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Dementia in Norway

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Between 80,000 and 100,000 people are living with dementia in Norway today. This number will rise with the increasing number of elderly people. The article addresses risk and protective factors that are essential for the development of the disease.

Demens innebærer hukommelsessvikt og blant annet problemer med å huske tid og sted. De fleste som rammes er over 75 år. Livsstilsfaktorer som forebygger hjertesykdom kan også redusere risikoen for demens. Illustrasjon: Folkehelseinstituttet/fetetyper.no
Illustrasjon: Folkehelseinstituttet/fetetyper.no

Between 80,000 and 100,000 people are living with dementia in Norway today. This number will rise with the increasing number of elderly people. The article addresses risk and protective factors that are essential for the development of the disease.


Main points

  • It is estimated that between 80,000 and 100,000 people are living with dementia in Norway.
  • Protective factors appear to be the same as those for cardiovascular disease: healthy diet, physical activity, non-smoking and good control of high blood pressure and cholesterol. A stimulating environment is also important. Diabetes is a risk factor.
  • Measures aimed to prevent cardiovascular disease and diabetes can probably also reduce the number of cases of dementia.
  • Age and genes play a significant role in the development of dementia.

About dementia

Dementia is the generic term for several brain disorders that lead to cognitive decline and other functional impairments. Most dementia cases are related to advanced age, see Table 1.

Dementia develops slowly over time and is incurable. Deterioration occurs faster as the disease progresses. Most patients with dementia die within a ten-year period after diagnosis, either from dementia or from other causes.

Facts: Types of dementia

Alzheimer’s disease is responsible for approximately 60 per cent of all age-related dementia (Qiu, 2007). The disease is associated with deposits of beta-amyloid plaques in the brain that damage the surrounding cells. The disease progresses in different stages.

Vascular dementia is responsible for approximately 20 per cent of cases (Qiu, 2007). Loss of blood supply to parts of the brain causes cells to die. This is often due to clogged blood vessels that have led to repeated heart attacks and strokes or hardening of the arteries (arteriosclerosis) which gradually restricts blood flow. This form of dementia typically progresses more incrementally than Alzheimer's disease and begins more abruptly.

Other forms include Lewy-body dementia and frontotemporal dementia.

There are unclear distinctions between the various dementia types, partly because symptoms for the various types overlap so strongly that it is difficult to give a definite diagnosis. The use of biomarkers and imaging gives a more precise diagnosis. Mixed type cases are very common and constitute perhaps nearly half of all dementia cases (Jellinger, 2010).

Data source

We have little direct knowledge of the prevalence of dementia among the Norwegian population. Estimates based on a large number of studies in Western Europe show a prevalence of 6.9 per cent among people over 59 years (Prince, 2013). Estimates from WHO show that 7.3 per cent of people over 59 who do not live in an institution have dementia (WHO / ADI, 2012).

Between 80,000 and 100,000 have dementia in Norway

Using data from studies in other European countries, Alzheimer Europe found that the prevalence of dementia in Norway was just under 80,000 people in 2013 (Directorate of Health, 2017). This figure is probably too low because many people live with undiagnosed dementia.

Based on WHO figures, there are probably between 80,000 and 100,000 people living with dementia in Norway today. There is reason to believe that these figures are somewhat low, both because general life expectancy has increased and because life expectancy in Norway is somewhat higher than in Europe and the rest of the West.

In Norway, there are good estimates of the prevalence of dementia in nursing homes and among people receiving home care. Just over 80 per cent of those who have long-term care in nursing homes have dementia, and over 40 per cent of those aged over 70 who receive home care have dementia. By combining these figures, it is estimated that there are approximately 71,000 people with dementia among home care recipients and nursing home residents. In addition, there are those who do not receive home services or are in a nursing home.

Age

Prevalence rises sharply with age, from an estimated 1.6 per cent in the 60-64 year age group to 43 per cent among people aged over 90 years (Prince, 2013). Almost every fifth person will die with dementia (Seshadri, 2006).

A minority of people develop dementia before retirement. There are probably over 4000 people aged under 65 who have dementia in Norway (Directorate of Health, 2017).

Table 1. Age- and gender-specific estimates for prevalence of dementia (%) in Western Europe. Based on Dementia. A Public Health Priority, WHO, 2012

Gender

Age

 

60-64

65-69

70-74

75-79

80-84

85-89

90+

60+

Men

1.4

 2.3

 3.7

 6.3

10.6

17.4

33.4

 

Women

1.9

 3.0

 5.0

 8.6

14.8

24.7

48.3

    

All

1.6

 2.6

 4.3

 7.4

12.9

21.7

43.1

7.3

 

More women than men affected

A predominance of women among dementia cases is partly due to higher female life expectancy (table 1). However, prevalence is also higher among women than among men within the same age groups. The percentage difference between the sexes increases with age. Results from a European survey also show that while the gender difference was small until 85 years of age, it was nearly 50 per cent higher among women than among men of the same age after 85 years (Lobo, 2000).

Mortality

Dementia is a progressive and terminal illness, and people with dementia have a shorter life expectancy than the general population.

Estimates made in Norway based on patients assessed for dementia and cognitive symptoms in the specialist health service show that 75-year-olds with dementia live on average 5-6 years after diagnosis. Younger people diagnosed at age 65 live for an average 6-7 years. By comparison, life expectancy in the general population is about 12 years for 75-year-olds and 20 years for 65-year-olds, according to figures for 2016 (Strand, 2019).

2905 people died of dementia in Norway in 2018, most of whom were over 70-years-old. The figures include Alzheimer's disease. However, because dementia particularly affects the elderly who may have other illnesses, the figures from the Cause of Death Registry are uncertain.

Future trends

If age-specific incidence does not change, the rise in life expectancy in Norway will more than double the number of people with dementia from 2015 to 2050. This is based on calculations that have estimated a doubled incidence in Western Europe during the same period (ADI, 2015). Worldwide, the number of people with dementia is estimated to triple or quadruple from 2015 to 2050.

These projections are worst-case scenarios. However, results from several studies show that over the past 20 years there has been some improvement in cognitive function among the elderly (Llewellyn, 2009; Christensen, 2013) and reduced risk of dementia (Matthews, 2013; Prince, 2016).

Increased educational levels, improved lifestyle habits, such as reduced smoking and healthier diets, plus better control of risk factors for cardiovascular disease, such as blood pressure treatment, may have helped reduce the risk.

Nevertheless, there is little change in the proportions within different age groups that have dementia. The most likely explanation for the increased prevalence of dementia in the total population is increased life expectancy in general and more elderly people, plus that people with dementia are living longer with the disease.

Socioeconomic differences in dementia

The incidence of dementia is higher among people with low education than among those with a higher education (Caamano-Isorna, 2006; Strand, 2014).

It appears that higher education can slow the development of dementia but does not provide permanent protection.

Differences between educational groups may also be due to lifestyle differences and different compliance to preventive treatment for cardiovascular disease.

International differences

Since knowledge about dementia prevalence in Norway is largely based on evidence from other countries, it is not yet possible to demonstrate differences or similarities between Norway and other countries.

Dementia prevalence appears to be highest in America and Europe, and lowest in Africa, according to calculations from an expert panel in 2010 (Sosa-Ortiz, 2012). The regional differences are probably related to life expectancy differences and access to health care services for diagnosis (Qiu, 2007; ADI, 2015; Sosa-Ortiz, 2012). There is little or no evidence to suggest that there are significant differences in prevalence between Western countries.

Causal factors and prevention

Genetic causes

Twin studies show that genes are slightly more important than general environmental factors as an explanation for Alzheimer’s (Bergem, 1997; Gatz, 2006). There are no corresponding research results for other dementia types.

Apart from age, a variant of the apolipoprotein gene (ApoE, allele ε4 on chromosome 19) is the strongest known risk factor for Alzheimer's disease. An estimated 40-80 per cent of patients with Alzheimer’s disease inherited this variant from at least one of their parents. If the gene is transferred from one parent, the risk is tripled and if the gene is inherited from both parents, the risk increases 11-fold (Schipper, 2011).

ApoE4 causes large accumulation of beta-amyloid in the brain before Alzheimer’s symptoms arise (Polvikoski, 1995). So far, ApoE4 has been primarily linked to Alzheimer's. However, the results described in a review article indicate that this gene is an equally strong risk factor for vascular dementia (Liu, 2012). In addition to ApoE4, there are about 20 other genes coding for dementia, but none with equally strong efficacy (Lambert, 2013).

Environmental factors and lifestyle

There is a great deal of uncertainty about causal and protective factors, and research is based on epidemiological studies.

The risk factors for Alzheimer's disease and vascular dementia are mostly similar. Nine risk factors that we can influence are defined and have significance during different life stages (Livingston, 2017). From childhood and adolescence, education is an important factor, while typical cardiovascular risk factors play a role later in life.

In addition, factors that are important for building and preserving brain reserves, such as hearing, social and intellectual activity and physical activity are also important (Fratiglioni, 2000; Plassman, 2010). See figure showing possible dementia prevention mechanisms (The Lancet, English). 

Consequences and challenges

Dementia is a strain and challenge for both the affected person, their relatives, the health and care services and the community.

The loss of cognitive and motor functions, together with additional psychological symptoms such as anxiety, depression and delusions, often lead to a great deal of suffering for those affected by dementia.

The disease can cause great stress among relatives, especially spouses and children. The gradual loss of a loved one is a painful and often lengthy process. In addition, the burden of care itself is often heavy and tiring. There are around 300,000 close relatives of dementia sufferers in Norway at any given time.

Cognitive failure and dementia require widespread use of health and care services and will pose an increasing societal challenge in the years ahead.

Currently, there are currently around 40,000 nursing homes in Norway (Gjøra, 2015). Around 80 per cent of the residents, i.e. at least 32,000, have dementia (Selbæk, 2007; Bergh, 2012). The vast majority of people with dementia die in nursing homes.

A national plan and national professional guidelines have been developed in order to meet the consequences and challenges of an increasing number of people with dementia. The Dementia Plan 2020 describes what should be the standard for care and support for people with dementia and their relatives. Person-centered care is key.

The professional guidelines from the Norwegian Directorate of Health describe the standard for assessing people with cognitive failure and dementia in primary health care. Recommendations are given when patients with unclear and complicated clinical symptoms should be referred to the specialist health services. The recommended treatment is aimed at achieving better function and quality of life.

References

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