Research conducted over the past 30 years confirms that there is a clear link between height and longevity. By exploring the links between nutrition and economic development in Europe and North America since the early-1700s, the researchers linked the changing size, shape and capability of the human body to economic and demographic change.   Co-authors Roderick Floud (Gresham College, United Kingdom), Robert W. Fogel (University of Chicago, Illinois USA), Bernard Harris (University of Southampton, United Kingdom), and Sok Chul Hong (Sogang University, Korea),  found that 200 years ago there were substantial differences in height between working-class and upper-class people. In the 1780s, the average height of a 14-year-old working-class child was 1.3m, while an upper class child was "significantly taller" at 1.55m. Today however, as health services, nutrition, sanitation and education have become universal, upper-class children have continued to grow taller, but at a slower rate than working-class children. The difference between the upper- and working-class adults has narrowed to less than 0.06m. Dr. Harris comments that: "Our work shows that there have been dramatic changes in child health (as reflected in achieved adult height) over the last 100 years, and other researchers have highlighted the existence of close links between improvements in child health and health in later life. These changes have profound implications for developments in later-life health, longevity and economic performance over the coming century.  The investments we make in the health of today's children can play a pivotal role in determining the economic wellbeing of future generations."