Health in populations vs. health in individuals

by Sofia

Yesterday in my population health class we discussed how health is different (and dealt with differently) in populations than it is in individuals. These are two distinctions I found particularly interesting.

Diet and genes on total cholesterolThe above table shows how genetic makeup may be more important in determining a health outcome for an individual (an individual’s options are seen by reading the table horizontally), but that societal trends are more important in determining the same outcome in a population (a population’s outcomes are seen by reading the table vertically).

Another interesting distinction is the best way to deal with a given outcome. An individual works to prevent developing disease outcomes that s/he is at high risk for, whereas a population focuses on reducing the risk for people at medium risk, as this is where the bulk of the incident cases of the disease will occur.

Semenza JC. Strategies to intervene on social determinants of infectious diseases. Euro Surveill. 2010;15(27):pii=19611.

A strategy that targets individuals at high risk of developing a disease will see far less benefit overall than if a total population-based approach is implemented (compare change in means in graph D versus graph B). It’s the prevention paradox at work: more improvement overall is achieved by creating smaller benefits in more people than in huge benefits in the people who need it the most/who would experience the greatest relative benefit.