Vitamin Information Center

Burden of Disease
FRANZ HESSEL
Health Economics Outcomes Research, Sanofi-Aventis
Pharma GmbH, Berlin, Germany
franz.hessel@sanofi-aventis.com
Synonyms
Burden of illness; Cost of illness
Definition
The term burden of disease generally describes the
total, cumulative consequences of a defined disease or
a range of harmful diseases with respect to disabilities
in a community. These consequences include health,
social aspects, and costs to society. The gap between
an ideal situation, where everyone lives free of disease
and disability, and the cumulated current health status,
is defined as the burden of disease.
In the 1990s, theWorld Health Organization (WHO),
in co-operation with Harvard University and the World
bank, developed a methodological concept to quantify
the global burden of disease; this was based to a large
extent on statistical measurement of the  disability-
adjusted life year (DALY). The DALY aggregates
the time lost because of premature mortality and the
time spent in a limited health state. Consequently, the
DALYs for a defined disease or health condition are
calculated as the sum of the years lost due to specific
premature mortality and the years lost due to disability
for incident cases of the health condition.
Basic Characteristics
The burden of illness or burden of disease approach
used in public health and the epidemiological literature
combines measurement of mortality and morbidity
with respect to non-fatal outcomes such as quality
of life aspects. With regards to these basic attributes,

burden of illness-concepts – and especially the DALY –
include some key elements of utility-concepts, such as
the QALY ( value, human life – utilities). However,
due to the lack of foundation in economic theory, burden
of illness is primarily seen as a descriptive epidemiologic
concept, such as the regular burden of disease
report of the US Center for Disease Control (Centers
for Disease Control and Prevention 2004). Although it
is possible to express the gain from the avoided loss of
burden of disease relative to additional costs, this specific
cost-outcome relation is very rarely found in the
literature and is not regarded as a common health economic
measure.
The most well-known and widespread concept following
the burden of disease principle is the DALY (Homedes
1996). DALYs represent one key element in the
WHO ranking of worldwide health care systems “The
global burden of disease” (Mathers et al. 2003; Murray
et al. 1997; Lopez et al. 2006). The first results of this
project, for the year 1990, have been published, with
regular updates and extension being carried out (Murray
2007; WHO 2007).
The cumulated disease-specific DALYs, aggregated
according to the country-specific prevalence of the diseases
and disabilities considered, reflect the burden of
disease of a specific society or a specific country. The
Global Burden of Disease concept of the WHO compares
large numbers of low-, middle- and high-income
countries with regard to their country-specific burden
of disease. It offers mortality figures, which refer to
the number of people who die and the causes of death.
Thus, a comprehensive and consistent set of estimates
of mortality and morbidity expressed by the single indicator
DALY and differentiating by age, sex, and region,
is given.
There are some specific aspects of the DALY concept,
such as further time discounting and non-uniform
age weights, which give less weight to years lived at
a younger age. According to this concept, the death
of an infant is equivalent to 33 DALYs and the death
of a person between 5 and 20 years of age is about
36 DALYs. Consequently, the death of 100 infants in
a society would be equivalent to 3,300 DALYs, which
corresponds to 5,500 persons with blindness at an age
of 50 years. The weight factors reflecting the severity
of the disability or disease (e. g. the disability weight for
blindness of 0.6) were originally defined by international
experts. New concepts using health-related quality of
life and utility concepts are currently being implemented.
In recent decades in most western industrial nations,
a clear tendency regarding the burden of disease can
be observed. There is an ageing of societies, with
a decrease in mortality, accompanied by an increase in
morbidity. The increase in morbidity is mainly due to
an increase in the prevalence of chronic diseases and
risk factors such as cardiovascular disorders, cancer,
diabetes, and obesity. Mortality estimates are higher in
low- and middle-income countries than in high-income
countries. People in low- and middle-income countries
die at a much younger age. In Africa, mortality is mainly
cause by infectious diseases – mainly HIV/AIDS and
malaria – which affect younger shares of the population
comparedwith China, where the pattern of diseases
is dominated by non-infectious diseases. The burden
of disease in Africa is estimated to be more than four
times higher than in high-income countries. The populations
of Africa and India represent about one third
of the population of the world, but the burden of disease
in these two regions is nearly half of the total global
burden of disease. Furthermore, the health inequities
gap is widening in a considerable number of countries.
The WHO Global Burden of Disease report from 2002
(Lopez 2006) reports three major trends: slowing down
of gains and widening of health gaps; increasing complexity
of the burden of disease; and globalization of
adult health risks.
Although an improvement in health conditions and burden
of disease has been observed in many low- and middle-
income countries over the last decade, a large proportion
of risk factors and diseases are still preventable,
e. g. about one-fifth of the global burden of disease can
be attributed to under-nutrition. In Africa about onefifth
of the burden of disease is attributed to unsafe sex
leading to HIV and other sexually transmitted infections.
Concerning high-income countries, tobacco consumption
is the leading avoidable risk factor, accounting
for 12 per cent of the burden of disease. Globally,
about 42 per cent of the total burden of disease can
be attributed to the leading 10 risk factors when joint
effects are taken into consideration. The leading five
risk factors are responsible for about one quarter of the
total loss of healthy years of life. These figures demonstrate
the enormous potential for improving mortality
and morbidity by prevention and decrease of wellknown
risk factors. This underlines the importance of

research to develop cost-effective strategies for a relatively
small number of risk factors to reduce a relatively
large share of the global burden of disease (Mathers
2003;Murray 2007).
Cross-References
 Disability Adjusted Life Years (DALYs)
 Value, Human Life – Utilities
WHO
References
Center for Disease Control and Prevention (2004) The Burden of
Chronic Diseases and their Risk Factors. CDC, Atlanta, USA
Homedes N (1996) The Disability-Adjusted Life Year (DALY).
Definition, Measurement and Potential Use. Human Capital
Development Working Papers No. 68. Worldbank, Washington
Lopez AD, Mathers CD, Ezzati M, Jamison DT, Murray CL
(2006) Global and Regional Burden of Disease and Risk Factors,
2001: Systematic Analysis of Population Health Data.
Lancet 367:1747–1757
Mathers C, Bernard C, Iburg K, Inoue M, Ma Fat D, Shibuya
K (2003) Global Burden of Disease in 2002: data sources,
methods and results. GPE Discussion Paper No. 54. World
Health Organization, Geneva
Murray CL (2007) Towards Good Practice for Health Statistics:
Lessons from the Millenium Goal Health Indicators. Lancet
369:862–873
Murray CJ, Lopez AD (1997) The Global Burden of Disease.
A Comprehensive Assessment of Mortality and Disability
from Diseases, Injuries, and Risk Factors in 1990 and projected
to 2020. Harvard University Press, Harvard
World Health Organization (2007) Global Burden of Disease.
http://www.who.int/topics/global_burden_of_disease/
en/. Accessed October 4th 2007

A national campaign to persuade every Scot to take daily supplements of vitamin D is needed if the country’s appalling health record is to be reversed, leading scientists believe.

A report, published this week, links poor weather to the lack of the “sunshine vitamin” in Scotland, and urges the Scottish government to launch a nationwide vitamin D programme to lower the incidence of devastating illnesses, such as heart disease, cancer and multiple sclerosis.

The research points to the country’s damp, cloudy climate as a significant contributor to its bleak record of ill health and disease.

Vitamin D deficiency – caused by lack of exposure to sunshine – is twice as common among the Scots as it is among the English. The average Scot has a vitamin D level four times lower than their neighbour south of the Border.
A five-year research project by Oliver Gillie, a scientist and writer, demonstrates extensive and remarkable parallels between Scotland’s dull weather and indices of disease.

It suggests that the “Scottish effect”, the country’s hitherto unexplained high mortality rate compared with other industrial countries, is in large part down to lack of sun. Crucially, a shortage of the “sunshine vitamin” is established as a factor in higher rates of multiple sclerosis (MS), diabetes, hypertension, arthritis, several types of cancer, cardiovascular disease and other ailments that together give Scotland one of the worst health records and highest premature mortality rates in Western Europe.

Dr Gillie’s study – Scotland’s Health Deficit: An Explanation and a Plan – echoes world-wide research on vitamin D deficiency but goes further, showing how the higher rates of disease in Scotland mirror closely the lower amount of available sunlight.

A lack of sunshine in Glasgow and the West of Scotland reflects levels of chronic illness that which cannot be explained by deprivation alone. A lack of sunshine on Orkney and Shetland – only 24 per cent of the maximum number of hours possible – corresponds to the highest prevalence of MS in the world.

By contrast, the South Coast of England, where such diseases are much less common, receives 400 more hours of sunshine a year than Scotland.

Dr Gillie says that successive reports on the state of Scotland’s health have failed to recognise that insufficient sunlight and vitamin D are important risk factors, and calls for firm action from the Scottish government on supplementation and the fortification of food.

Last week The Times convened a panel of experts who studied the report and endorsed unanimously the importance of vitamin D as an important ingredient in creating a healthy Scottish population.

Dr Harry Burns, the Chief Medical Officer for Scotland, said: “It is important that attempts to improve health in Scotland remain focused on action on the social, economic, behavioural and psychological determinants of health. If vitamin D supplements can be shown to contribute to that agenda then we will make the appropriate recommendations.”

Dr Adrian Martineau from Queen Mary’s School of Medicine, London, who is working on evidence that vitamin D can reduce cold and flu symptoms, said: “This is a very important initiative. What [Dr Gillie] has highlighted is that 85 per cent of us have lower Vitamin D levels than we should have and 85 per cent of our cells need vitamin D to function properly. It’s highly plausible that supplementation would be of great benefit.”

Flavonoids are highly beneficial anti-oxidant compounds found in many fruits and vegetables, as well as tea, red wine and even beer, and it’s now well established that a plentiful intake of anti-oxidants through foods, drinks and supplements is vital for optimal human health.

Anti-oxidants operate to neutralise the activity of so-called “free radicals”; compounds produced in the body as by-products of normal biochemical reactions, but which may nevertheless be highly damaging as they produce oxidative reactions damaging to cell structures. Ultimately this damage may contribute to the development of degenerative diseases characteristic of ageing, including cardiovascular disease, Parkinson’s Alzheimer’s and even some cancers.

The best known anti-oxidant nutrients are vitamins C and E, although these can only function properly when supported by adequate supplies of a wide variety of micro-nutrients, which include many of the flavonoids found in common fruits and vegetables. These compounds may therefore be regarded as important elements in the body’s anti-oxidant defences, but many of the more than 4,000 flavonoids identified have also been hailed for their beneficial effects on the immune system and anti-inflammatory properties.

From the point of view of incorporating flavonoids into a daily health regime, the good thing is the ease with which this can be achieved. Flavonoids are very widely found in fruits, vegetables, and even drinks normally regarded, for other reasons, as unhealthy. So even a diet ordinarily well provided with common fruits and vegetables may provide anything up to 800mg of various flavonoids.

Authoritative research has indicated that this level of flavonoid consumption may help protect against coronary heart disease and hardening of the arteries (atherosclerosis), an important precursor of both heart disease and stroke. These remain two of the major causes of premature mortality and disability in the Western world, and to this extent the UK government and health advisors’ frequent advice to consume five servings of fruit and vegetables each day is well founded.

The most potent of all the anti-oxidant flavonoids is believed to be a compound called quercetin, which is widely found in common or garden vegetables. The consumption of fruits with their skins on, such as apples, pears, grapes, bilberries, tomatoes etc will also provide a good supply. But perhaps the richest source is onions, a foodstuff also known since ancient times as a powerful anti-bacterial, anti-viral and anti-inflammatory agent.

There’s no doubt that a diet including plentiful supplies of fresh fruit and vegetables can only be beneficial to health. But the anti-oxidant properties of the flavonoids found in many common, even supposedly unhealthy, beverages should not be neglected.

For example, the anti-oxidant properties of the catechin polyphenols found in black and green tea and red wine are now well known and attested. But, as remarkable as it may sound, there is now evidence that even beer may contain unique anti-oxidants equal in potency to vitamin E. The flavonoid compounds, xanthohumol and isoxanthumol appear to be found only in beer and the hops that flavour it and although they have not been studied directly, there is speculation that they may be responsible for the remarkable and counter-intuitive finding that lager type beers may be more effective as anti-oxidants than red wine, grape juice or even green tea. Obviously there are other reasons, not least its high calorific value, why you wouldn’t want to depend on a high consumption of lager for your anti-oxidants, but in moderation it may indeed be beneficial.

In fact studies suggest that these particular flavonoid anti-oxidants may have a particular role in combatting the oxidation of low density lipids (LDLs), the so-called “bad cholesterol”, which is a known risk factor for the development of atherosclerosis and cardiovascular disease. The other main fat-soluble anti-oxidant which fights this process is vitamin E, and although there is evidence that the anti-oxidant potential of xanthohumol and isoxanthumol may be comparable with that of the vitamin, it is also clear that each of the three compounds functions best in the presence of each of the others.

Whilst orthodox medicine concedes, in fact insists, that further research is necessary, the implications of these findings are exciting; suggesting that there may be many more as yet undiscovered benefits of flavonoids. As always, however, the holistic functioning of the body means that maximum benefits will only be obtained by the consumption of the widest possible variety of all these compounds. As flavonoids are not yet widely available as supplements, this consumption is best achieved through the foodstuffs and beverages which combine them as nature intended. Such a flavonoid rich diet can only be of benefit to the action of the better known anti-oxidants, such as vitamins E and C, which are more readily obtainable in supplement form.

Flavonoids are highly beneficial anti-oxidant compounds found in many fruits and vegetables, as well as tea, red wine and even beer, and it’s now well established that a plentiful intake of anti-oxidants through foods, drinks and supplements is vital for optimal human health.
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