During my research I became involved with many different diseases. I had a large number of diverse interests. Almost all population researchers specialized in diseases, e.g. cardiovascular epidemiologists only examined cardiovascular disease, the infectious disease researchers, only examined infectious diseases, and the injury epidemiologists only investigated injuries.

There are certain articles that you will read in your life where, after reading them, you see the world in a totally different light. Omran's classic papers in the early 1970s have hardly been referenced. However, when I read his works, the world changed for me. I saw the world of health not as individual diseases, but the patterns of health tied together with a beautiful associations. Thus diseases in China can impact upon your country, so we needed to know the global patterns of disease. In addition, the changes in global health with rapid economic development in the past 50 years is totally predictable.

Omran was the first to tie together the changing patterns of fertility with the changes patterns of morbidity. He painted what I regard as the most elegant picture of health, and what drives health over time. He demonstrates how important it is to view health from a systems perspective.

This article changed much of my thinking of the health of the world, and my interests and approached to global health.