**5. Epidemiology and demography of ageing**

In the beginning of the 20th century 3 to 5 per cent of population in European industrial countries (similarly in USA) were people aged 65+ y. This percentage has grown up to 14 – 20 nowadays. Up to the fifties of previous century people died prematurely. During the last hundred years the life expectancy (LE) almost doubled which is one of the greatest achievements of mankind and science in general. Length of human life begins to approach to its biological limit. Probability of achieving advanced age is no longer exceptional, on the contrary it becomes a standard (Fauci et al., 2008; Pathy et al., 2006; Ratnaike, 2002).

Demographically, the ageing population due to changes in mortality and fertility decline – fewer children are born and more people live to old age. Crucial in this is played by more improved standard of living than in the past and progress of medicine.

Absolute and relative growth of number of the elderly both in developed and developing countries is a main feature of population development in the 21st century (Scherl, 2003). We speak about **population ageing**. There are approx. 580 mil. people aged 60+ in the today's world out of which 355 mil. live in developing countries. In 2050 there will be 2 billions of our planet inhabitants aged 60+ y. This age category will overweight children of < 14 y. The most rapid increase during the next decades is envisaged in the 80+ y. group in the industrial countries. It is the ageing of old population (Buttler, 2003). In the USA (fig.1), Canada and majority of European union countries it has been found that the most rapidly increasing group of population is the one of 85+ y.

**Ageing in the industrial** (developed) **countries** can be considered:


2. decay of physical performance, deteriorated regeneration after load and reduced

4. disintegrated ageing: big inter- and intra-individual differences (organs and systems) 5. effort to create new own homeostatic mechanisms (which accompanies growing

Senile performance decline is a consequence (Beers et al.., 2006) of general weakness, impaired locomotion and balance, lower stamina. The life expectancy is significantly influenced by risk factors, contingent metabolic changes and level of resistance to stress. A choice of life style is also essential. Ageing in human population is often connected with increased occurrence of degenerative affections, tumours and Alzheimer's disease

In fact it should be a period of life in which broad harmonic development of human personality goes on and on. Most people of advanced age should remain independent, selfsufficient and retaining their good psychic condition up to the terminal period of their life

In the beginning of the 20th century 3 to 5 per cent of population in European industrial countries (similarly in USA) were people aged 65+ y. This percentage has grown up to 14 – 20 nowadays. Up to the fifties of previous century people died prematurely. During the last hundred years the life expectancy (LE) almost doubled which is one of the greatest achievements of mankind and science in general. Length of human life begins to approach to its biological limit. Probability of achieving advanced age is no longer exceptional, on the

Demographically, the ageing population due to changes in mortality and fertility decline – fewer children are born and more people live to old age. Crucial in this is played by more

Absolute and relative growth of number of the elderly both in developed and developing countries is a main feature of population development in the 21st century (Scherl, 2003). We speak about **population ageing**. There are approx. 580 mil. people aged 60+ in the today's world out of which 355 mil. live in developing countries. In 2050 there will be 2 billions of our planet inhabitants aged 60+ y. This age category will overweight children of < 14 y. The most rapid increase during the next decades is envisaged in the 80+ y. group in the industrial countries. It is the ageing of old population (Buttler, 2003). In the USA (fig.1), Canada and majority of European union countries it has been found that the most rapidly

contrary it becomes a standard (Fauci et al., 2008; Pathy et al., 2006; Ratnaike, 2002).

improved standard of living than in the past and progress of medicine.

**Ageing in the industrial** (developed) **countries** can be considered:

• a consequence of improving life conditions after the industrial revolution

1. loss of functional parenchyma of individual organs = **involution**

tolerance towards load 3. influence of one or more diseases

involution) = **adaptability**.

**5. Epidemiology and demography of ageing** 

increasing group of population is the one of 85+ y.

In the **developing countries** on the other hand:

• prevailingly gradual

• progress in medicine

• ageing is more rapid

• connected with birth rate decrease

• birth rate decrease is dramatic

(Holmerova et al., 2007).

(Nemeth et al., 2007).

In 2020 aged 60+ - 70 per cent of them will live in the developing countries. The highest proportion of these elderly is envisaged in Japan (31 per cent), than in Greece and Switzerland (28 per cent), USA (23 per cent), etc.

Fig. 1. Demographic prognosis of old age population in the USA

The growth of population aged 65+ in Europe and Northern America during the next 30 years is estimated to reach 24 – 35 per cent. Growing number of the elderly brings also both absolute and relative increase of occurrence of affections which are typical for the advanced age and this becomes a serious worldwide social problem (Seitz, 2003). This covers not only typically somatic diseases such as atherosclerosis, cardio- and cerebrovascular events, heart failure, peripheral vasculopathies, parkinsonism, hypo-thyreoses, diabetes, osteoporosis and osteoarthrosis, diverticulosis, anemies, etc. but also mental diseases with all manifestations and consequences of dementia, especially the Alzheimer's type (Braunwald et al.., 2001; Sinclair & Finucane, 2003).

Analogically to the population ageing in society also medical science has experienced a phenomenon of the so called "**geriatrisation of medicine**" which means a significant prevalence of the elderly among all the patients to be treated (Asplund et al.., 2000). This aspect penetrates practically all the branches of medicine to begin with the front line up to the various special fields including ophtalmology.
