Watching Television and Risk of Mortality From Pulmonary Embolism Among Japanese Men and Women

Abstract

A lthough case series reporting pulmonary embolism or deep vein thrombosis after prolonged television watching have been published, 1 no prospective study has examined the association between time spent watching television and the risk of mortality from pulmonary embolism. We examined this association in a large cohort study of Japanese men and women. The Japanese Collaborative Cohort Study is a population-based cohort study that started between 1988 and 1990 in 45 regions of Japan involving 110 585 participants 40 to 79 years of age. 2 Written or verbal informed consent was obtained according to the guidelines of the Council of International Organizations of Medical Science. 3 This study was approved by the ethics committees of the Nagoya University and Osaka University. After the exclusion of those who did not provide information about time spent watching television and those who reported a history of cancer, stroke, myocardial infarction, or pulmonary embolism, 86 024 participants (36 006 men and 50 018 women) were included in the analysis. Baseline information was collected by a self-administered questionnaire that included items about demographic characteristics, medical history, and lifestyle factors. Participants were asked for their average time spent watching television in hours per day and then were classified into the prespecified 3 categories of <2.5, 2.5 to 4.9, and ≥5.0 h/d. Mortality from pulmonary embolism was ascertained on death certificates until the end of 2009. Hazard ratios for mortality from pulmonary embolism according to hours spent watching television were estimated with a Cox proportional hazards model. Hours spent watching television was evaluated as a categorical variable and separately as a continuous variable for each 2-hour increment. Covariates in the models were age (continuous), sex (female or male), body mass index (quintile), history of hyperten-sion (yes or no), history of diabetes mellitus (yes or no), smoking status (nonsmok-ers, ex-smokers, or <20 or ≥20 cigarettes per day), perceived mental stress (low, moderate, or high), educational level (13-15, 16-18, or ≥19 years of age on completion of education), walking activity (almost never or 0.5, 0.6-0.9, or ≥1 h/d), and sports activity (almost never or 1-2, 3-4, or ≥5 h/wk). Missing data were allocated to another category for each covariate. All statistical analyses were performed with SAS 9.4 software (SAS Institute, Cary, NC). During the median follow-up of 19.2 years, 59 deaths resulting from pulmonary embolism were documented. Television time was positively associated with the risk of mortality from pulmonary embolism, with multivariable hazard ratios of 1.7 (95% confidence interval, 0.9-3.0) for those watching television for 2.5 to 4.9 h/d and 2.5 (95% confidence interval, 1.2-5.3) for ≥5 h/d compared with <2.5 h/d (Table). The mortality rate from pulmonary embolism was 8.2 per 100 000 person-years among those watching television ≥5 h/d. An additional 2 hours of watching television was associated with an increased risk of mortality from pulmonary embolism, with a multivariable hazard ratio of 1.4 (95% confi