Can dementia risk be reduced by following the American Heart Association's Life's Simple 7? A systematic review and dose-response meta-analysis.

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• While the number of people with dementia has been predicted to increase worldwide, following the recommendations of the LS7, now LS8 could help to stop this trend.

Introduction

The aim of the study was to quantify the American Heart Association’s (AHA) Cardiovascular Health (CVH) metrics score called “Life’s Simple 7” (LS7) on cognitive outcomes. The LS7 prescription includes 4 behaviours (stop smoking, lose weight, eat better, get active) and 3 biometric measures (reduce blood sugar, control cholesterol, manage blood pressure).

Methods

• Pubmed and Embase were searched using the terms “cardiovascular health metrics”, “dementia”, and “cognitive decline”.
• There were a number of eligibility requirements for studies including: age for participants was >18 with no presence of cognitive decline at the start of the study; studies reporting less than 5 CVH metrics were excluded.
• Hazard ratio and corresponding 95% CI per one-point increase in CVH metrics score were estimated using a linear regression model with inverse-variance weights.
• Random-effects meta-analyses was conducted to estimate the summary hazard ratio and 95% CI of dementia with a one-point increase in a CVH metrics score; as well as the pooled β-coefficient with 95% CI of change in global cognitive decline rate per 10 years with a one-point increase in the CVH metrics score.

Results

• Of the 1286 studies identified 14 were deemed eligible. This included a total of 287, 058 participants, of which 8006 had been diagnosed with dementia and 24,596 cognitive decline.
• Participants' average age was 60.0 years.
• Participants who incorporated more LS7 guidelines had a lower risk of developing dementia. A one-point increase in CVH score is associated with a 6% decrease in incident dementia (hazard ratio 0.94, 0.92–0.96)
• A dose-response relationship was noted between LS7 adherence and dementia risk. The meta-analysis included 10 of the studies and resulted in a nearly J shaped dose-reponse curve between an increased favourable CVH score and reduced risk of dementia incidence.
• The beneficial impact for adopting LS7 in mid or late life was greater for dementia compared to cognitive decline.

Conclusion

• The study highlights that the LS7 guidelines positively impacts dementia risk.
• Adopting LS7 guidelines in mid or late life can reduce risk of dementia.

• This study emphasises the importance of adopting specific lifestyle changes in mid or later life to help reduce the risk of developing dementia and cognitive decline.
• Stopping smoking, incorporating exercise, controlling blood sugar, losing weight and managing total cholesterol and blood pressure may be particularly helpful in reducing the risk of dementia or cognitive decline.

• Given the link identified in this study between LS7 and brain health, future research on CVH would benefit from monitoring dementia and cognitive health outcomes concurrently. This could facilitate a greater understanding of the impact lifestyle changes have on brain function.
• Since the above article was published, the LS7 guidelines also incorporated healthy sleep. Known as LS8, the impact sleep has on dementia and cognitive decline will give further data on how to adopt a healthy lifestyle to help reduce the risk of dementia and cognitive decline.