Synergetic effect of temperature and PM_2.5 on mortality of cardiovascular and cerebrovascular diseases

Objective To explore the synergetic effect of temperature and PM_2.5 on cardiovascular and cerebrovascular diseases.

Method We collected cardiovascular and cerebrovascular death cases，air pollution and meteorological data during the same period in Pudong New Area from 2013 to 2018.We used generalized additive models （GAMs） with poisson regression including non-stratification model， nonparametric bivariate response model and pollution-stratified parametric model， to assess the interaction between temperature and PM_2.5 and on the number of cardiovascular cerebrovascular and cerebrovascular disease deaths.

Results The exposure-response relationship between temperature and the number of cardiovascular and cerebrovascular deaths exhibited "U" type and the most comfortable temperature was 18.9 ℃. When the concentrations of PM_2.5 increased by 10 μg·m^-3， the deaths of total， male， female， ≤75 years and >75 years increased， respectively， by 0.60%（95%CI： 0.30%‒0.91%）， 0.77%（95%CI：0.34%‒1.20%）， 0.46%（95%CI：0.05%‒0.86%）， 0.66%（95%CI：0.03%‒1.30%） and 0.59%（95%CI：0.26%‒0.92%）. With the increase of PM_2.5 concentration level， the impact of temperature on cardiovascular and cerebrovascular diseases gradually increased， and the impact was the most significant when the concentration of PM_2.5 was more than 150 µg·m^-3. There were different sensitive people in different seasons.

Conclusion PM_2.5 concentration levels of mild pollution and above can exacerbate the negative effects of temperature on cardiovascular and cerebrovascular diseases.