South Korean women recorded the largest increase in average adult height among women in a global analysis published in 2016. Comparing those born in 1896 and 1996, researchers estimated a gain of 20.2 centimeters, nearly 8 inches.
That number tells a bigger story than changing clothing sizes. Read alongside studies of childhood growth in North Korea, it illustrates how nutrition, illness, and living conditions can shape bodies across generations. The important question is not simply who ended up tallest, but what children had the chance to grow up with.
What the century-long study measured
Behind the headline was an unusually large dataset. The NCD Risk Factor Collaboration combined 1,472 population-based studies containing measured heights from more than 18.6 million participants to estimate trends across 200 countries. Scientists at Imperial College London led the international research effort.
The researchers estimated height at age 18 for people born in different years. They were not suggesting that individual adults had grown eight inches, or that the same people had been followed for a century. That distinction matters when interpreting a historical finding.
South Korean women’s estimated average rose from about 142 to 162 centimeters. Iranian men recorded the largest male increase, 16.5 centimeters, while women in the United States gained about 5 centimeters over the same comparison.
One peninsula, very different childhoods
The Korean Peninsula offers a revealing comparison because its populations shared a demographic history before the 1945 division. Shared ancestry does not make everyone genetically identical, but the contrasting childhood environments help explain why researchers look beyond genes.
In a 2009 meta-analysis, Daniel Schwekendiek and Sunyoung Pak reported that South Korean preschoolers were, on average, 6 to 7 centimeters taller than their Northern counterparts in 1997. The gap was about 8 centimeters in 2002, roughly 3 inches.
A separate study by Schwekendiek reported preschool height differences of up to 13 centimeters. That upper-end figure is not interchangeable with an average, and neither childhood comparison measures the century-long increase in South Korean women’s adult height.
Why the earliest years matter
The World Health Organization highlights the first 1,000 days, from conception to a child’s second birthday, as a particularly important period. Poor nutrition and repeated infections during this window can impair growth, leaving consequences that extend well beyond childhood.
Does that mean height is settled by age two? No, children continue growing through childhood and adolescence, and some catch-up growth can occur, although WHO describes established stunting as “largely irreversible.”
Genes still matter, especially when considering differences between individuals. But maternal nutrition, childhood diet, and the environment children grow up in also influence their eventual height. This makes population trends a useful, though imperfect, record of childhood conditions.
More than a change in the dinner menu
South Korea’s economic transformation provides important context, rather than a complete biological explanation. The World Bank records an increase in national income per person from about $67 in the early 1950s to $36,624 in 2024.
What matters for growth is how improved resources translate into everyday conditions. WHO identifies access to diverse foods, clean water, sanitation, and adequate health services as measures that can collectively reduce childhood stunting. A reliable dinner matters, but so does having safe water to drink alongside it.
North Korea’s food crisis showed the other side of that picture. A 1999 report from the Food and Agriculture Organization and World Food Programme cited a 1998 survey in which approximately 62% of children assessed had moderate or severe stunting. That was a snapshot of a historical emergency, not an estimate of conditions today.
Height is a signal, not a personal verdict
Being tall is not a virtue, and being short is not a diagnosis. These observational findings concern populations, not an individual’s health, and they do not establish how much of South Korea’s increase came from any single cause.
Other countries followed less encouraging paths during the study period. In parts of sub-Saharan Africa, average height declined by as much as 5 centimeters over 40 years, while U.S. women fell from fourth to 42nd in the rankings as gains stalled and other populations advanced.
“This study gives us a picture of the health of nations over the past century,” said Majid Ezzati, who led the research. The useful lesson is to improve children’s chances of healthy growth, not to chase a taller national average.
The study was published in eLife.
