This study provides an overview of factors associated with women's smoking in five European countries at the beginning of a time of rapid change in tobacco policy. We found that friends exert a strong influence on a woman's decision to start smoking in all five countries, especially in younger women. This has been reported from previous studies based in Europe and in studies based in the United States, Iran, Thailand and Mexico [6–12, 31–33]. We found that women in the Czech Republic and Sweden appeared to be more strongly influenced by friends and family smoking than in other countries.
We found that being divorced or separated is strongly associated with smoking, which has been reported previously . The association between divorce or separation and ever smoking appears to be strongest in Ireland and Italy, where rates of divorce and separation were lowest in our study sample. Our results also showed that in France, women who had never married were more likely to smoke than those who were married. Chaix and colleagues found similar results when they conducted a nationwide survey in France of 12 948 men and women .
Overall, we did not find a strong association between socioeconomic measures and smoking. This is in contrast to other findings on education status, low socioeconomic status (SES), and smoking initiation from Europe and other parts of the world [14–16, 36–41]. Our null findings could have partly been due the way the data were collected. Instead of asking for what level of education had been achieved, participants were asked how old they were when they completed their education. As individuals can complete different levels of education at different ages, this may have made our education groups more similar in terms of actual education level and biased the results toward the null. Also, since income can be a sensitive topic, there may have been reporting bias. The distribution of income levels was not as we expected; there was a disproportionate number of Italian women who reported having income well below the median and a disproportionate number of Czech women who reported having income around the median. This may be an indication that the way the question was asked made the responses subjective. There was a considerable amount of variation in the response rate between countries. Only 41.4% of women in Italy and 30.6% of women in the Czech Republic contacted who were eligible for participation agreed to participate. This may be another reason why the income distribution for these two countries was skewed. Our null findings on socio-economic status and smoking initiation could have also been due to generational differences between the younger and older women. In younger women, less education has been found to be associated with ever smoking; however, education has been found to be less predictive for older age groups. The generational shift varies in different European countries, with larger inequalities in Northern Europe, and this could have also diluted our overall results [42–47].
Alternatively, the null association between socioeconomic measures and ever smoking could in fact be accurate. Most studies investigating smoking initiation and socioeconomic factors look at populations that include both men and women. Women, however, may be less influenced by education and income status than men and more influenced by social factors such as friends and family. Many studies looking at SES and smoking status measure SES at the neighborhood level [14, 15, 36, 38]. Using neighborhood level data, rather than individual level data, may account for societal factors that may have a strong influence on women. One study showed that higher levels of smoking in deprived areas can only be partially explained by individual SES . Similarly, a study based in California found that the protective effects of individual SES may be reduced if an individual lives in a low SES neighborhood . Further investigation may provide interesting insight into what specific aspects of SES influence smoking in women.
As has been seen elsewhere [6–12], friends smoking was the top reason given for smoking initiation. The second most common reason for initiation was to 'look cool'. Spijkerman and colleagues also found that smoking was associated with wanting to be cool, rebellious and attractive . Watson and colleagues found that smoking was accepted as part of a 'cool' image . Friends smoking and looking cool was especially important for the younger women in our study.
Over 80% of the smokers in our study started smoking by 20 years of age. Those who initiate smoking in adolescence are of particular concern. Adolescents are more susceptible to nicotine addiction and require a shorter duration of smoking and fewer cigarettes to become addicted . Furthermore, the earlier one starts smoking, the greater the cancer risk in middle and old age [50, 51]. Average age at smoking initiation varied by country, income, education, and age cohort. Schulze and Mons also found mean age of smoking initiation differed by education level in Germany, and they found that the gap was widening among women . Consistent with our findings, La Vecchia et al. found that Italian women are initiating smoking at an earlier age than previous generations . Differences in age at initiation by country may be reflected in inter-country variation in lung cancer mortality by age .
We found depression to be associated with later smoking initiation. Since median age of onset of mood disorders, including major depressive disorder, ranges from 29 to 43 globally , it is not surprising that women who initiated smoking at a later age cited depression as a factor. In our study sample, 7.3% of women who started smoking at age 29 and older cited depression as a reason for initiating smoking compared to 1.2% in women who started smoking younger than 29 (p < 0.0001, data not shown). There is already much evidence linking depression and smoking [55, 56]; however, there is some debate as to the direction of the causality [57–61].
However, since depression was only evaluated by self-report, the definition of depression may have been used very broadly by the participants and it is difficult to make any specific clinical conclusions. It may be interesting for future studies to investigate if the relationship between depression and smoking differs by age at smoking initiation.
We found that individuals who stated they began smoking to reduce stress were more likely to have initiated at an older age. Other studies have found an association between stress and smoking [62–64]. Lloyd and Taylor found that the effect of former life stress predicts smoking independently of recent stress and that the effect of social stress on smoking is additive over time . In other words, stress at a younger age may affect future smoking; therefore, women who initiated smoking at a later age were more likely to cite stress as a factor.
One major limitation of the study was the stratified sampling approach using available telephone numbers. This method was chosen to allow the study to reach a large sample of women that was proportionally representative of smoking rates in each age group. However, administering the survey via telephone prevented us from verifying self-reported data. The potential for recall bias on reported age of initiation may have affected the accuracy of results. This bias was not likely to be differential by age group and thus should not affect the overall picture of the results. Also, since no mobile phone numbers were included in the phone list, the study could have excluded a substantial number of women from our study who may have unknown differences than those who could be reached by home telephone. Level of income and/or education may have affected whether women had a landline or whether they relied solely on cellular phone use. Thus, the participants may not be an accurate representation of their respective countries.
Though the five countries included in our study were at different stages of the tobacco epidemic  factors associated with smoking initiation were very similar. The association between friends and family smoking was found in all countries, but was strongest in Sweden and Czech Republic, two countries with very different tobacco epidemics. Mean age of smoking initiation was youngest in Sweden, which is in the more advanced stages of the tobacco epidemic. Mean age of initiation was oldest in the Czech Republic, which is in an earlier stage of the tobacco epidemic.
As rates of smoking are still rising among women in much of Europe, there is much to be done to prevent smoking-attributable mortality rates from also rising. The recent changes in Europe's tobacco policy have shown promising signs of slowing the epidemic. In a cross-sectional study of 18 European countries, countries with more developed tobacco control policies had higher levels of smoking cessation than in countries with less developed tobacco policies . In Ireland, Mullally et al. found a significant decline in cigarette consumption among bar workers and a significant drop in smoking prevalence in the general population one year after a nationwide ban on workplace smoking in March 2004 . In Scotland, Fowkes et al. found that smoking quit rates increased in the three months prior to introduction of the Scottish smoke-free legislation in March 2006 .