Saez M, Sunyer J, Castellsagué J, Murillo C, Antó J M
Department d'Epidemiologia i Salut Pública, Institut Municipal d'Investigació Mèdica, Barcelona, Spain.
Int J Epidemiol. 1995 Jun;24(3):576-82. doi: 10.1093/ije/24.3.576.
Many studies have reported that heatwaves increase mortality. However, it is not certain whether less pronounced rises in temperature also increase it. Such information might be important for predicting the impact of potential weather changes on mortality. We have assessed the relationship between daily mortality and moderate increases in weather temperature in Barcelona, Spain, following a time series approach.
The study included the period from 1 January 1985 to 30 December 1989. For all the population resident in Barcelona, Spain, we considered the following daily data: total mortality, mortality of those > 65 years, and cardiovascular and respiratory mortality. The meterological variables were: minimum temperature, maximum temperature, dew point temperature and relative humidity. Several transfer function (ARIMA) models were estimated for the entire period and for both winters and summers separately.
We found that unusual periods of at least three consecutive days of increased weather temperature increased mortality, independently of the V-shaped relationship also found. The occurrence of an unusual period increased total daily mortality by 2% on average (1.7% on summers) and by 2.6% in those over 65 (2% on summers). Cardiovascular mortality rose by 4.6% (4.2% on summers) and respiratory mortality by 21.6% (13.2% on summers). However, only those unusual periods with an excess temperature and humidity were associated with mortality increases.
The unusual periods observed in the present study cannot be classified as heatwaves because the weather temperature never reached high values and most of them occurred during the winter. The association of unusual periods with mortality was stronger during winters than in summers, maybe because unusual winter periods showed a temperature deviation from the average twice that in summer or because humidity during unusual winter periods was higher than in summer.
许多研究报告称热浪会增加死亡率。然而，气温不太明显的升高是否也会增加死亡率尚不确定。此类信息对于预测潜在天气变化对死亡率的影响可能很重要。我们采用时间序列方法评估了西班牙巴塞罗那每日死亡率与气温适度升高之间的关系。
研究涵盖1985年1月1日至1989年12月31日期间。对于西班牙巴塞罗那的所有常住居民，我们考虑了以下每日数据：总死亡率、65岁以上人群的死亡率以及心血管和呼吸系统死亡率。气象变量包括：最低气温、最高气温、露点温度和相对湿度。对整个时期以及分别对冬季和夏季估计了几个传递函数（自回归积分滑动平均）模型。
我们发现，天气温度连续至少三天异常升高的时期会增加死亡率，这与所发现的V形关系无关。异常时期的出现使每日总死亡率平均增加2%（夏季为1.7%），65岁以上人群增加2.6%（夏季为2%）。心血管死亡率上升4.6%（夏季为4.2%），呼吸系统死亡率上升21.6%（夏季为13.2%）。然而，只有那些气温和湿度过高的异常时期与死亡率增加有关。
本研究中观察到的异常时期不能归类为热浪，因为天气温度从未达到很高的值，且大多数异常时期发生在冬季。异常时期与死亡率的关联在冬季比夏季更强，可能是因为冬季异常时期的温度偏离平均值的幅度是夏季的两倍，或者是因为冬季异常时期的湿度高于夏季。
