American journal of epidemiology
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Prospective evidence of the associations of smoking cessation with chronic obstructive pulmonary disease (COPD) and other causes of death in Asia is scarce. Previous studies, which were mostly based on baseline smoking behavior only, were subject to sick-quitter bias and misclassification resulting from changes in smoking behavior during follow-up. We followed up a cohort for 18 years (1976-1994) to assess changes in smoking behavior and then for an additional 17 years (1994-2011) to examine the relationships of continuing to smoke and new quitting with mortality risk in 1,494 Chinese people (961 men, 533 women). ⋯ The corresponding relative risks were 0.69 and 0.45 for lung cancer, 0.78 and 0.51 for coronary heart disease, 0.76 and 0.84 for thrombotic stroke, and 0.89 and 0.61 for COPD, respectively. Smoking increased tobacco-related deaths, and particularly deaths from COPD, in China, whereas quitting at middle age (at approximately 50 years of age) substantially reduced the risks of death from these causes. The benefits of smoking cessation were underestimated in previous studies that did not use repeated measures.
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Epidemiologic studies have reported conflicting results on the relationship between daytime napping and mortality risk, and there are few data on the potential association in the British population. We investigated the associations between daytime napping and all-cause or cause-specific mortality in the European Prospective Investigation Into Cancer-Norfolk study, a British population-based cohort study. Among the 16,374 men and women who answered questions on napping habits between 1998 and 2000, a total of 3,251 died during the 13-year follow-up. ⋯ This association was more pronounced for death from respiratory diseases (for napping less than 1 hour, hazard ratio = 1.40, 95% confidence interval: 0.95, 2.05; for napping 1 hour or more, hazard ratio = 2.56, 95% confidence interval: 1.34, 4.86) and in individuals 65 years of age or younger. Excessive daytime napping might be a useful marker of underlying health risk, particularly of respiratory problems, especially among those 65 years of age or younger. Further research is required to clarify the nature of the observed association.
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The "prosecutor's fallacy" (the assumption that Pr [probability] (A|B) = Pr (B|A)) arises often in epidemiology but is often unrecognized as such, in part because investigators do not have strong intuitions about what the fallacy means. Here, we help inform such intuitions and remind investigators of this fallacy by using visualizations. In figures, we demonstrate the prosecutor's fallacy, as well as show conditions under which Pr (A|B) can be assumed to be equal to Pr (B|A). Visualizations can help build intuition around statistical concepts such as the prosecutor's fallacy and should be more widely considered as teaching tools.