10 weird things we've been told cause heart disease

Two cups of black coffee

It’s hard to read or watch the news without hearing of new things that could, apparently, cause heart disease. But can you believe what you read? Martina Dalton gives the lowdown on 10 of the most bizarre.

1. A weak handshake

A large study, published in the Lancet, was reported by some media to show that a weak handshake showed increased risk of cardiovascular disease and stroke. But this was not what was being measured. The study, by researchers from McMaster University, Ontario, did find that those with lower maximum grip strength (which is hardly the same as a handshake) were more at risk.

Looking at 140,000 people from 17 countries over a four year period, they looked at the chance of people dying, or suffering from cardiovascular disease or stroke. The study showed that grip strength was as strongly associated with dying from cardiovascular disease as systolic blood pressure (the top number in your blood pressure reading), but blood pressure was better at predicting whether someone would suffer from a non-fatal heart attack or stroke. So a simple blood pressure test is at least as likely to predict your risk.

This study does not tell us how grip strength is linked to risk. The researchers tried to account for common variables that may lead to weaker grip strength and increased cardiovascular disease risk (such as older age and smoking), and yet the association remained. It’s not clear whether this is because early signs of the illness are already  present, or a different factor puts people at increased risk.

So should we start measuring our own grip strength? Probably not. It is unclear what we’d do with the information, as we do not know whether improving grip strength would reduce risk. Meanwhile, there are several clearly established risk factors for cardiovascular disease, such as high blood pressure and high cholesterol, which do have effective treatments. You’re better off going to see your GP to talk about your individual risk factors and how they can best help you reduce your risk.

2. Being short

For more than 60 years, we’ve known that short people have an increased risk of heart disease. But until recently, it was thought that this was most likely due to environmental factors, such as nutrition.

As strange as it sounds, there is now research we’ve funded (published in the New England Journal of Medicine) to suggest that genes which pre-dispose us to being short, may also make us more likely to suffer from heart disease. It is not clear exactly how the two are related yet, but it may be that the genes which are involved in determining height are also be involved in controlling some other risk factor, possibly cholesterol levels.

As adults, there is nothing that we can do to change our height - it is what is called a non-modifiable risk factor.  But there are plenty of modifiable risk factors (for example smoking or a sedentary lifestyle) to tackle regardless of our height.

The reason that genetic research like this is useful is because it can help identify previously unrecognised molecular interactions that might be involved in the development of heart disease. This knowledge may, in turn, lead to new approaches to the prevention and treatment of heart disease.

3. Anger

News stories in February 2015 suggested that fits of anger increased your risk of a heart attack in the following 2 hours by 8.5 times. This was published in the journal Acute Cardiovascular Care and based on research done in Sydney, where 313 patients who had suffered a cardiac event were interviewed, but only a small number of the participants (7) actually reported anger preceding their heart attack.

In 2014 a systematic review of existing studies (covering 4,546 cases of heart attack plus smaller numbers of stroke, acute coronary syndrome and irregular heart rhythms) found that feeling angry increased heart attack risk in the following two hours by 4.74 times and stroke risk increased 3.72 times. It is important to not get alarmed by these results. A five-fold increase would only lead to 1-4 more cardiac events per 10,000 people, per year.

There are limitations to this kind of study, which mean we should be cautious about interpreting the results. Firstly, the patients were asked to remember how they felt in the hours before the event, and also their general anger levels over the year. There is potential for people to misremember events, or to give too much emphasis to them if they think they may be related to their heart problems.

Many of the studies done on this topic are small and the differing methods make it difficult to pool results to come to firm conclusions.  Theoretically, increased anger levels could lead to  physiological changes, such as a higher heart rate or blood pressure, that may increase risk, but more research is needed in this area.

4. Living near noisy roads

A study published in the European Heart Journal in June 2015 looked at the effect of road noise levels on cardiovascular disease and stroke risk across the whole of London. They found that higher noise levels were associated with a small increased stroke risk in adults and a small increased risk of stroke and cardiovascular disease hospital admission in the elderly.

There are limitations to this study, including that it was unable to look at the effects of individual risk factors and could not adjust the results for the fact that many would spend a large proportion of the day away from home. But previous studies, including a Danish study published in 2012, have also linked air pollution with an adverse effect on heart health.

The World Health Organisation (WHO) has produced guidelines on safe noise exposure which discuss the effects of high noise levels on increasing cardiovascular disease risk. This increased risk may be caused by increasing blood pressure and stress hormone levels, together with sleep disruption. The WHO is clear that the effect of high noise levels is small, and we would not suggest moving house; addressing other risk factors are likely to have a far larger effect on reducing your cardiovascular risk.

We already know that air pollution from traffic can make existing heart conditions worse and can cause heart attacks and strokes amongst the most vulnerable in our society. The evidence shows that reducing air pollution from traffic is a more important heart health issue than reducing noise.

5. Living in the north

Various news headlines in recent years have reported on a ‘North-South divide’ in life expectancy and in cardiovascular disease risk. What we do know is that life expectancy is much worse in poorer areas – more of which are found in the north than in the south. 

A review published in the Lancet in September 2015 looked at data from around the UK on causes of death, disease, and injury, as well as years lived with disability. It found that while life expectancy had increased between 1990 and 2013, the majority of those areas with highest deprivation (many of which were found in the north), were associated with lower life expectancy rates, and the most common cause of loss of years was heart disease. The difference in life expectancy between the least and most deprived areas was 8.2 years for men and 6.9 years for women.

The majority of risk factors, including diet, exercise, smoking levels, high blood pressure, high cholesterol and diabetes, are higher in areas of deprivation. But we can all take steps to reduce our risk, for example by being more physically active, losing weight, stopping smoking, and eating more fruit and vegetables.

6. Drinking less than 3 cups of coffee a day

How coffee might affect heart disease risk has been a controversial issue. The short term effects of caffeine are known to increase the risk of abnormal heart rhythms. Coffee consumption was also previously believed to cause an increased risk of cardiovascular disease, particularly as some studies showed a link between coffee and higher cholesterol levels. A study in 2013 suggested a link between drinking more than 4 cups a day and higher death rates, although this study had some weaknesses.

In 2014, a study published in the journal Circulation looked at coffee consumption and found that drinking 3-5 cups per day was linked to a decreased risk of cardiovascular disease. Above five cups a day, the beneficial effect disappeared but there was still no increased risk of cardiovascular disease compared to not drinking coffee.

This study was meta-analysis (where data from all relevant studies is analysed together) Due to the amount of data analysed (covering 1.2 million people) this type of study can provide fairly robust evidence. A study published in the journal Heart in 2015, based on a study of more than 25,000 people in South Korea, came to similar conclusions.

Differences between the latest studies and older ones may be due to changes in the way coffee is prepared and consumed. However, there is a long way to go in working out why the two are linked before we can recommend coffee drinking to prevent cardiovascular disease.

7. HRT

Hormone replacement therapy (HRT) is prescribed to treat symptoms of the menopause. It was previously believed to also reduce cardiovascular risk, though  it is not prescribed for this reason. However this belief has been challenged by a large study of 40,000 women, which showed that HRT had no protective effect on the heart. It also indicated that there may be a small increased risk of stroke in patients taking the treatment.

Women who are taking HRT or considering doing so should discuss with their GP the risks and benefits of HRT to help them decide whether this treatment is right for them. Whatever your decision, there are other ways to decrease your risk of stroke, for example by keeping active, eating a healthy diet and keeping your blood pressure under control.

8. Pessimism

There has been a lot of work looking at the effects of positive and negative attitudes on cardiovascular health, both before and after heart attacks. Several studies suggest an association between optimism and lower risk of cardiovascular disease. At least part of this seems to be related to higher levels of risk factors such as smoking, high cholesterol, diabetes and depression in the most pessimistic group, but there may be other factors involved.

A study from University College London, published in the journal Psychosomatic Medicine in April 2015 looked at the effect of optimism on recovery after a heart attack. It found that those with higher levels of optimism were more likely to have stopped smoking and increased their fruit and vegetable intake, lifestyle changes that we know can prevent heart disease.

When pessimism was associated with symptoms of depression, there was a significant increase in further serious cardiac events (such as fatal heart attack, cardiac surgery or readmission with heart attack) compared to those with an optimistic attitude. Furthermore, optimism appeared to protect against depressive symptoms, with fewer reporting them in the optimistic group.

The key message is to seek help from your doctor if you are concerned about your mood, or that of a loved one. Depression is common in the general population, and even more so in people with physical health concerns. Depression is treatable and can affect your physical health.

9. Gum disease

The link between gum disease, and increased cardiovascular disease risk was first suggested in the 1960s. A review of studies published in the Journal of Dental Research in 2010 suggested that gum disease has a role in causing cardiovascular disease, rather than there being another factor that makes individuals with gum disease more likely to suffer from heart disease (for example smoking is a risk factor for both), but said that more research is needed into why this might be the case.

We do know that chronic inflammation plays an important role in developing atherosclerotic plaques, however a definite mechanism for gum disease’s part in this, if any, remains unclear.

Other studies have shown certain markers of inflammation associated with heart disease to be reduced, and blood vessel function to be improved after treatment for gum disease. It is important to note that these studies have not followed up the participants over a longer period to assess whether their cardiovascular disease risk was affected.

What we do know is that 40 per cent of adults in the world have gum disease, and we would suggest regular check-ups with a dentist and to follow their advice on oral hygiene. Smoking is a risk factor for both gum disease and cardiovascular disease, so there is yet another reason to quit.

10. Working long hours

A study we funded analysed the results of 17 studies related to working hours and cardiovascular disease and stroke. This study, published in the Lancet, found a 13 per cent increase in risk of cardiovascular disease and 33 per cent higher risk of strokes in those working more than 55 hours per week, compared to those working a standard 35-40 hours per week.

This could be partly due to behavioural factors - people who work longer hours may have less time for physical activity, and may be more likely to choose convenience food than prepare healthy food due to time constraints. However the increased risk was still seen when lifestyle factors, such as  smoking, alcohol consumption and physical activity, and known risk factors, like high blood pressure and high cholesterol, were adjusted for.

Despite the strengths of this study, it cannot prove cause and effect, and further work is needed to establish how working hours and cardiovascular disease are linked. Either way, it is important for our general wellbeing that we have time to relax and unwind.

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