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Humans have increased in size over the past century thanks to better health and nutrition, but the change has not occurred equally in men and women, a new study suggests.
According to the study, published Wednesday in the journal, men have become twice as tall and heavy as women. Biology Letters.
Researchers from Italy, the United States and the United Kingdom analyzed data provided by the World Health Organization in 2003 on height and weight of more than 100,000 people in 69 countries. The study’s authors also used data from the Human Development Index (HDI), which measures national levels of human well-being.
The team found that every 0.2 increase in HDI increased height by about 1.68 cm (0.66 in) for women and 4.03 cm (1.59 in) for men, as well as 2.70 kg in average weight. (5.95 pounds) has increased. for women and 6.48 kg (14.29 pounds) for men.
This trend was also confirmed by examining data from the World Bank’s Gini Index, which measures income inequality at the national level, for 58 countries between 2000 and 2006.
Greater inequality was associated with reduced height and weight. According to the study, each unit increase in Gini was associated with an average decrease in height of about 0.14 cm for women and 0.31 cm for men, and an average decrease in weight of about 0.13 kg for women and 0.39 kg for men.
While it might be thought that more developed countries might have ethnic populations that are genetically taller, “we think that’s not the case,” said study author and environmental physiologist Lewis Halsey, of the University of is Professor of Roehampton. Behavioral and Energy Lab, University of Roehampton, London.
That’s because the researchers found a similar trend when looking at a compilation of adult height data from just one country: the United Kingdom.
Analyzing the heights of 49,180 men and women aged 23 to 26 from several UK studies published between 1905 and 1958, they found that women’s average height increased by 0.25 cm every five years, while men’s height increased by 0.25 cm every five years. The height has increased by 0.69 cm.
So what is behind this disparity?
“This is one of the first studies to establish a link between human evolution, which is ultimately driven by sexual selection with environmental influences on our phenotype, so how we ultimately present ourselves,” Halsey said. After all, how do we look specifically,” Halsey explained. CNN on Wednesday.
Halsey contrasts the rate at which men and women are becoming sexually selective. In the past, he said, taller, heavier men were stronger, enabling them to compete with other men, gain more access to women and pass on their tall genes.
However, even today, “women prefer tall men,” he said, while, “in contrast, women’s height is not as important. So, simply put, men don’t say, ‘Oh, me. Only tall women are liked.
“This is (a) good cross-country study that basically confirms (a) previously known theory about sex differences in ‘environmental sensitivity,'” said Professor Bogusław Pawlowski, Department of Human Biology, University of Wrocław, Poland. Head of , who was not involved in the study, told CNN via email on Wednesday.
“As (the) environmental or economic conditions improve and there is better access to resources, males have greater biological advantages than females. This is exactly the opposite when resources are scarce (males than females). I have ‘more pain’).
“The norm of tall men is something that is found in Western countries (but also in many Asian countries),” Pawlowski said. “This means that in these populations (a) a man’s height is an important aspect of a man’s attractiveness in the human mate market.”
The researchers found that differences in height between individuals of the same sex were smaller in countries with better living conditions. And, as seen in Britain, within the population of an individual country, the difference in height for men was smaller than for women as living conditions improved over time.
This is because men, being larger than women, “require more energy, grow longer” and, in particular, being more muscular, their tissues are “metabolically less dense.” are more active,” Halsey said.
This means that in growing me, “it takes longer and it’s more expensive, but it makes the male body more vulnerable to problems, problems, environmental influences, like disease,” he said. added.
Therefore, when there is a stressful environment with a high burden of disease, men’s size is more affected than women’s, he said.
Because men’s height is more sensitive to life circumstances than women’s, the study’s authors concluded that men’s height and height differences between the sexes “are particularly important for tracking population changes in health.” may be a useful biomarker for
Halsey added that the study suggests that any trait that is more prominent in one gender than another may be influenced by a more demanding environment.
