The changing global context of public health

We are living through what is, historically, a major transition in the health of populations.There have been broad gains in life expectancy during the past half-century. Fertility rates are declining. The profile of major causes of death and disease is being transformed; the pattern of infectious diseases has become much more labile (and antimicrobial resistance is rising widely); and health inequalities between rich and poor persist.

First, because social and material inequalities within a society generate health inequalities, an important task is to elucidate, through research, the underlying determinants of these health inequalities.4 That knowledge must then be applied, in part through professional practice, to the development of ameliorative social policies. Public health, as Virchow pointed out more than a century ago, is “politics writ large”.

In traditional, largely self-contained, agrarian-based societies that produce, consume, and trade on a local basis and with low-impact technologies, the social and environmental determinants of health are predominantly local. However, the industrialisation and modernisation of the past century has altered the scale of contact, influence and exchange between societies, institutionalised hierarchical economic relations, and has exacerbated the rich-poor gap worldwide and increased the scale of human impact on the environment.

Epidemiological analysis that is confined to studying “risk factor” differences between individuals gives little insight into variations in population health indices, either between populations or over time.

The individuallevel perspective fails to conceptualise the population’s health as a public good, as something that affects social functioning, community morale, and collective economic performance.14

There is also an emerging globalisation of ethical and judicial standards, which should render social and individual rights more secure.

Whereas global average per capita gross domestic product (inflation adjusted) more than doubled during the past half-century, the gains were unevenly shared, hugely widening the gap between rich and poor.23

The mix of rapid processes of socioeconomic change, demographic change, and global environmental change in today’s world requires a broad conception of the determinants of population health.

Koopman, recognising the general challenge, states that “epidemiology is in transition from a science that identifies risk factors for disease to one that analyses the systems that generate patterns of disease”.52