Int. J. Environ. Res. Public Health 2009, 6 611 scale of 1 to 10). A smoker was considered strongly dependent if she/he smoked more than 20 cigarettes per day, or if she/he reported smoking her/his first cigarette within 30 minutes after waking up. Comparisons between poor smokers and other smokers were performed with Pearson‟s χ² (for categorical variables) and Student‟s T (for numerical variables) tests. 2.3. Qualitative Analysis of Poor Smokers’ Motives To define poverty, we endorsed the sociological perspective initially developed by Simmel [20]: the poor person is the individual who receives assistance because of this lack of means. Such perspective was theoretically relevant, but it also provided an easy way to recruit respondents. Indeed, we contacted smokers through social workers who deliver assistance to the poor in two cities of South- Eastern France. In-depth semi-structured interviews were conducted by J.C. in either social service delivery settings or participants‟ homes at their convenience. A brief interview topic guide allowed conversation and meaning to emerge through an interplay between researcher and participant. Interviews lasted between 40 and 90 minutes. Interviews were tape-recorded with informed consent, then transcribed verbatim by J.C., with any personal identifying information removed to preserve anonymity and confidentiality (first names have been changed in the quotations infra). We endorsed an inductive approach based on grounded theory [21,22]. Data were analyzed concurrently with data collection: the themes emerging from the first five interviews helped to refine the topic guide used for the next five interviews, and so on. J.C. and P.P.W. coded the transcripts independently, then met to discuss their codes and to agree on any differences in language for the codes. Finally, we undertook a second round of coding to condense our set of initial codes into more abstract, second-line codes. We considered that the sample was saturated after 31 interviews (so data collection ceased), as the last interviews no longer elicited themes not already raised by previous participants. The 31 participants were 13 women and 18 men, seven aged 30 or less, 12 aged 30 to 50, 12 aged 51 to 60. All participants reported financial and/or housing problems, and 25 were currently unemployed. We referred to the analytic methods of grounded theory for guidance concerning the process of undertaking systematic data coding [21,22]. A range of themes emerged from the analysis, but we concentrated below on smoking motives. 3. Results 3.1. The Social Differentiation of Smoking in France, 2000-2008 Figure 1 displays the trends in smoking prevalence among executive managers and professional occupations, manual workers and the unemployed, as well as the evolution of the standard price of cigarette packs, between 2000 and 2008. Among the executive managers and the professional occupations, the smoking prevalence declined significantly between 2000 and 2003 (from 36% to 27%, p<0.001), concurrently to a sharp increase in cigarette price (from 3.20 € to 4.60 € per pack). Then it remained stable from 2003 to 2008, with no statistically significant variation. Overall, the smoking prevalence decreased by 19% ([36%-