Dementia risk reduction: why haven't the pharmacological risk reduction trials worked? An in-depth exploration of seven established risk factors

Identifying the leading health and lifestyle factors for the risk of incident dementia and Alzheimer's disease has yet to translate to risk reduction. To understand why, we examined the discrepancies between observational and clinical trial evidence for seven modifiable risk factors: type 2 diabetes, dyslipidemia, hypertension, estrogens, inflammation, omega-3 fatty acids, and hyperhomocysteinemia. Sample heterogeneity and paucity of intervention details (dose, timing, formulation) were common themes. Epidemiological evidence is more mature for some interventions (eg, non-steroidal anti-inflammatory drugs [NSAIDs]) than others. Trial data are promising for anti-hypertensives and B vitamin supplementation. Taken together, these risk factors highlight a future need for more targeted sample selection in clinical trials, a better understanding of interventions, and deeper analysis of existing data.

Automated summary

The discrepancies between clinical trial and observational evidence on the impact of health and lifestyle factors on the risk of dementia and Alzheimer's disease have hindered risk reduction. Some interventions, such as non-steroidal anti-inflammatory drugs, have more mature epidemiological evidence, while clinical trial data show promise for anti-hypertensives and B vitamin supplementation to be effective interventions. Further research is needed to improve targeted sample selection, intervention understanding, and data analysis in future clinical trials.