Environment, temperature and death rates

Area of Science:

• Environmental Health
• Epidemiology
• Gerontology

Background:

• Monthly and daily death records from England and Wales, and New York were analyzed.
• Previous research indicated associations between temperature and mortality for most diseases, excluding cancers.

Purpose of the Study:

• To investigate the relationship between ambient temperature and daily mortality from myocardial infarction, stroke, and pneumonia.
• To determine the influence of temperature changes duration and the elderly's susceptibility.

Main Methods:

• Statistical analysis of daily death data correlated with daily minimum temperatures.
• Examination of short-term (1-2 days) versus medium/long-term (7+ days) temperature change effects.
• Analysis of time lags between temperature changes and mortality events.

Main Results:

• Mortality from myocardial infarction, stroke, and pneumonia showed a U-shaped relationship with minimum temperature, increasing below -10°C and above 20°C.
• The elderly exhibited a stronger association between temperature and mortality.
• Medium-term and longer-term temperature changes had a more significant impact on death rates than short-term changes.
• Time lags between temperature change and death were shortest for myocardial infarction (1-2 days), intermediate for stroke (3-4 days), and longest for pneumonia (~7 days).

Conclusions:

• A probable causal relationship exists between temperature variations and mortality from various diseases.
• Autonomic thermoregulation failure in the elderly is a potential proximal mechanism.
• The observed mortality risk is present across all temperature ranges, not solely attributable to hypothermia.