Seasonal Variation in Mortality from Ischemic Heart Disease and Cerebrovascular Disease in Okinawa and Osaka: the Possible Role of Air Temperature.

Abstract

Okinawa is located in a subtropical area and is well-known for low mortality due to ischemic heart disease (IHD) and cerebrovascular disease (CVD). However, the factors that contribute to these low mortality rates remain unclear. We examined the seasonal variation in the mortality due to IHD and CVD among Okinawa and Osaka residents, aged 45 to 84 years, between 1992 and 1996. In addition, we studied if there was a relationship between the monthly mortality rate from IHD or CVD and the monthly mean daily air temperature in Naha City and Osaka City. Data on the monthly mean daily air temperature was obtained from the meteorological stations in Naha City and Osaka City. Our results showed that there were inverse correlations between the monthly mean daily temperature in a city and each of the monthly mortality from IHD in Okinawa (r=-0.794, p<0.01), the monthly mortality from CVD in Okinawa (r=-0.837, p<0.001), and the monthly mortality from CVD in Osaka (r=-0.954, p<0.001). In Osaka, the monthly mortality rate from IHD was at or near its minimum value when the mean daily temperature was approximately 25 (in September), and it increased in a linear fashion as the mean monthly temperature fell (r=-0.975, p<0.001). The difference between the monthly mortality from IHD or CVD among the Okinawa and the Osaka residents increased in the winter season in comparison with that in the other seasons, with the exception for IHD in July and in August. These findings indicate that the lower mortality from IHD and CVD in Okinawa is affected, at least in part, by Okinawa's warm winter.

Lower air temperature is associated with ambulance transports and death in Takamatsu area, Japan

“…In turn, lower air temperature is also associated with severe health problems [5][6][7][8][9][10]. We have also reported that lower air temperature was associated with higher frequency of ambulance transports in Sakata area located in northern part (Tohoku area) and cold climate area in Japan [11].…”

“…Low air temperatures were significantly associated with intestinal infectious diseases, respiratory diseases, endocrine, nutritional and metabolic diseases [8]. Also in Japan, Tanaka et al [9] evaluated the mortality due to ischemic heart disease and cerebrovascular disease among Okinawa and Osaka area, and found that lower mortality from ischemic heart disease and cerebrovascular disease in Okinawa is affected, at least in part, by Okinawa's warm winter. Abe et al [10] showed the cold air temperature is related to an increased risk of asthma in adults.…”

“…In addition, in Japan, the first factor of death is cancer, and then followed by heart disease, pneumonia and cerebral vascular disease (CVD) [18], especially pneumonia increased remarkably. It is well known that these factors are associated with low air temperature [6][7][8][9]. Therefore, these factors may affect the relationship between low air temperature and the number of death in Takamatsu area as well as all over Japan.…”

Seasonal Influence on Blood Pressure in Elderly Normotensive Subjects

“…We observed a difference between pre-wake-up-time SBP and wake-up-time SBP, and the morning surge was greater in the cold seasons than in the warm seasons. This is likely to be related to the high frequency of cardiovascular and cerebrovascular events in the winter (26)(27)(28)(29)(30)(31)(32)(33). Goodwin et al reported significantly higher morning BP in elderly men in winter than in summer (34).…”

Impact of a cold wave on disease course, hemodynamics, carbohydrate metabolism, and blood rheological properties in cardiac patents

“…Полученные данные свидетельствуют, что снижение температуры атмосферного воздуха на 1 °С ниже порого-вого уровня ассоциируется с увеличением общего числа смертей на 1,35%, смертности от ССЗ на 1,72%, от респи-раторных заболеваний на 3,3% и от сосудисто-мозговых болезней на 1,25%. Увеличение зимней смертности от ССЗ описано во многих европейских странах [1][2][3][4][5], включая Россию [1,6], США [7], Китай [8], Японию [9], Австралию [10] и Новую Зеландию [11]. Однако причина этого явления неизвестна.…”