Short People Are More Likely To Die From Dementia, Scientists Say

Why Short People Are More Likely To Die From Dementia
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Being short increases your chances of dying from dementia, according to a new health study.

Scientists analysed 18 population studies with more than 180,000 participants and compared the risk of dying from dementia for the tallest and shortest men and women.

They found that men under 5ft 6in in height were 50% more likely to suffer death from Alzheimer's or other forms of dementia than those taller than 5ft 10in.

Meanwhile, women were less at risk, but those shorter than 5ft 1in were still 35% more likely to have their lives ended by the disease than those taller than 5ft 5in.

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Scientists stressed that there was no evidence that lack of height triggered the brain-deteriorating condition, the most common form of which is Alzheimer's.

But height could be a marker of other factors that might influence dementia risk, even early in life.

Senior author Dr David Batty, from University College London, said: "Short height in itself of course does not 'cause' dementia.

"Rather, height captures a number of early life factors, including early-life illness, adversity, poor nutrition and psychosocial stress, and so allows us to examine the effect of these factors on dementia more closely."

Men and women taking part in the studies had average heights of 5ft 8in and 5ft 3in respectively.

The risk of dying from any form of dementia was examined over an average period of 9.8 years. Of the total, 426 men and 667 women died as a result of developing the disease.

Participants were divided into four groups ranging from the tallest to the shortest. The study found that, for men, every 7.3 centimetre reduction in height was associated with a 24% increased risk of dementia death.

For women, each 6.8 centimetres of height loss coincided with a 13% increase in risk.

Study leader Dr Tom Russ, from the University of Edinburgh, said: "The association between height and dementia death remained when we took into account early life or adult socio-economic status and other relevant factors, including obesity, smoking, cardiovascular disease risk factors, and long-standing illness."

Writing in the British Journal of Psychiatry, the researchers concluded: "We have demonstrated a dose-response association between height and later dementia death which was robust to adjustment for a series of covariates.

"We propose the hypothesis that the mechanism driving this association may be early-life circumstances and thus add to the growing evidence of the role of pre-adult factors in later dementia risk."

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Early Symptoms of Dementia
No Initiative (01 of10)
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At times everyone can become tired of housework, business activities, or social obligations. However a person with dementia may become very passive, sitting in front of the television for hours, sleeping more than usual, or appear to lose interest in hobbies. (credit:John Rensten via Getty Images)
Changes in Personality (02 of10)
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A person with dementia may seem different from his or her usual self in ways that are difficult to pinpoint. A person may become suspicious, irritable, depressed, apathetic or anxious and agitated especially in situations where memory problems are causing difficulties. (credit:fStop Images - Carl Smith via Getty Images)
Mood Changes(03 of10)
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Everyone can become sad or moody from time to time. A person with dementia may become unusually emotional and experience rapid mood swings for no apparent reason. Alternatively a person with dementia may show less emotion than was usual previously. (credit:Mike Chick via Getty Images)
Misplace Things (04 of10)
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Anyone can temporarily misplace his or her wallet or keys. A person with dementia may put things in unusual places such as an iron in the fridge or a wristwatch in the sugar bowl. (credit:Oli Kellett via Getty Images)
Problems With Keeping Track of Things (05 of10)
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A person with dementia may find it difficult to follow a conversation or keep up with paying their bills. (credit:Chris Red via Getty Images)
Increasingly poor Judgement(06 of10)
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People with dementia may dress inappropriately, wearing several layers of clothes on a warm day or very few on a cold day. (credit:Jessica Peterson via Getty Images)
Distortion of Time and Place (07 of10)
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We sometimes forget the day of the week or where we are going but people with dementia can become lost in familiar places such as the road they live in, forget where they are or how they got there, and not know how to get back home. A person with dementia may also confuse night and day. (credit:Jupiterimages via Getty Images)
Problems With Language(08 of10)
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Occasionally everyone has trouble finding the right word but a person with dementia often forgets simple words or substitutes unusual words, making speech or writing hard to understand. (credit:Jupiterimages via Getty Images)
Difficulty Performing Familiar Tasks(09 of10)
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People with dementia often find it hard to complete everyday tasks that are so familiar we usually do not think about how to do them. A person with dementia may not know in what order to put clothes on or the steps for preparing a meal. (credit:Anthony Harvie via Getty Images)
Memory Loss(10 of10)
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Declining memory, especially short-term memory, is the most common early symptom of dementia. People with ordinary forgetfulness can still remember other facts associated with the thing they have forgotten. For example, they may briefly forget their next-door neighbour's name but they still know the person they are talking to is their next-door neighbour. A person with dementia will not only forget their neighbour's name but also the context. (credit:Compassionate Eye Foundation via Getty Images)

They called for continuing public health policies "on a broad front" to improve early-life conditions, taking into account pre-school education, parenting schemes and vaccination programmes.

An estimated 850,000 people in the UK are thought to be suffering from dementia, 60% of whom have Alzheimer's.

Commenting on the findings, Dr Doug Brown, director of research and development at Alzheimer's Society, said: "The data suggests that very short people are at increased risk of dying with dementia.

"While the study was robust and detailed, because a very small number of people actually had dementia when they died it is very difficult to conclude that height is one of the most important risk factors for dementia," he added.

"Future work in this area needs to understand exactly which factors that contribute to our height are important - whether that be childhood nutrition or genetic inheritance - and use that information to help us understand more about how dementia develops.

"Once fully grown there is nothing we can do to change our height, however we do know that we may be able to reduce our risk of dementia by making changes to our lifestyle. Not smoking, taking regular exercise and eating a healthy diet are all things that could improve our brain health."

Dr Simon Ridley, from the charity Alzheimer's Research UK, said: "Separating cause from effect is a big challenge of observational studies. However, the findings of this well controlled research encourage us to focus on early life, which influences adult height, as a small contributing factor to later dementia risk, and particularly in men.

"Evidence is mounting for the potential to prevent dementia through lifestyle and environment, and this study will contribute to building our knowledge around the factors we might control to reduce disease risk throughout life."