【作者】 杨军；

【导师】 陈平雁； 欧春泉；

【作者基本信息】 南方医科大学 ， 流行病与卫生统计学， 2013， 硕士

【摘要】 研究背景在全球气候变化的议题下,气象因素对健康的影响越来越引起政府、气象研究者和公众的关注。而气候变化会增加极端气象事件(如：热浪、寒流、水灾等)发生频率及持续的时间。以往气象流行病学的研究指出气温对居民死亡有显著影响。但这些研究主要集中在温带的发达国家,而来自发展中国家,尤其是对热带、亚热带地区的相关研究非常稀少。实际上,由于较弱的应对气候变化的能力以及较差的生活环境,这些地区的人群更容易受气候变化的影响。故为了更好的评估气候变化对全人类的影响,来自不同地区,尤其是热带、亚热带地区的研究显得非常必要。以往气象健康研究重点放在气温上,即日均温度、日最高温度和日最低温度,而忽略了其他气象因素,像日温差、相对湿度、大气气压等。其中日温差(日最高温度与日最低温度之差)被认为评估全球气候变化非常重要的气象指标。同样,相对湿度、大气气压也是非常重要的气象因素。目标研究气象因素与广州市居民死亡的关系。其中气象因素包括：日温差、日均温度、相对湿度、大气气压、热浪。本研究还将探讨气温与其它气象因素的交互效应,以及不同气象因素的敏感人群。方法数据来源2003-2007年死亡数据来自于广东省卫生局,2008-2011年死亡的数据来自广州市疾病预防控制中心。死亡数据包括个体基本信息,如：性别、出生日期、死亡日期、教育程度、职业水平等。气象数据来自于国家气象数据共享中心,其中包括日均温度、日最高温度、日最低温度、相对湿度、大气气压等。而空气污染的数据(如：NO2、SO2、PM10)则来自于广州市环保局。数据分析本研究采用分布滞后非线性模型来评估温度与死亡非线性的关系以及温度滞后效应。日温度、相对湿度、大气气压的影响,同样采用分布滞后非线性模型来拟合,同时控制气温、空气污染、季节趋势和星期几、节假日效应等混杂因素。日温差、相对湿度、大气气压与温度的交互效应,本研究分别用二变量的三次样条函数来拟合。而热浪影响,通过计算热浪超额死亡人数以及热浪时期与对照时期死亡率之比来评估。结果高温的影响急促但一般局限在5天内,而低温的影响可持续12天。高温影响,即气温从第90百分位数变化到第99百分位数引起居民非意外死因的死亡率上升15.46%(95%CI：10.05%-20.87%),而低温影响,即第10百分位数下降到第1百分位数则引起居民非意外死因的死亡率上升20.39%(95%CI：11.78-29.01%)。与非意外死因比较,气温对心脑血管-呼吸系统疾病的患者影响更加显著。在年龄组中,老年人更容易受低温与高温的影响。女性更易受高温的影响。教育程度和职业情况同样是高温与低温的修正效应。日温差的影响急促一般可持续4天。日温差每变化1℃引起居民非意外死因的死亡率上升0.47%(95%CI：0.01%-0.93%)。在不同死因中,中风患者更易受日温差的影响。与男性、年轻人、教育程度相对高的人群比较,女性、老年人、教育程度低下的人群更易受日温差的影响。低于22℃时,气温与日温差存在着交互效应。相对湿度、大气气压与死亡呈现非线性单调的关系。低湿度、低气压是居民死亡危险因素,特别是对心血管疾病的患者。而与小于75岁的年轻人、男性、教育水平高的人群比较,大于75岁的老年人、女性、没接受教育者更易受低湿度、低气压的影响。而气压特别高的时,一样能引起死亡的增加。2003-2006年,我们得到2005年6月12日到21日共9天的热浪时期。在这个热浪时期,超额死亡人数达到145人。热浪对非意外死因人群有显著影响(RR-1.23,95%CI:1.11-1.37)。而与非意外死因比较,热浪对心血管疾病、呼吸系统疾病患者的影响更加显著。女性、老年人和社会经济地位低下的人群是热浪的敏感人群。结论低温和高温、日温差、低湿度和低气压对居民死亡有显著性影响,导致居民死亡风险增加。在低温时,温度与日温差有交互效应,低湿度、低气压同样与温度存在交互效应。女性、老年人、社会经济地位相对低下者、心脑血管-呼吸系统疾病的患者为本研究气象因素的敏感人群。本研究强调大众加强对气象因素危害防范的重要性。更重要的是,本研究提示即使在亚热带地区,低温同样是死亡重要的危险因素,这为冬天在南方集中供暖的议题提供有力的证据。还有本研究为针对敏感人群提供保护措施和建立热浪和较大日温差的早期预警提供依据。更多还原

【Abstract】 BackgroundThe impacts of meteorological factors on health outcomes have become growing concerns to governments; researchers and public, as climate change is associated with an increase in the frequency, intensity and duration of extreme weather events (e.g., heat waves and floods).Extensive epidemiological studies have consistently shown that mortality is associated with ambient temperatures. However, most of previous researches came from developed countries in temperate regions. Less evidence on weather factors and mortality was conducted in developing countries. In fact, populations in these countries were anticipated to be more vulnerable to climate change, due to poor living condition and limited capacity of coping with heat and cold weather.It is required to understand the characteristics of health impacts of these adverse events for assessing the impact of climate change. Previous studies focused on ambient temperatures, measured by daily mean temperature, maximum and minimum temperature. Diurnal temperature range (DTR), defined as the difference between daily maximum temperature and minimum temperature, is viewed as an important meteorological indicator associated with global climate change. Relative humidity and atmospheric pressure are also important weather indicators. However, little literature is available on the impacts of DTR, relative humidity and atmospheric pressure on mortality.ObjectiveThis study was conducted in Guangzhou, a subtropical city in China’s mainland. I aimed to examine the association between mortality and a variety of meteorological measures, including mean temperature, diurnal temperature change (DTR), relative humidity, atmospheric pressure and heat waves. I also explored the potential interaction between temperature and above meteorological factors. And I identified the subpopulations that are more vulnerable to the effects of meteorological measures.MethodsData sourcesThe Guangzhou Bureau of Health provided individual information for112,280deaths at the six urban areas in Guangzhou from1January2003to31December2007, including date of birth, date of death, cause of death, sex, educational attainment and occupation. We collected individual data for all77,099registered deaths between1January2008and31December2010from Guangzhou Center for Disease Control and Prevention.Daily meteorological data were obtained from China Meteorological Data Sharing System, including daily mean temperature, minimum and maximum temperature, relative humidity and atmospheric pressure. Weather data were collected from a single station (Wushan station) in Guangzhou. Daily data on particulate matter less than10μm in aerodynamic diameter (PM10), nitrogen dioxide (NO2) and sulphur dioxide (SO2) were obtained from Guangzhou Bureau of Environmental Protection.Statistical methodsA Poisson regression model combined with distributed lag non-linear model (DLNM) was applied to assess the non-linear and lag patterns of the association between daily mean temperature and mortality in Guangzhou. Effects of DTR, relative humidity and atmospheric pressure were examined by using a Poisson regression model combined with DLNM, after controlling for daily mean temperature, air pollutants, season and day of the week. The joint effects of DTR/relative humidity/atmospheric pressure and mean temperature were fitted by a natural spline. The impact of heat wave was assessed by calculating excess deaths and rate ratio (RR) of mortality comparing the case period to a summer reference period in the same year.ResultsHot effect was immediate and limited to the first5days, with an overall increase of15.46%(95%confidence interval:10.05%to20.87%) in mortality risk comparing the99th and the90th percentile temperature. Cold effect persisted for approximately12days, with a20.39%(11.78%to29.01%) increase in risk comparing the first and the10th percentile temperature. The effects were especially remarkable for cardio-respiratory mortality. The effects of both hot and cold temperatures were greater among the elderly. Females suffered more from hot-related mortality than males. The educational attainment and occupation class significantly modified coldand hot effects.The effect of DTR generally appeared immediately and lasted for4days for all cause-specific deaths. A1℃increase in DTR at lag0-4days was associated with a0.47%(95%confidence interval:0.01%-0.93%) increase in non-accidental mortality. Stroke mortality was most sensitive to DTR. Female, the elderly and those with low education were more susceptible to DTR than male, the youth and those with high education, respectively. Joint effects of DTR and daily mean temperature on mortality were observed when mean temperature was lower than22℃.A decrease in atmospheric pressure and relative humidity was associated with an increase in mortality, in particular cardiovascular mortality. Women, people aged≥75, and those with non-education were more sensitive to decreased atmospheric pressure and relative humidity than men, those aged<74, and those with higher education, respectively. Low atmospheric pressure and relative humidity increased the temperature effect on mortality. Extreme high atmospheric pressure also elevated the temperature-related mortality.During2003-2006, a9day heat wave was identified from July12to July21in2005. During this heat wave, the total number of excess deaths was145with an average of12deaths per day. We found statistically significant effect of the heat wave on non-accidental mortality (RR=1.23,95%CI:1.11-1.37). Greater effects were observed for cardiovascular mortality (RR=1.34,95%CI:1.13-1.59) and respiratory mortality (RR=1.31,95%CI:1.02-1.69). Females, the elderly and persons with lower socioeconomic status were at significantly higher risk of heat wave-related mortality.ConclusionsCold and hot temperatures, DTR, low relative humidity and atmospheric pressure were associated with increased risk of mortality in subtropical city of Guangzhou, China. Joint effects were observed between DTR and low mean temperature, and between low relative humidity/atmospheric pressure and mean temperature. The elderly, females, persons with low socioeconomic status and subjects with cardio-respiratory diseases have been identified as especially vulnerable to the effects of meteorological factors.Our findings highlight a need to strengthen risk perception and protective behaviors against adverse weather effects. Particularly, cold exposure is still an important mortality risk even in subtropical climate, providing strong evidence for the necessity of constructing a central heating system in Southern China. This knowledge can also help develop early warning system of extreme temperature and impending large temperature change in current day and build targeting strategies to protect those vulnerable subpopulations from adverse weather impacts.更多还原