Mortality and diurnal temperature range in Virginia.

Area of Science:

• Environmental epidemiology
• Public health
• Climate science

Background:

• Diurnal temperature range (DTR) is a measure of daily temperature fluctuation.
• Previous research has primarily focused on the health impacts of high temperatures, with less attention paid to DTR.
• Understanding DTR's impact is crucial for public health, especially with changing climate patterns.

Purpose of the Study:

• To investigate the association between diurnal temperature range (DTR) and daily mortality in seven major Virginia metropolitan areas.
• To quantify the relative risk of mortality associated with high DTR events.
• To identify the temporal lag effects and characteristics of high DTR days impacting mortality.

Main Methods:

• Utilized data from 2005 to 2020 for seven large metropolitan areas in Virginia.
• Employed distributed lag non-linear models (DLNM) to analyze the relationship.
• Controlled for ambient temperature and humidity in the statistical models.

Main Results:

• A significant increase in the relative risk of mortality was observed on days with very high DTR.
• A short lag effect, lasting several days, was identified for mortality risk following high DTR events.
• High DTR days, rare and often occurring in spring, were associated with elevated respiratory and cardiovascular mortality, particularly affecting the elderly.

Conclusions:

• Very high DTR is an independent risk factor for daily mortality, especially in spring.
• The physiological mechanisms linking high DTR to mortality require further investigation, as responses resemble those to high temperatures.
• Findings suggest that acclimatization to temperature fluctuations plays a role in cardiovascular and respiratory health, highlighting the need for public health strategies addressing DTR extremes.