Background: Alzheimer's disease (AD) is a devastating, irreversible, neurodegenerative disease with a high prevalence in our ageing society. Up to 50% of people over 85 years are believed to be affected, and this number only increases with age. Understanding the risk factors associated with such an impactful illness is of utmost importance, as is the investigation of factors which could prevent or at least slow its progression. Objective of this paper is to discuss the epidemiology and risk factors associated with Alzheimer?s disease as well as the potential protective factors and biomarkers available for its early diagnosis. Risk factors: There are both genetic and non-genetic risk factors associated with AD. The mutated genes associated with hereditary early-onset AD are presenilin 1 (PSEN1), presenilin 2 (PSEN2) and the amyloid precursor protein (APP). For sporadic AD, the e4 allelic variant of apolipoprotein E (APOE) is a well-known risk factor. Having one e4 allele increases the risk of sporadic AD three-fold, having two copies increases this risk up to fifteen times. Between 40 and 80% of all individuals with AD are carriers of at least one apoE4 allele. Of non-genetic risk factors, the most harmful ones include the presence of other underlying diseases such as cardiovascular disease, hypertension, obesity, and traumatic head injury. The most protective factors for preventing AD include education, physical activity and a healthy diet. Conclusion: Since the main risk factor for developing AD is age, there is little that can be done in terms of stopping ones ageing. However, implementing lifestyle choices that are preventative and decreasing those that are harmful, may at least slow down the progression of AD. Finding reliable biomarkers of the disease would be hugely beneficial in screening individuals at risk, and is currently an area of great interest in AD research, with potential plasma biomarkers including increased Neurofilament Light (NFL), decreased Aß42/40 ratios, and increased T- and P-Tau. Kulcsszavak: Epidemiology of Alzheimer?s disease, amyloid-beta, biomarkers, risk factors, ageing