Measurable health effects associated with the daylight saving time shift

Area of Science:

• Public Health
• Chronobiology
• Epidemiology

Background:

• Daylight saving time (DST) is implemented for energy conservation.
• Previous research suggests DST transitions may increase risks for cardiovascular and cerebrovascular events.

Purpose of the Study:

• To evaluate the impact of DST shifts on a wide spectrum of diseases.
• To inform the risk-benefit analysis of DST implementation.

Main Methods:

• Population-based, cross-sectional analysis using large insurance claim and national inpatient datasets from the US and Sweden.
• Comparison of observed and expected diagnosis rates for hundreds of sex- and age-specific diseases following spring and autumn DST shifts.

Main Results:

• Significant associations found between DST shifts and elevated risks for cardiovascular diseases, injuries, mental disorders, and immune-related diseases.
• A notable increase in relative risk (approx. 10%) observed for several conditions.
• Estimated 150,000 US and 880,000 global incidences linked to spring DST shifts.
• First identification of diseases with decreased relative risks post-spring DST shift, including infections.

Conclusions:

• DST shifts are associated with adverse health outcomes across multiple disease categories.
• The spring DST shift may trigger a stress response that temporarily boosts the immune system, potentially reducing risks for certain infections.