Weight gain and increasing diabetes prevalence are stalling efforts to reduce the number of heart attacks and strokes, according to research funded by the British Heart Foundation (BHF) published this week in prestigious medical journal The Lancet Regional Health – Europe.
Researchers from the London School of Hygiene & Tropical Medicine found that decreases in three major risk factors contributed to a fall in the number of heart attacks and strokes between 1990 and 2014. However, progress in reducing numbers further has been stalled by increasing body mass index (BMI) and diabetes prevalence over the same period.
The team used Scottish health data to calculate the change in numbers of heart attacks and strokes between 1990 and 2014. This showed that the number of heart attacks fell from 1,069 per 100,000 people to 276 per 100,000. Ischaemic strokes (a type of stroke caused by a blood clot) fell from 608 per 100,000 to 188 per 100,000 people.
They found that 74 per cent of this fall in heart attacks and 68 per cent of that in strokes could be accounted for by changes in risk factor prevalence. This was driven by decreases in blood pressure, cholesterol levels and smoking rates.
Average systolic blood pressure in Scotland in this period fell from 140mmHg to 129mmHg, cholesterol levels fell from 6.4mmol/L to 5.0mmol/L, and adult smoking rates more than halved.
However, average BMI increased, from 27.2kg/m2 to 28.1kg/m2, and diabetes prevalence in Scotland more than doubled from 4 to 9 per cent of the population. This was estimated to have led to a 20 per cent increase in heart attacks and a 15 per cent increase in ischaemic strokes attributable to these two risk factors.
The researchers estimate that increased diabetes prevalence contributed to nearly as many heart attacks as the decline in smoking prevented.
While the team could be confident that changes in risk factors had an impact on the incidence of heart attacks and strokes, they viewed each risk factor in isolation in their analysis which means that their estimated impact is likely to be exaggerated.
The picture is likely to be similar in Northern Ireland.
Figures show that the number of people here with diabetes and obesity has significantly increased over the last few decades. Analysis also shows that the contribution of diabetes to heart and circulatory diseases in Northern Ireland is increasing.
In 1990 the proportion of deaths from heart and circulatory diseases in Northern Ireland associated with diabetes was estimated at 12 per cent. By 2019 this had doubled to 24 per cent.
Dr Anoop Shah, BHF clinical research fellow at the London School of Hygiene & Tropical Medicine, led the research.
He said: “The amount that different risk factors contribute to heart attacks and strokes has shifted over the last 25 years. Weight gain and diabetes now play a more prominent role in the development of these conditions. Public health policy urgently needs to incorporate these, taking a more holistic view of the range of risk factors that can lead to heart and circulatory diseases.
“There’s a time lag between people contracting diabetes and developing heart and circulatory disease. We need to act now to address these important risk factors or we risk seeing the impact of these increases for decades to come.”
Professor Sir Nilesh Samani, medical director at the British Heart Foundation, said: “Whilst it’s great to see the positive impact that public health measures, such as the smoking ban, have had on the number of people experiencing heart attacks and strokes over the last 25 years, it’s concerning that increasing BMI and diabetes prevalence now appear to be slowing progress.
“Obesity is a major cause of type 2 diabetes and this research highlights that governments across the UK need to press on with the bold pledges in their obesity strategies. Excess weight is a complex issue and we cannot rely on individual willpower and exercise alone to increasing BMI across the population. We need to address the environmental factors that drive weight gain and the development of diabetes so that we don’t lose the gains we have made in reducing the burden of cardiovascular diseases.”
Fearghal McKinney, head of British Heart Foundation Northern Ireland, said: “Obesity is one of the most important public health challenges in Northern Ireland, with 65 per cent of adults either overweight or obese. Being overweight or having obesity increases the risk of type 2 diabetes, heart attacks and strokes.
“It’s vital that the Northern Ireland Executive’s new 10-year obesity prevention strategy addresses the root causes of obesity so that more people in Northern Ireland can live long and healthy lives free of heart and circulatory conditions.”
Why does obesity lead to an increased risk of diabetes and how to combat it?
Being overweight stresses the insides of individual cells. Specifically, overeating stresses the membranous network inside of cells called endoplasmic reticulum (ER). When the ER has more nutrients to process than it can handle, it sends out an alarm signal telling the cell to dampen down the insulin receptors on the cell surface. This translates to insulin resistance and to persistently high concentrations of the sugar glucose in the blood - one of the clear indicators of diabetes.
To prevent obesity, cut sugar and refined carbs from your diet as the resulting rise in blood sugar stimulates the pancreas to produce higher levels of insulin.
Over time, this can lead to progressively higher blood sugar and insulin levels, until the condition eventually turns into type 2 diabetes.
It is also a good idea to work out regularly, avoid a sedentary lifestyle and remain adequately hydrated.
Exercise increases the insulin sensitivity of your cells. So when you exercise, less insulin is required to keep your blood sugar levels under control. Quitting smoking is also a massive factor in diabetes reduction, as is a low-carb diet which will mean your insulin levels won’t rise much after you eat. You should also think about watching portion sizes and increase fibre and vitamin D intake.
How to reduce your risk of heart attack and stroke
Certain factors can increase your risk, such as smoking, kidney disease or a family history of early heart disease. Knowing your risk factors can help you and your health care team decide on the best treatment plan for you. Many risk factors can be improved with lifestyle changes.
Again, eating a healthy diet full of fruit and vegetables is key, as is reducing refined crabs and processed meats. Being more physically active, watching your weight, ditching the cigarettes and managing conditions such as high blood pressure (hypertension) and high cholesterol are also important. Minimising stress, getting enough sleep and looking after your mental health are also important factors to consider.
If you have a health condition, your doctor may prescribe statins or other medications to help control cholesterol, blood sugar and blood pressure. Take all medications as directed. But don’t take aspirin as a preventive measure unless your doctor tells you to. If you’ve never had a heart attack or stroke, a daily aspirin may not help you at all and could cause problems including risk of bleeding. If you’ve had a heart attack or stroke, your doctor may want you to take a low dose of aspirin to reduce your risk of having another.
The bottom line?
Healthy living is the best way to delay or avoid many heart and brain diseases. Take charge of your health and create healthy habits you can sustain each day in order to mitigate against heart disease and stroke.