Key points

• Every year, approximately 40,000 people receive specialist healthcare services related to angina or myocardial infarction; 16,000 for heart failure; and 11,000 for stroke.
• A fifth (21 per cent) of the entire population currently lives with established cardiovascular disease or with a high risk of developing the disease. Approximately 1.1 million Norwegians use therapeutic drugs to either prevent or treat cardiovascular disease.
• The number of new cases of myocardial infarction per 100,000 inhabitants per year is declining. Of those affected, fewer people are suffering serious myocardial infarction.
• The reduction in smoking and improvements in treatment account for much of the decline in the number of new cases of infarction.
• Among those with low education, a higher proportion experience myocardial infarction than among those with higher education.
• Mortality due to cardiovascular disease has shifted to higher age groups in the population. Half of all deaths occur after the age of 83 years among men and after 89 years among women.
• The number of people with cardiovascular disease will increase in the future.

About cardiovascular disease

The most frequent cardiovascular diseases are angina pectoris (angina), myocardial infarction, heart failure and stroke, and these diseases are the topic of this document.

Morbidity is mainly associated with atherosclerosis, a process which results in fatty deposits, narrowing and blockage (blood clots or thrombosis) of the vessel wall.

Data materials

Mortality and prevalence of cardiovascular diseases are ascertained using statistics from the Norwegian Cause of Death Registry, the Norwegian Cardiovascular Disease Registry and the Norwegian Prescription Database.

Trends in myocardial infarction morbidity are based on research data of hospital discharge diagnoses collected from every hospital in Norway (Sulo, 2013; Sulo, 2018). 

Trends in different types of myocardial infarction are based on the Tromsø Health Survey, which uses an infarction registry with validated diagnoses (Mannsverk, 2016), together with results from international research (Rosamond, 2012; Yeh, 2010).

Current situation and trends

In the following, we describe the status and trends in new cases of myocardial infarction and the proportion of people who currently live with cardiovascular disease and/or receive treatment for cardiovascular disease in Norway. This is followed by a discussion of mortality due to these diseases.

Number of people being treated by the health service

The large number of people receiving preventive treatment or living with a chronic cardiovascular disease results in many primary and specialist health services consultations.

Patients in the primary health service:

• In 2016, approximately 515,000 people in the age range 0 – 74 years were in contact with a GP or emergency medical clinic due to cardiovascular disease (Norway Control and Payment of Health Reimbursement Database - KUHR).

Patients evaluated in specialist health services:

• In 2016, just under 40,000 patients were admitted to hospital or received outpatient treatment with a primary diagnosis of myocardial infarction or angina pectoris; see Table 1. Of these, 11,401 patients had acute myocardial infarction, according to figures from the Norwegian Cardiovascular Disease Registry.
• A total of approximately 60,000 people had an outpatient consultation or were admitted to hospital due to ischemic heart disease (myocardial infarction or angina), as either their primary or secondary diagnosis. See also statistics from the Norwegian Cardiovascular Disease Registry’s statistical database.

Table 1. Number of patients with outpatient consultation in the specialist health service or admitted to hospital in 2016 for cardiovascular disease. The table shows selected primary diagnoses. Source: Norwegian Cardiovascular Disease Registry, 2016.

Number of patients with primary diagnosis
Primary diagnosis	Number
Heart failure	16,638
Stroke	11,330
Acute myocardial infarction (heart attack)	11,401
Total myocardial infarction (heart attack) and angina pectoris	39,102*

*Of these, 11,504 were treated by widening coronary arteries.

Therapeutic drug users

The number of people using therapeutic drugs to treat or prevent cardiovascular disease has increased over time. Population growth, an ageing population and improved survival rates for cardiovascular disease are factors that have contributed to this increase.

• The proportion of the population using at least one therapeutic drug to treat or prevent cardiovascular disease has increased from 18 per cent in 2005 to 21 per cent in 2016. In 2016, there were approximately 1.1 million users of these drugs; see Figure 1.

The proportion increased in all age groups; see Figure 2a.

• In the age group 70-74 years, two thirds (67 per cent) used drugs to treat or prevent cardiovascular disease in 2016.
• In the age group 40 – 44 years, the proportion was 10 per cent (Source: Norwegian Prescription Database).

The figures include drugs under drug code C, which are primarily used to treat high blood pressure (hypertension) or high cholesterol levels in patients with known cardiovascular disease (secondary prophylaxis) or to prevent cardiovascular disease (primary prophylaxis). Drugs to combat blood clots are not included (ATC code B01), but most people who take such medicines also take at least one cardiac medicine (ATC code C). 

Many people take therapeutic drugs for high blood pressure and high cholesterol. During the period 2005 to 2016, there was an increase in both the proportion of those using blood pressure drugs (ATC codes C02, C03, C07, C08 and C09) and the proportion using cholesterol-lowering drugs (ATC code C10).

• Antihypertensive drugs: In the age group 70-74 years, 57 per cent used such drugs in 2016, while in the 40-44 year group, the proportion was 7 per cent; see Figure 2b (Source: Norwegian Prescription Database). 
• Cholesterol-lowering drugs: the proportions in 2016 were 40 per cent and 3 per cent respectively in the 70-74 year group and 40-44 year group; see Figure 2c (Source: Norwegian Prescription Database).

Decline in number of new cases of myocardial infarction per year

The number of new cases of myocardial infarction per 100,000 inhabitants has declined from 2001 to 2014: a decline of 29 per cent for men and 32 per cent for women of all age groups combined (Sulo, 2018).

See Figures 3, 4 and 5 which show the trend in new cases of myocardial infarction for men and women in different age groups. As the figures show, the number of cases per 100,000 per year has decreased.

In the youngest age groups in the age range 25 to 44 years, fewer people are suffering a first-time infarction. In an earlier analysis for the period 2001 to 2009, there was not the same positive trend for the under-45 age group (Sulo, 2013). The trend had flattened out and the risk was perhaps on the rise. The updated analysis up to and including 2014 showed a positive trend, but the decline began around 2009. New data indicates that also this age group is exhibiting a positive trend. During the period 2009 to 2014, the decrease was 5.3 per cent per year for men and women combined; see Figure 6 (Sulo 2018).

Additional Figure 6 shows new cases of myocardial infarction in the age group 25-44 years. Age-adjusted rates per 100,000. Source: CVDNOR project, Norwegian Institute of Public Health and University of Bergen.

More men are affected

In all age groups, we can see that more first myocardial infarctions concern men than women, measured per 100,000 inhabitants per year. A study from the Tromsø survey analysed whether risk factors such as blood pressure and cholesterol could explain these gender differences but found no satisfactory explanation (Albrektsen, 2016). 

More people living with cardiovascular disease

The number of people living with cardiovascular disease among the population depends on several factors, including the prevalence of risk factors, the number of new people affected, and the age at which the disease first occurs. In addition, the number of people living with cardiovascular disease reflects the effectiveness of the treatment, with improvements in treatment resulting in more people surviving the disease and fewer dying prematurely.

Today, many people live with a cardiovascular disease or with risk factors such as high blood pressure, high cholesterol and/or diabetes. This is reflected in the high number of individuals taking therapeutic drugs: see Figures 2a-c above.

The number of people with cardiovascular disease will increase in the future

The decrease in the number of new cases of myocardial infarction in recent decades has been outweighed by a higher absolute number of elderly people in the population. In the years ahead, it is expected that:

• Both the proportion and number of people living with cardiovascular disease will increase. One fifth (21 per cent) of the entire population is currently living with established cardiovascular disease or at a high risk of developing such a disease, assessed on the basis of using at least one cardiovascular drug.
• Patients will become older. Since other diseases also increase with age and are treated more effectively than before, patients with cardiovascular disease will, increasingly, also have other health problems.

The increased prevalence of cardiovascular disease is due to:

• An ageing population. Most people who suffer an infarction are over 60 years of age. The number of new cases of cardiovascular disease is expected to increase as the post-war generation ages. By 2025, all the cohorts born during the period 1945 to 1955 will have passed 70 years of age.
• A relatively higher proportion of the population suffer less severe myocardial infarction or other cardiovascular disease, thereby increasing the years living with a cardiovascular disease (Mannsverk, 2016). A few years ago, many of these patients would have died.
  The survival rate for stroke has also improved (NIPH, 2017).

Mortality: sharp decline

Mortality for cardiovascular diseases in Norway peaked in 1970 and has since declined. 

The decline is particularly marked for myocardial infarction in the oldest age group over 75 years; see Figure 5a. There was also a decline in the age group 45-74 years.

From 2000 through to the present day, mortality for myocardial infarction and other ischemic heart diseases has more than halved in the population. Figures 7a and /b show mortality from myocardial infarction and stroke from 1990 to 2018.

 See the table and more details in Norhealth’s statistical database.

Men have higher mortality due to myocardial infarction than women. Gender differences regarding mortality have decreased since 2000 in both the under and over 75 year age groups, see figure 7a.

For strokes, see Figure 7b below.

See the table and more details in Norhealth’s statistical database.

Cardiovascular diseases have long been the group of disease which causes the most deaths when we consider all age groups combined. Today, cancer is almost as frequent a cause of death as cardiovascular disease. See also the section on disease burden.

As fewer people than before die from cardiovascular disease in the younger age groups, the deaths are "delayed” to the older years. Table 2 shows that the median age for death rose by more than two years from 2000 to 2016.  

Table 2. Median age of death caused by cardiovascular diseases in Norway in 2000 and 2016. 'Median age' means that half of people died before and half after this age. 'Interquartile variation' is the age range for the middle 50 per cent of deaths (25-75 %). Source: Norwegian Cause of Death Registry.

	2000		2016
	Median  ages	Interquartile  variation	Median  ages	Interquartile  variation
Men	80.0 years	73.0 - 85.6 years	82.6 years	72.4 - 88.9 years
Women	85.2 years	79.8 - 89.8 years	88.9 years	82.7 - 93.3 years

Differences in mortality between counties and health regions

Historically, northern Norway (particularly Finnmark) has had higher cardiovascular mortality than the national average. Mortality has been lowest in Western Norway. These differences are now much less marked than they were earlier. Figure 8a below shows the trends for men and women separately in the country as a whole and in the health regions.   

See the table and more details in Norhealth.

Causes of the decline in mortality 

Causes of the decline in mortality rate due to myocardial infarction and other ischaemic heart diseases:

• Reduction in risk factors: The proportion of smokers has decreased markedly; see Norhealth.no and  the report on intoxicants in Norway in 2016 for figures before 1997. In addition, results from both the Tromsø survey and the Health Survey in Nord-Trøndelag (HUNT) indicates that both cholesterol and blood pressure levels have fallen (Hopstock 2015; Hopstock 2017; Krokstad, 2011). These are key risk factors for myocardial infarction (Manssverk, 2016). The overall change in risk factors for myocardial infarction during the period 1994 to 2008 explained 66 per cent of the decline in new cases of myocardial infarction, according to figures from the Tromsø survey (Mannsverk, 2016).
• Fewer people have severe heart disease: A higher proportion of patients who receive treatment for myocardial infarction have less severe infarctions. The proportion of patients with a severe infarction (and therefore high mortality) fell during the period 1995 to 2010, according to figures from the Tromsø survey (Mannsverk, 2016). This may be due both to better prevention and the fact that myocardial infarctions are being identified at an earlier stage due to better diagnostic methods (Mannsverk, 2016).
• Medical and technological advances such as new drugs for treatment and primary and secondary prevention, better non-drug treatment methods, such as unblocking of the coronary arteries, and improved logistics for faster emergency medical treatment have undoubtedly been key factors behind the decline in mortality due to cardiovascular disease.
• Higher survival rates. Fewer people die of myocardial infarction both in and outside hospitals. This applies to all age groups. The trend towards more people having less severe heart disease is a key part of the reason why mortality has fallen in every age group (Mannsverk, 2016; Yeh, 2010).  

Social health differences 

There are major educational differences in the number of new cases of acute myocardial infarction. Analyses of figures from the CVDNOR project from the period 1994 to 2009 have shown that individuals with low education are more likely to suffer myocardial infarction and more likely to suffer a fatal myocardial infarction than those with a high education (Igland, 2014, Igland 2014).  

Mortality has declined in all education groups, but the gap between those who have completed only a lower secondary education and those who have any college or university education is still considerable; see Figures 9a and 9b.

As the figures show, there has been a particularly steep decline in mortality due to cardiovascular disease among individuals with a high education. The decline has not been as marked in the other education groups. This also applies to other diseases where smoking is an important risk factor, such as COPD and lung cancer (Strand, 2014).

People with a high education tend to smoke less, be more physically active and have lower blood pressure and obesity rates compared with those with a low education. This is according to figures up to 2008 from the Health Survey in Nord Trøndelag (HUNT) and the Tromsø survey (Eggen 2014; Ernstsen 2012). These education-related differences in risk factors are a major factor in explaining the education-based differences in mortality due to myocardial infarction (Strand, 2004).

Comment regarding Figure 9a: It is apparent that the inequality between the education groups overall peaked during the 1990s. It is also apparent that several diseases create the differences (see the colour codes). During the 1960s, there was no clear primary cause. During the next decade, mortality due to cardiovascular disease led to the steadily increasing inequalities between the education groups. During the 2000s, differences in cardiovascular mortality remained significant, but were less marked than during the previous decade. 

Comment regarding Figure 9b: It is apparent that the difference between the education groups overall peaked during the 2000s. It is also apparent that several diseases create the differences (see the colour codes). During the next decade, mortality was due to cardiovascular disease which led to the considerable inequalities between the education groups. During the 2000s, the importance of death due to cardiovascular disease has declined slightly. However, the importance of lung cancer and COPD has increased.

Heart disease, COPD and lung cancer are diseases where smoking is a key risk factor. Different smoking habits within low- and high-education groups are likely to be a particularly important factor behind the social inequalities in mortality in Norway (Mackenbach, 2008; Mackenbach, 2016; Strand, 2010; Strand, 2014). A decline in smoking will therefore help to improve public health, particularly in groups with a low education.

Cardiovascular diseases in the Sami population

The SAMINOR health survey was conducted in municipalities with Sami, Kven and Norwegian populations in 2003-2004, with 61 per cent of those invited taking part. The data on the prevalence of cardiovascular disease are self-reported.

• There were no differences between those with Sámi and non-Sámi backgrounds as regards the proportion with previous myocardial infarction and stroke (Eliassen, 2016; Eliassen, 2015).  
• A higher proportion of Sámi than non-Sámi reported angina pectoris and chest pain (Eliassen, 2014).
• The known risk factors for cardiovascular disease were at approximately the same level among the Sámi and non-Sámi populations (Eliassen, 2015).  

Cardiovascular diseases among immigrants in Norway

There is considerable variation in risk between immigrant groups. Some immigrant groups in Norway are at lower risk of suffering cardiovascular disease than the population as a whole, while other groups are at greater risk:

• Immigrants from South Asia (India, Pakistan, Bangladesh, Sri Lanka, Nepal, Bhutan and Myanmar) are at considerably greater risk of suffering both myocardial infarction and stroke compared with the ethnic Norwegian population (Rabanal, 2015).
• Immigrants from the former Yugoslavia are also at greater risk of suffering myocardial infarction. Men in this group are also at greater risk of stroke (Rabanal, 2015).
• Immigrants from East Asia are at less risk of contracting cardiovascular disease than the ethnic Norwegian population (Rabanal, 2015).
• With regards to risk factors in many immigrant groups, few people have raised blood pressure and few smoke, particularly among women. This is offset by an increased tendency to be overweight and physically inactive, as well as a greater tendency to develop diabetes, among the same groups (Kumar, 2009; Rabchannel, 2013).

• See the chapter: Health in the immigrant population

Internationally: Norway on a par with the Mediterranean countries for mortality

During the 1970s, cardiovascular mortality in Norway was among the highest in the world. This situation has changed dramatically, and Norway is now on a par with the Mediterranean countries. See Figures 10a and b, which present a comparison between certain European countries for the age group under 65 years.

Mortality due to cardiovascular diseases is falling in most European countries but remains considerably higher in central and eastern Europe than elsewhere in Europe (Nichols, 2012).

Globally, one in four deaths is due to myocardial infarction or stroke. On a global scale, myocardial infarction and stroke are the two principal causes of death, years of life lost and loss of disability-adjusted life years (DALY) (Lozano, 2012; Murray, 2012). (GBD 2015 DALYs and HALE Collaborators, 2016; GBD 2015 Mortality and Causes of Death Collaborators, 2016).

Risk factors and prevention

Risk factors for cardiovascular disease have been summarised by the World Health Organization (WHO, 2011). The Norwegian Directorate of Health has adopted these in the National guidelines for the prevention of cardiovascular diseases (Directorate of Health, 2017).  

The key risk factors are:

• tobacco smoking
• high blood pressure
• high cholesterol
• diet: a diet low in sugar, low in red meat, and with frequent consumption of fish, white meat, fruit, vegetables, legumes, nuts and olive oil are linked to lower prevalence of cardiovascular disease (Estruch, 2013; Mozaffarian, 2016).
• low level of physical activity
• diabetes
• overweight
• high alcohol consumption increases the risk of high blood pressure and stroke, although it is still debated whether regular low consumption can protect against myocardial infarction (Lidal, 2013).
• family history/hereditary conditions
• high age
• being male
• ethnicity, see the separate section above

When multiple risk factors occur simultaneously, they often increase the risk by far more than their sum would imply (Selmer, 2017). See the NORRISK 2 risk model (Norwegian) and the NORRISK figure (English).

The risk factors for stroke are much the same as for myocardial infarction, but with this disease, blood pressure and atrial fibrillation play a more important role, while blood cholesterol is less important (Vangen-Lønne 2017). Smoking is a very important risk factor for both stroke and myocardial infarction.

The main risk factors for heart failure are previous myocardial infarction, high blood pressure and heart valve disease, atrial fibrillation, diabetes and obesity.

Future challenges 

Cardiovascular diseases remain a major public health problem, even though there has been a positive trend in mortality and a decline in the number of new cases (per 100,000 inhabitants per year) in age groups over 45 years. Many people live with symptoms or illness and diagnoses, treatments and check-ups consume a lot of the health service’s resources.

Social inequalities in cardiovascular diseases indicate that we face challenges in this regard too, yet there are also opportunities as regards prevention. Inequalities between education groups are mainly due to higher levels of risk factors in groups with a lower socioeconomic status (Strand, 2004).

Among efforts aimed at prevention, instruments targeted at the entire population, such as the Smoking Act, will help to reduce social inequalities in health. There is likely to be considerable untapped potential in other structural interventions that can improve people’s diet and make the population more active. 

Norway has signed up to the WHO’s goals to combat non-communicable diseases. The aim is to reduce premature deaths (before 70 years) caused by non-communicable diseases by 25 per cent by 2025, compared with 2010. ‘Non-communicable diseases’ is an umbrella term for cardiovascular diseases, cancer, diabetes and chronic obstructive pulmonary disease. These diseases have several common risk factors: tobacco use, poor diet, physical inactivity and harmful alcohol consumption. There was a decrease of 18 per cent in such premature deaths during the period 2010 to 2015. Norway is on track to achieving the goal of a 25 per cent reduction by 2025.

In Norway, the positive trend in the population for the risk factors of smoking, cholesterol and blood pressure has to some extent been counteracted by the increase in prevalence of overweight and obesity (2016).