13-2Bath-related deaths in Kagoshima, Japan from 2006 to 2013: Differences in epidemiological factors between locations where the death occurred / 日本温泉気候物理医学会雑誌

ABSTRACT

  In Japan, sudden death in the bathroom (‘bath-related death’) occurs particularly in the elderly population in winter. Previously, we showed that bath-related death in Kagoshima Prefecture occurs at similar frequency as that in other prefectures, despite its warm environment. In this study, we performed a retrospective review of the inquest records in Kagoshima from between 2006 and 2013 in order to compare the demographic and circumstantial factors of the following 3 groups classified by the location where the death occurred home bathroom, spa, and nursing home bathroom. The total number of the deaths was 1533 (759 males and 774 females), which corresponds to a crude mortality rate of 11.3 per 100,000 person-years. Most of the deaths occurred at home (1319; 86.0%), followed by spa (159; 10.4%), nursing home (18; 1.2%), and others (37; 2.4%). In all 3 groups, most of the deceased were over 65 years old and were found sinking in the bathtub. The greatest number of deaths occurred in the winter at home (52.6%) and at a spa (54.7%) compared to other seasons. In contrast, death occurred most frequently in the spring at nursing homes (44.4%), when unexperienced staff begin to work in Japan. There was no significant difference in gender between home and nursing home cases, whereas significant more men died at a spa (p=0.0014). Although most deaths occurred at home between 1600 and 2000, a time when the elderly usually take a bath in Japan (49.4%), those at a spa and nursing home occurred earlier (1200-1600). The most common past history of illness was hypertension in home and spa cases, and that in nursing home cases was cardiovascular disease. Cardiac events leading to tragic results may occur more frequently in people with these illnesses than in healthy individuals while bathing. A history of drinking alcohol before bathing was observed in minor populations in home and spa cases, although it is also a known risk factor for death. However, the positive rate of spa cases was higher than that of home cases (8.2% vs. 3.3%). In all 3 groups, the most common cause of death indicated on the death certificate was heart disease such as myocardial infarction and arrhythmia (about 50%), followed by drowning. Except for 10 cases in which autopsy was performed, the cause of death in most cases was determined by only external examinations. Instead of autopsy, postmortem computed tomography (PMCT) scanning was performed in 44.9% of cases from 2010 to 2013. Cases that were diagnosed as drowning based on the findings by PMCT imaging have increased in recent years. However, PMCT is inferior to autopsy in detecting intrinsic disease and in elucidating a pathophysiological mechanism leading to drowning. In order to reduce the number of bath-related deaths, it is necessary to accumulate further evidence by increasing the number of cases undergoing autopsy, and to prompt the government and society to develop protective activities not only for known risk factors for death, but also for those peculiar to the bathing location.