There’s a big new study of average heights around the world over the last century:
Published July 26, 2016
Cite as eLife 2016;5:e13410
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.
Height is always interesting as a not-wholly-perfect analog for the Flynn Effect in IQ.
From the NYT write-up:
American men reached their maximum average height in 1996, and women in 1988. Two of the study’s authors, James Bentham and Majid Ezzati, both of Imperial College, London, speculated that the decline could be because of worsening nutrition standards for poor Americans but conceded that they had not measured the effects of immigration from, for example, Central American countries with substantially shorter citizens.
Average heights in North America, Western Europe and Japan rose quickly in the 20th century, then plateaued or shrank slightly, the authors said. African and South Asians have not grown very much and, in some countries, have shrunk slightly.
Africans were taller when the colonial era ended in the 1960s. They may have lost height because of collapsing health care systems, rising population density and less dietary diversity among urbanites, the authors said.