Throughout the 20th century, the average height of men increased at a rate double that of women. This interesting disparity can primarily be attributed to improved living conditions, alongside biological, nutritional, and socio-economic factors. Let’s examine.
The evolution of human height serves as a vital indicator of the well-being and development of populations. Since the start of the 20th century, advances in nutrition, healthcare, and hygiene have led to a significant increase in average height in many countries.
Nonetheless, this growth has not been uniform: men have grown roughly twice as much as women. What accounts for this inequality? Is it solely due to biological differences, or is it also influenced by environmental and societal factors?
An Uneven Increase Between Genders
Statistics That Speak
A comprehensive study carried out by Imperial College London, published in the journal eLife, examined growth trends across 200 countries from 1914 to 2014. The findings are striking:
- The average height of men increased by 14 cm over the century.
- The average height of women only rose by 7 cm, which is half that of men.
For instance, in France, an average man stood at 1.66 m in 1914, compared to 1.79 m today, whereas women’s height increased from 1.55 m to 1.63 m.
What Causes This Difference?
While improvements in living quality have benefitted all, men appear to have reaped greater rewards. This is due to several reasons:
- Men’s greater nutritional needs: The male metabolism demands a higher intake of calories and essential nutrients for optimal growth.
- Later onset of puberty in men: This allows for a longer growth period compared to women.
- Historical inequalities: Access to food and healthcare was often more favorable towards men in certain patriarchal societies.
Improved Living Conditions as a Growth Catalyst
A Richer and More Diverse Diet
The 20th century saw a significant change in living conditions in many countries, directly impacting human growth. Access to protein-rich foods (meat, fish, dairy) and micronutrients (iron, calcium, zinc) fostered optimal human development.
In France, the average consumption of animal protein increased from 30 g/day in 1900 to over 100 g/day by 2000, contributing to better bone and muscle growth, particularly among men.
Enhanced Medical Care
Advancements in combating childhood diseases, such as tuberculosis and malnutrition, have enabled children to grow better. Vaccinations, access to antibiotics, and pediatric follow-ups have significantly reduced growth delays that were prevalent in the early 20th century.
In France, infant mortality dropped from 140 out of 1,000 births in 1900 to only 3 out of 1,000 today, ultimately offering children better growth prospects.
Improved Hygiene Conditions
With widespread access to clean drinking water and better waste management, gastrointestinal infections that hinder growth have significantly declined.
- In 1900, fewer than 50% of French households had access to clean water.
- Today, that figure is close to 99%, thus reducing diseases that restricted childhood growth.
Biological Differences Between Genders
The Role of Hormones
Human growth is significantly influenced by hormones, and there are major differences between men and women in this regard. Testosterone, the primary male hormone, plays a crucial role in stimulating bone and muscle growth. It promotes the lengthening of long bones, allowing men to achieve greater heights. Additionally, this hormone supports increased muscle mass and bone density, contributing to a more imposing stature.
On the other hand, estrogen, the dominant hormone in women, accelerates bone maturation, which leads to earlier closure of growth plates. Consequently, women’s lengthening growth phase typically ends sooner, around 16 years of age, whereas men may continue to grow until around 18 to 20 years, or even longer in some cases.
Genetics
It is estimated that genetics determines approximately 60 to 80% of adult height. Some populations have a higher genetic potential for stature. For example, Northern European populations, such as the Dutch, are well-known for their tallness, while other regions of the world exhibit lower averages, shaped by evolution and environmental adaptation.
Nevertheless, this genetic potential can only be fully realized under favorable living conditions. A balanced diet, good overall health, and absence of nutritional deficiencies are critical for optimal growth. Therefore, external factors like malnutrition or chronic illnesses can hinder the full expression of genetic potential.
Later but Extended Growth in Men
Another significant distinction between the sexes is the timing of growth. Girls typically reach puberty earlier than boys, generally between the ages of 10 and 12, leading to a rapid but short-lived growth spurt.
Conversely, boys enter puberty later, around 12 to 14 years, allowing for a longer growth period. This later but extended growth phase generally enables boys to surpass girls in height.
Before puberty, it is common to find that girls are taller than boys of the same age; however, boys typically end up exceeding them due to the prolonged growth period.
Public Health Implications
Health Risks Associated With Greater Height
Being taller comes with its own health risks. Taller men are more susceptible to certain conditions, including:
- Joint Issues: Height puts extra strain on joints, especially the knees and spine, increasing the risk of chronic joint pain and osteoarthritis.
- Cardiovascular Diseases: Greater height is linked to a higher metabolism, which might escalate the risk of hypertension and heart failure.
- Cancers: Studies indicate that taller individuals may have a slightly elevated risk of developing certain cancers, attributed to having more cells in their bodies and increased cell proliferation during growth.
For example, men taller than 1.85 m are more prone to back and knee pain due to the added load on their skeletal system.
Influence of Societal Standards
In our society, height is often perceived as a key factor in how individuals are viewed, affecting various aspects of daily life:
- In the Workplace: Studies indicate that taller individuals are generally seen as more competent and authoritative, which can provide them with advantages in career advancement and leadership roles.
- In Personal Relationships: Height often serves as a crucial factor in attraction across many cultures, impacting self-esteem and social interactions.
- Psychological Well-Being: Shorter individuals, particularly men, may experience diminished self-confidence or anxiety due to beauty standards that favor taller stature.
The faster increase in the height of men compared to women throughout the 20th century results from a mix of biological, nutritional, and socio-economic factors. Although advancements have improved health for everyone, the benefits have not been distributed evenly between men and women.
IMPORTANT TO NOTE
According to the same study, when a country’s Human Development Index (HDI) increases by 0.2%, women grow an average of 1.7 cm and gain 2.7 kg, while men increase by 4 cm and 6.5 kg.
