Health Health Article

OBJECTIVE AND SUBJECTIVE PERCEPTIONS OF HEALTH

A well-trained physician, or an observant member of a family, can often tell at a glance that someone is unwell. There are obvious signs—pallor, sweating, unsteady gait, a bone-shaking cough. The converse is more challenging. Someone who appears to be outwardly perfectly fit—hale and hearty, sound in wind and limb—may harbor an early cancer that is eating away at a vital organ, or, when asked the right questions may reveal a potential mental health problem, though there is no physical evidence of a departure from excellent health. Health has many dimensions, and each must be assessed and measured on some sort of scale. This is what physicians do when conducting a routine medical history and physical examination, which includes various laboratory tests. The results of such an examination have a range of values that usually follow a normal distribution, and for many of these the decision that a particular value lies within or outside the range of normal is rather arbitrary, although it is based on empirical experience. For example, experience and follow-up of many sets of observations allow us to agree on what level of systolic and diastolic blood pressure give grounds for a confident recommendation that treatment is needed to reduce an excessively high pressure that could lead to a stroke or heart attack.

Conversely, many severely disabled people can function efficiently and cheerfully within their limited capacity—paraplegics can perform with consummate speed and skill in road races in wheelchairs, and blind people can play chess and swim in competitive tournaments. The theoretical physicist Stephen Hawking, described in his book, A Brief History of Time (1988), the full and productive life he leads, though he is profoundly disabled physically by amyotrophic lateral sclerosis (Lou Gehrig's disease). Physical, mental, and emotional health are clearly three different dimensions of health.

Determinants of Health. Both individual and population health are determined by physical, biological, behavioral, social, and cultural factors. First among the physical factors is the radiant energy of the sun, which is ultimately essential for all life on earth. In Airs, Waters, and Places, Hippocrates identified climate, environmental topography, and aspects of behavior as determinants of health. Climate is assuming greater importance than hitherto due to the climate changes caused by increasing industrialization and energy consumption. Environmentally, the presence or absence of trace elements in the soil or water, such as fluorides to toughen dental enamel, iodine to stimulate the thyroid gland, and lead compounds that damage the developing brain, act to enhance or impair our health.

Biological determinants of health are inherent or acquired. Genetic heritage is a contributing factor to longevity, and to susceptibility or resistance to a wide range of diseases that include the pathogenic microorganisms responsible for some of the great plagues that have afflicted humans for millennia. Molecular geneticists have demonstrated that the interaction of human communities with the plague bacillus, the influenza and smallpox viruses, the malaria parasite, and with several other microorganisms, played a role in determining the differentiation and distribution of early races of humans in Africa and Asia. On a much shorter time scale, pathogenic microorganisms may be the most important biological determinants of health and disease. Immunity or resistance to pathogens is a very important determinant of good health. Immunity is enhanced by prior exposure, or by maternal exposure in the case of newborn infants, who acquire maternal (passive) immunity to some infections before they are born, and have it reinforced after birth by antibodies in breast milk. Routine immunization of infants and small children protects them from harm by many common and formerly dangerous pathogens including those that cause diphtheria, tetanus, measles, poliomyelitis, and whooping cough. Nutritional status is another important influence on resistance to infection. Individuals and populations are most vulnerable when they are malnourished or starved, which is why plagues often accompany famines.

Behavioral determinants have been much studied. An association of certain diseases with particular personality types has been observed empirically for centuries. An irascible temperament, for example, has been linked to occurrence of strokes, and an association has been demonstrated between high risk of coronary heart disease and a type A personality, marked by forceful and aggressive behavior. Research on mind-body interactions, which unites the disciplines of psychology, neurology, and immunology, made great progress in the last quarter of the twentieth century and began to clarify and explain these relationships.

Social factors that influence or determine health are also complex. There is epidemiologic evidence that good health is determined at least in part by social connectedness. Persons who have many and frequent interactions with other family members and with a network of friends have a more favorable health experience in many ways than those who are socially isolated, live alone, are estranged from their family, and have little or no family and social support systems. It is difficult however, to unravel social connectedness and personality factors that may encourage gregariousness or a solitary way of life. Position in the social hierarchy plays a role. Michael Marmot, a professor at University College in London, and his colleagues studied British civil servants, showing that top managers lead healthier lives than middle managers, who in turn are healthier than semi-skilled and unskilled clerical workers. Social networks and support systems, and social positions, are in part determined by factors beyond the control of individuals. While they are interrelated with personality factors, they are very complex and not well understood.

Studies have shown that economic conditions dramatically effect health and longevity. A consistently strong relationship has been demonstrated between income levels and health status in every country where the relationship has been examined. Many interactions between social, economic, and cultural factors also help to determine or influence community health.

Culture is defined as the set of customs, traditions, values, intellectual, and artistic qualities, and religious beliefs that distinguish one social group or nation from another. Culture influences behavior through customs such as use of or abstention from meat, alcohol, and tobacco; the practice of rituals such as circumcision; marital customs such as the prevailing age at which women marry; attitudes toward family size, childbearing, and child rearing; personal hygiene; disposal of the dead; and much else. People's values may be the most significant component of culture that affects behavior and through behavior, health. For example, since the late nineteenth century, an understanding of the importance of personal hygiene has become part of the value system of many cultures. In the late twentieth century, values in many nations shifted towards a rejection of tobacco smoking as a socially acceptable custom. In the 1960s, the oral contraceptive pill contributed to the sexually liberated values and behavior that encouraged casual promiscuity, and which was only partially overshadowed by the threat of infection with HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome) in the 1980s and later.