In defense of a population-level approach to prevention: why public health matters today.

A focus on populations, and a corresponding population-level approach to intervention, is a foundation of public health and is one reason why public health matters today. Yet, there are indications that this foundation is being challenged. In some policy and practice domains, and alongside growing concern about the social determinants of health and health equity, there has been a shift from a population-level or universal approach to intervention, to a targeted approach focusing on those experiencing social or economic vulnerability. More than 30 years ago, Geoffrey Rose articulated strengths and limitations of population-level and high-risk approaches to prevention. In light of a strong analogy between "high risk" and "targeted" approaches, it seems timely, in a forum on why public health matters today, to revisit Rose's points. Focusing on points of overlap between strengths and limitations of the two approaches as described in public health (population-level; high-risk) and social policy (universal; targeted), I illustrate strengths of a population-level approach from the point of view of health equity. Although different circumstances call for different intervention approaches, recent discourse about the weakening of public health suggests that there is value in discussing foundations of the field, such as the population-level approach, that we as a community may wish to defend.