Functioning, functioning status or functional ability, are commonly used terms, and could be define in a very broad theoretical range. Nevertheless, when these synonyms are used in the connection to old age, three components are present in almost all definitions: self-care, self-preservation and ability to perform physically active life, as long as it is possible. A simple explanation of functional status in old age is personal ability of fulfilling different needs. It depends of person's biological, psychological and social capacities, which synchronically enable all activities (Allen & Mor, 1997). It is not a constant but changeable value, under the influence of number positive or negative modulators. Physical functioning addresses to person's ability to perform activities of daily living necessary to live and survive in modern society. Assessment includes three major domains: activities of daily living (ADLs), instrumental activities of daily living (IADLs) and mobility (Pearson, 2000).

Functional status does not always reflect the physician-related health state of the individual. It is a very important factor for a person's evaluation of each overall health status as 'good' or 'bad'. Functional ability constitutes in many cases the key concept for individuals, especially the old, prior to their decision to use health services. Bad functional status is one of the physical status variables leading to the more frequently use of health services, especially in the population of old people (Vlachonikolis & Philalithis, 2002). Physical and cognitive function deficits are among primary predictors of decreased quality of life in home-dwelling elders (Borowiak & Kostka, 2004).

Assessment of functioning is one of the five components of Comprehensive Geriatric Assessment, the multidimensional process of determination of medical, psychological and functional capabilities of elderly (Wieland & Hirth, 2003). Although, it is necessary to spend approximately 60 minutes to assess an older patient (Butler, 1999) our general practitioners are usually limit to less than15 minutes per patient. In that brief time at the outpatient primary care practice, the elderly patients can't communicate the full scope of their problems and doctors cannot perform geriatric assessment. The old patients usually come only for prescriptions in the GP's office, entering the “circulus vitiosus”: the bad functioning increases the use of health services, but the health service is not interested for performing the geriatric assessment. In such a way, it is not surprising a lack of information concerning the functional ability of old people in Serbia.

The purpose of the survey was to assess the level of functional ability and to determinate variables associated with functional ability in old age.

Sample

Assessment of Functional Status

The applied research instrument was questionnaire that had passed the process of validation and allows the comparison with the results for the population of elderly in Serbia, twenty years ago (WHO, 1983). Beside general questions about socio-demographic status of the elderly, it contained questions about different basic and instrumental activities of daily living as well the social and health needs. Functional ability index is weighted sum of nine variables (Table 1), calculated by the following formula (Oyen, 1990):

Figure 1

The weights (w_i) of the standardized variables included in the index were estimated by the principal component analyses (Table 1). Variables were coded as follows: 1=cannot do; 2= can do only with help; 3= can do without help but with difficulty; 4= can do without difficulty; the minimum value of FAI-I is –22.5, and it is the value of all nine variables equals 1=“cannot do”. The maximum value is +3.44, in the case when all nine variables equal 4=“can do without difficulty”. A positive value of the index indicates that at least one of the variables has a value higher than its mean for whole data; a negative value indicates that at least one of the variables has a value lower than the mean.

Statistics

The values of FAI-I, are presented according to age and sex of the respondents (Table 3), with no significant sex differences in FAI-I between age groups (p=0.06). The values of the FAI-I demonstrate decline of functional ability due to ageing and higher variety in certain age groups (70-74 years of age and 75-79 years of age), while the FAI-I of the first group (65-69), shows the highest homogeneity (Fig. 3).

Ten variables were selected for univariate logistic regression testing (Table 4). Logistic regression coefficients were used to estimate odds ratios for each of the independent variables in the model. After the procedure, the six variables were chosen to enter in a model of multivariate regression model. The analysis pointed out that the number of chronic conditions is most strongly associated with the functional status in population of elderly persons. The age is the second variable in the model, according to its score, and the other four are: physical activities, financial status, education and feeling unwanted (Table 5).

Figure 2

Table 1: The weights of the standardized variables included in the index

Figure 3

Table 2: Baseline characteristics of the study population according to sex

Figure 4

Figure 1: Daily physical activities of elderly, for fitness and health

Figure 5

Figure 2: Ability and independence of old people in performing certain everyday activities

Figure 6

Table 3: FAI-I according to age and sex of the subjects

Figure 7

Figure 3: Functional Ability Index I according to the age of subjects

Figure 8

Table 4: FAI predictors- univariation logistic regresson

Figure 9

Table 5: FAI predictors- model of multivariation logistic regresson

Our results confirmed polimorbidity of old age. Although, the data for Europe pointed out about 20% people older than 65 without any chronic condition (Oyen, 1990), we have found only 6.9% of our subjects with that characteristic. Subjective assessment of health in population of elderly in Serbia got worse till the time of WHO survey –”The elderly in eleven countries” (WHO, 1983). Today, more than 50% of elderly estimate their health condition as poor or very poor (vs. 40% twenty years ago). Not changed stayed the fact that the health status assessment is ranked the highest among the best-educated old people (p=0.001). Leading health problems remain the same but with higher percentage. Hypertension stayed most prevalent disease but during the twenty years the percentage rise from 25% (for men) and 33.3% (for women) to 57.5% of our elderly population. The high prevalence of hypertension and heart failure are very close to the results from Estonia (Saks, et al., 2001), confirming the large differences in cardiovascular rates between Eastern and Western Europe.

We have fount high prevalence of smoking in our sample. Comparing with the data from USA (10.9% regular smokers among older than 65), and from Japan (49% regular older smokers), our results are disturbing- 66% regular smokers among men and 24% among old women (Bratzler, Oehlert & Austelle, 2002; Ishii & Kuyama, 2002;).

The level of physical activity among elderly is very undesirable. Two thirds of them live with completely sedentary life and, if we paraphrase the WHO experts, it is unnecessary lost of human resources (WHO, 2001). That percentage is even worst considering aged people in single households –more than 85% physical inactive persons. There were no sex differences in physical activity. This finding is in agreement with another study, according to which the elderly women and men are equally physical active or, in our case, equally inactive (Westerterp, 1998). Functional ability, presented through the values of FAI-I, is inversely related to age, as it is shown in most of the studies (Dittmar, Reber & Hofmann, 2001; Papadopoulou, et al. 2003;). There were no significant sex differences between age groups (p>0.05), although, the results of FAI-I for all age groups were lower for women. Nevertheless, most of the studies on the large, representative samples managed to prove significantly lover level of functional ability for elderly women (Dunlop, Manheim, Sohn, Liu & Chang, 2002; Von Strauss, Fratiglioni, Viitanem, Forsell & Winblad, 2001; West, Rubin, Munoz, Abraham & Fried, 1997).

The logistic regression model supports the fact that the developing of functional disability is highly individual process and couldn't be predicted and explained only by age of a person. The analysis pointed out that the number of chronic conditions is more powerful predictor of the functional status in population of elderly. We have confirmed the connection between functional ability in old age and financial status, in the model with lower level of education (Breeze, Fletcher, Leon, Clarke & Shipley, 2001; Evans, et al., 1997). Presence of level of physical activity in the model is expected outcome yet, it is one of the variables in the model that could be improved through public health efforts. Logistic regression analysis supports that the important determinants of functional ability in old age are: the number of chronic conditions, age, physical activity, financial status, feeling unwonted anymore and education. FAI-I demonstrate decline of functional ability due to ageing with no sex differences. The period of prolonged national crisis left its consequences on health and functional status of the elderly population; the leading health problems remain the same with the higher prevalence yet, the functional status declined.