Four Decades of Research in Alzheimer's Disease (1975-2014): A Bibliometric and Scientometric Analysis.

BACKGROUND: Bibliometric and scientometric methods can be applied to the study of a research field.

OBJECTIVE: We hypothesized that a bibliometric and scientometric analysis of the Alzheimer's disease (AD) research field could render trends that provide researchers and funding agencies valuable insight into the history of the field, current tendencies, and potential future directions.

METHODS: We performed searches in publicly available databases including PubMed, Scopus, Web of Science, and Alzheimer's Funding Analyzer for the period 1975-2014, and conducted a curve fitting analysis with non-linear regression.

RESULTS: While the rate and impact of publications continue to increase, the number of patents per year is currently declining after peaking in the late 2000s, and the funding budget has plateaued in the last 5-10 years analyzed. Genetics is the area growing at a fastest pace, whereas pathophysiology and therapy have not grown further in the last decade. Among the targets of pathophysiology research, amyloid-β continues to be the focus of greatest interest, with tau and apolipoprotein E stagnant after a surge in the 1990s. The role of inflammation, microglia, and the synapse are other research topics with growing interest. Regarding preventative strategies, education attainment, diet, and exercise are recently gaining some momentum, whereas NSAIDs and statins have lost the spotlight they once had.

CONCLUSION: Our bibliometric and scientometric analysis provides distinct trends in AD research in the last four decades, including publication and patent output, funding, impact, and topics. Our findings could inform the decision-making of research funding agencies in the near future.