Christian Boudreau

Methods of the International Tobacco Control (ITC) Four Country Survey

This paper outlines the design features, data collection methods and analytic strategies of the International Tobacco Control (ITC) Four Country Survey, a prospective study of more than 2000 longitudinal respondents per country with yearly replenishments. This survey possesses unique features that sets it apart among surveys on tobacco use and cessation. One of these features is the use of theory-driven conceptual models. In this paper, however, the focus is on the two key statistical features of the survey: longitudinal and “quasi-experimental” designs. Although it is often possible to address the same scientific questions with a cross-sectional or a longitudinal study, the latter has the major advantage of being able to distinguish changes over time within individuals from differences among people at baseline (that is, differences between age and cohort effects). Furthermore, quasi-experiments, where countries not implementing a given new tobacco control policy act as the control group to which the country implementing such a policy will be compared, provide much stronger evidence than observational studies on the effects of national-level tobacco control policies. In summary, application of rigorous research methods enables this survey to be a rich data resource, not only to evaluate policies, but also to gain new insights into the natural history of smoking cessation, through longitudinal analyses of smoker behaviour.

Socioeconomic disparities in quit intentions, quit attempts, and smoking abstinence among smokers in four western countries: Findings from the International Tobacco Control Four Country Survey

INTRODUCTION Lower socioeconomic status (SES) groups have higher rates of tobacco use, are less likely to successfully quit, and may also be less likely to intend or attempt to quit. However, results are inconsistent for some outcomes, and little is known about how socioeconomic disparities vary across countries and over time. METHODS This study examined the associations between SES and quitting-related behaviors among representative samples of smokers in Canada, the United States, the United Kingdom, and Australia, using data from the first five waves (2002-2006/2007) of the International Tobacco Control Four Country Survey (35,532 observations from 16,458 respondents). Generalized estimating equations modeling was used to examine whether education and income were related to intentions to quit, incidence of quit attempts, and smoking abstinence. Potential differences in the associations over time and across countries were also considered. RESULTS Smokers with higher education were more likely to intend to quit, to make a quit attempt, and to be abstinent for at least 1 and 6 months; smokers with higher income were more likely to intend to quit and to be abstinent for at least 1 month. Some between-country differences were observed: U.K. and U.S. smokers were less likely to intend to quit than Australians and Canadians; and, although U.K. respondents were least likely to attempt to quit, those that did were more likely to be abstinent. DISCUSSION The results suggest that socioeconomic disparities exist at multiple stages in the path to smoking cessation. Potential effects on socioeconomic disparities should be considered when implementing cessation interventions.

Perceived effectiveness of pictorial health warnings among Mexican youth and adults: a population-level intervention with potential to reduce tobacco-related inequities

PurposePictorial health warnings on cigarette packages are a prominent and effective means of communicating the risks of smoking; however, there is little research on effective types of message content and socio-demographic effects. This study tested message themes and content of pictorial warnings in Mexico.MethodsFace-to-face surveys were conducted with 544 adult smokers and 528 youth in Mexico City. Participants were randomized to view 5–7 warnings for two of 15 different health effects. Warnings for each health effect included a text-only warning and pictorial warnings with various themes: “graphic” health effects, “lived experience”, symbolic images, and testimonials.ResultsPictorial health warnings were rated as more effective than text-only warnings. Pictorial warnings featuring “graphic” depictions of disease were significantly more effective than symbolic images or experiences of human suffering. Adding testimonial information to warnings increased perceived effectiveness. Adults who were female, older, had lower education, and intended to quit smoking rated warnings as more effective, although the magnitude of these differences was modest. Few interactions were observed between socio-demographics and message theme.ConclusionsGraphic depictions of disease were perceived by youth and adults as the most effective warning theme. Perceptions of warnings were generally similar across socio-demographic groups.

Smokers' beliefs about the relative safety of other tobacco products: Findings from the ITC Collaboration

Most tobacco control efforts in western countries focus on the factory-made, mass-produced (FM) cigarette, whereas other tobacco products receive relatively little attention. Noncombusted tobacco products (i.e., referred to as smokeless tobacco), particularly Swedish-style snus, carry lower disease risks, compared with combusted tobacco products such as cigarettes. In this context, it is important to know what tobacco users believe about the relative harmfulness of various types of tobacco products. Data for this study came from random-digit-dialed telephone surveys of current smokers aged 18 or older in Australia, Canada, the United Kingdom, and the United States. Three waves of data, totaling 13,322 individuals, were assessed. Items assessed use of and beliefs about the relative harms of cigars, pipes, smokeless tobacco, and FM and roll-your-own cigarettes, as well as sociodemographics and smoking behaviors. Cigars (2.8%-12.7%) were the other tobacco products most commonly used by current cigarette smokers, followed by pipes (0.3%-2.1%) and smokeless tobacco (0.0%-2.3%). A significant minority of smokers (12%-21%) used roll-your-own cigarettes at least some of the time. About one-quarter of smokers believed that pipes, cigars, or roll-your-own cigarettes were safer than FM cigarettes, whereas only about 13% responded correctly that smokeless tobacco was less hazardous than cigarettes. Multivariate analyses showed that use of other tobacco products was most strongly related to beliefs about the reduced harm of these other products. Use of other tobacco products was low but may be growing among smokers in the four countries studied. Smokers are confused about the relative harms of tobacco products. Health education efforts are needed to correct smoker misperceptions.

The impact of smokefree legislation in Scotland: results from the Scottish ITC Scotland/UK longitudinal surveys

BACKGROUND To evaluate how Scotlands smokefree law impacted self-reported secondhand smoke (SHS) exposure in hospitality venues, workplaces and in peoples homes. In addition, we examine changes in support for the law, pub and restaurant patronage, smoking cessation indicators and whether any observed changes varied by socioeconomic status. METHODS A quasi-experimental longitudinal telephone survey of nationally representative samples of smokers and non-smokers interviewed before the Scottish law (February to March 2006) and 1 year later after the law (March 2007) in Scotland (n = 705 smokers and n = 417 non-smokers) and the rest of the UK (n = 1027 smokers and n = 447 non-smokers) where smoking in public places was not regulated at the time. RESULTS Dramatic declines in the observance of smoking in pubs, restaurants and workplaces were found in Scotland relative to the rest of the UK. The change in the percent of smokers reporting a smokefree home and number of cigarettes smoked inside the home in the evening was comparable in Scotland and the rest of the UK. Support for smokefree policies increased to a greater extent in Scotland than in the rest of the UK. Self-reported frequency of going to pubs and restaurants was generally comparable between Scotland and the rest of the UK; however, non-smokers in Scotland were more likely to frequent pubs more often. No differences in smoking cessation indicators were observed between countries. CONCLUSION The Scottish smokefree law has been successful in decreasing secondhand smoke exposure while causing none of the hypothesized negative outcomes.

High-Dose Therapy and Autologous Hematopoietic Stem Cell Transplantation for Patients With Primary Systemic Amyloidosis: A Center for International Blood and Marrow Transplant Research Study

OBJECTIVE To determine the outcome of high-dose therapy with autologous hematopoietic stem cell transplantation (HSCT) in patients with primary systemic amyloidosis reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). PATIENTS AND METHODS A total of 107 recipients of autologous HSCT for amyloidosis from 48 transplantation centers were reported to the CIBMTR between 1995 and 2001. Hematologic and organ responses were assessed at 100 days and 1 year. Transplantation-related mortality (TRM) was assessed at day 30 after HSCT. A multivariate analysis assessed factors that influenced overall survival. RESULTS Improvement at day 100 was seen in 1 or more amyloidosis-affected sites (bone marrow, kidney, liver, and/or heart) in 28 (36%) of 77 patients; the 1-year responses included complete response (16%), partial response (16%), stable disease (31%), and disease progression (10%). With a median follow-up of 30 months, the 1- and 3-year survival rates were 66% (95% confidence interval [CI], 56%-75%) and 56% (95% CI, 45%-66%), respectively. The day 30 TRM was 18% (95% CI, 11%-26%). In the multivariate analysis, only the year of transplantation (patients who most recently underwent transplantation) was associated with post-HSCT survival (P-.02). CONCLUSION In this multi-institutional CIBMTR study, the 3-year survival rate was comparable to single-center results, with patients who more recently underwent transplantation faring better. Of note, the TRM was higher than that reported by single centers, which may reflect differences in patient selection and/or experience in treating this challenging disease. We hope that a better understanding of the recently recognized prognostic factors and more stringent patient selection will result in lower TRM and improved survival.

Comparative impact of smoke-free legislation on smoking cessation in three European countries

BACKGROUND Little is known about the differential impact of comprehensive and partial smoke-free legislation on smoking cessation. This study aimed to examine the impact of comprehensive smoke-free workplace legislation in Ireland and England, and partial hospitality industry legislation in the Netherlands on quit attempts and quit success. METHODS Nationally representative samples of 2,219 adult smokers were interviewed in three countries as part of the International Tobacco Control (ITC) Europe Surveys. Quit attempts and quit success were compared between period 1 (in which smoke-free legislation was implemented in Ireland and the Netherlands) and period 2 (in which smoke-free legislation was implemented in England). RESULTS In Ireland, significantly more smokers attempted to quit smoking in period 1 (50.5%) than in period 2 (36.4%) (p < 0.001). Percentages of quit attempts and quit success did not change significantly between periods in the Netherlands. English smokers were significantly more often successful in their quit attempt in period 2 (47.3%) than in period 1 (26.4%) (p = 0.011). In the first period there were more quit attempts in Ireland than in England and fewer in the Netherlands than in Ireland. Fewer smokers quitted successfully in the second period in both Ireland and the Netherlands than in England. CONCLUSION The comprehensive smoke-free legislation in Ireland and England may have had positive effects on quit attempts and quit success respectively. The partial smoke-free legislation in the Netherlands probably had no effect on quit attempts or quit success. Therefore, it is recommended that countries implement comprehensive smoke-free legislation.

Influence of age and histology on outcome in adult non-Hodgkin lymphoma patients undergoing autologous hematopoietic cell transplantation (HCT): a report from the Center For International Blood & Marrow Transplant Research (CIBMTR).

To compare the clinical outcomes of older (age > or =55 years) non-Hodgkin lymphoma (NHL) patients with younger NHL patients (<55 years) receiving autologous hematopoietic cell transplantation (HCT) while adjusting for patient-, disease-, and treatment-related variables, we compared autologous HCT outcomes in 805 NHL patients aged > or =55 years to 1949 NHL patients <55 years during the years 1990-2000 using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). In multivariate analysis, older patients with aggressive histologies were 1.86 times (95% confidence interval [CI] 1.43-2.43, P < .001) more likely than younger patients to experience treatment-related mortality (TRM). Relative death risks were 1.33 times (CI 1.04-1.71, P = .024) and 1.50 times (CI 1.33-16.9, P < .001) higher in older compared to younger patients with follicular grade I/II and aggressive histologies, respectively. Autologous HCT in older NHL patients is feasible, but most disease-related outcomes are statistically inferior to younger patients. Studies addressing supportive care particular to older patients, who are most likely to benefit from this approach, are recommended.

Myeloablative therapy with autologous stem cell rescue for patients with Ewing sarcoma.

The aim of this study was to identify risk factors associated with PFS in patients with Ewing sarcoma undergoing ASCT; 116 patients underwent ASCT in 1989–2000 and reported to the Center for International Blood and Marrow Transplant Research. Eighty patients (69%) received ASCT as first-line therapy and 36 (31%), for recurrent disease. Risk factors affecting ASCT were analyzed with use of the Cox regression method. Metastatic disease at diagnosis, recurrence prior to ASCT and performance score <90 were associated with higher rates of disease recurrence/progression. Five-year probabilities of PFS in patients with localized and metastatic disease at diagnosis who received ASCT as first-line therapy were 49% (95% CI 30–69) and 34% (95% CI 22–47) respectively. The 5-year probability of PFS in patients with localized disease at diagnosis, and received ASCT after recurrence was 14% (95% CI 3–30). PFS rates after ASCT are comparable to published rates in patients with similar disease characteristics treated with conventional chemotherapy, surgery and irradiation suggesting a limited role for ASCT in these patients. Therefore, ASCT if considered should be for high-risk patients in the setting of carefully controlled clinical trials.

Estimating and testing for center effects in competing risks

The problems of fitting Gaussian frailties proportional hazards models for the subdistribution of a competing risk and of testing for center effects are considered. In the analysis of competing risks data, Fine and Gray proposed a proportional hazards model for the subdistribution to directly assess the effects of covariates on the marginal failure probabilities of a given failure cause. Katsahianbiet al. extended their model to clustered time to event data, by including random center effects or frailties in the subdistribution hazard. We first introduce an alternate estimation procedure to the one proposed by Katsahian et al. This alternate estimation method is based on the penalized partial likelihood approach often used in fitting Gaussian frailty proportional hazards models in the standard survival analysis context, and has the advantage of using standard survival analysis software. Second, four hypothesis tests for the presence of center effects are given and compared via Monte-Carlo simulations. Statistical and numerical considerations lead us to formulate pragmatic guidelines as to which of the four tests is preferable. We also illustrate the proposed methodology with registry data from bone marrow transplantation for acute myeloid leukemia (AML).