A new study has found that Alzheimer's Disease (AD) is more likely to develop under the influence of nine risk factors, which have been identified by scientists after reviewing previous researches. As AD is most commonly linked to environmental influences and genetic features, the objective of the said study is to assess the relationship between AD and the changeable risk factors associated with it.
The researchers systematically retrieved information from the database systems of PubMed and the Cochrane Database of Systematic Reviews. The researchers included both prospective cohort and retrospective case-control studies up to July 2014, including the references used by these researches.
The findings of the study, published in the Journal of Neurology, Neurosurgery & Psychiatry, included data from 323 articles with 93 factors that have the criteria required for meta-analysis. Upon review of the data, the researchers were able to identify medical, dietary, biochemical, psychological, comorbidity and lifestyle exposures that may up the probability of individuals to develop AD.
These factors include high body mass index (BMI) during the midlife stage, which may be associated with obesity; carotid artery disease; hypertension; depression; frailty; poor educational background; elevated amounts of hyperhomocysteine, which is a naturally developing amino acid; and, for those of Asian descent, smoking and being diagnosed with Type 2 diabetes. No significant associations were established between AD and occupational factors.
On the other end of the spectrum, the researchers found that dietary factors such as intake of coffee, folate and vitamins C and E, as well as the intake of nonsteroidal anti-inflammatory, statins, and antihypertensive medication and estrogen supplements may decrease the risk of developing AD.
"The current evidence from our study showed that individuals would benefit from [addressing] the related potentially modifiable risk factors," said Dr. Jin-Tai Yu, study lead author and an associate specialist in neurology at the University of California, San Francisco and also the senior editor of the Journal of Alzheimer's Disease.
However, Yu emphasized that the risk factors identified in the study have presented an association with AD, which is highly different from a cause-and-effect relationship between one of the exposures and the development of AD. With this, he stressed that it may be impossible to detect the precise and detailed preventive benefits that may be gained should an individual try to eradicate any one of the conditions.
In the end, the researchers said that the study results imply that working to prevent the identified modifiable risk factors may decrease the chance of individuals to develop long-term AD. Then again, an overall healthy lifestyle and changing or adding habits just by mere intake of the mentioned supplements or medications may not provide sufficient support, comments Dr. Anton Porsteinsson, a professor of psychiatry and director of the Alzheimer's Disease Care, Research and Education Program at the University of Rochester School of Medicine.
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