Saturday, July 30, 2016

Is Increasing Tallness a Sign of Societal Well-Being?

As I discuss in Chapter 11 of my text, the health and mortality transition in the world is associated with larger people. This means that as the population grows, our improved health is associated partly with a better diet and, in turn, the demand for food grows faster than the population is growing. Majid Ezzati at Imperial College London, along a large group of collaboraters, has just published an analysis of global trends in human height over the 100 year span from the beginning of the 20th century to the beginning of the 21st century. The abstract sums up the main points:
Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3–19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8–144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
The Economist Espresso pulled together a graph from the data that provides a nice picture of a century of growth in height among the tallest people in the world, who are Europeans:


Now, in the interest of full-disclosure, I am 6' 2" so I may pay more attention to the tallness issue than might otherwise be the case, but the societal correlation between changes in average tallness and changes in average well-being is compelling.

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