How do grandfathers differ from grandmothers?
Differences between the sexes and aging
In the modern literature devoted to gender differences in the later stages of life, various approaches to analysis are used, such as cultural-historical, social, structural, socio-economic, feminist, political and biological. The main subject of this discussion is the relationship between behavior and changes occurring in the human brain.
In her recent book "Why Men Die First," Marianne J. Legato, approaching the question from a purely biological point of view, argues that men in general are physiologically weaker and more vulnerable than women. This pattern is observed already during intrauterine development and childbirth: at the stage of conception, 20% more male embryos are formed, which, however, die much more often than female ones. It is believed that throughout life women are more resistant to diseases and better mobilize their forces, which allows women to bear children and take care of them. However, the application of this model to the elderly population may be unreasonable.
Over the past decades, a new evidence-based model has been introduced into scientific gerontology, providing a positive view of aging. Instead of treating aging as a gradual loss of functionality, this concept highlights the positive aspects of the aging process – the so-called active aging. By optimizing physical, psychological and social functions, an "actively aging" person can not only strengthen his health and physical fitness, but also improve cognitive function and emotional standing, as well as activate participation in social life. There are empirical data confirming the importance of the above aspects of active aging. For example, active participation in various activities improves the results of tests evaluating cognitive function and slows down its extinction.
Unfortunately, the literature on active aging rarely focuses on the principles of successful and healthy aging, specific to different sexes.
One of the most pronounced differences between men and women is the long life expectancy of women. There are many reasons for this, including biological and socio-cultural aspects, such as differences in behavior patterns. For example, traditionally men smoke and drink more, take risks and show aggression more often, they are more exposed to harmful production factors than women. However, some authors state that in recent years there has been a noticeable decrease in this gender gap. One possible reason for this trend is an increase in the number of women who smoke, accompanied by an increase in female mortality from lung cancer. At the same time, a number of studies provide figures demonstrating a fairly stable average life expectancy of women exposed to the same adverse factors at work as their male colleagues.
In addition to the simultaneous increase in the life expectancy of both sexes, there is another interesting trend that can be interpreted in the light of "active aging". In recent decades, the increase in the number of years during which people maintain good (according to the results of a subjective assessment) health has outstripped the increase in average life expectancy. However, there is evidence that in the later stages of life, women are more pessimistic about their physical condition, while men, more often suffering from life-threatening diseases, tend to overestimate their state of health.
Brain
It is known that the structural features of the brain and its neural networks affect human behavior, but I would like to know how behavioral and thought processes, including emotions and cognition, are controlled. It would be interesting to understand the reverse pattern: how behavior can affect the brain and related physiological processes.
Regardless of age, certain regions of the male brain contain more neurons, which causes a larger size of the male brain. On the other hand, women are characterized by a more complex structure of the frontal and parietal lobes, which increases the area of the cerebral cortex. At the cellular level, women are characterized by a greater amount of gray, and men – white matter. At the macrostructural level, the female brain is more symmetrical, which is manifested by differences in the structure of the corpus callosum, planum temporale (the structure of the temporal lobe of the cerebral cortex, which plays an important role in the perception, recognition and construction of speech) and the anterior cingulate cortex.
Against the background of aging, sex differences become more pronounced. In men, an age-related decrease in the volume of nervous tissue occurs more often and is more pronounced not only in the frontal and temporal lobes, but also throughout the entire volume of the brain. At the same time, the stronger decrease in the hippocampus and parietal lobe observed in women may lead to more pronounced memory disorders. However, these data are ambiguous, since according to the results of other studies, women retain better memory than men. The morphology of most regions of the brain of men and women is characterized by different models of age-related changes, so sex differences change during life. However, there are areas whose features are stable, such as the lateral temporal-parietal regions, the cortex of which is thicker in the female brain at any age than in men.
According to the results of studies in which brain imaging methods were used, memory disorders and attention deficit in old age are associated with a decrease in the amount of gray matter and a decrease in the activation of the frontal and mid-temporal zones of the brain.
Sex differences are characteristic of many complex cognitive functions, as well as associated disorders associated with functional asymmetry of the brain. According to one of the hypotheses, which is based mainly on the results of behavioral research, in women, certain tasks can activate both numerous regions of one hemisphere and regions of both hemispheres, whereas in men, the performance of one function is more limited to one of the hemispheres. With the help of functional magnetic resonance imaging (fMRI), selective activation of the left hemisphere was shown in men solving linguistic tasks, whereas in women solving similar tasks caused activation of both hemispheres. Perhaps this mechanism protects women from speech disorders.
Sex hormones Sex hormones not only control sexual behavior, but also have a very pronounced effect on all types of behavioral and psychological functions, including emotional and cognitive.
Sex hormones interact with neurotransmitters in the brain, and, accordingly, directly control the processing of information entering the neurons. The levels of sex hormones change significantly as a person grows up and ages, so their role cannot be ignored when analyzing possible differences between the sexes. Below are the data indicating the exceptional importance of sex hormones for the functioning of the nervous system, even in old age.
During puberty, which is a phase of serious hormonal changes in both sexes, hormones trigger changes both in the structure of the brain and at the functional and behavioral levels. After that, the levels of female sex hormones change during the menstrual cycle, reach peak values during pregnancy and decrease during menopause. After menopause, their production is greatly reduced, which affects nervous and physiological functions.
Very little has been studied about how hormonal fluctuations occurring during life affect age-related changes in the body; this is partly due to the lack of systematic longitudinal studies.
In general, the physiological effects of sex hormones can range from relief of depressive symptoms and protection from stress to mild antipsychotic effects and effects on cognitive abilities. In the modern literature, data for and against the neuro- and psychoprotective effects of estrogens are discussed from the point of view of their use as hormone replacement therapy during and after menopause.
The results of a study conducted within the framework of the Women's Health Initiative (WHI) demonstrated both positive and negative effects of hormone replacement therapy on the cognitive functions of menopausal women. The results of subsequent studies also did not provide evidence of stable reproducibility of positive effects. In addition to adverse reactions, these studies have revealed an increased risk of mild cognitive disorders and dementia in women taking hormonal drugs. Therefore, such therapy is not recommended from the point of view of preventing dementia. Perhaps the inconsistency and uncertainty of the results of various studies is explained by the fact that the neuroprotective effects of hormone replacement therapy in postmenopause manifest themselves only during certain time periods.
Recently, experts have begun to describe a kind of male analogue of menopause – andropause, however, based on the available scientific data, the severity of this hormonal shift is much less than the severity of the hormonal shift during menopause. Experts are discussing the feasibility of using testosterone replacement therapy for men with reduced levels of this hormone in the blood serum. Hormone therapy in men can improve physical indicators such as bone density and muscle strength, but it is not as effective in relation to the emotional state as in women.
Cognitive functions Until now, when conducting gerontopsychological studies of cognitive abilities, gender was practically not given importance, despite a lot of literature data on the difference in age-related changes in cognitive abilities depending on gender.
The results of a number of studies indicate a more pronounced age-related deterioration of cognitive functions in men compared to women. However, unambiguously convincing results have not yet been obtained, which may be due to population or methodological errors.
The purpose of a large number of ongoing studies is to identify certain habits and activities that can reduce the risk of cognitive degradation and dementia in old age. For example, a longitudinal study involving Swedish twins showed that participation in intellectual and cultural activities is associated with a reduced risk of developing Alzheimer's disease in women, but not in men.
Some authors note a significant protective effect of physical activity on the cognitive functions of older people regardless of gender, while others demonstrate clear differences depending on gender and type of activity. Moreover, there is evidence that regular physical activity has a protective effect on the risk of developing dementia, but in women, physical exercise is generally more useful for maintaining cognitive ability, which may be due to the relationship between physical activity and hormonal metabolism.
Another subject of study in the context of the relationship between aging, cognition and gender differences is intelligence. According to well-founded theories, aging is accompanied by the preservation of "crystallized" abilities (for example, speech) and the simultaneous deterioration of "mobile" abilities with individual differences (for example, processes associated with high speed of thinking).
However, unfortunately, the results concerning gender differences in cognitive abilities in old age are very ambiguous. Data collected over 8 years as part of the ALSA – Australian Longitudinal Study of Aging (n = 1947, age 65-105 years) demonstrated the superiority of women in three cognitive areas: quick thinking, involuntary memory and speech capabilities. On the other hand, a number of studies have demonstrated that, despite the less pronounced general age-related deterioration of cognitive functions in women, men have the advantage in thinking speed.
A recent study that examined the impact of academic achievement and gender differences on mobile intelligence, crystallized intelligence and academic knowledge regarding the ability to read, mathematical calculations and writing, showed that women get significantly higher results in writing, and men – in mathematical tests, while other gender differences were not significant.
Within the framework of the Swiss Interdisciplinary Longitudinal Study with the participation of people of the most advanced age (Swiss Interdisciplinary Longitudinal Study on the Oldest Old), the cognitive abilities of men and women over the age of 80 were evaluated. The authors have identified dynamic associations between the speed of information perception and participation in various types of activities. The most pronounced negative correlation was observed between a decrease in the speed of perception and participation in events related to the work of the media and entertainment events. However, in this case, there was no evidence of the existence of sexual differences.
Another example of a study in which people of the most advanced age participated is the Berlin Aging Study (BASE), in which 516 men and women aged 70-103 years over a 19-year period underwent examinations concerning physiological, psychological and social changes in the late and late stages of life. Processing of the obtained data did not reveal significant sex differences. Small differences between men and women did not persist after the statistical correction of differences in the level of education.
Another 15-year study (Australian Longitudinal Study of Aging, ALSA), on the contrary, demonstrated gender differences in the levels of memory, speed of thinking and speech capabilities. Women consistently showed the best results in all parameters, even after adjusting for a whole range of background variables, including the level of education. It is obvious that at the present stage it is impossible to draw final conclusions concerning the influence of gender on the state of cognitive function in old age.
Emotions In most works in this field, the object of study is young people and middle–aged people, and the subject of study is the correspondence of existing cliches to reality, for example, finding out that women, unlike men, more clearly show emotions through behavior, or confirming the fact that it is more difficult for men to recognize sadness, disgust or anger by facial expression.
Differences in the ability to distinguish emotions between representatives of different sexes are observed in young and adult people, but the evidence for their existence is ambiguous and needs further study. There is practically no data on this issue for older groups, although the latter may be of interest in the formation of interpersonal relationships and social life, since successful recognition of emotions is considered a critical factor ensuring adequate interpersonal communication and a high quality of life, including in old age.
A number of attempts have been made to analyze changes in the ability to recognize emotions (mainly by facial expression) in old age. For example, Ruffman et al. We have received evidence that old people are worse than young people at recognizing anger, fear and sadness both by facial expression and by other physical manifestations. However, the authors did not analyze the sex differences in the aging population.
According to the data obtained during brain imaging of adult young people, sex differences largely depend on the emotional valence of facial expressions. For example, a happy face is more likely to cause multidirectional activation of the lateral zones of the amygdala in men and women: men have activation of the right, and women have activation of the left part of this formation. Frightened faces, on the contrary, cause extensive activation of the amygdala in both sexes. Such observations could be important for elderly people, however, unfortunately, relevant data are not available. Perhaps due to the age-related decrease in the volume of the frontal and temporal lobes, which are closely interrelated with the structures responsible for emotions, such as the amygdala, such differences between the sexes worsen with age. This indicates the need to study the alleged patterns using fMRI of certain areas of the brain, such as the amygdala.
Another interesting phenomenon to study is empathy. For example, according to the Baron-Cohen theory, empathy is more characteristic for women, while men show themselves better in systematization, but the available data do not allow us to talk about possible age-related changes.
Another complex psychological phenomenon is stress, especially household stress, which is considered to be associated with microstructural changes in brain regions that play particularly important roles in information processing. For example, in stressful situations, limbic structures are activated in women, and structures associated with thinking are activated in men. In this case, there is also no information about the differences between the representatives of different sexes of old age.
A number of experts are of the opinion that women and men cope with stress differently. Perhaps this is achieved by activating brain regions responsible for different problem-solving strategies. Women approach problem solving from a global perspective, while men use a more focused approach. However, in general, elderly people show better results in solving everyday problems than young people, as they combine emotion management strategies and rational approaches more effectively.
Mental disordersFor young cohorts, data were obtained on fairly stable significant differences in the frequency of development and age of onset of symptoms of mental illness in men and women.
For example, for men, the peak incidence of schizophrenia occurs between the ages of 15 and 25, while for women there are two peaks: around the age of 30 and at the end of menopause. There is an assumption that estrogen has a protective function against this disease.
The abuse of addictive substances, especially alcohol, is also more typical for men, but over the past 30 years this gap has narrowed very much, which may be due to the convergence of lifestyles of representatives of different sexes. Unlike alcohol and narcotic substance abuse, affective disorders and disorders accompanied by increased anxiety are significantly more likely to develop in women of all age cohorts.
From the point of view of differences in the models of the relationship between brain features and behavior, changes and mood disorders are associated with changes in the course of the stress reaction and the work of the hypothalamic-pituitary-adrenal system. It is believed that the functioning of the latter is regulated by sex hormones. Since the levels of sex hormones and, in particular, their quantitative ratio, change significantly with the onset of menopause, this can act as a trigger triggering the development of mental illness in women of the appropriate age group. The situation is also aggravated by other social and psychological changes, such as the so-called "empty nest" syndrome caused by the departure of children from their parents' home, divorce, the need to care for elderly parents, etc.
Alzheimer's disease is another example of a disease that affects women more often. However, if we make adjustments for the higher life expectancy and survival rates characteristic of women after diagnosis, it becomes obvious that the main risk factor for the development of senile dementia is not gender, but age. As mentioned above, there is evidence both for and against the neuroprotective effect of estrogens, so there is still no final decision on the feasibility of using hormone replacement therapy to prevent the development of mental illness in women.
As for another type of dementia – vascular dementia – there are data on both a higher incidence of development in men and comparable indicators for both sexes. Since vascular diseases are a risk factor for the development of vascular dementia, against the background of convergence of lifestyle parameters of both sexes, a decrease in the severity of differences between morbidity rates looks plausible.
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It is obvious that the data concerning psychophysiological differences between the sexes obtained when working with young people of reproductive age cannot be extrapolated to older people (for example, women in the post-productive phase).
When studying age-related sex differences, it is necessary to take into account the following closely intertwined aspects: specific and/or non-specific genetic factors, gender-specific features of the structural organization of the brain, the influence of sex hormones, environmental influences, the nature of learning and gender-specific cognitive strategies. As a person grows older, the relationship between these factors gradually becomes more complicated due to changes in parameters such as lifestyle, education, role models, personality traits, changes in social networks and value systems, and many others.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of article I.Kryspin-Exner, E.Lamplmayr, A.Felnhofer
Geropsychology: The Gender Gap in Human Aging – A Mini-Review (Gerontology 2011;57:539–548).
16.10.2012