Published on Oct 18, 2016
The life course approach suggests that your current state of health is usually a result of your previous life experiences.
Reproduced from: https://www.paho.org/salud-en-las-americas-2017/?p=69
BUILDING HEALTH THROUGHOUT THE LIFE COURSE
Table of Contents
Health is a component of and a key resource for human development. It results from a cumulative process of continuous interaction between exposures and experiences, which have an impact at both the individual and population levels, not only episodically but over time, and with trans-generational effects (1). The increase in human life expectancy by approximately 30 years over the last century provides a compelling reason to expand health-related goals beyond simple survival (2, 3).
In the Region of the Americas, the effort to increase life expectancy has been successful; however, the increase in healthy life expectancy has not kept pace. On average, 8 of every 10 people who are born in the Region will live beyond age 60, and more than 4 in 10 will live past 80 (4). One-quarter of those who live past 80 will live with poor health (4). According to estimates, people in the Region live on average 9 years with functional limitations or disability (5). An increased lifespan, but with longer periods of illness and dependence on care provided by others, is a great burden for States, societies, and families, and a significant challenge for public health.
Health throughout the life course
Halfon and colleagues define health throughout the life course as a dynamic process that begins before conception and continues for an entire lifetime (6). This concept, even in evolution, is based on bio-psychosocial and post-genomic models, in which health is considered a process that is integral to complex systems (7).
Acting upon that vision of health requires going beyond interventions targeted to specific diseases and their consequences and instead treating health as an essential resource in producing and maintaining capacities and reserves in individuals and populations, throughout the life course. Health is a dimension and a marker of sustainable development, since it reflects the combined effects of social, economic, and physical living conditions on the population. A healthy population displays greater labor and economic productivity, leading to more inclusive and sustainable growth (8).
The life course approach
In the life course approach, the health of individuals and populations is conceived as the result of dynamic interaction between exposures and events throughout life, conditioned by mechanisms that embody the positive or negative influences that shape individual trajectories and the development of society as a whole. According to this conceptual framework, health is a fundamental dimension of human development and not merely an end in itself.
The life course comprises the succession of events that occur throughout the existence of individuals and populations. These events interact to influence health from preconception until death, and may extend even further to affect future generations. The life course perspective provides a basis on which to predict future scenarios in health. Trajectories, temporary conditions, transitions, critical periods, the interconnection of lives, and cumulative effects form a conceptual platform that, as part of the available scientific evidence, can be used to model scenarios in health (9, 10).
There are longstanding efforts to transcend the narrow vision of health as merely the absence of disease. However, these efforts have been limited to philosophical definitions, conceptualizations, and theoretical models of public health (11, 12). Clinical practice, the organization of services, indicators, and financing are key aspects of health that continue to revolve around disease, even though the “traditional model of disease” is less and less applicable to contemporary pathological disorders.
Building health means investing in the creation of a capacity or resource that enables individuals and populations to develop according to expectations and the demands of their environment (13). It provides necessary tools not only for their development, but for their adaptation to unexpected situations such as natural disasters, infectious disease outbreaks, or violent events, or to challenges that can persist a long time, such as climate change, chronic diseases, disabilities, human rights violations, lack of job security, or violent situations (14).
People-centered health policies
… enabling people to increase control over, and to improve, their health. To reach a state of complete physical, mental and social well-being, an individual or group must be able to identify and to realize aspirations, to satisfy needs, and to change or cope with the environment. Health is, therefore, seen as a resource for everyday life, not the objective of living (15).
Building health implies not only preventing disease, but also promoting the development and sustainability of physical, mental, and social capacity throughout life. This capacity, although it has a genetic component, is not innate, since one is not born with “maximum capacity” that is then gradually lost through an unhealthy lifestyle; rather, this capacity is actively created, subject to environmental and social determinants, enabling individuals to adapt to and modify the environmental demands in their present and future life (13).
The life course concept includes the influence of the determinants of health on individuals and populations. According to this approach, these determinants not only can lead to disease and death, but also are decisive in building health. Understanding this can contribute to greater clarity about the influence of health on the model of life trajectories and on human development, and about the real impact of investments in health in the short, medium, and long term. Furthermore, it demonstrates that in health, both action and inaction have consequences. This vision of public health provides a more realistic view of the problems and sharpens the focus on the priorities and needs of the population.
In the Americas, health must be considered in an increasingly diverse population context. For the first time in history, five generations are alive at the same time (16). These generations have had different life trajectories: the first was born without access to vaccines or antibiotics; another experienced the double burden of malnutrition (undernutrition along with overweight); still others started out with high levels of illiteracy and today must adapt to global connectivity and coexist with other generations that are growing up and becoming educated in this new world. Some people are born and move through their lives with certain health protections, only to lose them in later stages of life, which poses new challenges of adaptation. All this represents a challenge for public health, and any future design of universal health must take into account these generational differences. They are added to the amply documented, but largely unresolved, inequities associated with ethnicity and gender and with the different geographic and social contexts where people live.
Inequities in the Region of the Americas have been the main cause of failures related to health, and over the next decade will continue to be a barrier to progress. Efforts to reduce and eradicate inequities should be guided by a life course perspective and by a better understanding of the “inherited” nature of health as a resource and of its intergenerational transmission. Health inequities that affect some subgroups are not limited to a single health problem, nor confined to narrow, transitory environments, but exert pernicious and pervasive effects throughout the life course (17).
The cycle of inequity
The health of mothers directly affects the health of their children, and this creates a cycle of inequities between the different generations. According to a study conducted in the Dominican Republic, a newborn whose mother has no formal education is 5.6 times more likely to not be registered at birth compared to the newborn of a mother with higher education. Social inequity in health continues when the child reaches adolescence and, in the case of women, childbearing age. The unmet need for family planning among women of childbearing age in the poorest quintile is almost double (1.9 times) the unmet need of women in the richest quintile. When they become pregnant, adolescents without formal education are 9.3 times more likely than adolescents from professional families to receive no prenatal care (18).
The dynamic conception of health is grounded in solid theoretical and philosophical arguments. However, the aspiration to place people — and not diseases — at the center of health policies will not be realized until practical ways to carry out the life course approach are designed and implemented.
Building health for a lifetime
Building health is a continuous process, one in which interventions and results are not isolated but cumulative over time, with periods of stability and of transformation. This interaction shapes trajectories that may be regarded as health pathways, at both the individual and population levels.
Progress in health
A girl born in Chile in 1910 had a life expectancy of 30 years (19); for the same child born today, this figure has almost tripled, to 84 years (17). The probability of today’s child dying before her fifth birthday has declined from 36% to less than 2%. Moreover, she has less risk of dying in childbirth, contracting infections such as tuberculosis, or suffering from anemia or cancer in middle age. When she becomes an adult, she will have the opportunity to decide how many children she wishes to have; the fertility rate in the second half of the 20th century fell from 5.3 children to 2.3. If born today, that girl would likely be taller and stronger and have greater intellectual ability than if she were born a century ago. Her life would be not only longer, but healthier.
The analysis of this process reveals both the needs and the influence of protective factors, as well as their impact on the development and maintenance of the capacities of persons and populations. An understanding of trajectories is essential in order to identify and predict the “how and when” of health, making it possible to design and implement more efficient and better-organized health policies (20). The health sciences, which for centuries have sought to understand the trajectories of diseases, will need to focus in the coming years on understanding life trajectories and, specifically, the health trajectories of individuals and populations.
It is important to emphasize that health is not innate; it is built over time. All individuals are born with a genetic capacity that underlies their personal potential and influences their health and longevity. However, we now know that genetic capacity accounts for only 30% of this influence, while the remaining 70% stems from the impact of positive and negative factors during the individual’s life trajectory (21). Contemporary genomic medicine already has a knowledge base concerning the genetic capacity of individuals and how to influence or manipulate it. This has improved the ability to diagnose genetic errors and genetic diseases, making it possible to predict clinical symptoms long before they appear and physiological changes in individuals before they occur (22). Modern genetics is capable of forecasting very early in life the diagnosis of diseases such as breast cancer or Alzheimer’s (23). It is also possible to predict which patients will be sensitive, or not, to a given treatment. These discoveries and others associated with biotechnology, nanotechnology, and pharmacology are part of an important group of interventions known as precision medicine, which will influence clinical practice in the coming decade (24).
Public health authorities in the countries of the Region should seek to understand the impact of these interventions and the ethical dilemmas they pose. For example, the decision of whether to intervene based on genetic risk (25) must take into account the high costs of such interventions and their potential effects on health coverage, as well as questions of access and financing (26).
Advances in epigenetics explain how gene expression can be modulated in response to environmental signals and how these changes can persist across several generations (27). A growing body of evidence makes clear that this plasticity is present not only in the early stages of life, but at other points during the life course, a finding that will have a great impact on medicine and public health (2, 28). In their adaptive response, human beings exhibit a high degree of plasticity (the capacity to modify developmental biology in response to environmental stimuli) that enables them to cope with the changes and different circumstances that they face (29).
However, the greatest advances in increasing life expectancy and improving health indicators are due to interventions that influence the life trajectories of individuals. The vast majority of the actions implemented in the Americas to date that have proved highly effective and efficient are related to health promotion. They include immunization, proper nutrition, physical activity, and the crusade against tobacco use, among others. There is great scope for increasing actions aimed at promotion and prevention. The barriers imposed by poverty and, especially, inequality, as well as the high costs associated with technology, will continue to limit access to new advances in public health and medicine for the vast majority of the population. This chapter and others in this report highlight this reality and its influence on the health situation in the Americas.
The importance of a good beginning
The impact of events on the life course is not uniform. A single stimulus — negative or positive — can have different impacts, depending upon the time of life when it occurs (30). During particularly sensitive periods, such as the prenatal stage, childhood, and adolescence, these stimuli can trigger adaptive responses in the individual and in populations, with long-term effects that extend to other stages of life. A reduced growth rate in utero and after birth has been associated with an increased risk of cardiovascular diseases and diabetes (29). In recent decades, greater knowledge of such time-linked effects, known since the mid-20th century as the “fetal origins of adult disease,” has increased the body of evidence regarding specific and critical moments of greatest susceptibility, the mechanisms involved, and the results (31).
Pregnancy and maternal health. With adolescent pregnancies in the Region at alarmingly high rates already, there is evidence of a new and troubling phenomenon: the increase in pregnancies among girls 14 years of age or younger in some countries (32). There has also been a relative increase in pregnancies among women 35 years of age or older, with a consequent rise in complications and mortality associated with assisted reproductive technology practices. The current functional relationship between maternal mortality and age results in a U-shaped curve, whose upper ends correspond to girls under 15 and women over 35 (32). The Region of the Americas is experiencing an obstetric transition that recalls the classical epidemiological models of demographic and epidemiological transitions. Although some less-developed countries and territories still have high rates of births and of direct maternal mortality, the predominant situation across the Region is a smaller number of births, a reduction of maternal mortality, and greater life expectancy for women. In this context, maternal mortality is linked to indirect obstetric causes and to the increased number of pregnancies that occur in complex circumstances, such as in women with noncommunicable diseases, transplants, and similar health problems. These different scenarios, shaped by economic, social, and cultural factors, will need an appropriate response from the health sector in the coming years. The goals and strategies for ending preventable maternal mortality require a specific and realistic framework to guide strategic planning. Furthermore, they should be sufficiently flexible so they can be interpreted and adapted effectively in various national contexts, and especially in the local contexts where they are applied.
Ample evidence exists that an inappropriate intergenesic space has an unfavorable effect on both the woman and her offspring. To ensure that a woman begins her pregnancy in the best circumstances, it is key to intervene with accurate information, while strictly respecting her self-determination (33). This perspective, which is not yet widespread in the Region, is linked to a focus on preconception, which in the coming years should be accorded the importance it deserves, just as occurred with prenatal care in last century (34). The impact of adverse conditions during pregnancy can be reduced through preconception care that is based on the provision of biomedical interventions and on the promotion of favorable habits and socio-environmental conditions, directed both to women and to their partners. The evidence suggests that births in disadvantageous conditions are often due to poor health behaviors, exposure to harmful environmental factors, and lack of access to health care (35).
Newborn health. Health at birth is a factor that helps to predict long-term results, such as education, income, and disability. In the Region of the Americas, even today, 8% of all newborns have low birthweight (less than 2,500 g) and 8.6% are premature. Both low birthweight and prematurity require prenatal care, which is provided to 88.2% of pregnancies in the Americas. Regionwide, 94.1% of deliveries take place in hospitals, although these figures obscure inequalities both within and between countries (36).
There is steadily increasing knowledge available about the protective effect on fetal health of various interventions, including expanded coverage of influenza vaccination — which helps prevent premature birth — as well as expansion of complementary nutrition, improvements in environmental health, reduction of violence against women, increased use of conditional cash transfers, and better understanding of maternal and fetal health (35). The association between the height of the child and of the mother, or between low birthweight in girls and the body composition and intrauterine growth of their eventual offspring, demonstrates the intergenerational effect of these influences (37).
High-quality care at the time of birth means achieving adequate coverage of the interventions with proven effectiveness, those that have a positive effect on maternal and newborn health. Examples of these interventions are timely clamping of the umbilical cord, early skin-to-skin contact, immediate initiation of breastfeeding, neonatal screening tests, and maternal-infant bonding to promote early development.
Breastfeeding and early childhood development
In the 21st century, breastfeeding is more relevant than ever, whether in a high- or low-income country or in a rich or poor family. The physical and emotional bond between a mother and her child is strengthened and influences epigenetic programming (38, 39). Adequate nutrition and a safe and nurturing environment favor early brain development and are essential in promoting better cognitive development, minimizing the risk of overweight, and protecting against certain chronic diseases (40, 41).
A good beginning means that the woman is attended by skilled personnel and that her delivery takes place in an appropriate institution and surroundings. Later, balancing the requirements of breastfeeding with the mother’s need to work implies extending maternity protection to provide mothers with a time, a private space, and an appropriate place to store breast milk and breastfeed safely. Society still does not provide a favorable and enabling environment to the majority of women who wish to breastfeed. Successful breastfeeding should be regarded as a collective social responsibility, involving health systems, families, communities, and workplaces. Rates of breastfeeding and indicators of adequate complementary feeding can be improved considerably in a very short time. Policies and programs to support nursing mothers in health centers, homes, and workplaces have a greater effect if they are designed and implemented as part of a package of interventions, but they require financing and political will (42).
Health in childhood
The life course approach clearly identifies the most critical or sensitive periods of life, which are “windows of time” characterized by heightened susceptibility, when exposure to certain factors can change the direction of a person’s life trajectory and modify the biological programming or social trajectory of individuals and populations, with short-term and long-term effects (43). According to the United Nations Convention on the Rights of the Child, all children have the right to achieve their full development potential and enjoy maximum health (44). Healthy children have greater opportunity to grow and develop into adults who are healthy and productive. The child population has particular characteristics and health needs that require specific responses and actions. The recognition of factors that promote their health and growth requires an understanding of the demographic, socioeconomic, and equity conditions that shape their lives, as well as factors related to family and social cohesion, health promotion policies, nutrition, the environment, and access to and utilization of services, among others (45).
Preventing disease and death is not sufficient to ensure a healthy childhood. In 2015, WHO presented the Global Strategy for Women’s, Children’s and Adolescents’ Health (46), one objective of which is to enable children to achieve their full development, which in turn yields high returns throughout the life course. It has been recognized that early childhood development provides a solid basis for the formation of human capital (22, 47). Today it is known that the foundations of brain architecture are laid and consolidated in the first years of life, through a dynamic interaction of genetic, biological, psychosocial, and environmental influences. The child’s brain begins developing at conception, and during the first two or three years of life this process advances more rapidly than at any other time (48).
Child development during early childhood
In 2016, Britto and colleagues (49) proposed three packages of effective measures aimed at creating opportunities for every child to achieve his or her maximum development potential: (a) a package of measures to support and strengthen families; (b) a package of multigenerational nurturing care measures; and (c) a package of early protection and learning measures (Figure 1). The challenge is to ensure that families and children benefit from these interventions, particularly children affected by multiple disadvantages.
The child’s environment can modify his or her genetic map, especially during a critical period of life. The environment does not change DNA, but it produces chemical changes that affect the development and neurocognitive-motor performance of the child. Moreover, these chemical signals can be transmitted from one generation to the next. The dynamic interactions between the environment and genetics place children on different trajectories that affect their health throughout life, along with their cognitive abilities, behavior, and social functioning, and those of future generations (22). The current literature on early childhood development emphasizes the need to adopt a broader approach to the physical, emotional, cognitive, and social development of children (51). This is a topic with intersectoral implications, encompassing health, education, nutrition, well-being, and social protection, among other areas (52). The interactions between children, their parents, and other caregivers — including those who provide health and social services — constitute the most important external influence, together with the exposure to environmental risks in the home and community. Parents and caregivers, both women and men, can help offset the negative effects of possible disadvantages by providing health care, nutrition, nurturing, security, and early learning – if they receive support to help them provide an appropriate upbringing to children.
In the Region of the Americas today, we have the necessary knowledge to eliminate infant mortality due to preventable causes, as well as to greatly improve the health and well-being of children and carry out the transformations needed to ensure a more prosperous and sustainable future (53).
Transitions and critical moments of life: adolescence as a model
As discussed, the life trajectories of individuals and populations contain transitions that are milestones in themselves and that constitute moments of change. These transitions can be biological, psychological, social, economic, political, or even geographic in origin, and they are not necessarily predetermined nor always foreseeable: examples include retirement, menarche, menopause, school entry, the beginning of working life, and migration. Other changes that can be mentioned include changes in social roles or, from the biological perspective, the acquisition or loss of functions that accompanies the beginning or end of physiological processes (54).
Adolescence represents the most documented example of the life course concept. It is one of the life stages with the most complex transitions and also one of the most sensitive periods of human development, during which behaviors are modeled and habits and lifestyles are adopted. The development of the human brain continues throughout life through a process known as neuroplasticity. Research suggests that the brain transformations taking place in adolescence are quite different from those that occur in childhood. During childhood, the focus is on dendritic outgrowth and synaptogenesis or synaptic growth, which permits the brain to increase substantially in size and weight. The evolution of the brain during the second decade of life and into early adulthood seems to concentrate on synaptic pruning, in which the process of eliminating weak or irrelevant synapses is necessary in order to obtain greater brain efficiency. Synaptic pruning is believed to depend on the responses of neurons to environmental factors and external stimuli. As a result, this stage is regarded as a critical period in which the individual is highly receptive to environmental stimuli, which in turn has enormous consequences for the neurological development of adolescents. This explains the adaptive form of learning and the rapid acquisition of interpersonal and emotional skills during adolescence (55).
An analysis of this process points to the importance of ensuring a secure and stable social environment for adolescents in order to support optimal development of the brain functions that are essential for longevity and for social and emotional well-being in adulthood (56, 57, 58) (Figure 2). Although the family can provide the primary structure of protection and security during this period, adolescents by nature are exposed to and sensitive to many other influences, such as friends, school, communications media, the community, and the world of work. This sensitivity that is so characteristic of adolescence implies that the communications media can influence the attitudes, values, and behavior of the individual more than during any other stage of life. The digital revolution has facilitated exposure to new ideas and contacts with like-minded people, but it also carries new risks, such as the marketing of unhealthy products and the promotion of fixed consumption habits.
Young people leave the educational system and enter the world of work, where they assume steadily increasing responsibility for their own decisions, including those that influence their health. This is the time of life when the human body acquires the capacity to reproduce, and it is also the stage when young people typically encounter tobacco, alcohol, and other possible health hazards for the first time (56). For this reason, parental monitoring and supervision of adolescents’ activities is indispensable in reducing health risks to adolescents. The effects of this relationship are documented: for example, the scientific evidence, although limited, suggests that communication between parents and adolescents – especially between mothers and daughters – on sexual subjects helps delay the beginning of sexual relations and promotes the use of contraceptive methods (59).
Giving birth at a young age is associated with greater risks to health. Unwanted early conception contributes to unsafe abortion, to mortality, and to health problems in the short and long term. Pregnancy in adolescence affects the life trajectories of the mothers and of their offspring, and has biological, social, and economic consequences. Young maternal age is associated with shorter gestation periods, low birthweight, poor nutrition, and lower educational attainment in children. Girls who become pregnant are more likely to interrupt their education, thus reducing their capacity to earn income throughout life and to support themselves and their children (60). The prevention of adolescent pregnancy and the provision of support to help adolescents control their own fertility not only helps save their lives, but also allows them to complete their reproductive development, increases their chances to acquire education and income, and improves the development prospects of future generations.
Health in middle age and beyond: a vision limited to disease?
In the next decade, efforts to provide comprehensive care to people in midlife should be reoriented to the health needs of people, rather than to diseases. The health issues of men and women in the post-reproductive stage of life have not received the necessary attention. These middle generations are subject to major social and family pressures related to caregiving, extension of the retirement age, and the implications of being viewed by health providers as bearers of diseases or risk factors. It is urgent to evolve toward a holistic vision of the person, using a life course approach.
Building mental health
Mental health is the result of interaction between protective factors and risk factors throughout the life course, including the prenatal period and intergenerational transmission. Failure to achieve key physical, cognitive, and socioemotional competencies leads to insufficient mental health development and can cause diseases (61). Cumulative exposure to stressors can have a negative effect, increasing the likelihood of the deterioration in mental health (62). Being a victim of child abuse can have effects that persist into adolescence and adulthood (63, 64). Psychosis, depression, and anxiety are disorders that originate in critical periods of early development (65–67).
A life course approach to the analysis of these trajectories and transitions provides strategic opportunities to design programs for disease prevention and promotion of mental health (68, 69). Mental health policies should treat the long-term combined effects of the biological, psychological, and environmental vulnerabilities of specific groups. By mediating or moderating the effects of exposure to risk, protective factors can have a cumulative effect on the life course (70). Cumulative risk indices make it possible to more accurately evaluate mental health and estimate the probability of suffering from mental illness; this in turn can lead to greater efficacy and efficiency in prevention and treatment, as well as a reduction in the equity gap determined by the accumulation of risks and disadvantages in certain populations (71, 72).
The WHO mhGAP intervention guide is an evidence-based model with a life course perspective, geared to the prevention and treatment of mental, neurological, and substance use disorders in non-specialized health contexts (71). It offers strategies tailored specifically to pregnant and lactating women, children, adolescents, and older persons. The guide also provides tools for comprehensive care of priority disorders through the use of optimized and simplified algorithms for clinical assessment, decision making, and monitoring, as well as a new module on implementation to support the proposed interventions with the necessary infrastructure and resources (73).
Intersections between violence against women and violence against children from the life course perspective
Violence against children and violence against women represent a global public health problem and are serious violations of human rights. The Sustainable Development Agenda recognizes both forms of injury as barriers to countries’ progress. An increasing body of scientific evidence points to the various intersections throughout the life course between these two forms of abuse (74). Violence against women during pregnancy is associated with negative outcomes for the health of women and their children (75, 76). The consequences of child abuse often persist into adulthood, leading to long-term changes in brain structure, causing physical and mental health problems, predisposing the individual to engage in risky behaviors, and even reducing life expectancy at birth (77–80). All this suggests that violence experienced during critical periods of development — whether directly experienced or witnessed — has harmful and lasting effects on the risk factors for health.
Building health in old age: functional capacity as the focus of care
Every 25 years, the global population of adults aged 60 or older doubles, and it is expected that by 2050 the Region will have approximately 400 million older people (79). In the Americas, a person who lives to age 60 will live on average 20 years more, and a person who turns 80 can expect to live another 7 years (4). In this demographic transition, healthy aging has been defined as a process that promotes and maintains the functional capacity required to permit well-being in old age (4). This functional capacity, which has various health-related dimensions, enables people to live and act according to their beliefs and values. Although this is true throughout the life course, old age is the stage where it is essential to boost efforts to prevent a deterioration in functional capacity, thus preserving a healthy life expectancy, or at the very least, freedom from disability. The overarching goal is to enable older people to lead active and independent lives and to prevent an unnecessary increase in the burden of long-term care.
The situation of older persons and patients is perhaps the clearest expression of the new needs in health, which in turn call for a substantial transformation in the model of health care at both the individual and population levels. Because of its importance for the Region, this topic is further explored in section 2.4 Aging and health.
Many health services are organized around the care of diseases and consider the person as a secondary priority (13). The appropriate treatment of chronic diseases is impossible without the participation of the individuals who suffer from them and the support of the community. A person who suffers from a chronic disease has a continuous relationship with that disease and must make decisions every day about his or her activities, diet, and prescribed medications. Meanwhile, that person’s contact with the health services is episodic and is limited to a number of hours or minutes every year. Hence, health systems should adopt programs of self-care that facilitate active autonomy, so that each person takes care of his or her own health. Such programs must help people properly monitor their own symptoms and comply with treatments in a responsible way. The goal is to promote well-being and the most active life possible, whether or not a person is living with disease (13). There is a great deal of evidence on the efficacy of self-care programs, not only in terms of their effectiveness and impact on individuals, but also because they help reduce demand for and unnecessary costs of health services (13).
Investment in health: a long-term strategy
Health is at the center of social development and economic growth. Healthy people and populations are more productive; children who enjoy good health develop better, growing into productive adults. An expanded response over the next few decades should include not only increases in financing directed to specific stages of life, but a commitment by all relevant sectors to carry out activities aimed at reducing health inequalities and inequities throughout life. To this end, it will be important to evaluate the long-term impact of investments and interventions in health, using the life course perspective.
Nutrition. Nutrition is one of the key factors that influences human health and longevity. More than for any other factor, theoretical arguments and empirical evidence support the role of nutrition in shaping the life trajectory and building health from preconception to death. Good nutrition in the first two years of life is associated with greater height and better cognitive and school performance. It has also been associated with greater economic productivity and its corresponding impact on personal income (19). Nutrition and its mediating circumstances influence the socioeconomic status of women and the birthweight of children in the next generation (28). However, the mechanism that links a woman’s early nutritional experiences with the nutrients transferred to her fetus is still unknown (81, 82). Malnutrition during the first years of life can negatively influence fetal and child growth in the next generation, whether through genetic, epigenetic, or physiological mechanisms. At present, obesity is one of the principal risks to longevity in the Region. Many population groups suffer from a double burden of nutritional problems, that is, undernutrition along with overweight (83).
Nutrition has been shown to have a determining effect on the maintenance of muscle mass and on the intrinsic and functional capacity of older persons, which in turn has an important impact on the ability to maintain a healthy and active lifestyle for the longest period possible (84).
Physical activity. The role of physical activity in building health throughout the life course must inform health strategies in the coming years. Sedentary lifestyles have favored an increase in chronic diseases associated with physical inactivity (85). Individuals with less mobility suffer greater morbidity, disability, and mortality (86). Several studies demonstrate that 25% of all people who engage in some type of physical activity spend less time with disability or with some type of injury, in comparison with people who do not perform any regular physical activity (87, 88). According to one study, participation in a physical activity program of moderate intensity for approximately 2.6 years can reduce mobility impairment in older persons (89).
Immunization. The success of immunization strategies is perhaps one of the best arguments in favor of the life course approach. Vaccines have a lasting impact on the economy through their mediating effect on health. Bloom and Canning propose a causal chain to explain this link between health and income (8). The following points illustrate these links between health and income:
a. Education: Immunization has a significant, long-term effect on intellectual performance and on health, which is manifested in an increase in cognitive capacity.
b. Productivity: Workers in healthy communities are less prone to absenteeism related to their own illness or the need to care for an ill family member. Bloom and Canning estimate that a one-year increase in life expectancy improves productivity by 4% (8).
c. Saving and investment: Healthy people can expect to live longer, and as a result, they are more prone to save for their retirement. They also are capable of working productively for a longer time, thereby increasing their savings. The economic consequences of immunization are not limited to the direct effects associated with the costs of health services or disease prevention, but extend much further to include indirect effects mediated by cognitive development, level of education, labor productivity, income, savings, and investment.
Sensory health. In 2015, disorders of the sensory organs were the second-ranking cause of years lived with disability (88), accounting for more than 68 million disability-adjusted life years (DALYs) (89). Unoperated cataracts continue to be the main cause of blindness, and uncorrected refractive errors are the main cause of visual impairment (90). Retinopathy of prematurity affects newborns in low- and middle-income countries due to deficient neonatal care (91, 92). A reduction in DALYs caused by visual impairment is a feasible and high-impact strategy for the years ahead. The high effectiveness of the interventions (glasses to correct refractive errors, and curative surgery for cataracts) in relation to their costs justifies greater attention to the burden associated with vision loss (91).
The Global Burden of Disease Hearing Loss Expert Group estimates that in Latin America in 2008, the prevalence of auditory disability was 1.1% in children 5 to 14 years of age and 9.6% and 12% in girls and boys over 15 years of age, respectively (93). Early identification and intervention in cases of hearing loss has a significant association with better language development in children (94). The early detection of auditory disability in children, the timely use of antibiotics for treatment of otitis media and meningitis, as well as the provision of hearing aids for conductive hearing loss can reduce this burden (91).
Evidence supports the importance of oral health in the different stages of life, as well as its intergenerational scope. According to a prospective cohort study, the presence of caries in adults 32 years of age is related to the oral health of the mother (71), and in a low-income Hispanic population an association was found between levels of cariogenic bacteria in the saliva of mothers and their children in early infancy (95).
In the near future, public health, the organization of health services, and clinical practice will all be affected by changes in traditional patterns. The contemporary patient will have high life expectancy but also chronic illnesses that may persist for many years, increasing functional limitations, and a need to interact with the health services over a long period of time. Such patients, in spite of their diseases, can enjoy well-being and feel healthy (7).
Today, we can already glimpse the beginning of the evolution toward an approach in which individuals are no longer the “objects of health interventions” but instead become increasingly active subjects in building their own health and managing their diseases. Despite profound inequalities, people tend to be more — although not necessarily better — informed, and they are making autonomous decisions earlier and more frequently, often without the involvement of the health services. Contemporary public health cannot ignore the participation of people and other actors in health promotion. Developing strategies that take account of the bidirectional influence between these new actors and health professionals in building health will pose a great challenge in the next decade.
From the standpoint of measurement and indicators, the life course approach should be integrated into health care systems as a dynamic process. Toward this end, information systems will need to be revamped, modernized, and strengthened to upgrade their coverage, quality, and analytical capacity. Impact assessment of the life course model should be enriched by reliable sources of information from multiple sectors (education, transportation, environment, finances, employment, and the legal system, among others), as well as from elements of the private sector. Information systems should be reoriented to prioritize indicators of well-being, functioning, and quality of life, as well as environmental indicators, and will need interoperability with the databases of other sectors. It will be up to regional agencies and national governments to advocate the adoption of the life course approach in order to achieve a broader understanding of population health and the delivery of health services.
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