Alzheimer's disease (AD) is the most common type of dementia, characterized by progressive cognitive and social decline. Clinical drug targets have heavily focused on the amyloid hypothesis, with amyloid beta (Ab), and tau proteins as key pathophysiologic markers of AD. However, no effective treatment has been developed so far, this prompts researchers to focus on other aspects of AD beyond the Ab and tau proteins. Additionally, there is mounting epidemiologic evidence that various environmental factors influence the development of dementia, and that dementia etiology is likely heterogeneous. In the past decades, new risk factors or potential etiologies have been widely studied. Here, we review general background information on Alzheimer's disease and several novel risk factors, and their links to AD that were published in recent years