A new study published in the Journal of Neurology Neurosurgery and Psychiatry found that nine potentially modifiable risk factors may contribute to two thirds of Alzheimer's disease cases worldwide. The analysis shows how the risk factors vary because of the innate complexity of Alzheimer's disease development. But researchers suggest the preventive strategies targeting diet, drugs, body chemistry, mental health, pre-existing disease and lifestyle may help fight dementia. 

Given that there is no cure, 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 to potentially reduce the overall risk of developing the disease. 

Researchers first dug through massive research databases, looking for relevant studies published in English from 1968 up to July 2014. 

After analyzing a total of 17,000 studies, a total of 323 covered 93 various risk factors and more than 5,000 people could be included in the analysis. Researchers the pooled the data from each of these studies, and graded the evidence based on its strength. 

An example would be high or low body mass index (BMI) in mid-life and low educational attainment were associated with increased risk, where as high BMI later in life. Exercising one's brain, current smoking standards and light to moderate drinking along with stress had an associated lower risk. There were no significant associations for workplace factors. 

The nine risk factors included obesity, smoking, carotid artery narrowing, type 2 diabetes, high levels of homocysteine, depression, high blood pressure and frailty.