Effectiveness of the public health policy for breast cancer screening in Finland: population based cohort study

Abstract

Objective: To examine the research evidence for the health consequences of obstructive sleep apnoea and the effectiveness of continuous positive airways pressure. Design: A systematic review of published research, studies being identified by searching Medline (1966-96), Embase (1974-96), and CINAHL (Cumulative Index to Nursing and Allied Health Literature) ; scanning citations; and consulting experts. Studies in all languages were considered which either investigated the association between obstructive sleep apnoea in adults and key health outcomes or evaluated the effectiveness of treatment of obstructive sleep apnoea with continuous positive airways pressure in adults. Main outcome measures: Mortality, systematic hypertension, cardiac arrhythmias, ischaemic heart disease, left ventricular hypertrophy, pulmonary hypertension, stroke, vehicle accidents, measures of daytime sleepiness, and quality of life. Results: 54 epidemiological studies examined the association between sleep apnoea and health related outcomes. Most were poorly designed and only weak or contradictory evidence was found of an association with cardiac arrhythmias, ischaemic heart disease, cardiac failure, systemic or pulmonary hypertension, and stroke. Evidence of a link with sleepiness and road traffic accidents was stronger but inconclusive. Only one small randomised controlled trial evaluated continuous positive airways pressure. Five non-randomised controlled trials and 38 uncontrolled trials were identified. Small changes in objectively measured daytime sleepiness were consistently found, but improvements in morbidity, mortality, and quality of life indicators were not adequately assessed. Conclusions:The relevance of sleep apnoea to public health has been exaggerated. The effectiveness of continuous positive airways pressure in improving health outcomes has been poorly evaluated. There is enough evidence suggesting benefit in reducing daytime sleepiness in some patients to warrant large randomised placebo controlled trials of continuous positive airways pressure versus an effective weight reduction programme and other interventions.

Breast cancer mortality trends in two areas of the province of Florence, Italy, where screening programmes started in the 1970s and 1990s

“…Mammographic screening has been shown to reduce breast cancer mortality rates (Vainio and Bianchini, 2002). Several studies in northern European countries (Hermon and Beral, 1996;Hakama et al, 1997; Van den Akker-van Marle et al, 1999;Blanks et al, 2000;Jonsson et al, 2001;Botha et al, 2003;Otto et al, 2003;Tabar et al, 2003) have reported a decrease in breast cancer mortality where nationwide screening programmes have been implemented. There has, however, been considerable debate concerning the relative contributions of screening and of improved therapy to the observed trends (Carnon et al, 1996;Blanks et al, 2000;Peto et al, 2000).…”

Evaluation of breast cancer service screening programme with a Bayesian approach: mortality analysis in a Finnish region

“…Table 3 shows the estimated results using Bayesian sequential approach outside Finland. With the incorporation of successive information in chronological order, including Dalarna study [9], Gothenburg study [10] in Sweden, the early nationwide study in Finland [3], the adjusted RR based on these sequential priors together with the Pirkanmaa data was 0.67 (0.55-0.80). Table 3 The estimated results of relative mortality rate adjusted by self-selection bias with Bayesian acyclic graphic model …”

“…As illustrated in Eq. 1 (Appendix), the baseline group for selfselection bias adjustment is the uninvited group with the background breast cancer mortality equivalent to 21.1/ 100,000 (63 deaths among the 299,228 women-years) derived from Hakama et al study [3]. The reason for using Bayesian approach is that as Pirkanmaa is one of local areas that have organized screening program within nationwide screening program since 1987, evaluation of long-term effectiveness in mortality reduction may be subject to insufficient sample size.…”

“…Consequently, two types of prior, non-informative and informative priors are incorporated in the Bayesian acyclic graphic model. The former is simply based on the data from the current screening program in Pirkanmaa center, whereas the latter uses data from Pirkanmaa screening and the external information from nationwide study that reported a 0.76 relative rate of death from breast cancer in the birth cohorts invited opposed to the uninvited birth cohorts [3]. Second, we considered how to apply the Bayesian approach to sequentially incorporate prior information from previous randomized studies in Sweden.…”

“…Good quality of this service screening programme has been reported [1,2] and the early evaluation of the effectiveness of the breast cancer screening regime during the first 3 years of this service screening program by comparing the invited women with the control cohort who have not been invited to screen yet showed a 24% non-significant mortality reduction for the invited women [3]. Since the effectiveness of breast cancer screening is subject to many factors (such as age, attendance rate, and inter-screening interval), it therefore suggests that any population-based organized service screening even small areas should be evaluated once launched.…”