On the Preservation of Health

HEALTH IS INTRINSICALLY UNSTABLE AND IS SUBJECT to erosive forces across the life trajectory, from intrauterine life to old age. As a result, few individuals achieve idealized versions of the lifespan (ie, good health and functional status into very advanced years, with compression of morbidity toward the end of life). Each person may be thought of as having, at birth, a certain quantum of health expectancy, determined by the characteristics of the individual genome and the biological quality of the intrauterine environment in which the fetus has developed. The quantum is affected over time as the biological, psychosocial, and behavioral characteristics of the individual interact with environmental, socioeconomic, and educational factors, and with the amount and quality of the health care received over the life course. Programs aimed at reduction of risk through health promotion at the individual or population level have been effective to some degree, but such efforts are frequently post hoc in nature, addressing secondary or tertiary prevention needs. In addition, these efforts are disarticulated across the lifespan, with childhood and adolescent clinical and public health interventions discontinuous from those in the adult years. Furthermore, the latter often focus on behavioral and environmental health risks only after they have been unaddressed for long periods, with incipient, clinically silent disease already established. In fact, risk exposures tend to increase in number, chronicity, and cumulative importance over the life trajectory, resulting in gradual erosion of health status and of future health prospects. A more consistent effort organized around health preservation as a framing paradigm, instituted early in life, and addressed to mitigating risk factors through a more syncytial and coherent life course approach is suggested by a number of factors. First, health risks are present throughout the life course and vary in nature over time, from intrauterine life to old age. Second, many clinical disorders that manifest in adult life represent late stages of long-standing occult disease, suggesting that earlier, even lifelong, application of preventive or moderating efforts might be more effective. Third, increasing evidence suggests that important causes of morbidity in adult life have their origins very early and, in some instances, may be to a significant degree determined before birth or neonatally. Fourth, healthrelated behaviors are acquired in more or less staccato fashion over the lifespan, and once-acquired, health-adverse behaviors are often difficult to disestablish, such as eating and physical activity patterns acquired in childhood, initiation of tobacco use, or exposure to illicit drugs in adolescence. Despite an increase in life expectancy at birth of approximately 30 years during the past century in the United States, most individuals are subject to gradual impairment of health. These impairments often become overt in the middle years of life; chronic diseases are the most common proximate causes. With advancing age, the occurrence and continuation of chronic disease is common; 80% of communitydwelling US individuals older than 65 years have at least 1 identified chronic disease and 48% have 3 or more chronic diseases. The disorders that represent the chief causes of death largely reflect longstanding risk factors and many are characterized by long clinical latency and progress silently often for years before becoming clinically apparent. To a considerable extent, these disorders reflect the effect of healthadverse personal behaviors that are responsible for an estimated 40% of deaths in the United States. The health effects of many of the major risk factors are avoidable or reversible to substantial degrees. Realization of the targets established in the most recent Healthy People 2010 report is estimated to potentially increase healthy life expectancy by 5.8 to 8.1 years. Studies among the Seventh Day Adventist population have suggested that optimal healthrelated personal behaviors could add 10 years to average life expectancy. Other studies indicate sharp reductions in health risk with cessation of smoking and with the adoption of regular exercise patterns, even in old age. Appropriate clinical interventions in disease management have also been associated with improved health outcomes, such as myocardial infarction, depression, low birth weight, cataracts, and breast cancer. Mitigation of social and economic factors that adversely impact health presents a more complex set of issues. Many of these factors are related to public policy, such as the availability of adequate housing, the nature and comprehensiveness of health insurance programs, remediation of toxic environments, and efforts to reduce poverty and thereby its health impacts.