London - Being tall may come with practical problems, such as the lack of legroom on aeroplanes, but there are some perks, too.
Last month, researchers at Ohio State University reported that tall people are, on average, cleverer and have better social skills.
They said this could explain why studies in the past have found that tall people tend to earn more - as much as an extra £100 000 over a 30-year career.
That study followed research showing tall people are less likely to develop heart disease than short people. In fact height is now attracting a great deal of attention as a predictor of future health, affecting your risk of a range of diseases, from dementia to stroke.
Here's how your height may affect your health...
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DEMENTIA RISK HIGHER FOR SHORT PEOPLE
A number of studies suggest that height is linked to the risk of developing dementia. Perhaps the strongest evidence for this came from a study published last November in the British Journal of Psychiatry, which analysed data from 18 studies.
The team found that men under 5ft6in (167cm) had a 36 percent higher risk of dementia than men over 5ft 10in (177cm).
That doesn’t mean being short causes dementia. Shorter height can be associated with certain pressures in early life, such as stress, illness or poor nutrition, which may predispose someone to dementia, says lead author Dr Tom Russ, lecturer in old age psychiatry at the University of Edinburgh.
He says early life stresses may affect a person’s cognitive reserve - the brain’s resistance to age-related damage. “People think of dementia as a disease of old age, but this suggests you are accumulating risk factors throughout the course of your life.”
But remember, the overall risk of dementia is low - about one in 20 over-65s are affected - so these increases in risk are relatively small.
HOW HEIGHT PROTECTS THE HEART
When it comes to heart health, the news for shorter people may not be great, either. It seems they may also be more prone to heart disease, according to research published last month by the University of Leicester.
The researchers found a 5ft (153cm) tall person had a 32 percent higher risk of heart disease than someone who is 5ft 6in (167cm).
This association isn’t new. Analysis of data from more than a million people, published in the International Journal of Epidemiology in 2012, found clear links between shortness and higher risk of dying from heart disease, stroke and heart failure.
The latest research suggests the link is down to genes, rather than environmental factors such as diet. The team looked at 180 genetic variants that are known to control height, and found that those variants linked with shorter stature also had an effect on cholesterol, fat levels and overall heart disease risk.
Another theory is that taller people have larger coronary vessels, “which take longer to become blocked by fatty deposits”, according to David Wormser, the epidemiologist who led the 2012 study.
CANCER MORE COMMON IN TALL PEOPLE
It’s not all good news if you’re tall, however. In 2013, Dr Geoffrey Kabat, an epidemiologist at the Albert Einstein College of Medicine in the US, published research on post-menopausal women which found that for every additional 10cm of height, the risk of developing any cancer rose by 17 percent. So compared with a woman of 5ft 5in, a woman of 5ft9in would be that much more at risk said the researchers.
The strongest associations between height and cancer were for melanoma (skin cancer), colon, uterus, kidney and thyroid.
In another study in men, Dr Kabat found the risk of cancer rose by five percent for every extra 10cm of height.
Why would this be? Cancers are caused by the uncontrolled growth of abnormal cells, and so factors that are associated with increased growth in childhood and adolescence may also affect the risk of cancer, he says.
One theory is that tall people may have higher levels of a protein called insulin-like growth factor, or IGF, which is released in response to growth hormones and also seems to be linked to cancer.
Another explanation is that taller people naturally have more cells overall because their organs are bigger. So the chance of one of these cells mutating is higher, says Dr Kabat.
However, he stresses that the risks from height are small, and certainly lower than those of smoking, drinking too much and sun exposure. For example, being a smoker raises your risk of developing lung cancer by 2 000 percent compared with someone who never smoked.
TALL WOMEN MORE LIKELY TO HAVE TWINS
A 2006 study in the US comparing the heights of new mothers found that those who had twins or triplets were, on average, an inch taller than the national average.
Dr Gary Steinman, an obstetrician at Long Island Jewish Medical Centre, who led the research, said it may be down to IGF. He says one of its effects is to make the ovaries more sensitive to the follicle-stimulating hormone that triggers the ovaries to produce eggs.
Heightened sensitivity to the hormone raises the chance of two eggs being produced per cycle, and, in turn, the chance of a multiple pregnancy. Previous studies have shown that shorter people have lower levels of IGF.
SHORT PEOPLE FEEL LOOKED DOWN UPON
Height also seems to be linked to our emotional state. Some research suggests that taller people are happier.
A 2005 Swedish study found suicides were twice as common among men shorter than the average height compared with those who were taller than the norm.
Across the whole group, every 5cm increase in height was associated with a nine percent drop in suicide risk, even after the factors such as weight or wealth were taken into account.
The researchers offered several explanations: they said psychological stress and disrupted family life in childhood may impair growth and that short children may suffer discrimination.
Last year Oliver Freeman, a professor of psychology at Oxford University, conducted an experiment where 60 women were given virtual reality headsets and went on two simulated trips on the London Underground.
On the second trip, without telling the women, he altered their perspective so the world looked like they were about a head’s height shorter.
The women, who had no history of mental illness, reported increased feelings of inferiority, weakness, incompetence and paranoia in the second journey.
“The evolutionary view put forward is that height is a marker of physical strength and, hence, power, dominance and respect,” says Professor Freeman, adding that taller people are probably benefiting from an unconscious bias towards them.
... AND MIGHT BE MORE AT RISK OF GOING DEAF
Some evidence suggests those who are short in height are predisposed to hearing problems.
In 2003, Swedish research published in the British Medical Journal showed that shortness was associated with a family history of hearing loss.
In a group of men who were exposed to noise in their jobs, short men were three times more likely to have hearing loss than tall workers.
It was suggested that low levels of IGF may be to blame. The hormone may be important for the development of the cochlea, part of the inner ear.
BUT SHORT MEN MAY LIVE LONGER
Protection against cancer may be one of the reasons short men lived longer in a study by researchers at centres including the University of Hawaii.
They looked at 8,003 American men of Japanese descent and found those who were 5ft 2in (159cm) or shorter lived longer than those who were 5ft 4in(164cm) or taller.
The researchers found the shorter men were more likely to have a protective version of a gene we all have called FOX03, which is linked to ageing and longevity. The study found that men with this variant of the gene had less cancer and lower insulin levels.
A separate study, published in 2012, which looked at men born in Sardinia between 1866 and 1915 found that the shortest men (under 5ft 3in, or 161cm tall) lived two years longer than those who were taller.
TALLER PEOPLE ARE MORE LIKELY TO BREAK A BONE
Several studies, including one published in the New England Journal of Medicine in 1995, have shown taller men and women have a higher risk of hip fracture.
One possible explanation is that tall people fall from a greater height, meaning the impact is greater and the bone is more likely to fracture.
However, some researchers say the effect may be lessened by the fact that the bones of taller people may be stronger.
“It’s an interesting observation,” says Zameer Shah, consultant trauma and orthopaedic surgeon at Guy’s & St Thomas’ Hospital and London Bridge Hospital.
“But there are many other better established risk factors for fractures, such as having been a smoker, a sedentary lifestyle, poor diet, a high BMI and poor balance.”
....AND DEVELOP A BLOOD CLOT IN THE LEG
A Norwegian study published in 2011 found that men who were 6ft (183cm) or taller were 2.6 times more likely to develop deep vein thrombosis than men who were 5ft 8in (173cm) or shorter.
In deep vein thrombosis, a clot forms in the deep veins, normally the legs. An increased risk was also seen in taller women; and in both sexes, being tall and obese was the riskiest.
Lead researcher Sigrid Braekkan suggested that “in tall people, the blood must be pumped a longer distance by the calf muscle... which may cause reduced flow in the legs and thereby raise the risk of clotting.”
THE HEIGHTS OF PASSION
Last year, an analysis of 5 000 families by New York University found that men who were 5ft 7in (170cm) or shorter were 32 percent less likely to divorce.
The researchers said this finding was likely due to the fact that short men married less and later, suggesting “a selection process in which some women opt out of a marriage with short men before it begins”. Though it may or may not also be related to the fact the short men were found to do more housework.
And a study last year in the Journal of Sexual Medicine found that shorter men have more sex - men under 5ft 7in and of healthy weight reported the highest “coital frequency”, found the team at the University of Debrecen in Hungary.
Daily Mail