Cardiovascular disease in Norway
Cardiovascular disease is a term that covers several diseases, including angina pectoris, myocardial infarction, heart failure and stroke.
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- Mortality from cardiovascular disease is declining in all age groups.
- New cases of myocardial infarction (heart attacks) have decreased in the over-65 age group.
- There is a worrying increase in hospital admissions for younger adults who experience their first heart attack.
- The number of patients with cardiovascular disease may rise because of an ageing population and improved survival following acute illness.
- Cardiovascular disease causes most deaths when all age groups are combined, but cancer causes most deaths in the ages below 80 years.
- There has been a decrease in cholesterol levels, blood pressure and smoking, but more people are overweight.
- Small changes in lifestyle and diet can make a big difference.
About cardiovascular disease
Cardiovascular disease is a term that covers several diseases, including angina pectoris, myocardial infarction, heart failure and stroke. Morbidity is mainly linked to atherosclerosis, a process that causes narrowing and clogging of the coronary arteries, which are the blood vessels that bring oxygen to the heart musculature. Ischaemic heart disease means that the tissues are damaged by lack of oxygen.
Current situation in Norway
Mortality and the incidence of cardiovascular diseases are studied using statistics from the Norwegian Cause of Death Registry and the Norwegian Cardiovascular Disease Registry. Trends in heart attack morbidity are based on a research project that uses discharge diagnoses collected from every hospital in Norway.
In 2012, ischaemic heart disease (acute coronary heart disease, myocardial infarction, chronic coronary heart disease or angina) was the primary or secondary diagnosis for 66,029 patients with an outpatient consultation or hospital admission. Of these, 26,102 patients had this as the main diagnosis, see Table 1. Patients with cardiovascular disease constitute a large proportion of outpatient consultations and hospital admissions.
|Number of patients with primary diagnosis|
|Heart failure (reduced function of the heart musculature)||7550|
|Stroke (ischaemic stroke or intracranial bleeding)||10672|
|Acute myocardial infarction (heart attack||11888|
|Ischaemic heart disease ( all acute and chronic coronary heart disease combined)||26102|
|Myocardial infarction and angina treated with coronary angioplasty||10304|
The age distribution of patients with ischaemic heart disease is evident from Figure 1.
|Figure 1. Number of patients examined in an outpatient clinic or admitted to specialist health service in 2012 with ischaemic heart disease (heart attack, chronic coronary heart disease or angina) as a primary or secondary diagnosis, men and women. Source: Norwegian Cardiovascular Disease Registry.|
Most patients admitted to hospital survive
99 per cent of patients under 50 years were still alive 28 days after admission to hospital with a heart attack, whereas the survival rate was 97 per cent for those aged 50 to 70 years and 84 per cent for those over 70 years (Norwegian Cardiovascular Registry in 2012).
20 per cent of those who experience their first heart attack die before arriving at hospital (Sulo, 2013).
Cardiovascular disease causes most deaths when we look at all age groups combined. Many of those who die do so in old age, especially women. 5975 men and 7035 women died from cardiovascular disease in Norway in 2013, see Table 2.
Deaths from cardiovascular diseases, men
Deaths from cardiovascular diseases, women
We see the following trends:
- Mortality from cardiovascular disease has fallen in the last 40 years.
- For acute heart attacks, we see a worrying trend among young adults, measured by the number of admissions to hospital for first time cases per 100, 000 people.
- Among the elderly, the number of first time cases has decreased.
- The total number of patients with chronic or past cardiovascular disease may rise due to an ageing population and improved survival after acute illness.
- There is a strong decline in mortality from cardiovascular disease in all parts of the country
Mortality from cardiovascular disease peaked in Norway in 1970 and has since fallen. This trend has continued, and from 2000 until today, the mortality rate was almost halved, see Figure 2.
|Figure 2: Mortality from cardiovascular diseases 2000-2012. Age-adjusted rates per 100,000 individuals per year. Source: Norwegian Cause of Death Registry.|
Worrying heart attack trend among younger adults
Regarding the first time cases of acute myocardial infarction, for all age groups combined there has been a decrease of 24 per cent from 2001 to 2009 (Sulo, 2013). The decline conceals differences among different age groups, see Figure 3a-d.
In the age group 25-44 years there is no decline from 2001, see Figure 3a.
Closer inspection shows that there was a decrease in the number of deaths outside hospitals at all ages, even in the 25 to 44 year age group, but here the number of hospital admissions for first-time heart attacks increased by 11 per cent from 2001 to 2009 (Sulo, 2013) (not shown in figure).
This suggests that the decline in mortality among younger adults is because more survive their infarction, probably due to more effective treatment, and because heart attacks have become less severe over time. The concern is that these diseases have not fallen, as they have among the elderly.
Changes in trends in cardiovascular disease have previously been seen only among younger adults, so the figures in this age group are important.
An analysis which includes multiple heart attacks confirms the concern about trends in the under-65 age group (Sulo, 2014).
The diagrams below show four different age groups:
|Figure 3a. No decline in the age group 25-44 years, levelling off in the age group 45-64 years. Incidence rates per year for acute myocardial infarction for women and men, 25-44 years and 45-64 years. Age-adjusted. Source: Sulo|
|Figure 3b. Decrease in the age group 65-84 years and in the over-85 year age groups. Incidence rates for acute myocardial infarction for women and men, 65-84 years and 85+ years. Age-adjusted. Source: Sulo|
Differences between groups in the population
Geographical differences are decreasing
Historically, northern Norway (particularly Finnmark) has ranked high, while cardiovascular diseases have been lowest in western Norway. This has now evened out more, and in 2012 there were only small differences between the regions, see Figure 2.
Gender differences are decreasing
At every age, men have higher death rates than women, but the gender gap has diminished since 2000, see Figure 2.
Large social inequality in mortality from cardiovascular diseases
The social inequality in mortality from cardiovascular diseases is significant and the gap has increased in recent decades. There is a decline in all subgroups by education, but the decline has been most steep among people with higher education (Strand, 2010).
Some groups of immigrants have a lower risk of cardiovascular disease than ethnic Norwegians, but the picture is mixed (Kumar & Selmer, 2009). Among women in many immigrant groups, few smoke or have elevated blood pressure, but in some groups this is countered by an increased tendency to obesity, physical inactivity and diabetes (Rabanal, 2013).
One in four deaths due to heart attack or stroke globally
In the 1970s, cardiovascular diseases in Norway were among the highest in the world. This picture has changed drastically. Now Norway is on par with the Mediterranean countries, see Figure 4a-b.
|Figure 4a: Mortality from ischaemic heart disease in Slovakia, Greece, Finland, Norway, Spain and France, women 0-64 years. Source: WHO HFA database.|
|Figure 4b: Mortality from ischaemic heart disease in Slovakia, Greece, Finland, Norway, Spain and France, men 0-64 years. Source: WHO HFA database.|
Cardiovascular diseases are the main cause of loss of disability-adjusted life years (DALY) and premature death globally (Murray, 2012; Lozano, 2012). Globally, one in four deaths is due to heart attack or stroke. Mortality from cardiovascular disease is falling in most European countries, but is still considerably higher in Central and Eastern Europe than in the rest of Europe (Nichols, 2012).
Risk factors for cardiovascular disease
The risk factors for cardiovascular disease are assessed by a committee of the World Health Organization (WHO, 2011) that has reviewed existing scientific knowledge (WHO 2010 Ezzati, 2012). The WHO report was followed up by the Norwegian Directorate of Health in 2013.
The main risk factors for coronary heart disease are (Norwegian Directorate of Health, 2013):
- tobacco smoking
- diet with a lot of saturated fat and trans fats (which increase blood cholesterol) and high intake of sugary drinks
- high salt intake (which increases blood pressure) and low intake of fruits and vegetables
- physical inactivity
- diabetes and obesity
- high alcohol intake
Small changes in diet and lifestyle can have a major impact over time. A diet low in sugar, low in red meat, and with frequent consumption of fish, white meat, fruit, vegetables, legumes, nuts and olive oil led to lower incidence of cardiovascular disease in a study (Estruch 2013).
When multiple risk factors occur simultaneously, they increase the risk far more than their sum would imply, see Figure 5a-b.
|Figure 5a: 10-year risk of death from cardiovascular disease based on the NORRISK risk model, men 60 years. Source: Selmer, 2008; Norwegian Directorate of Health, 2009.|
|Figure 5b: 10-year risk of death from cardiovascular disease based on the NORRISK risk model, women 60 years. Source: Selmer, 2008; Norwegian Directorate of Health, 2009.|
The risk factors for stroke are largely the same as those for heart attacks, but blood pressure and atrial fibrillation have more important roles.
Decline in key risk factors, but not in obesity and diabetes
Estimates from Sweden have concluded that the decrease in blood cholesterol, blood pressure and smoking are the main reason for the decline in mortality from heart attacks from 1986 to 2002 (Björck, 2009).
From 1974 to 2002, blood pressure and blood cholesterol levels declined across Norway (Jenum, 2007) and studies in Nord-Trøndelag (Krokstad, 2001) and Tromsø (Eggen, 2014) show a continued decline from 1990 to around 2008. However, the positive trend development is opposed by an unfortunate trend in body weight, low physical activity and an increasing proportion of the population with type 2 diabetes.
There is evidence that depression (Hare, 2013) and certain types of air pollution increase the risk for cardiovascular disease, and may contribute to deterioration among people who are already affected. A high alcohol intake increases the risk, while a regular, low intake seems to protect against cardiovascular diseases.
Primary and secondary prevention
Cardiovascular disease can be prevented in various ways.
Primary prevention consists of interventions to prevent new cases. If successful, it gives lower health care expenditures and lower loss of health for inhabitants. It is well-documented that the absence of tobacco smoking, a healthy diet, physical activity and low alcohol consumption are likely to prevent both cardiovascular disease, chronic obstructive pulmonary disease (COPD), type 2 diabetes and various cancer types (Norwegian Directorate of Health, 2013).
The most effective are interventions that apply to all, regardless of individual risk (Norwegian Directorate of Health, 2013; Ezzati, 2012). Examples include tobacco legislation, the introduction of low-fat milk and a ban on trans-fatty acids. These interventions affect the general public, including a large group of people with a low to moderate risk, but which has the potential to recruit the majority of tomorrow's patients. Structural interventions counteract social inequality by making it easier to make healthy choices.
Educational measures, such as health campaigns and information on internet, are also important in prevention.
A third type of primary prevention consists of tailored help to individuals with a particularly high risk.
Secondary prevention consists of tailored help to prevent new events or deterioration after the disease has begun. It is important to seek help for rehabilitation if the ability to function is threatened.
Prevention and challenges
Reasons for the decline in mortality: Better treatment or decline in risk factors?
The decline in mortality may be due to fewer new disease cases (healthier lifestyle and prevention), or more effective treatment, or a combination of both.
Medical and technological advances have undoubtedly had an impact on the decline in mortality from cardiovascular diseases. In addition, there has been a sharp reduction in major risk factors for cardiovascular disease since the 1970s.
Calculations of the role of the different factors in the decline in mortality from cardiovascular diseases have not been carried out in Norway. Swedish calculations concluded that more than half of the decline in mortality between 1986 and 2002 could be attributed to a decline in the major risk factors, especially total serum cholesterol.
We do not know how much of the decline in the 2000s is due to changes in risk factors and how much is due to preventive drug use and better medical treatment, such as coronary angioplasty.
In 2013, 40 per cent of people in the 70-79 year age group used cholesterol-lowering medication, while 70 per cent of 80-89 year olds used drugs that are mainly used for high blood pressure (about 85 per, according to a study by Blix, 2012).
The percentage of users of blood pressure and cholesterol-lowering drugs increased over the period 2005-2013.
Still a major public health problem
Cardiovascular diseases are still a major public health problem, even though there has been a positive trend in mortality. It is expected that the absolute this number affected will increase as the post-war generation ages. Improved survival is also expected to increase both the number and proportion of people living with the disease, as shown in Denmark (Koch, 2013).
An expression of this disease burden is that 7550 patients had over 10,000 hospital admissions due to heart failure in 2012 (Norwegian Institute of Public Health, 2014). Heart failure is a life-threatening and distressing condition in which the heart's pumping function is impaired. Heart attacks are the most common cause.
It is unclear how cholesterol and blood pressure levels will evolve, and how long the weight increase will continue. A study from Finland and one from Sweden show an increase in total serum cholesterol since 2007, and in Sweden there was also an increase in the intake of saturated fats (Vartiainen, 2012; Johansson, 2012).
The increase in hospital admissions for heart attacks among young adults is a reminder of the need for prevention. Dr. Hans Stam, President of the European Heart Network, comments:
“Today most public health expenses are linked to treatment. Urgent investment is required in order to improve the health of the European population and to stem the socioeconomic consequences.”
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