places than low-income earners (19.2%). Individuals who used alcohol were more likely to be exposed than those who did not use alcohol at home (12.0% vs. 6.9%) and in public places (27.2% vs. 11.0%) [Supplementary [Table 1] and [Table 2].
The mean number days of exposure to tobacco smoke at home in the past 7 days was 4.02 ± 2.35 days. The frequency of exposure to tobacco smoke at home was found to be significantly associated with gender only (P < 0.01). Females were likely to have a higher frequency of exposure at home than males. Most people were exposed to smoke at home for 1-2 days/week except for females (45.6%) and professionals/skilled worker (40.0%) who were exposed for 5-7 days/week [Supplementary [Table 3]. The mean number of days of exposure to smoke in public per week was 3.6 ± 2.2 days. Significant association was demonstrated between frequency of exposure and sex (P = 0.01), marital status (P = 0.01), and locality (P = 0.02) as shown by [Supplementary [Table 4].
In a typical day, duration of exposure to SHS at home for most people (86.7%) was <5 h and there was no significant association between selected respondents' characteristics and intensity of exposure to SHS [Supplementary [Table 4]. Among respondents exposed to passive smoke in the public places significant association was observed between the intensity of exposure and gender, occupation, and alcohol use. Men were more likely to be exposed to tobacco smoke in a typical day (P < 0.01). Skilled and semi-skilled workers were mostly exposed to smoking for less than an hour in a day (P = 0.04). The intensity of exposure was significantly higher among individuals who drink alcohol (P < 0.01) than those who do not alcohol.
Predictors of exposure to SHS at home were being male OR = 1.85 (1.20-2.83) and use of alcohol OR = 2.06 (1.04-4.09). On the other hand, the risk of exposure to SHS in public places was significantly associated with young age (<35 years) OR = 1.55 (1.10-2.20), being a male OR = 2.73 (1.95-3.81) and use of alcohol OR = 2.55 (1.51-4.29) [Table 3] and [Table 4].
| Discussion|| |
Self-reported prevalence of SHS exposure was twice as high in public places (16.4%) than at home (7.7%). Most times higher prevalence of SHS exposure in public places than home reflects weakness or absence of smoking restrictions. In countries where smoking regulation (especially in public places) is in force, a negative correlation has been observed between tobacco restriction and prevalence of exposure to tobacco smoke at home.  The reported prevalence of SHS in this study is lower than 37% earlier reported in two cities in Northern Nigeria by Desalu et al.  Furthermore, higher prevalence of SHS exposure at home ranging between 17.3% and 73.1% has been reported in other low- and middle-income countries. ,, Higher prevalence of exposure was reported in Spain for both males and females, where more than half of the population were exposed to SHS. 
Taking into consideration, the sociodemographic characteristics of the respondents, prevalence of exposure to SHS at home and in public places was higher for males, younger adults (<35 years), rural dwellers, semi-skilled and unskilled laborers and alcohol users. Prevalence of SHS was the same for those with either high- or low-educational status. While for individuals with high-income indoor exposure and lower for individuals for higher income, the converse was the case for outdoor exposure. Respondents with high educational and higher income were at greater risk of exposure to SHS at public places. Exposure to SHS in public places was found to be higher among those with high education and income.
High exposure of males than females is probably because most smokers in Nigeria are young, unmarried males who often smoke among their peers. Females are more conservative in the use of tobacco in Nigeria, hence are less often associated with smoking, and are less likely to expose fellow females to tobacco smoke. The risk of exposure among females, especially at home is increased where a close family member or spouse is a smoker. However, the trend of smoking among females in the country is on the increase and it is feared that the development may in the long run lead to increased exposure of females to cigarette smoke if adequate control measures are not put in place. 
There is not a consistent pattern of rural-urban difference on prevalence of SHS in different localities. Although our study like several other studies revealed higher rural prevalence, some others have reported higher exposure to tobacco in urban communities. ,,, A study in the United States has associated high level of exposure to SHS among the rural populace with a higher tolerance of smoking and low awareness of dangers of smoking, consequent on less access to tobacco control-related health education messages. In countries where smoking regulation is in place, enforcement is more likely to be weaker in rural communities than urban communities. Second, because of the high level of activity in urban areas most people are exposed to SHS without knowing. Among the occupational groups higher prevalence of exposure was observed among semi- and un-skilled workers. Studies have revealed an association between low-socioeconomic status and higher exposure to SHS. More professionals and skilled workers were exposed to SHS in their workplaces than at home, despite being more likely to be aware of the harmful effects of tobacco smoke. This is invariably a reflection of the weakness of enforcement of anti-smoking interventions in public places. The country, therefore, will require more robust measures including legislation if progress must be made in protecting the public from the harmful effects of tobacco. Health education alone may not be effective in reducing exposure of individuals to smoke in public places. At present, only a few public places - airport, some offices, shops, and transport companies observe the ban on smoking in the country.
The average the numbers of days/week individuals were exposed to SHS at home was 4.02 ± 2.35 days. While the majority of them (45%) were not exposed to SHS for more than 2 days at home, about 30% were exposed for 6-7 days/week. A survey in Wisconsin, United States, which assessed the prevalence of exposure of SHS at homes, reported that the proportion of homes in which smoking took place 7 days in week was 20%. The frequency of exposure to SHS at home was higher for female, older people, being married, professionals/skilled workers, urban residents, high-income earners and among those who did not consume alcohol. However, this association was not statistically significant except for gender. On the other hand, mean number of days/week of outdoor exposure was 3.6 ± 2.2 days. About 24% of them were exposed for up to 6-7 days/week compared to 30% of them who are exposed at home, whereas 48% of them were exposed for fewer than 3 days in the public places. The chance of being more frequently exposed SHS at home is high if the individual is female, aged <35 years, high-income earner, consumed alcohol and lived in the urban area. Gender, marital status, and locality were significantly associated with often <5 h; however, about 12.6% of were exposed to tobacco smoke for more than 5 h. Duration of exposure is longer at home than at public places. Shorter duration of exposure to tobacco smoke in public than at home has earlier been reported elsewhere. , Women and those who do not use alcohol were least likely to have prolonged exposure to smoke in public while professionals among other category of workers were at greatest risk of prolonged exposure outside their home.
The risk factors associated with exposure to smoke at home were male gender, consumption of alcohol, low income, and being an unskilled worker. On the other hand, risk factors for exposure at public places also included being a male and consumption of alcohol as well as being < 35 years, low education status, resident in the rural area and being an unskilled worker. Studies have identified male gender, younger age, low education and income level, locality, and use of alcohol as risk factors for exposure to SHS.  In Australia exposure to SHS has been associated with younger age and poor socioeconomic status and this increases the burden of ill-health among them.  Occupation type has also been significantly associated with increased frequency and intensity of exposure to SHS and associated morbidity.  Individuals who work in places where smoking is frequent, for example, bars, casinos, pubs, etc., are more likely to be more exposed.  For instance, a study of casino workers in the UK revealed frequency and intensity of exposure to SHS to be 83% and 75%, respectively, among them.  A Spanish study reported a significant correlation between age, gender, marital status, educational, and nature of the occupation. Singles are more likely to be exposed because they spend more of their leisure time in places such as bars and restaurants. ,
The limitations of this study derive from the fact that cross-sectional data based on information gathered by questionnaire are potentially subject to some degree of systematic error. Other possible potential places where exposure could occur, such as in public places other than work and in passenger vehicles, were not included. Finally, the method used here to measure SHS exposure is based on self-report using questionnaire and is a less objective method compared to measuring biological markers of passive exposure. These limitations notwithstanding, the measurement of "perceived" SHS exposure with a set of simple questions may provide sufficiently valid estimates in the absence of expensive biomarker data.
| Conclusions|| |
Because of the low prevalence of exposure to SHS compared to most countries, measures to control tobacco use and SHS exposure should focus both on preventing smoking initiation among nonsmokers, particularly youths and women and promotion of smoking cessation programs among current smokers. These could be done by reducing the affordability of tobacco products through increased taxation and reducing the acceptability of smoking by strengthening the policy banning the use of tobacco products in public places.
Increasing public awareness of the harmful effects of smoking has shown to result in a change in the attitude of nonsmokers and also changing the behavior of smokers thereby resulting in decreasing exposure to smoke. Even though, the prevalence of SHS at home is lower than exposure in public places controlling exposure at home should be part of the integral policy aimed at reducing exposure to smoke. Finally, designing effective interventions aimed at reducing exposure to SHS in the state must target both sociodemographic and socioeconomic risk factors if it must succeed.
Financial support and sponsorship
This study was supported by the Abia State Health Systems Project II.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]