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Height

Height or stature is the distance from the bottom of the feet to the top of the head in a human body, standing erect.

It is measured using a stadiometer.

It is measure in centimetres when using the metric system or SI system,or feet and inches when using United States customary units or the imperial system.

Height is closely correlated with other health components, such as life expectancy.

A correlation between small stature and a longer life expectancy exists.

Individuals of small stature are also more likely to have lower blood pressure and are less likely to acquire cancer. 

The longevity gene FOXO3 that reduces the effects of aging is more commonly found in individuals of small body size.

Short stature decreases the risk of venous insufficiency.

When populations share genetic backgrounds and environmental factors, average height is frequently characteristic within the group. 

The development of human height can serve as an indicator of two key components of welfare: nutritional quality and health.

With poverty or warfare, environmental factors like chronic malnutrition during childhood or adolescence may result in delayed growth and/or marked reductions in adult stature.

Determinants of growth and height

The study of height is known as auxology.

Growth is a measure of the health of individuals.

Growth trends are tracked for significant deviations, and growth is also monitored for significant deficiency from genetic expectations. 

Genetics is a major factor in determining the height of individuals, though it is far less influential regarding differences among populations. 

Average height is relevant to the measurement of the health and wellness, and standard of living and quality of life of populations.

The significant reason for the trend of increasing height in parts of Europe are the egalitarian populations where proper medical care and adequate nutrition are relatively equally distributed.

The uneven distribution of nutritional resources makes it more plausible for individuals with better access to resources to grow taller, while individuals with worse access to resources have a lessened chance of growing taller.

Average height in a nation is correlated with protein quality. 

Nations that consume more protein in the form of meat, dairy, eggs, and fish tend to be taller, while those that obtain more protein from cereals tend to be shorter.

Populations with high cattle per capita and high consumption of dairy live longer and are taller. 

Malnutrition including chronic undernutrition and acute malnutrition is known to have caused stunted growth in various populations.

Height, like other phenotypic traits, is determined by a combination of genetics and environmental factors. 

A child’s height based on parental heights is subject to regression toward the mean, therefore extremely tall or short parents will likely have correspondingly taller or shorter offspring, but their offspring will also likely be closer to average height than the parents themselves. 

Genetic potential and several hormones, are a basic determinant for height, while other factors include the genetic response to external factors such as diet, exercise, environment, and life circumstances.

Humans grow fastest, other than in utero, as infants and toddlers, rapidly declining from a maximum at birth to roughly age 2, tapering to a slowly declining rate, and then, during the pubertal growth spurt.

The average girl starts her puberty and pubertal growth spurt at 10 years and an average boy starting his puberty and pubertal growth spurt at 12 years.

There is a rapid rise to a second maximum at around 11–12 years for an average female, and 13–14 years for an average male, followed by a steady decline to zero. 

The average female growth speed trails off to zero at about 15 or 16 years.

The average male curve continues for approximately 3 more years, going to zero at about 18–19.

Limited research suggests minor height growth after the age of 19 in males.

Stressors such as malnutrition, severe child neglect have  great effect on height,

The pregnant mother’s health is essential for her but also the fetus as gestation is itself a critical period for an embryo/fetus, affecting height.

Thus, there is a generation effect such that nutrition and health over generations influence the height of descendants to varying degrees.

There is a gradual increase in height with maternal age, though these suggesting  the trend is due to various socio-economic situations that select certain demographics as being more likely to have a first birth early in the mother’s life.

Children born to a young mother are more likely to have below-average educational and behavioural development, suggesting an ultimate cause of resources and family status rather than a purely biological explanation.

Differences in human height is 60–80% heritable, and is considered polygenic.

A genome-wide association (GWA) study has identified hundreds (697) of genetic variants in at least 423 loci associated with adult human height.

These 697 variants can be partitioned into 3 specific classes, (1) variants that primarily determine leg length, (2) variants that primarily determine spine and head length, or (3) variants that affect overall body size. 

There is a correlation between small stature and a longer life expectancy. 

Individuals of small stature are also more likely to have lower blood pressure and are less likely to acquire cancer. 

The “longevity gene” FOXO3 that reduces the effects of aging is more commonly found in individuals of a small body size.

Short stature decreases the risk of venous insufficiency.

Studies have shown that height is a factor in overall health while some suggest tallness is associated with better cardiovascular health and shortness with longevity.

Cancer risk has also been found to grow with height.

Moreover, scientists have also observed a protective effect of height on risk for Alzheimer’s disease.

Tallness is an adaptive benefit in colder climates such as those found in Europe.

Shortness helps dissipate body heat in warmer climatic regions.

The relationships between health and height cannot be easily generalized since tallness and shortness can both provide health benefits in different environmental settings.

Being excessively tall can cause various medical problems, including cardiovascular problems, because of the increased load on the heart to supply the body with blood, and problems resulting from the increased time it takes the brain to communicate with the extremities. 

Women whose height is under 150 cm (4 ft 11 in) may have a small pelvis, resulting in complications during childbirth as shoulder dystocia.

There is a strong inverse correlation between height and suicide among Swedish men.

Evidence indicates that shorter, smaller bodies age more slowly, and have fewer chronic diseases and greater longevity. 

Several human studies have found a loss of 0.5 years/centimeter of increased height (1.2 yr/inch). 

Height is measured to monitor child development, and is a better indicator of growth than weight in the long term.

For older people, excessive height loss is a symptom of osteoporosis.

Height is also used to compute indicators like body surface area or body mass index.

Shorter people are considered to have an advantage in certain sports-gymnastics, race car driving, whereas in many other sports taller people have a major advantage. 

In most occupational fields, body height is not relevant to how well people are able to perform.

However, several studies found that success was positively correlated with body height, although factors such as sex or socioeconomic status that are correlated with height which may account for the difference in success.

A demonstration of the height-success association can be found in the realm of politics: the United States presidential elections, the taller candidate won 22 out of 25 times in the 20th century.

Growing evidence suggests that height may be a proxy for confidence, which is likewise strongly correlated with occupational success.

Modern humans living in developed countries are taller than their ancient counterparts, but this was not always the case. 

Certain ancient human populations were quite tall, even surpassing the average height of the tallest of modern countries: Hunter-gatherer populations living in Europe during the Paleolithic Era and India during the Mesolithic Era averaged heights of around 183 cm (6 ft 0 in) for males, and 172 cm (5 ft 7+1⁄2 in) for females.

Human height worldwide sharply declined with the advent of the Neolithic revolution, likely due to significantly less protein consumption by agriculturalists as compared with hunter-gatherers.

Height varied significantly by region during the Bronze Age.

The people of Ancient Egypt stood around 167.9 cm (5 ft 6 in) for males and 157.5 cm (5 ft 2 in) for females.

The Ancient Greeks averaged 166.8 cm (5 ft 5+1⁄2 in) for males and 154.5 cm (5 ft 1 in) for females. 

The Romans were slightly taller, with an average height of 169.2 cm (5 ft 6+1⁄2 in) for males and 158 cm (5 ft 2 in) for females.

In the 150 years since the mid-nineteenth century, the average human height in industrialized countries has increased by up to 10 centimetres (3.9 in): these increases appear to have largely levelled off.

South Koreans are about 12 cm (4.7 in) taller than their North Korean counterparts due to a period of a famine where hundreds of thousands, if not millions, died of hunger.

The tallest man in modern history was Robert Pershing Wadlow (1918–1940), from Illinois, United States, who was 272 cm (8 ft 11 in) at the time of his death. 

The tallest woman in history was Trijntje Keever of Edam, Netherlands, who stood 254 cm (8 ft 4 in) when she died at the age of seventeen. 

The shortest adult human on record was Chandra Bahadur Dangi of Nepal at 54.6 cm (1 ft 9+1⁄2 in).

Adult height between populations often differs significantly.

Depending on sex, genetic and environmental factors, shrinkage of stature may begin in middle age in some individuals but tends to be universal in the extremely aged. 

This decrease in height is due to such factors as decreased height of inter-vertebral discs because of desiccation, atrophy of soft tissues, and postural changes secondary to degenerative disease.

There is a positive relationship of economic development and average height. 

Generally speaking, self-reported height tends to be taller than its measured height, although the overestimation of height depends on the reporting subject’s height, age, gender and region.

Some countries may have significant height gaps between different regions: there is 10.8 centimetres (4.3 in) gap between the tallest state and the shortest state in Germany.

Height can vary over a day, because of factors such as a height increase from exercise done directly before measurement, or a height increase since lying down for a significant period.

A study revealed a mean decrease of 1.54 centimetres (0.6 in) in the heights of 100 children from getting out of bed in the morning to between 4 and 5 p.m. that same day.

Men from Bosnia,Herzegovina, the Netherlands, Croatia, Serbia and Montenegro have the tallest average height.

The Tutsi of Rwanda, they are believed to be the tallest people in Africa.

Dinka peoples are the tallest people in the world.[92]

Until two years old, recumbent length is used to measure infants.

Length measures the same dimension as height, but height is measured standing up while the length is measured lying down. 

In developed nations, the average total body length of a newborn is about 50 cm (20 in).

Standing height is used to measure children over two years old[94] and adults who can stand without assistance. 

Standing height is about 0.7 cm (0.3 in) less than recumbent length.

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