Environmental variables and the incidence of disease

How do climate and the natural environment affect incidence of disease?

• Temperature can dictate the type of disease that is most common in an area (e.g., malaria vs. influenza).

• Environmental hazards caused by climatic conditions (e.g., drought and flooding) can affect factors that impact health.

What is an example of how the climate links to the incidence of disease?

Seasonal affective disorder (SAD).

What are some statistics about SAD?

• 2-5% of Canadians have severe SAD, and 25-35% have winter blues.

• 80% of SAD sufferers are women.

• It is treated using light therapy/antidepressants.

• SAD can lead to other knock-on health effects.

What is the most common climatic impact on health in the UK?

• Everyday, seasonal ailments such as the common cold and flu during winter.

• Allergies and hay fever during spring and summer.

How can topography impact on health?

The topography can impact drainage conditions and levels of oxygen in the air.

How can altitude impact health?

Mountain sickness and high altitude and pulmonary edema can be fatal for those who are not acclimatised. Heights above 25,000 ft are considered the 'death zone' where people are likely to experience thickening blood, more frequent urination and faster breathing/heart rate.

How can drainage affect health and what diseases are associated with poor drainage?

• Poor drainage and unsafe water supplies can cause diarrhoea, schistosomiasis and cholera.

• 2 million die annually due to cholera.

• WHO states that improving water quality and hygiene could save 4% of global disease burden.

How did the Haiti earthquake impact health?

• Malnutrition was significant as food security was impacted by the earthquake.

• There were over 700,000 cases of cholera after the earthquake due to a lack of a sewage system, vaccination and unhygienic conditions in refugee camps.

• Less than half of the population had access to drinking water services.