How weather and climate patterns may silently drive mortality rates, from heart failure to infectious diseases.
Study: Expert judgement reveals current and emerging UK climate-mortality burden. Image Credit: Sepp photography/Shutterstock.com
A recent Lancet Planetary Health study analyzed experts' views on how weather and climate patterns influence country-level mortality burden.
Climatic changes and human health
Human health is directly or indirectly impacted at various levels by weather. For instance, a storm or flash flood causes injuries or deaths. Furthermore, heat stress triggered due to persistent high temperatures can overwhelm the body’s thermo-regulatory systems, particularly in older people with comorbidities. An elevated temperature could result in sleep disorders and induce insomnia.
Weather and climate patterns are also associated with seasonal infections, including a higher incidence of tick-borne diseases, such as Lyme disease, if the spring is particularly warm. A comprehensive understanding of the association between weather hazards and health impacts could help develop preventive strategies to decrease their effect.
The majority of UK and European climate-health reports focus on short-term quantifiable weather-related health outcomes. There is a scarcity of research related to the health consequences of long-term exposure to weather hazards.
At present, for most weather-health assessments, researchers use process-based models associated with the physics of the earth system. These models are linked with statistical-based models to determine the health risks due to climate and weather patterns.
Owing to the complexities of the climate and health nexus, existing models' predictions are often biased. Structured expert judgment (SEJ) could overcome this challenge and provide a holistic view of how climate change could increase mortality from specific conditions or injuries.
This strategy is widely used to assess nuclear risks and volcanology. Expert judgment was invaluable concerning the social cost of carbon and different health system interventions.
About the study
The current study utilized the SEJ strategy to elucidate the contributions, complexities, and uncertainties associated with weather and climate change and all causes of mortality.
Since weather and climate hazards are specific with regard to a country and its impacts on a population, this study selected well-validated and open meteorological and health data, particularly from the UK.
Based on the eligibility criteria, a total of 30 experts from 15 institutions, mostly from the UK, were recruited. They completed the survey within a month of receiving the survey invitation through email.
The UK National Risk Register was used to determine relevant weather and climate hazards. These conditions were categorized into five groups: cold, heat and drought, wildfire, storms and flooding, and compound climate, linked with multidimensional environmental conditions that favor the spread of allergens or infectious diseases. These conditions were linked with different health outcomes.
Study findings
The current study revealed that an increase in the global mean temperature is a potential UK hazard relevant to health. It must be noted that the affluent UK and European populations having access to well-established health systems are more resilient to climate change compared to the lower middle-income countries.
As per the upper Paris Agreement goal, the UK has succumbed to two risk transitions. However, the significant uncertainties in hazard transition underscored the difficulties and complexities of predicting health hazards based on climate-weather patterns. The statistical modeling indicated that fewer people die from wildfires in the UK, but a significant number die from extreme temperatures.
Besides heat and drought hazards, the compound climate hazard that causes infectious disease-related mortality is also large. The mortality rates due to cold temperatures were also found to be high.
The heat-related respiratory and cardiovascular mortality is particularly high in the UK’s aging population. Lightning strikes, exposure to radioactive material from flooding, and trauma from storm debris also contribute to mortality rates.
Many studies have shown the cardiovascular response to extremely high and low temperatures. For instance, heatstroke and hypothermia are cardiac conditions linked to changes in vascular constriction with temperature.
Besides cardiac disease burden, elevated temperature also increases renal disease and skin cancer health burden. Long-term exposures to hot nights disrupt sleep quality, which has been linked with the incidence of neurodegenerative diseases, such as Alzheimer’s disease or Parkinson’s disease. These health burdens are directly associated with the high cost of healthcare services.
Conclusions
The current evidence on the impact of weather on mortality rates in the UK was dominated by short-term exposure to hot and cold temperatures that cause respiratory and cardiovascular failure.
However, this study also revealed how cold temperatures impact musculoskeletal health and infectious diseases from compound hazards increase mortality rates. Poor mental health conditions due to flooding and infectious diseases could also influence cause-specific mortality.
Similar research must be conducted in the future to explore how climate and weather patterns impact health in other regions of the world.
Bright night light exposure increases mortality risk, while daylight reduces it