New Delhi: Compared to other countries, Indian women and men have grown taller at some of the slowest rates in the past century, reveals a new study released on Tuesday. A global study looked at the average height of 18-year-old men and women in 200 countries between 1914 and 2014 and found that people everywhere have seen an increase in average heights in the past century.
What is striking, however, is that changes in adult height over the century varied drastically across countries. In India, the mean height of women increased by 5 cm from 147 cm in 1914 to 152 cm in 2014 and that of men by only 3 cm from 161 cm to 164 cm. This is much less than countries such as South Korea, where women grew by 20 cm and men by 15 cm over the century.
Interestingly, South Korean and Japanese men and women, and Iranian men, had larger gains than European men, and a similar trend is now showing in China and Thailand, according to the study. The authors point out that these gains may also partially account for the fact that women in Japan and South Korea have achieved the first and fourth highest life expectancy in the world. The rise in height seems to have stopped early in South Asia.
While Indian men ranked 101 among 200 countries in terms of height in 1914, they ranked 178 in 2014. Indian women are now among the 10 shortest (by nationality) in the world ranking—192 in 2014 as compared to 163 in 1014.
“There are two primary factors responsible for these results—India has one of the highest undernutrition and malnutrition levels in the world. Post-independence, malnutrition may have increased and the health of pregnant women which is poor can adversely affect the height of a child," said V. Mohan, chief of diabetology at Dr Mohan’s Diabetes Specialities Centre, one of India’s largest diabetes clinic chains. Mohan added that the Indian diet -- rich in carbohydrates but poor in proteins -- and the increasing lack of physical activity are important factors in the slow height increase.
The comprehensive study published in peer-reviewed journal eLife reanalysed 1,472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for 18-year-olds between 1914 and 2014 in 200 countries.
“Our study also shows the English-speaking world, especially the USA, is falling behind other high-income nations in Europe and Asia Pacific. Together with the poor performance of these countries in terms of obesity, this emphasises the need for more effective policies towards healthy nutrition throughout life," said Majid Ezzati from the School of Public Health at Imperial College, UK, in a press release.
The study says that although height is one of the most heritable human traits, cross-population differences are believed to be related to non-genetic, environmental factors.
As an exception to the steady rise in heights in most countries, adult height decreased or remained the same in many countries in sub-Saharan Africa for cohorts born after the early 1960s, by around 5 cm from its peak in some countries.
The study highlights that height in early adulthood, which varies considerably across countries and over time, provides a measurable indicator for sustainable development, with links to health and longevity, nutrition, education and economic productivity.
“This study gives us a picture of the health of nations over the past century, and reveals the average height of some nations may even be shrinking while others continue to grow taller. This confirms we urgently need to address children and adolescents’ environment and nutrition on a global scale, and ensure we’re giving the world’s children the best possible start in life," added Ezzati who led the research.