Director of Public Health Annual Report 2022: Preventing heart disease and stroke in Buckinghamshire

2.2 Clinical risk factors

2.2.1 High blood pressure

High blood pressure (also called hypertension) affects more than one in four adults and increases the risk of stroke, heart disease, kidney failure and some types of dementia.

Surveys suggest that 30% of men and 26% of women have high blood pressure and the prevalence increases with age, rising to more than 50% in people aged over 60 years. It is more common in men than women up to the age of 65 years. High blood pressure is more common in people of South Asian, black African, black Caribbean or Irish ethnicity and people who have a relative with high blood pressure. People living in the most deprived areas are 30% more likely to have high blood pressure compared to people living in the least deprived areas.

High blood pressure is responsible for 12% of all visits to GPs with an estimated annual cost to the NHS of over £2 billion.

In England, only 57% of the estimated number of adults who have high blood pressure have had it detected, and only 56% of people under 80 who have been diagnosed with high blood pressure have achieved the NICE recommended target of BP of 140/90 mmHg.

Modifiable factors that increase the risk of high blood pressure include being overweight, being insufficiently active, eating an unhealthy diet containing too much salt and not enough fruit and vegetables, drinking too much alcohol and smoking.

The higher the blood pressure the higher the risk of harm. Each 2mmHg rise in systolic blood pressure is associated with a 7% increase in deaths from heart disease and 10% increase in deaths from stroke. High blood pressure can be reduced by drug treatment. Reducing salt in food, eating healthily, drinking less alcohol, being more physically active and losing weight if overweight can also help to reduce blood pressure. Research suggests that for every 10mmHg reduction in blood pressure the risk of heart disease and heart failure reduces by 17% and 28% respectively and the risk of stroke reduces by 27% and deaths from all causes reduce by 13%.

Detecting high blood pressure

People with high blood pressure may not know they have it because they may not have any symptoms. The only way to detect high blood pressure is through a simple measurement using a blood pressure machine. The longer high blood pressure goes undiagnosed or uncontrolled, the greater the risk of harm to health.

Residents who are aged 40 to 74 years are eligible for the NHS Health Check once every five years. This checks for high blood pressure and other risk factors for heart disease and stroke and staff can give advice to promote a healthier life and refer to behaviour change or other services.

High blood pressure and COVID-19

High blood pressure is linked to higher risk of serious illness if someone develops COVID-19.51 Some studies suggest that people with high blood pressure are more at risk of getting seriously ill with and dying of COVID-19. Research into the link between high blood pressure and COVID-19 is ongoing. However, people with untreated high blood pressure seem to be more at risk of complications from COVID-19 than those whose high blood pressure is managed with medication.

During the COVID pandemic, an estimated 49,208 fewer people in the Buckinghamshire, Oxfordshire and Berkshire West (BOB) area had their high blood pressure managed to the target level. This means for the BOB area that there is now the risk for an extra 736 heart attacks and strokes over the next three years.

2.2.2 Diabetes

Diabetes is one of the most common chronic diseases in the UK with 4.1 million people living with a diagnosis of diabetes and a further 850,000 people estimated to be living with diabetes but not yet diagnosed. Diabetes diagnoses have doubled in the last 15 years, and 13.6 million people are estimated to be at risk of developing diabetes in future.

Diabetes comprises a group of disorders characterised by persistently raised levels of sugar in the blood. There are two main types of diabetes – the most common is type 2 accounting for nine in ten cases. Type 1 and type 2 diabetes are both associated with an increased risk of cardiovascular disease and other health problems.

People with type 2 diabetes have double the risk of cardiovascular disease, such as heart attack, heart failure and stroke, and have an increased risk of other problems, including loss of sight, and kidney disease. The life expectancy of people with type 2 diabetes is reduced by up to ten years.

There are several risk factors that may make someone more likely to be diagnosed with type 2 diabetes – a combination of characteristics people are born with and features of our environment and behaviours. The main modifiable risk factor for type 2 diabetes is being overweight or obese, which accounts for 80-85% of the overall risk. Being overweight is associated with a three-fold increased risk and being obese is associated with a seven-fold increased risk of diabetes compared to people of a healthy weight. Another contributor is higher levels of sedentary behaviour, which itself is associated with a two-fold increased risk of diabetes. A further predictor of future type 2 diabetes diagnosis is elevated blood sugar levels during pregnancy – gestational diabetes. Gestational diabetes is associated with a seven-fold increased risk of type 2 diabetes in later life.

Diabetes is also a significant contributor to health inequalities. People of Asian, African, and Afro-Caribbean ethnicity have up to a three to six times increased risk of type 2 diabetes compared to people of white ethnicity, and their risk of developing type 2 diabetes increases earlier from age 25 compared to from age 40 for people from white groups. Nationally, people living in the most deprived areas are 2.5 times more likely to develop diabetes compared to people in the least deprived areas. People with diabetes living in the most deprived areas are also three times more likely to develop serious complications from diabetes.

It is estimated that more than half of cases of type 2 diabetes can be prevented or delayed. People can reduce their risk of developing diabetes by (1) eating a healthy diet, such as one that is high in fibre and with a low glycaemic index (the glycaemic index is a rating of how quickly carbohydrate foods affect blood sugar levels. Low index foods are broken down more slowly, thereby causing more gradual rises in blood sugar levels); (2) being more physically active (not sitting for long length periods of time and being physically active in line with national guidelines); and (3) losing weight if overweight. The NHS Diabetes Prevention Programme (DPP) was launched in 2016 and aims to provide personalised support to people at risk of developing type 2 diabetes, such as adults with a fasting plasma glucose between 5.5-6.9 mmol/L or with a history of gestational diabetes. Individuals can find out if they are at risk and register for the DPP on the Healthier You website.

2.2.3 Cholesterol

Cholesterol is the main fat found in the blood. Elevated levels of total cholesterol (above 5mmol/L) causes narrowing of the arteries with fatty deposits leading to cardiovascular disease. There are two important types of cholesterol – high density lipoprotein (HDL) or non-high density lipoprotein (non-HDL). It is now known that non-HDL cholesterol, rather than low density lipoprotein (LDL) cholesterol specifically, is the key risk factor for cardiovascular disease (NICE, 2021). For these purposes the terms are interchangeable. Non-HDL cholesterol is often referred to as ‘bad’ cholesterol, and a raised level (above 4mmol/L) is also an important cause of atherosclerosis. HDL cholesterol is often referred to as ‘good’ cholesterol as it has a protective role against cardiovascular disease. However, the beneficial effects of ‘good’ cholesterol may only occur up to a certain level (approximately 1.4mmol/L), and extremely high levels (above 2.3mmol/L) may also be harmful.

High levels of ‘bad’ cholesterol are estimated to cause one quarter of cardiovascular disease in Buckinghamshire.

In the majority of cases, high cholesterol levels are due to a combination of environmental factors and health behaviours, including a diet high in saturated fat, low levels of exercise, smoking and drinking excess alcohol, although the specific relationships with ‘good’ and ‘bad’ cholesterol may vary. For example, evidence has shown that, within reasonable limits, the more someone is active the more they can raise their ‘good’ cholesterol; but more intense activity may be needed in order to start reducing ‘bad’ cholesterol levels. Other risk factors for high cholesterol levels include being male, being from a South Asian background and being older.

It is estimated that one in 250 people have a genetic condition called familial hypercholesterolaemia (FH) which results in high cholesterol levels. If untreated half of men and one third of women with FH develop coronary heart disease by the time they reach 55 years old, but if FH is identified and treatment started early enough people with FH can have the same life expectancy as the general population.