Drinking coffee or tea may be linked to a reduced risk of stroke and dementia. That’s according to a study of healthy individuals aged 50-74 and published in the journal PLOS Medicine. Drinking coffee was also linked with a lowered risk of post-stroke dementia.
Strokes are life-threatening events which are linked to 10% of deaths worldwide. Dementia is a general term for symptoms related to a decline in brain functions and is a global health concern that causes high economic as well as social burdens. Post-stroke dementia is a condition where an individual starts suffering from dementia symptoms following a stroke.
Researchers from Tianjin Medical University in China studied 365,682 participants from the UK Biobank, recruited between 2006 and 2010. The participants were followed until 2020. They self-reported their own coffee and tea intakes. Over the course of the study, 5,079 of the participants developed dementia and 10,053 had at least one stroke.
People who had 2-3 cups of coffee or 3-5 cups of tea each day, or a combination of 4-6 cups of coffee and tea had the lowest incidence of stroke or dementia. Those who had 2-3 cups of coffee and 2-3 cups of tea daily had a 32% lower risk of stroke and a 28% lower risk of dementia when compared with those who drank neither coffee nor tea. Coffee alone or in combination with tea was also linked with a lower risk of post-stroke dementia.
The participants were a relatively healthy sample when compared to the general population. This reduces the chance to generalise these associations. What’s more, relatively few people developed dementia or stroke which makes it harder to extrapolate to a larger population.
Finally, correlation does not imply causation. It’s entirely possible that there are other factors that played a part and while it’s possible that coffee or tea consumption might hep combat stroke, dementia, or post-stroke dementia, “causality cannot be inferred from these associations” according to Science Daily.
It’s a bit like a study that found that fruits and vegetables are linked to reduced wrinkles. The Daily Mail reported that “an apple a day keeps the wrinkles at bay.” The researchers obviously didn’t take one group and had them eat fruits and vegetables and took another to McDonald’s. They had to follow people during certain points in their lives. People who eat more fruit and vegetables are likely to lead a healthier lifestyle in general than for example people who eat a lot of fast food.
And it’s possible that there are other lifestyle factors that affected the results of this study.
Image: Cibao Chua