Why was the Interdisciplinary Study of Inequalities in Smoking ( ISIS ) cohort set up ?

The Interdisciplinary Study of Inequalities in Smoking (ISIS) is a cohort study investigating the joint effects of residents’ socio-demographic characteristics and neighbourhood attributes on the social distribution of smoking in a young adult population. Smoking is a behaviour with an increasingly steep social class gradient; smoking prevalence among young adults is no longer declining at the same rate as among the rest of the population, and there is evidence of growing place-based disparities in smoking. ISIS was established to examine these pressing concerns. The ISIS sample comprises non-institutionalized individuals aged 18–25 years, who are proficient in English and/or French and who had been living at their current address in Montréal, Canada, for at least 1 year at time of first contact. Two waves of data have been collected: baseline data were collected November 2011-September 2012 (n1⁄4 2093), and a second wave of data was collected January-June 2014 (n1⁄4 1457). Data were collected from respondents using a selfadministered questionnaire, developed by the research team based on sociological theory, which includes questions concerning social, economic, cultural and biological capital, and activity space as well as smoking behaviour. Data are available upon request from [katherine.frohlich@umontreal.ca]. VC The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association 1 International Journal of Epidemiology, 2015, 1–14 doi: 10.1093/ije/dyv036 Cohort Profile Int. J. Epidemiol. Advance Access published May 6, 2015 by gest on Jne 5, 2016 http://ijerdjournals.org/ D ow nladed from Why was the Interdisciplinary Study of Inequalities in Smoking (ISIS) cohort set up? Although the overall population prevalence of cigarette smoking in North America is at an all-time low, smoking rates are increasingly socially stratified. Smoking prevalence is consistently higher among young people in their early twenties compared with any other age group. As well, proportionally more people from lower socioeconomic status (SES) groups smoke for more years and experience less success in quitting than higher SES smokers. Lower SES smokers suffer a higher burden of illness associated with smoking and their children are more likely to initiate smoking than higher SES youth. Growing evidence of place-based disparities in smoking has created an area of enquiry which posits that general social inequalities in smoking may also be related to neighbourhood inequalities in smoking. The overarching aim of the ISIS study is thus to understand: (i) why do lower SES smokers not follow the secular trend in smoking reduction at the same rate as the rest of society; and (ii) what attributes of neighbourhoods are associated with social inequalities in smoking. The ISIS project grapples with an unanswered question in place and health inequalities research: Can we better understand how shared characteristics of neighbourhood residents (for example, their education level), also called ‘compositional factors’, interact with neighourhood-level characteristics or ‘contextual factors’ (for example, availability of green space) in shaping inequalities in health? The ISIS project was specifically designed to capture the complexity of this interaction using a theoretical model developed by our research team (Figure 1). ISIS characterizes neighbourhoods as unique configurations of five domains in which health-related resources can be accessed: the economic, institutional, community organization, local sociability and physical domains. With regard to compositional factors, we view them conceptualized as capitals, including economic, cultural, social and biological capital. We posit that neighbourhood resources made available (or not) through the five domains are shaped by residents’ capital levels over time, and hence the need for longitudinal data. ISIS takes place in Montréal, Canada, at the École de Santé Publique de l’Université de Montréal (ESPUM) and the Institut de recherche en santé publique de l’Université de Montréal (IRSPUM). The project received pilot funding from the Canadian Tobacco Control Research Initiative (2008) and the Public Health Agency of Canada (2011) to develop a questionnaire and a neighbourhood observation grid, as well as 4-year funding (2011–15) in an operating grant from the Canadian Institutes of Health Research (CIHR) for the first two waves of data collection. Our multidisciplinary team includes 12 researchers with diverse expertise, graduate students, post-doctoral fellows, staff, visiting scholars and an advisory board composed of governmental partners [www.isis-montreal.ca]. Who is in the ISIS cohort? ISIS is a cross-lag panel study of individuals embedded in their residential neighbourhood. Our study population is a sample of non-institutionalized young adults aged 18–25, proficient in English and/or French, who have resided at their current address for at least 1 year at time of first contact. We requested that the Régie de l’Assurance Maladie du Québec (RAMQ), the publicly funded health insurance programme in Quebec, draw an equal-size simple random sample of 172 individuals between the ages of 18 and 25 years from each of the 35 Centres Locaux de Santé Communautaire (CLSC) territories on the Island of Montreal (n1⁄46020). CLSCs were used as the primary sampling units since they are related to postal code area and variability in area-level deprivation has been documented. Given that smoking rates vary by sex, we also ensured that each CLSC sample was divided into equal numbers of males and females. The RAMQ provided the names, mailing addresses, sex, preferred language of Key Messages • The unique combination of individual resident characteristics and street-section attributes in ISIS will allow examination of their interaction over time along with their joint effects on social inequalities in smoking. • At wave 1 there was a non-random social distribution of smoking outcomes according to residential-level material deprivation. • Where young adults live and conduct daily activities (i.e. their activity spaces) are socially graded; less educated respondents live and conduct activities in areas of higher deprivation than their more educated counterparts. • Poor mental health was associated with having fewer commercial and recreational resources in one’s activity space whereas the number of resources available in one’s residential neighbourhood was not. 2 International Journal of Epidemiology, 2015, Vol. 0, No. 0 by gest on Jne 5, 2016 http://ijerdjournals.org/ D ow nladed from