Objective: To investigate the relationship between extreme hot and cold temperatures and deaths of cardiovascular disease (CVD) in Jinan, a temperate city in northern China.
Methods: We collected daily mortality data, including number of deaths, gender, age and meteorological data including daily maximum, mean and minimum temperatures and relative humidity over the period of 2011-2014. Descriptive analyses were firstly conducted to characterize temperature extremes including heat waves and cold spells, seasonality and trend. Spearman correlation and cross-correlation analysis were performed to detect lagged effects of meteorological variables. Comparison between exposure days (heat waves and cold spells) and non-exposure days were performed.
Results: A total number of 87, 607 CVD deaths were reported over the study period, of which >65y age group accounted for 80.19% (70, 254/87, 607) with a male to female ratio of 1:0.95. Daily number of CVD deaths displayed a strong seasonal pattern, with the higher number of deaths in winter (December-February) and lower in summer (June-August). After considering lagged effects, CVD deaths and temperatures were significantly correlated with a higher correlation among the older group. The number of CVD deaths during heat wave days (56.66±14.02) and cold spell days(86.93±14.93)were both significantly higher than those from non-exposure days(p<0.01).
Conclusions: Both extreme high temperatures and low temperatures have significantly increased the risk of CVD deaths in Jinan, especially among older people.