Introduction

Tobacco is a major risk factor for multiple non-communicable diseases (NCDs), including cancer, chronic lung diseases, and cardiovascular diseases. Tobacco use presently accounts for around seven million deaths every year worldwide [1], and this is projected to increase to eight million by 2030 [2]. A 30% relative reduction until 2025 in the prevalence of current tobacco use in people aged 15 years or older is one of the nine voluntary global targets defined to reduce the preventable and avoidable burdens of morbidity, mortality, and disability due to NCDs [3].

Low- and middle-income countries are facing increased in tobacco use, while the opposite is occurring in high-income countries [4,5,6]. It is also estimated that nearly 80% of the world’s tobacco smokers are from low- or middle-income countries [7].

Although information on the prevalence, trends, patterns, and determinants of tobacco use is still limited for sub-Saharan Africa [8,9], there is evidence of increasing use in some countries [9]. Smoking is expected to increase in the region as a result of the tobacco industry’s strategy of creating new consumers to offset the declines in traditional markets [10,11].

In Angola, which ratified the Framework Convention on Tobacco Control in 2007, there is no national survey on tobacco consumption, and the defined policies in the convention that aim at effective tobacco prevention and control have not been fully implemented, especially regarding smoke-free environments, taxation, health warnings on tobacco product packages, and bans on advertising, promotion, and sponsorship of such products [12,13,14]. The leading causes of mortality and morbidity in Angola are communicable, maternal, neonatal, and nutritional diseases, but the rates of premature deaths due to NCDs are rising [15]. The urbanization process and westernization of life habits in Africa is followed by increased exposure to behavioural risk factors for NCDs, such as alcohol consumption and tobacco use [3,4].

Tobacco, one of Angola’s major industries, was established in the country during the Portuguese Colonial War (1961–1974) and has experienced 400% growth since 2002, although there are no tobacco plantations or manufacturing industries in the country [16]. The going market price for a pack of 20 cigarettes is around $1, and since 2009, British American Tobacco has held a monopoly in the country’s tobacco industry [14,16].

There is concern about the increasing use of tobacco in Angola following rapid economic growth, given the low prices for tobacco products and in the absence of restrictive legislation or organized health promotion campaigns. However, there is scarce information on the frequency and determinants of tobacco use in representative samples, further limiting health plan efforts and evaluation of interventions. The present study is the first report on the use of tobacco and the level of nicotine dependence among smokers in a large Angolan community sample of people aged 15–64 years.

Materials and methods

Results presented herein were extracted from a community-based survey conducted in the catchment area of the Dande Health and Demographic Surveillance System (Dande HDSS) [17], located in the Dande Municipality of Bengo Province, between 18 September 2013 and 28 March 2014. This study, named CardioBengo, constituted a larger survey of cardiovascular risk factors [18], and was based on the World Health Organization STEPwise approach to Surveillance (STEPS) to Chronic Disease Risk Factor manual (core and expanded version 3.0) [19].

Results

As shown in Table 1, the great majority of the participants reported never using any type of tobacco (86.1% overall: 94.1% of females, 77.5% of males). The prevalence of current smoking was 6.1%, and was higher among males (10.0%) than females (2.6%), and the prevalence of ex-smokers was 7.5% (12.2% in males and 3.2% in females). Only five participants reported use of smokeless (chewing) tobacco (0.2%, 95% CI: 0.1–0.5).

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Table 1. Prevalence, characteristics of tobacco use and nicotine dependence in smokers, by gender.

https://doi.org/10.1371/journal.pone.0188586.t001

Around one-third of ever-smokers (current and ex-) began smoking before age 18 (Table 1). The average age at initiation was 20.1 (±6.9) years; 19.8 (±6.1) years for males and 21.4 (±9.3) for females. None of the current smokers reported intermittent use, with most reporting five or fewer cigarettes per day (84.8% of females, 59.7% of males) (Table 1). The average number of daily smoked cigarettes was 6.6 (±6.8), higher among males (7.5 ± 7.2) than females (3.4 ± 3.3).

The nicotine dependence level was rated very low or low in 83.6% of the smoker population. Only 9.1% of females presented a medium level and none were above, while 18.4% of males had a medium or higher level (Table 1). Table 2 shows a breakdown of the mean values of nicotine dependence by variable categories, revealing that males had consistently higher levels of dependence than females. Among males, younger individuals presented a slightly higher mean value, as with males from urban areas or who reported daily alcohol consumption. Among females, the highest values of mean nicotine dependence were found in rural areas and among women aged above 45 years (Table 2).

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Table 2. Prevalence of smoking and ex-smoking by socio-demographic caracteristics and alcohol consumption frequency, by gender.

https://doi.org/10.1371/journal.pone.0188586.t002

As shown in Table 2, the prevalence of smoking was highest in the 55–64 age group for both sexes. The rural area had a higher smoking prevalence. Participants with 10 or more years of education had the lowest prevalence in both sexes. The prevalence was similar among income categories but slightly higher for those with lower levels of family income. Those who consumed alcohol (especially daily users) presented a higher prevalence of smoking. Similar trends were found for ex-smokers (Table 2).

Discussion

The analysis of the results from this survey contributes to the small body of tobacco-use-related literature on Angola. Quite recently, the Global Burden of Disease Study (GBD) estimated a smoking prevalence of 1.6% in females and 14.2% in males for Angola in 2015 [6].

Without a national prevalence survey, only a subnational survey from Huambo Province was conducted under the auspices of the World Health Organization in 2010, and in a sample aged 13–15 years found a 2.3% prevalence of smoking (3.2% in boys, 0.3% in girls) [21]. Three other studies published since 2000 provided data on tobacco smoking: a survey of 667 adult students of health sciences in Lubango estimated a prevalence of 4.0% [22]; a study conducted on 615 active employees of the University Agostinho Neto, Luanda, found a value of 7.2% (10.2% in males, 4.4% in females) [23]; and in 1,464 individuals aged 25–64 years, surveyed in 2011 for hypertension in the same area as in the present study, the prevalence was 9.8% (18.3% in males, 4.3% in females) [24].

To integrate our results with the GBD estimation and these four studies, it was necessary to look at the age range of each. This survey included individuals aged 15–64 years, and none of the above surveys had such a wide age range. The two with younger populations—Huambo and Lubango [21,22]—had lower prevalence (2.3% and 4.0%, respectively), and the two with older populations—Luanda and Bengo [23,24]—were higher (7.2% and 9.8%, respectively). This situates the present findings in the middle, at 6.1%.

Smoking prevalence estimates present vast heterogeneity among countries in the sub-Saharan Africa region [25,26]. National estimates for those countries, mainly after STEPS surveys, ranged from 1.8% in Zambia to 37.7% in Sierra Leone [11,25,27]. In this way, the present results evidently place Angola low in prevalence rankings for the region.

A commonality between the present study and the rest of the Angola-based studies regarding tobacco is that the prevalence of current smoking has been consistently higher among males than females. Smoking is the preferred type of tobacco consumption for males when compared with females [26,28]. As in other populations, smoking among females was significantly less prevalent, across all socio-demographic characteristics [26–29]. Culturally, female smokers are not generally well accepted [29], and use of smokeless tobacco is more frequent among females than males in Sub-Saharan Africa [28]. However, social changes and economic growth in Angola may reflect females’ empowerment, including more equitable access to income and educational opportunities and, therefore, accompanied by shifts in societal suitability and acceptance of female smokers [29].

The rural areas have a higher proportion of smokers them the urban areas in this survey, while it is more common to encounter greater prevalence of smokers in urban areas of sub-Saharan African countries [27,30]. The region where the survey was conducted is only 60 km from the capital. It serves as a commercial post between the capital and the northern cities, and in this way may influence the publicity of tobacco in rural areas located near major roads to other provinces.

The relation between smoking and education level, with a higher prevalence of smokers among the less-educated, who may lack health literacy to critically evaluate their decisions regarding tobacco use [7,31], is common in other African surveys. Low levels of family income are usually associated with low levels of education, and indeed the prevalence of smokers was also higher among low-income individuals in the present study. This reveals a higher level of exposure among the population’s more disadvantaged groups, which further contributes to inequalities in health promotion.

Together with the economic difficulties that youth show as a reason for not smoking in Angola [14], the long period of colonial and civil war (1961–2002) may have strongly influenced the higher prevalence among older groups and the initiation age of the majority of the individuals. This evidence is reinforced by the prevalence of ex-smokers among older people and the duration of smoking habits that correspond with normal years of active military duty. This phenomenon of smoking, together with alcohol consumption and the use of other drugs among populations from regions with armed conflict is described in other studies, and often associated with rituals of manhood and integration in armed groups [32,33].

This connection associated with the higher prevalence of current and ex-smokers in the groups of less-educated and less-wealthy males and females must be acknowledged and further studied with qualitative approaches that enable understanding of the impact of war and post-traumatic stress on tobacco and alcohol consumption patterns in Angola. This accumulation of behavioural risk factors, which occurs in this population, must be a concern focused on in future interventions addressing addiction and health education.

With regard to addiction, the present results revealed that low nicotine dependence levels were still predominant in this population, with low mean numbers of cigarettes smoked daily (3.4 in females and 7.5 in males). The efficacy of individual smoking cessation strategies can be improved by considering the target group’s nicotine dependence level [34].

The low rates of smoking prevalence and nicotine dependence among smokers, and the substantial rate of ex-smokers, can be associated with individuals’ weighty economic difficulties and the end of the war period. Angola has never had a legal framework for tobacco control; this is now predicted in the national plan for health development for 2012–2025 [14]. There are also absolutely no cessation programs or health promotion initiatives that specifically target tobacco use. This owes to the inadequacy of health structures and lack of health professionals trained in this subject, as identified by the Ministry of Health [14].

Acknowledgments

We thank all Dande—Health Demographic Surveillance System and Bengo General Hospital staff for their continuing support during fieldwork, namely Joana Paz and Ana Oliveira, who supervised the field work, Eduardo Saraiva for data entry supervision and database management, Edite Rosário for the training of field workers and assistance in data collection. Most importantly, the local administration, and all of the individuals who accepted to take part in the study. We also thank Adam Goulston, MS, ELS, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.