Study of 418,000 Europeans finds different foods linked to different types of stroke
February 24, 2020
Science Daily/European Society of Cardiology
Different types of food are linked to risks of different types of stroke, according to the largest study to investigate this, published in the European Heart Journal today (Monday).
Until now, most studies have looked at the association between food and total stroke (all types of stroke combined), or focused on ischaemic stroke only. However, the current study of more than 418,000 people in nine European countries investigated ischaemic stroke and haemorrhagic stroke separately.
The study found that while higher intakes of fruit, vegetables, fibre, milk, cheese or yoghurt were each linked to a lower risk of ischaemic stroke, there was no significant association with a lower risk of haemorrhagic stroke. However, greater consumption of eggs was associated with a higher risk of haemorrhagic stroke, but not with ischaemic stroke.
Ischaemic stroke occurs when a blood clot blocks an artery supplying blood to the brain or forms somewhere else in the body and travels to the brain where it blocks blood flow. Haemorrhagic stroke occurs when there is bleeding in the brain that damages nearby cells. About 85% of strokes are ischaemic and 15% are haemorrhagic. Stroke is the second leading cause of deaths worldwide.
Dr Tammy Tong, the first author of the paper and a nutritional epidemiologist at the Nuffield Department of Population Health, University of Oxford (UK), said: "The most important finding is that higher consumption of both dietary fibre and fruit and vegetables was strongly associated with lower risks of ischaemic stroke, which supports current European guidelines. The general public should be recommended to increase their fibre and fruit and vegetable consumption, if they are not already meeting these guidelines.
"Our study also highlights the importance of examining stroke subtypes separately, as the dietary associations differ for ischaemic and haemorrhagic stroke, and is consistent with other evidence, which shows that other risk factors, such as cholesterol levels or obesity, also influence the two stroke subtypes differently."
The total amount of fibre (including fibre from fruit, vegetables, cereal, legumes, nuts and seeds) that people ate was associated with the greatest potential reduction in the risk of ischaemic stroke. Every 10g more intake of fibre a day was associated with a 23% lower risk, which is equivalent to around two fewer cases per 1000 of the population over ten years.
Fruit and vegetables alone were associated with a 13% lower risk for every 200g eaten a day, which is equivalent to one less case per 1000 of the population over ten years. No foods were linked to a statistically significant higher risk of ischaemic stroke.
Based on UK estimates, two thick slices of wholemeal toast provide 6.6g of fibre, a portion of broccoli (around eight florets) provides about 3g, and a medium raw, unpeeled apple provides about 1.2g of fibre. The European Society of Cardiology (ESC) and the World Health Organization Regional Office for Europe recommend consuming at least 400g of fruit and vegetables a day; the ESC also suggests people should consume 30-45g of fibre a day.
The researchers found that for every extra 20g of eggs consumed a day there was a 25% higher risk of haemorrhagic stroke, equivalent to 0.66 extra cases per 1000 (or around two cases per 3000) of the population over ten years. An average large-sized egg weighs approximately 60g. Egg consumption in the EPIC study was low overall, with an average of less than 20g eaten a day.
The researchers say the associations they found between different foods and ischaemic and haemorrhagic stroke might be explained partly by the effects on blood pressure and cholesterol.
Dr Tong and her colleagues analysed data from 418,329 men and women in nine countries (Denmark, Germany, Greece, Italy, The Netherlands, Norway, Spain, Sweden and the United Kingdom) who were recruited to the European Prospective Investigation into Cancer and Nutrition (EPIC) study between 1992 and 2000. The participants completed questionnaires asking about diet, lifestyle, medical history and socio-demographic factors, and were followed up for an average of 12.7 years. During this time, there were 4281 cases of ischaemic stroke and 1430 cases of haemorrhagic stroke.
Food groups studied included meat and meat products (red meat, processed meat and poultry), fish and fish products (white fish and fatty fish), dairy products (including milk, yogurt, cheese), eggs, cereals and cereal products, fruit and vegetables (combined and separately), legumes, nuts and seeds, and dietary fibre (total fibre and cereal, fruit and vegetable fibre).
Major strengths of the study include the large numbers of people studied in several different countries and long follow-up period. Most types of food were included in the study, although information on diet was collected at only one point in time, when the participants joined the study. As the study is observational it cannot show that the foods studied cause an increase or decrease in risk of ischaemic or haemorrhagic stroke, only that they are associated with different risks. Information on medication use (including statins) was not available.
https://www.sciencedaily.com/releases/2020/02/200224102024.htm
Living in a noisy area increases the risk of suffering a more serious stroke
The work analysed data from nearly 3,000 patients treated at Hospital del Mar
October 29, 2019
Science Daily/IMIM (Hospital del Mar Medical Research Institute)
The high levels of environmental noise we are subjected to in large cities can increase both the severity and consequences of an ischaemic stroke. More precisely, researchers from the Hospital del Mar Medical Research Institute (IMIM) and doctors from Hospital del Mar, together with researchers from the Barcelona Institute for Global Health (ISGlobal), CIBER in Epidemiology and Public Health (CIBERESP), and Brown University, in the United States, put the increased risk at 30% for people living in noisier areas. In contrast, living close to green areas brings down this risk by up to 25%. This is the first time that these factors have been analysed in relation to stroke severity. The study has been published in the journal Environmental Research.
The researchers looked at the influence of noise levels, air pollution (particularly suspended particles smaller than 2.5 microns; PM2.5), and exposure to green areas on nearly 3,000 ischaemic stroke patients treated at Hospital del Mar between 2005 and 2014. To do this, they used data from the Cartographic Institute of Catalonia, as well as models to analyse atmospheric pollutant levels, the noise map of Barcelona, and satellite images to define areas with vegetation. Also taken into account was the socioeconomic level of the place the patients lived.
Dr. Rosa María Vivanco, from the IMIM's Neurovascular Research Group and first author of the study, points out that the study gives us initial insight into how noise levels and exposure to green spaces influences the severity of ischaemic stroke. "We have observed a gradient: the more green spaces, the less serious the stroke. And the more noise, the more serious it is. This suggests that factors other than those traditionally associated with stroke may play an independent role in the condition," she explains. At the same time, Dr. Xavier Basagaña, one of the authors of the study and a researcher at ISGlobal, a centre supported by "la Caixa," stresses that "exposure to green spaces can benefit human health through various mechanisms. For example, it can reduce stress, encourage social interaction, and increase levels of physical activity." However, in this study no link was seen with atmospheric pollution. The researchers warn that one of the limitations of the work was the lack of variability in pollutant concentrations to which the study population is exposed. This made it difficult to draw conclusions, and they point out that more studies are needed in this field.
More noise, greater stroke severity
"Previous studies have demonstrated that living in places with high levels of air pollution or noise, or with fewer green areas, exposes the population to a higher risk of suffering an ischaemic stroke. This work broadens our knowledge in this field, showing that the place where we live affects not only the risk of suffering a stroke, but also its severity if it occurs," explains Dr Gregory A. Wellenius, from the Epidemiology Department at Brown University and final author of the study. In this sense, the results indicate that patients living in noisier areas presented more severe strokes on arrival at hospital.
The researchers have analysed the effects of stroke on neurological deficits, such as speech impairment and mobility, using the NIHSS (National Institute of Health Stroke Scale). "The severity of a stroke depends on various factors, including the extent of the brain injury, the specific area of brain affected, the subtype of stroke, the existence of associated risk factors (diabetes, atrial fibrillation, atherosclerotic load), and so on. The fact that we have demonstrated, in addition to all these factors, that environmental aspects like green spaces and urban noise levels affect the severity of a stroke and therefore our health, shows that this information must be taken into account by political and health planners," emphasises Dr. Jaume Roquer, head of the Neurology Service at Hospital del Mar, coordinator of the IMIM's Neurovascular Research Group, and one of the main authors of the work.
The researchers did not aim to determine which noise levels lead to increased risk, but rather to detect a gradient by comparing patients living in noisier areas with those living in quieter areas. Indeed, the World Health Organisation (WHO) recommends traffic noise limits of a maximum of 53 decibels during the day and 45 decibels at night. "The average noise level to which patients have been exposed, as well as the general population of the study area, requires reflection, as it is considerably above the WHO recommendations," points out Carla Avellaneda, an IMIM researcher and author of the work. The same researchers have already revealed that high levels of air pollution from diesel engines increase the risk of suffering atherothrombotic stroke by 20%.
Stroke
In Spain, stroke is the leading cause of death in women and the third ranked in men, and is estimated to affect 1 in 6 people throughout their lives (in 2012, it caused the death of 6.7 million people around the world, according to WHO data). In Catalonia there are 13,000 cases and 3,800 deaths from stroke each year. The two main types of stroke are haemorrhagic and ischaemic.
Ischaemic stroke is due to the obstruction of a blood vessel in the brain and accounts for 80-85% of all cases. This lack of blood flow in the affected area of the brain can lead to permanent damage. The risk of having a stroke is closely related to factors including age, smoking, high blood pressure, diabetes, obesity, a sedentary lifestyle and, as recently demonstrated, other factors like air pollution.
https://www.sciencedaily.com/releases/2019/10/191029103311.htm