As part of the Annual Bank Conference on Development Economics  in Paris, I was fortunate to attend a presentation by Professor Janet Currie, from Columbia University, on the effects of early life health on adult health, education and earnings.  Professor Currie said the size and weight of newborns were indicators of a country’s development, just like average wages or the proportion of children enrolled in school.
How so? According to Currie, knowing the average weight of its newborns can help us make some predictions about a country:
A country where the majority of babies are born with a low birth weight may face significant health costs, because these babies are more vulnerable to disease and tend to remain so throughout their lives (unless they change the environment, food, etc.)
A country where babies are born with a higher-than-average birth weight may also have to face significant health costs, but for different reasons. These babies are more likely to develop cardiovascular diseases linked to obesity in particular.
Moreover, evolution in size is an indicator of a population moving towards a relatively rich and varied diet. Here is a surprising example:
The people of East Asia have long been ridiculed because of their small size. In Japan—one of the richest countries in the region—things began to change in 1954. That year the Japanese government enacted a law on school meals to promote the physical and mental development of children. Children were given a daily ration of milk in school cafeterias, and lunches carefully followed nutritional guidelines.
Today, the average size of males in Japan is about 5.7 meters (which is one of the tallest in the world), while in other countries in East Asia—where the economic situation is worse—no significant change has been observed. The exception is North Korea, where the average size has decreased.
Around the world, studies have shown that malnutrition is responsible for a reduction in the size of infants, and that as soon as the children’s diet becomes normal, they can partially reverse their growth retardation.
Paying attention to newborn size can help anticipate risks and tackle them with policies that give mothers the means to prevent their children from being born too heavy or too light, and to maintain a healthy weight after birth.
“If you care about the health of children, care first about the health of pregnant mothers,” Professor Currie said. Policies focused on mothers and children can significantly reduce the incidence of diseases, including hereditary diseases.