Classification of methods for determining biological age by a set of markers (Belozerova, 1999)

Material and methods

The analysis of scientific medical literature was carried out.

Results and discussion

An analysis of the studied literature showed that attempts to assess the level of health according to the criteria of biological age (BV) as an indicator of the “wear and tear” of functional and morphological structures in the body per unit of biological time have been and are being made by many gerontologists and hygienists [8]. In our opinion, the history of this issue is most fully covered in the works of Belozerova L.M.
In the domestic literature, the first work on biological age was published by P.N. Sokolov (1935), having calculated a table of age shifts to highlight informative features (skin wrinkling) according to their degrees of intensity, using the ranks of the average members of age groups and describing the procedure for calculating the biological age index [3]. In 1975 T.L. Dubina, A.N. Razumovich [3] published the first review in Russian on biological age. Dubina T.L.
can rightly be called a pioneer in the development of methods for determining the biological age of humans and laboratory animals in our country. The heyday in the study of biological age and the development of new methods for its measurement falls on the 80s of the last century, when detailed studies were carried out by employees of the Institute of Gerontology of the USSR Academy of Medical Sciences under the guidance of V.P. Voitenko [7]. Then, studies of biological age were concentrated in the laboratory of ontogeny of the Perm Medical Academy, where new methods for determining the biological age of a person were created [3, 4, 5].

The main manifestations of biological age during aging are violations of the most important vital functions and a narrowing of the range of adaptation, the occurrence of diseases and an increase in the probability of death or a decrease in life expectancy. There are various approaches to assessing biological age [3]: the method of development of sexual characteristics, the method of skeletal maturity, the method of dental maturity, the Damon method, the Dirken method, the Morgan method, the Webster I method, the Webster II method, the Furukawa method, the Radiation Science Research Foundation method, Suominen method, Kiskinen method, Borkan method, Nakamura I method, Nakamura II method, Dubina-Mints method, Voitenko-Tokar method, method of the Institute of Gerontology of the USSR Academy of Medical Sciences, method of physical performance, method of mental performance, method of physical and mental performance, method of bioelectrical activity of the brain, methods for determining the biological age of individual body systems have also been developed. All methods (with the exception of methods of physical performance and methods of the Institute of Gerontology – in terms of blood pressure, the duration of holding the breath on inhalation and exhalation, vital capacity of the lungs, body weight, hearing and vision, static balancing, the speed of propagation of the pulse wave through the arteries of the elastic and muscular type and their ratio, electrocardiographic indicators, subjective health assessment, symbol-digital test) are not widely used among researchers and practitioners due to the requirements for their use of special equipment and knowledge of author’s changes even in generally accepted examination methods. The task of determining the biological age is to calculate the biological age of an individual based on the relationships known for a given population between indicators and chronological age, based on the individual values of these indicators. For this, various groups of domestic and foreign researchers have proposed various sets of tests. So far, it has not been possible to unambiguously answer the question of what number of indicators is optimal for determining BV [8]. Only some of the physiological indicators used to assess the biological age of a person clearly correlate with age, have fairly small individual scatter, and are little dependent on other indicators. The best correlations with age are noted for indicators of the cardiovascular system. In Russia, the problem of searching for aging biomarkers in order to determine the biological age of a person is most successfully developed at the Perm State Medical Academy, the St. Each method for assessing BV is characterized by a specific set of aging markers [4, 5, 6, 7, 9]. A classification of methods for determining biological age by a set of markers has been developed [3].

Classification of methods for determining biological age by a set of markers (Belozerova, 1999)

1. Anatomical markers:

1.1. method of development of sexual characteristics;

1.2. skeletal maturity method;

1.3. dentition method.

2. Physiological markers:

2.1. Dirken’s method – according to the parameters of vision, hearing, character recognition, attention, ability to classify, forced expiratory volume and adaptation (maximum working capacity, systolic blood pressure, heart rate, oxygen uptake at the height of the load);

2.2. method of the Foundation for Scientific Research on Radiation – according to the state of hearing and vision, dynamometry of the hand, skin elasticity, vibration sensitivity, reaction time;

2.3. Suominen method – in terms of vital capacity, systolic blood pressure, vibration sensitivity, symbol-digit test, hearing and maximum oxygen uptake during exercise;

2.4. Kiskinen method – according to the parameters of vibration sensitivity, vital capacity, pulse pressure, hand dynamometry, reaction time, accuracy of small movements, hearing condition;

2.5. Nakamura II method – for maximum oxygen uptake, maximum ventilation of the lungs, their ratio, heart rate during and after maximum physical activity;

2.6. Dubina-Mints method – according to hand dynamometry, vibration sensitivity, short-term memory;

2.7. method of the Institute of Gerontology – in terms of blood pressure, the duration of breath holding on inhalation and exhalation, vital capacity, body weight, hearing and vision, static balancing, the speed of propagation of a pulse wave through elastic and muscular arteries and their ratio, electrocardiographic parameters, subjective health assessment, symbol-digital test;

2.8. method of physical performance – according to submaximal physical performance; heart rate, systolic and diastolic blood pressure at the height of the load;

2.9. method of mental performance – in terms of short-term memory, mental productivity, thinking and attention;

2.10. the method of physical and mental performance – according to the totality of indicators of the two previous methods;

2.11. method of bioelectrical activity of the brain – according to the parameters of the characteristics of the main biorhythms in computer electroencephalography.

3. Anatomical and physiological markers:

3.1. Damon’s method – according to the condition of the hair, dynamometry of the hand and anthropometry data.

4. Physiological and biochemical markers:

4.1. Morgan’s method – in terms of blood pressure, hearing, vision, tapping test, dental indices;

4.2. Borkan method – according to hemoglobin content, creatinine clearance, forced exhalation, systolic blood pressure, hand dynamometry, tapping test;

4.3. Webster method I – according to the content of urea in the blood, cholesterol in plasma, serum calcium, forced expiratory volume, systolic blood pressure, erythrocyte sedimentation rate;

4.4. Webster II method – according to the parameters of vital capacity of the lungs, systolic blood pressure, blood urea, plasma cholesterol, serum calcium;

4.5. Furukawa method – in terms of blood pressure, height, body weight, vital capacity, hand dynamometry, trunk flexibility, phenol sulfophthalein test, visual condition, tapping test, heart rate after the Master’s test;

4.6. Nakamura I method – according to the content of hemoglobin, albumin, serum cholesterol, blood urea, glutamine-pyruvate transaminase, glucose during sugar load, forced vital capacity of the lungs, systolic blood pressure, state of vision.

5. Physiological and immunological markers:

5.1. Voitenko-Tokar method – according to systolic blood pressure, pulse wave propagation velocity, lung capacity, vision, hearing, static balancing, body weight, character recognition test, lymphocytic blast transformation test.

Each aging biomarker has both advantages and limitations. Optimal, apparently, is a set of tests covering various systems and organs, which at the same time reflect age-related physiology, age-related chronic pathology. In addition, it is necessary to use stress tests that reflect physical and neuropsychic performance, functional reserves and limits of adaptation, as well as self-assessment of the state. The main requirements for aging markers are safety for the subject and technical ease of implementation; heterogeneity; conjugation with the most important vital functions and integral viability [3, 4, 6, 7, 8, 10]. The simplicity of conducting a particular test does not indicate its low information content. However, the question of what indicators are most suitable for determining BV has not yet been resolved. In the case when it is impossible to give preference to any of the methods, it makes sense to take the arithmetic mean of the estimates obtained by all methods as the BV estimate. This technique makes it possible to reflect in the final assessment the advantages of the information content of all the methods used and at the same time reduce the role of the error of each of them.

BV models are used to process the results obtained in the process of measuring biological age and interpret them [7]. Distinguish:

1) analytical (fundamental and diagnostic (applied);

2) complete (absolute assessment of BV) and incomplete (relative assessment of BV);

3) structured and unitary;

4) integral and partial;

5) regression and discriminant, factor, cluster, others.

1. The division of sciences into fundamental and applied, especially the allocation of fundamental and applied aspects, within the limits of one science is always conditional. With regard to gerontology, fundamental sciences can be considered tasks, the solution of which makes it possible to build models of age-related processes in humans as a biological species. Based on these models, it is possible to estimate the degree of aging of a given individual, which will reflect the applied aspect of the BV problem. An intermediate position is occupied by models that characterize the dynamics of aging in individual population (gender, regional, or occupational) samples.

2. BV models are considered complete if they are built using all 3 types of indicators characterizing aging: CV, a set of heterogeneous aging markers, viability indicators. Such models are most consistent with the fundamental aspects of gerontology (and BV modeling as a method for solving fundamental problems). The exclusion of one type of variables from the model makes it incomplete and reduces its information content. These are incomplete models built without including viability indices; relative estimates of BV are based on them.

3. BV models are unitary, which allow assessing the degree of aging of an individual using one value (number). Structured models make it possible to characterize the degree of aging using several values (numbers), each of which reflects only one “layer” of age-related processes. Since aging is a complex (rather than unitary) process, which concerns not only the whole organism, but also individual cells, since each cell has a high level of systemic complexity, the structured models of BV are theoretically quite justified. Meanwhile, unitary models are widely used in practice (IQ for assessing intelligence, calendar age).

4. Integral models are built on the basis of markers that characterize the state of various physiological systems of the body (ideally –
all); partial models reflect the aging of only one of the systems. Such, for example, are the models of “cardiopulmonary BV”, “psychometric BV”, “anthropometric BV”. Comparison of integral and partial models (estimations of BV in the same individual) allows us to draw nontrivial conclusions about intersystem interactions in the aging process and their role in the formation of age-related pathology.

5. Any BV models are mathematical, and any estimates of BV in a particular individual are of a statistical nature.

The most important consequences of age-related processes are a decrease in the life expectancy, a violation of the main vital functions and a narrowing of the range of adaptation, which can lead to the development of disease states. Biological age is an integral indicator of the level of individual human health, characterizing the functional, regulatory and adaptive characteristics of the organism.

For a growing organism, a significant advance and lag of biological age in relation to the calendar one can be interpreted as a sign of a decrease in the level of human health. As the body ages, there is also a decrease in its functional reserves. In the course of various studies, it was found that the discrepancy between passport and biological age is observed in all age groups, and the biological age of women is less than that of men in all age groups. Increased body weight, reduced index of physical activity, smoking worsen the indicator of biological age. Persons whose BV significantly exceeds the population standard constitute one of the most numerous risk groups in relation to the occurrence of diseases, disability and death [1, 2, 3]. The study of BV in the dispensary observation groups showed that a decrease in BV from its proper value for 6 years is a critical level between the norm and pathology. A further decrease in BV characterizes the pathological state of the body, regardless of the nosological form. The battery of aging markers makes it possible not only to calculate an individual BV indicator, which can be used to assess the degree of alleged health disorders, but also to build a direct prediction of the possible number of diseases in a given individual [7, 9, 10]. A number of studies have shown the high sensitivity of most BV indicators to external influences purposefully used to reduce BV. This opens up prospects for the use of tests based on multiple regression models in determining the effectiveness of geroprophylaxis courses.

findings

1. To date, there are no common approaches to which biomarkers provide reliable data on the true age of an individual, which dictates the continuation of scientific research in this direction.

2. Biological age must be taken into account in order to predict the individual health of a person.

3. The use of the method of determining biological age in the daily practice of doctors will lead to the activation of the preventive direction in medicine, which is relevant in terms of improving the level of individual health and the quality of life of a modern person.

4. Determination of biological age is also advisable to use in evaluating the effectiveness of geroprophylaxis courses.

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