According to a recent research from the University of Cambridge, one in three cases of Alzheimer’s disease worldwide is preventable.
The main risk factors for the disease are a lack of exercise, smoking, depression and poor education, it says.
Previous research from 2011 put the estimate at one in two cases, but this new study takes into account overlapping risk factors.
According to the study, published in The Lancet Neurology, the Cambridge team analyzed population-based data to work out the main seven risk factors for Alzheimer’s disease.
Alzheimer’s disease main risks are:
Low educational attainment
The main risk factors for Alzheimer’s disease are a lack of exercise, smoking, depression and poor education
The researchers worked out that a third of Alzheimer’s cases could be linked to lifestyle factors that could be modified, such as lack of exercise and smoking.
They then looked at how reducing these factors could affect the number of future Alzheimer’s cases.
They found that by reducing each risk factor by 10%, nearly nine million cases of the disease could be prevented by 2050.
Current estimates suggest that more than 106 million people worldwide will be living with Alzheimer’s by 2050 – more than three times the number affected in 2010.
Prof Carol Brayne, from the Institute of Public Health at the University of Cambridge, said: “Although there is no single way to treat dementia, we may be able to take steps to reduce our risk of developing dementia at older ages.
“We know what many of these factors are, and that they are often linked.
“Simply tackling physical inactivity, for example, will reduce levels of obesity, hypertension and diabetes, and prevent some people from developing dementia.
“As well as being healthier in old age in general, it’s a win-win situation.”
Of the seven risk factors, the largest proportion of cases of Alzheimer’s in the US, UK and the rest of Europe can be attributed to physical inactivity.
The study says about a third of the adult population in these countries are physically inactive.
Physical inactivity is also linked to increased risks of other health problems, such as cancers and cardiovascular diseases.
A new study review says that measuring blood pressure in both arms should be routine because the difference between left and right arm could indicate underlying health problems.
The Lancet research found that a large difference could mean an increased risk of vascular disease and death.
Although existing guidelines state that blood pressure should be measured in both arms, it is not often done.
A heart charity said it was too early to judge the findings.
The arm with the higher pressure can vary between individuals, but it is the difference between arms that counts, the study suggests.
Dr. Christopher Clark and colleagues, from the Peninsula College of Medicine and Dentistry at the University of Exeter, UK, reviewed 28 previous study papers looking at this area.
Most people in the study had an elevated blood pressure risk and about one-third had a normal level of risk.
A new study review says that measuring blood pressure in both arms should be routine because the difference between left and right arm could indicate underlying health problems
The study concluded that a difference in systolic blood pressure of 10 mm of mercury (mm Hg) between arms could identify patients at high risk of asymptomatic peripheral vascular disease.
A difference of 15mm Hg would also indicate an increased risk of cerebrovascular disease, a 70% increased risk of cardiovascular mortality and 60% increased risk of death from all causes, the authors said.
Peripheral vascular disease (PVD) is the narrowing and hardening of the arteries that supply blood to the legs and feet. There are often no symptoms.
The UK vascular check programme for over 40s which includes a test for hypertension, advises that blood pressure measurements be taken in both arms.
“But surveys have shown that the average GP doesn’t do it,” said Dr. Christopher Clark.
Early detection of PVD is important because these patients could then benefit from stopping smoking, lowering their blood pressure or being offered statin therapy.
Dr. Christopher Clark said the findings supported the need for blood pressure checks in both arms to be the norm.
Writing in The Lancet, Prof. Richard J. McManus, department of primary care health sciences at the University of Oxford and Prof. Jonathan Mant, from the department of public health and primary care at the University of Cambridge, said the review supports existing guidelines.
“Further research is needed to clarify whether substantial differences between arms should prompt aggressive management of cardiovascular risk factors.
“Ascertainment of differences should become part of routine care, as opposed to a guideline recommendation that is mostly ignored.”
Natasha Stewart, senior cardiac nurse at the British Heart Foundation, said measuring blood pressure on both arms to assess vascular disease is, theoretically, a quick and simple task.
“But it’s too early to say whether this idea could become part of standard healthcare practice and so we need more research to confirm the findings.”
Prof. Bryan Williams, from the Blood Pressure Association and the University of Leicester, said the study reinforced the message already in the guidelines from health watchdog NICE.