Evaluation Of The Impact Of Low Temperature And Cold Wave On Cardiovascular Disease Mortality Burden For The Older Adults

BackgroundDespite the rise in land surface temperature due to global warming,the frequency and intensity of extreme low temperature and cold waves have not decreased in some regions,especially in mid-latitudes of the Northern Hemisphere.Studies have proven that exposure to low temperature will increase the death risk of cardiovascular disease(CVD).Furthermore,for older adults,their physical powers are declining,and the adaptation to low temperature became weaken,causing more adverse CVD events.However,most of the available researches have focused on heat and heat wave early warning systems,less attention was paid to low temperature and cold waves,and let alone vulnerable population represented by older adults.In conclusion,it is necessary to conduct the research on the impact of low temperature and cold wave on CVD for older adults.ObjectivesTo explore the effects of low temperature and cold waves on total CVD and cause-specific CVD deaths in older adults,identify high-risk subgroups populations and CVD diseases,and preliminarily discuss the temperature early warning and prevention measures.MethodsIn this study,data of meteorological,environmental pollutants and CVD death in Jinan from 2011 to 2020 were used to carry out research,the research subjects were older adults(≥65 years old).The main research content included two parts:one part used the distributed lag nonlinear model to explore the exposure-response relationship between temperature and CVD death,lag effect,and attributable risk of low temperature.The other part applied the time-stratified case-crossover study design to analyze the influence and characteristics of cold wave events(A period time when the daily average temperature ≤the 10th,5th,and 1st percentile of the study period that lasts for more than two days)on CVD death for older adults.ResultsThe main results are as follows:(1)The exposure-response profiles between temperature and the death outcomes of CVDs were generally "U/J"-shaped in Jinan for older adults(0-14 day).For older adults,the minimum mortality temperature(MMT)was 20.5℃,and the MMT of subgroups varied among specific subgroups,mostly ranging from 19℃ to 24℃.(2)Extreme low temperature(P2.5)increased the death risk of CVD for older adults in Jinan.≥85 group had the highest single-day lag risk[RR=1.07(95%CI:1.03,1.11)]compared with 65-74 and 75-84 groups,while 75-84 group had the highest cumulative lag(0-14day)effect[CRR=1.40(95%CI:1.12,1.68)];The maximum single-day lag effect[RR=1.07(95%CI:1.03,1.11)]and the cumulative lag effect[CRR=1.40(95%CI:1.18,1.66)]of extreme low temperature on men were higher than female[RR=1.03(95%CI:1.02,1.04),CRR=1.20(95%CI:1.13,1.28)];The maximum single-day lag effect[RR=1.08(95%CI:1.05,1.12)]and cumulative lag effect[CRR=1.39(95%CI:1.19,1.64)]of the older adults lived in non-urban areas were higher than those in urban areas[RR=1.02(95%CI:1.01,1.03)],[CRR=1.22(95%CI:1.14,1.31)];Among the cause-specific subgroups of CVDs,hypertension had the highest death risk in extreme low temperature[RR=1.11(95%CI:1.02,1.20),CRR=1.58(95%CI:1.06,2.37)].(3)The attributable death risk of CVD was related to population characteristics and disease classification,and the death burden attributable to low temperature(medium cold temperature)was dominant.The 75-84 group had the highest attribution fraction of low temperature[10.0%(3.3%,15.8%)],in which male(9.5%)was higher than female(1.6%),non-urban(9.6%)area was higher than in urban area(1.6%).The death attribution fraction of hypertension was higher than that of other subtypes of CVD.(4)Three definitions of cold waves all have significant lag effect on CVD death for older adults,and when the lower temperature threshold was defined by cold wave,the stronger death effect and the earlier maximum significant death effect was shown.ConclusionsLow temperature and cold waves significantly increased the death risk of CVD for older adults,with lag effect.The death risk of age,gender,residence area and cause-specific CVD were different,older adults,women,and hypertension were more susceptible to the influence of temperature.This study may contribute to understanding the vulnerable groups under low temperature weather in Jinan,and provide scientific evidence for the government to introduce relevant policy strategies and build low temperature warning platform.