(Press-News.org) Nine potentially modifiable risk factors may contribute to up to two thirds of Alzheimer's disease cases worldwide, suggests an analysis of the available evidence, published online in the Journal of Neurology Neurosurgery & Psychiatry.
The analysis indicates the complexity of Alzheimer's disease development and just how varied the risk factors for it are.
But the researchers suggest that preventive strategies, targeting diet, drugs, body chemistry, mental health, pre-existing disease, and lifestyle may help to stave off dementia. This could be particularly important, given that, as yet, there is no cure, they say.
The researchers wanted to look at the factors associated with the development of Alzheimer's disease in a bid to determine the degree to which these might be modified and so potentially reduce overall risk.
They therefore trawled key research databases, looking for relevant studies published in English from 1968 up to July 2014.
Out of almost 17,000 studies, 323, covering 93 different potential risk factors and more than 5000 people, were suitable for inclusion in the analysis. The researchers pooled the data from each of the studies and graded the evidence according to its strength.
They found grade 1 level evidence in favour of a protective effect for the female hormone oestrogen, cholesterol lowering drugs (statins), drugs to lower high blood pressure, and anti-inflammatory drugs (NSAIDs).
They found the same level of evidence for folate, vitamins C and E, and coffee, all of which were associated with helping to stave off the disease.
Similarly, the pooled data indicated a strong association between high levels of homocysteine--an amino acid manufactured in the body--and depression and a significantly heightened risk of developing Alzheimer's disease.
The evidence also strongly pointed to the complex roles of pre-existing conditions as either heightening or lowering the risk.
The factors associated with a heightened risk included frailty, carotid artery narrowing, high and low blood pressure, and type 2 diabetes (in the Asian population). Those associated with a lowered risk included a history of arthritis, heart disease, metabolic syndrome, and cancer.
Certain factors seemed to be linked to altered risk, depending on the time of life and ethnic background.
For example, high or low body mass index (BMI) in mid-life and low educational attainment were associated with increased risk, whereas high BMI in later life, exercising one's brain, current smoking (excluding the Asian population), light to moderate drinking, and stress were associated with lowered risk.
There were no significant associations found for workplace factors.
The researchers then assessed the population attributable risk (PAR) for nine risk factors which had strong evidence in favour of an association with Alzheimer's disease in the pooled analysis, and for which there are data on global prevalence.
PAR refers to a mathematical formula used to define the proportion of disease in a defined population that would disappear if exposure to a specific risk factor were to be eliminated.
The nine risk factors included obesity, current smoking (in the Asian population), carotid artery narrowing, type 2 diabetes (in the Asian population), low educational attainment, high levels of homocysteine, depression, high blood pressure and frailty.
The combined PAR indicated that these nine factors, each of which is potentially modifiable, contribute up to around two thirds of cases globally.
This is an observational study, so no definitive conclusions can be drawn about cause and effect, but the researchers suggest that preventive strategies, targeting diet, prescription drugs, body chemistry, mental health, underlying disease, and lifestyle might help curb the number of new cases of Alzheimer's disease.
INFORMATION:
In a Policy View published in The Lancet Neurology journal, a group of leading experts on the epidemiology of dementia state that the number of people with dementia - both new cases and total numbers with the disease - in some Western European countries is stabilising despite population ageing, in direct contrast to the "dementia epidemic" reported in some recent studies.
The Policy View discusses data from five large epidemiological studies done in Sweden, the Netherlands, the UK, and Spain that compare dementia occurrence in old people across two periods of time using ...
Highlights
Among kidney transplant recipients, patients with mostly IgG3 donor-specific HLA antibodies had a higher likelihood of organ rejection soon after transplantation.
If rejection occurred in those with mostly IgG4 antibodies, it was usually much later after transplantation.
Washington, DC (August 20, 2015) -- The dominant antibody type present in the blood of transplant recipients may indicate their likelihood of experiencing organ rejection, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). ...
DALLAS, Aug. 20, 2015 -- Caregiver spouses of stroke survivors are at an increased risk of mental and physical health issues that may continue for years, according to research in the American Heart Association journal Stroke.
Swedish researchers evaluated 248 stroke survivors, below age 70 (average mid-sixties), and their spouses at stroke onset and compared the results with 245 non-stroke controls for seven years after the stroke event.
At the seven-year follow-up, 16.5 percent of survivors had suffered a recurrent stroke. Spouses of survivors reported lower scores ...
Boston, MA -- A widely used class of industrial chemicals linked with cancer and interference with immune function--perfluorinated alkylate substances, or PFASs--appears to build up in infants by 20%-30% for each month they're breastfed, according to a new study co-authored by experts from Harvard T.H. Chan School of Public Health. It is the first study to show the extent to which PFASs are transferred to babies through breast milk, and to quantify their levels over time.
"We knew that small amounts of PFAS can occur in breast milk, but our serial blood analyses now show ...
In-depth interviews conducted by researchers at the Johns Hopkins University School of Medicine of 20 young women attending an urban sexually transmitted disease clinic have documented a variety of unexpected, unintended sexual encounters linked to their alcohol use before sex occurs.
Links between alcohol use and risky or deleterious sexual encounters are not necessarily new, say investigators, but this small study identifies very specifically the disconnect between what young women have in mind when they drink and have sex and what really happens.
"The idea behind ...
According to a survey conducted by Rhode Island Hospital researchers, there is significant variability regarding how clinicians manage catheters placed in the arteries of patients in intensive care units. Some practices may increase risk of infection associated with these catheters. Fewer than half of those surveyed complied with current Centers for Disease Control and Prevention (CDC) infection prevention guidelines for arterial catheter insertions. The study was published today in Critical Care Medicine.
"Barrier precautions are employed inconsistently by critical care ...
Washington, DC - August 20, 2015 - Swedish exchange students who studied in India and in central Africa returned from their sojourns with an increased diversity of antibiotic resistance genes in their gut microbiomes. The research is published 10 August in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.
In the study, the investigators found a 2.6-fold increase in genes encoding resistance to sulfonamide, a 7.7-fold increase in trimethoprim resistance genes, and a 2.6-fold increase in resistance to beta-lactams, all of this without ...
PHOENIX, Ariz. -- Aug. 20, 2015 -- A study by the Translational Genomics Research Institute (TGen) and other major research institutes, found a new set of genes that can indicate improved survival after surgery for patients with pancreatic cancer. The study also showed that detection of circulating tumor DNA in the blood could provide an early indication of tumor recurrence.
In conjunction with the Stand Up To Cancer (SU2C) Pancreatic Cancer Dream Team, the study was published in the prestigious scientific journal Nature Communications.
Using whole-exome sequencing ...
If dark energy is hiding in our midst in the form of hypothetical particles called "chameleons," Holger Müller and his team at the University of California, Berkeley, plan to flush them out.
The results of an experiment reported in this week's issue of Science narrows the search for chameleons a thousand times compared to previous tests, and Müller, an assistant professor of physics, hopes that his next experiment will either expose chameleons or similar ultralight particles as the real dark energy, or prove they were a will-o'-the-wisp after all.
Dark energy ...
Management of boreal forests needs greater attention from international policy, argued forestry experts from the International Institute for Applied Systems Analysis (IIASA), Natural Resources Canada, and the University of Helsinki in Finland in a new article published this week in the journal Science. The article, which reviews recent research in the field, is part of a special issue on forests released in advance of the World Forestry Congress in September.
"Boreal forests have the potential to hit a tipping point this century," says IIASA Ecosystems Services and Management ...
