To the best of our knowledge, this is the first study carried out in Portugal regarding the evolution of smoking inequalities. Findings show that over the 1987–2006 period inequalities in smoking behaviour reversed for men, related to higher cessation rates among high socioeconomic groups in all surveys analysed coupled with higher initiation rates among low socioeconomic groups in the first three surveys, particularly in younger cohorts (1960–1969). A similar trend for current smoking was observed among women but not enough to observe that reversal in the social gradient. This could be explained by higher initiation rates among high socioeconomic groups in all surveys, and the emergence of inequalities in cessation favouring the richer in the last survey, especially in the youngest cohort.
Results confirm that Portugal belongs to the group of Southern countries where women lag behind men in the smoking epidemics [4,5]. However, unlike Italy and Spain, the reversal in inequalities has not been observed yet among younger women [19,20]. For example, in Italy, low educated men aged 25 to 49 years old were more likely to smoke (OR = 1.26), while for women in the same age group inequalities reversed . This suggests either it is too early to observe a reversal, or Portugal experiences a different path.
This last interpretation is consistent with Thun, Peto, Boreham, and Lopez . These authors suggest an update of the epidemiological model of smoking, based on the observation that paths among women significantly vary across countries. For example, in Spain, the late attenuation of smoking cultural prohibition to women delayed women smoking-related mortality and most likely reduced the maximum prevalence levels that would be attained, when compared with countries such as the United States or the United Kingdom . Similarly, a study from Bosdriesz, Mehmedovic, Witvliet, and Kunst found higher prevalence of women smoking in high socioeconomic groups in Latin America and Eastern Mediterranean countries . Authors justify this pattern with the later emancipation of women and with the proximity to Southern European countries, where there is a higher acceptability of smoking among women, coupled with a conservative environment in low socioeconomic and rural groups .
Portugal might experience a similar trend with prevalence among women growing late, and with persisting higher prevalence among richer and higher-educated persons. Further study of the most recent trends in countries such as Portugal may show in more detail alternative paths of inequalities in the smoking epidemic.
Although national health surveys are widely used because they provide large sample sizes and important information on health, they suffer from well-known limitations . Firstly, smoking status and cessation were self-reported. However, the validity of self-reports of smoking was showed in most studies . Authors usually recommend validation of smoking status (e.g. by biochemical tests) only in intervention studies, and self-administered questionnaires . Also, the validity of the self-reported smoking status has proved to be high in population-based studies . Self-reported smoking could be a more serious limitation to this study if under-reporting was related to socioeconomic status. For example, in lower socioeconomic classes, characterized by traditional and conservative environments, the acceptability of smoking among women could be lower. If this is the case, our results may over-estimate the pro-rich socioeconomic inequalities in smoking among women.
Secondly, the last survey was from 8 years ago and the inequalities have probably changed by now. In particular, important tobacco policies have been implemented since then, like the protection against involuntary tobacco exposure, implemented by the 2007 legislation. Further study may be relevant to provide evidence on the impact of recent tobacco control policies on inequalities, for which no consistent evidence has been produced yet .