The Impact of Ambient Temperature on Cardiorespiratory Mortality in Northern Greece

Abstract

It is well-established that exposure to non-optimum temperatures adversely affects public health, with the negative impact varying with latitude, as well as various climatic and population characteristics. This work aims to assess the relationship between ambient temperature and mortality from cardiorespiratory diseases in Eastern Macedonia and Thrace, in Northern Greece. For this, a standard time-series over-dispersed Poisson regression was fit, along with a distributed lag nonlinear model (DLNM), using a maximum lag of 21 days, to capture the non-linear and delayed temperature-related effects. A U-shaped relationship was found between temperature and cardiorespiratory mortality for the overall population and various subgroups and the minimum mortality temperature was observed around the 65th percentile of the temperature distribution. Exposure to extremely high temperatures was found to put the highest risk of cardiorespiratory mortality in all cases, except for females which were found to be more sensitive to extreme cold. It is remarkable that the highest burden of temperature-related mortality was attributed to moderate temperatures and primarily to moderate cold. The elderly were found to be particularly susceptible to both cold and hot thermal stress. These results provide new evidence on the health response of the population to low and high temperatures and could be useful to local authorities and policy-makers for developing interventions and prevention strategies for reducing the adverse impact of ambient temperature.

The Effect of Apparent Temperature on All-Cause Mortality in England, UK

“…The relationship between thermal stress and natural-cause mortality per region was described with a standard time-series Poisson regression model for over-dispersed data combined with a distributed lag non-linear model (DLNM) with a lag period of 21 days (to account for the delayed and non-linear effects of temperature on mortality) [10]. Consistent with previous studies [1,4,7], the exposure-response association was modeled using a natural cubic spline with 3 internal knots placed at the 10th, the 75th, and the 90th percentile of the region-specific AT distributions, and the lagged response was modeled using a natural cubic spline with 3 internal knots placed at equally spaced values in the log scale. The long-term trends and seasonality were controlled by a natural cubic spline for time with 8 degrees of freedom per year and categorical variables for weekdays and holidays.…”

“…Then, using the region-specific MMAT as reference value, the relative risks of mortality were calculated for both extreme and moderate thermal exposure, defined at the 1st (extreme cold), 10th (moderate cold), 90th (moderate heat) and 99th (extreme heat) percentile of the region-specific AT distribution. Finally, the fractions of mortality attributed to moderate cold (temperatures between MMAT and the 1st percentile), extreme cold (temperatures lower than the 1st percentile), extreme heat (temperatures higher than the 99th percentile) and moderate heat (temperatures between MMAT and the 99th percentile) were estimated using the backward estimation approach [1,4,7].…”

“…A large part of the international literature [1][2][3][4][5][6][7] has associated exposure to both high and low temperatures with mortality and/or morbidity from several causes. However, except for air temperature, other meteorological variables including relative humidity and wind speed are known to affect thermal comfort.…”

Association between ambient temperature and emergency room visits of total and cause-specific cardiovascular disease: A time-series study in Lanzhou, China

“…Referring to previous relevant studies [12,23,24], minimum morbidity temperature (MMT) was treated as the reference value of the association, which corresponds to a minimum risk of cardiovascular morbidity. We identi ed the MMT from each estimated curve representing the overall cumulative exposure-response (The MMTs for total CVD, IHD, HRD and CD were − 12.3℃, for HF, which was 29.7℃).…”

“…To check the main ndings of this study, sensitivity analyses were conducted by changing the degrees of freedom (6,8,9 per year) for the long-term trends. We also adjusted for the degrees of freedom (3,5,6) of PM 10 , SO 2 , and NO 2 and the degrees of freedom (22,23,24) of maximum lag day to examine the robustness of our ndings.…”