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Diet fizzy drinks linked to dementia and stroke? Dr Hinesh Topiwala comments

Friday 26 May 2017

Dr Hinesh Topiwala is a Clinical Research Fellow at the Centre for Dementia Prevention, University of Edinburgh. He works on the European Prevention of Alzheimer’s Dementia (EPAD) Longitudinal Cohort Study. EPAD aims to identify warning signs of Alzheimer’s disease that are present in midlife that may predict which people are likely to develop dementia in later life.

Hinesh’s main research interest is lifestyle and neurodegeneration in midlife and he has previously completed Psychology (BSc) and Medicine (MBBS) degrees at University College London. He is member of the Royal College of Psychiatrists (MRCPsych) and has worked as a clinician for the NHS since 2008.

Find out more about Dr Topiwala here:

Dr Topiwala provided his commentary on recent headlines claiming diet fizzy drinks are linked to dementia and stroke, versus the findings of the study to which they refer.

1. Were the headlines right or were they misleading in some way?

This original study was published in Stroke, a peer reviewed journal of the American Heart Association in May 2017. The findings of the study were widely disseminated via the media, including newspapers. The headlines in the New York Times and Telegraph were both fair and balanced. The headlines highlight an interesting trend that warrants further investigation.

The bold and eye catching headline in the Daily Mail was somewhat misleading. The first part of the headline ‘Diet drinks TRIPLE your risk of stroke and dementia’ is based on data which had not taken into account the numerous health and lifestyle factors which may influence the relationship between diet drinks and dementia and stroke. The second part of the headline, which states that diet drinks ’are FAR more dangerous than drinks sweetened with sugar’ is not supported by the data in this study.

2. How important is this story/study for furthering dementia research? Should we be excited?

This study has identified an exciting platform from which further research can take place into the relationship between sweetened soft drink consumption and the risk of stroke and dementia. The study had a large sample size, participants were regularly followed up, the researchers used statistical modelling to adjust for a number of possible alternative explanations for correlations in the data and the study used well established data collection tools such as the Harvard semiquantitative food-frequency questionnaire (FFQ).

Nevertheless, the findings from this study should be interpreted with caution. The authors of the study acknowledge that they cannot exclude the possibility that they have not accounted for all possible alternative explanations for correlations identified in the data and that some of the findings may be attributable to chance. Also, there is an absence of ethnic minorities in the sample which limits the generalizability of the findings and the FFQ, a self-reported questionnaire may be subject to inaccuracies, as participants may not precisely remember their food and beverage consumption over the past year.

3. What might be the impact of this story/study in the scientific community?

This forward-thinking study into stroke and dementia is certainly a step in the right direction and we need to build upon these study findings. There has been very little research looking at the relationship between sweetened beverages and the risk of stroke and dementia.  Additionally, the findings from previous research have been conflicting. This large observational study adds to the current evidence base.

4. What are the next steps?

The authors of the study have concluded that artificially sweetened soft drinks consumption was associated with a higher risk of stroke and dementia. However, when the authors used an adjusted statistical model taking into account demographic, lifestyle and health factors, the association between artificially sweetened drinks and risk of dementia and stroke was less robust. 

Further research is needed to replicate the study findings in a different population and to investigate the possible mechanisms underlying the reported associations. In the future, clinical trials may be helpful to establish whether the consumption of artificially sweetened beverages is causally related to dementia and stroke.