Determinants of health

Health is multifactorial, influenced by factors within the individual and those external to the society in which they reside. It is a fundamental truth that an individual’s constitution and susceptibility to diseases depend on a combination of genetic and environmental factors. These factors interact, and such interactions can either promote health or have deleterious effects. Therefore, the health of individuals and entire communities can be viewed conceptually as the outcome of numerous complex interactions.

Human biology/Hereditary

The physical and mental traits of every human being are to some extent determined by the nature of his genes at the moment of conception. The genetic make-up is unique in that it cannot be altered after conception. A number of diseases are now known to be of genetic origin, e.g., chromosomal anomalies, errors of metabolism, mental retardation, some types of diabetes, etc. The state of health, therefore depends partly on the genetic constitution of man.

Nowadays, medical genetics offers hope for prevention and treatment of a wide spectrum of diseases, thus the prospect of better medicine and longer, healthier life. A vast field of knowledge has yet to be exploited. It plays a particularly important role in genetic screening and gene therapy.

Thus, from the genetic stand-point, health may be defined as that “state of the individual which is based upon the absence from the genetic constitution of such genes as correspond to characters that take the form of serious defect and derangement and to the absence of any aberration in respect of the total amount of chromosome material in the karyotype or stated in positive terms, from the presence in the genetic constitution of the genes that correspond to the normal characterization and to the presence of a normal karyotype.

Environment

It was Hippocrates who first related disease to environment, e.g., climate, water, air, etc. Centuries later, Pettenkofer in Germany revived the concept of disease­ environment association.

Environment is classified as “internal” and “external”.

The internal environment of man pertains to “each and every component part, every tissue, organ and organ system and their harmonious functioning within the system”. Internal environment is the domain of internal medicine.

The external or macro-environment consists of those things to which man is exposed after conception. It is defined as “all that which is external to the individual human host”. It can be divided into physical, biological and psychosocial components, any or all of which can affect the health of man and his susceptibility to illness. Some epidemiologists have used the term “micro-environment” (or domestic environment) to personal environment which includes the individual’s way of living and life style e.g. eating habits, other personal habits (e.g., smoking or drinking), use of drugs, etc. It is also customary to speak about occupational environment, socio-economic and moral environment. It is an established fact that environment has a direct impact on the physical, mental and social well-being of those living in it. The environmental factors range from housing, water supply, psychosocial stress and family structure through social and economic support systems, to the organization of health and social welfare services in the community.

The environmental components (physical, biological and psychological) are not water-tight compartments. They are so inextricably linked with one another that it is realistic and fruitful to view the human environment in to when we consider the influence of environment on the health status of the population. If the environment is favourable to the individual, he can make full use of his physical and mental capabilities. Protection and promotion of family and environmental health is one of the major issues in the world today.

Behavioural and socio-cultural conditions (lifestyles)

The term “lifestyle” is rather a diffuse concept often used to denote “the way people live”, reflecting a whole range of social values, attitudes and activities. It is composed of cultural and behavioural patterns and lifelong personal habits (e.g., smoking, alcoholism) that have developed through processes of socialization. Lifestyles are learnt through social interaction with parents, peer groups, friends and siblings and through school and mass media.

Health requires the promotion of healthy lifestyle. A considerable body of evidence has accumulated which indicates that there is an association between health and lifestyle of individuals. Many current-day health problems especially in the developed countries (e.g., coronary heart disease, obesity, lung cancer, drug addiction} are associated with lifestyle changes.

In developing countries traditional lifestyles still persist, risks of illness and death are connected with lack of sanitation, poor nutrition, personal hygiene, elementary human habits, customs and cultural patterns. It may be noted that not all lifestyle factors are harmful. There are many that can actually promote health. Examples include adequate nutrition, enough sleep, sufficient physical activity, etc.

In short, the achievement of optimum health demands adoption of healthy lifestyles. Health is both a consequence of an individual’s lifestyle and a factor in determining it

Socio-economic conditions

Socio-economic conditions have long been known to influence human health. For the majority of the world’s people, health status is determined primarily by their level of socio-economic development, e.g., per capita GNP, education, nutrition, employment, housing, the political system of the country, etc. Those of major importance are:

(i) Economic status: The per capita GNP is the most widely accepted measure of general economic performance. There can be no doubt that in many developing countries, it is the economic progress that has been the major factor in reducing morbidity, increasing life expectancy and improving the quality of life. The economic status determines the purchasing power, standard of living, quality of life, family size and the pattern of disease and deviant behavior in the community. It is also an important factor in seeking health care. Ironically, affluence may also be a contributory cause of illness as exemplified by the high rates of coronary heart disease, diabetes and obesity in the upper socio-economic groups.

(ii) Education: A second major factor influencing health status is education (especially female education). The world map of illiteracy closely coincides with the maps of poverty, malnutrition, ill-health, high infant and child mortality rates. Studies indicate that education, to some extent, compensates the effects of poverty on health, irrespective of the availability of health facilities.

(iii) Occupation: The very state of being employed in productive work promotes health, because the unemployed usually show a higher incidence of ill health and death. For many, loss of work may mean loss of income and status. It can cause psychological and social damage.

(iv) Political system: Health is also related to the country’s political system. Often the main obstacles to the implementation of health technologies are not technical, but rather political. Decisions concerning resource allocation, manpower policy, choice of technology and the degree to which health services are made available and accessible to different segments of the society are examples of the manner in which the political system can shape community health services. The percentage of GNP spent on health is a quantitative indicator of political commitment. What is needed is political commitment and leadership which is oriented towards social development, and not merely economic development. If poor health patterns are to be changed, then changes must be made in the entire socio­political system in any given community. Social, economic and political actions are required to eliminate health hazards in people’s working and living environments.

Health services

The term health and family welfare services cover a wide spectrum of personal and community services for treatment of disease, prevention of illness and promotion of health. The purpose of health services is to improve the health status of population. For example, immunization of children can influence the incidence/prevalence of particular diseases. Provision of safe water can prevent mortality and morbidity from water-borne diseases. The care of pregnant women and children would contribute to the reduction of maternal and child morbidity and mortality. To be effective, the health services must reach the social periphery, equitably distributed, accessible at a cost the country and community can afford, and socially acceptable. All these are ingredients of what is now termed “primary health care” which is seen as the way to better health.

Health services can also be seen as essential for social and economic development. It is well to remind ourselves that “health care does not produce good health”. Whereas, there is a strong correlation between GNP and expectation of life at birth, there is no significant correlation between medical density and expectation of life at birth. The most we can expect from an effective health service is good care. The epidemiological perspective emphasizes that health services, no matter how technically elegant or cost-effective, are ultimately pertinent only if they improve health.

Ageing population

By the year 2020, the world will have more than one billion people aged 60 and over, and more than two-thirds of them living in developing countries. Although the elderly in many countries enjoy better health than hither to, a major concern of rapid population ageing is the increased prevalence of chronic diseases and disabilities, both being conditions that tend to accompany the ageing process and deserve special attention.

Gender

The 1990s have witnessed an increased concentration on women’s issues. In 1993, the Global Commission on Women’s Health was established. The commission drew up an agenda for action on women’s health covering nutrition, reproductive health, the health consequences of violence, ageing, lifestyle related conditions and the occupational environment. It has brought about an increased awareness among policy-makers of women’s health issues and encourages their inclusion in all development plans as a priority.

Other factors

We are witnessing the transition from postindustrial age to an information age and experiencing the early days of two interconnected revolutions, in information and in communication. The development of these technologies offers tremendous opportunities in providing an easy and instant access to medical information once difficult to retrieve. It contributes to dissemination of information worldwide, serving the needs of many physicians, health professionals, biomedical scientists and researchers, the mass media and the public.

Other contributions to the health of population derive from systems outside the formal health care system, i.e. health related systems (e.g., food and agriculture, education, industry, social welfare, rural development), as well as adoption of policies in the economic and social fields that would assist in raising the standard of living. This would include employment opportunities, increased wages, prepaid medical programmes and family support systems.