Of the factors associated with an increased risk of stroke, smoking is considered to be one of the most significant, therefore many studies consider smoking status alongside coffee consumption.
Meta-analyses have considered the associations between coffee consumption and stroke with similar results.
- Data from a 2011 meta-analysis of 11 prospective studies, with 10,003 cases of stroke and 479,689 participants, concluded that moderate coffee consumption may be weakly inversely associated with risk of stroke. Compared with no coffee consumption, consumption of 2 cups of coffee per day was associated with a 14% reduction and 3 cups per day with a 17% reduction in risk of stroke. The reduction in risk was reduced at higher intakes of coffee16
- A further meta-analysis of 9 cohort studies published in 2012 concluded that coffee consumption of 4 cups or more per day showed a preventive effect on stroke. In the European subgroup, increased coffee drinking showed an 18% reduction in risk of stroke17
- A 2018 overview of systematic reviews and meta-analyses concluded that a high consumption of nuts, fruits, vegetables, dairy foods, fish and tea, and moderate consumption of coffee and chocolate demonstrated a protective effect on the incidence of stroke23
A number of studies have considered coffee consumption and the incidence of stroke, concluding that there is no indication of an association and some suggestion of a protective effect:
- A large prospective cohort study from the US Nurses’ Health Study of 83,076 female participants, followed over 24 years with 2,280 cases of stroke, observed a significant inverse association for coffee consumption and incidence of stroke. This association was even stronger in the subgroup of past and non-smokers. The authors concluded that coffee consumption may modestly reduce the risk of stroke in women18
- Two further studies, one prospective cohort study from Japan11, and a case-cohort study from the Netherlands19, included male and female participants. Both studies were smaller in total number of participants, number of years of follow up, and number of cases. Neither of these studies observed any association between coffee consumption and stroke
- In a study on thromboembolism in women with 37,393 participants, followed over 19 years with 1,950 incident cases, no statistically significant association with coffee was seen20
- A further study in 33,994 adults, where daily coffee consumption ranged from 0 to 20 cups, concluded that heavier daily coffee consumption is associated with decreased stroke prevalence, despite a smoking tendency in heavy coffee drinkers. Interestingly, heart failure, diabetes, and hypertension were less frequent, and high cholesterol more frequent in those consuming more than 3 cups of coffee per day21
- A Japanese study of 82,369 Japanese adults aged 45-74 years without cardiovascular disease also concluded that coffee consumption was associated with an inverse risk of CVD and cerebral infarction22
- A 2017 Korean study concluded that coffee consumption of more than 3 cups a day was associated with a 38% lower odds ratio for stroke in women, although no significant association was found in men24