3. Details on selected Health Determinants:
Conceptual Models of Population Health
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Doctors are taught to treat individuals, which is appropriate to the clinical care setting.
However, we have long known that patterns of health in populations (which diseases are common) are driven by fundamental characteristics of the society in which people live. These are the ‘social determinants of health’: structural aspects of society and the environment that drive the base rate of illness in a population (e.g., obesity and diabetes are common in industrial societies).
In turn, personal characteristics, or risk factors, are influenced by the determinants and produce individual variation around the base rate: some people watch their diet and exercise regularly; others do not. Social determinants mould the basic conditions in which people live; they form underlying "causes of the causes" of disease and illness. Their influence is mediated through risk factors such as whether or not a person chooses to smoke. Determinants account, for example, for the health differences between indigenous and non-indigenous Canadian populations, determining how many people in each group get sick. Risk factors influence which individual will get sick.
List of Determinants
Most public health agencies have proposed lists of determinants; there is no correct or incorrect version, and you just have to take your pick.
The WHO lists three determinants that take a 'Big Picture' view:
- Physical environment (including shelter; stable ecosystem; peace; sustainable resources);
- Social Environment (income; education; social security; equity; social justice and respect for human rights; access to health care services);
- Biological and Behavioural determinants (genetic factors; ethnicity; lifestyle, such as smoking, immigration, etc.)
The Public Health Agency of Canada currently lists 12 determinants:
- Physical environments;
- Employment and working conditions;
- Social environments;
- Social support networks;
- Health services;
- Income and social status;
- Education and literacy;
- Personal health practices and coping skills;
- Healthy child development;
- Biology and genetic endowment;
Many of these determinants may be grouped under the general heading of socio-economic status (SES). We know that virtually all aspects of health vary systematically by SES. Morbidity and mortality rates are correlated with education, with income, occupation and other factors, but each of these reflects broader differences in social determinants (such as the 12 listed) that are the actual drivers of the broad patterns of health.
Physicians spend most of their time treating the end-result of these complex issues that cause poor health. In effect, they treat the symptoms of social conditions: the health determinants. This can be professionally frustrating for health workers, who see the same consequences repeatedly. It has led to the Health Advocate CanMEDS role and to patient-centered medicine.
Understanding the role of health determinants will help you identify what factors impact your patient’s health and health choices. It will help you avoid stereotyping patients based on social status, race, gender, etc. It can also help you tailor solutions to your patient (for example, choosing a medication that your patient can afford).
It is also important to understand that a cure-focused approach instead of a preventative or health determinants-focused approach is economically wasteful. In many cases, preventing a disease (or modifying the social factors that increase risk of a disease) may be less costly than cure and may benefit many people, not just your own patient.
In light of the impact of health determinants on health and on health expenditures, you may choose to be a medical professional who works on improving and addressing health determinants in addition to curing disease.
If you’re interested in reading a philosophical perspective on health care and social determinants, see Gopal Sreenivasan’s paper “Health Care and Equality of Opportunity”. Sreenivasan concludes that a more effective method to fairly distribute health would be to devote the money currently being allocated to health care towards evening out social determinants of health.
Every disease or health condition arises from a chain of causal influences. It is convenient to distinguish between various categories of causal factor.
A cause is a generic term that refers to many types of factor (bacterium, behaviour, environmental circumstance, personal characteristic, etc.) without which the condition would have not arisen. This is a 'counterfactual' conception – without the factor this case of the disease would not have occurred. In this conception, causes are necessary precursors, although they are rarely sufficient. Other factors may be classified as contributing causes, to indicate either that they were not strictly necessary, but may have amplified the effect of other causal factors, or else that they lay further 'upstream' in the causal chain.
In common parlance, cause is typically used retrospectively: "Doctor, what caused my heart attack?" The term risk factor is often used prospectively, in discussions of whether a disease may or may not occur. Risk factors usually refer to factors operating at the individual level that increase the likelihood that a disease will arise: they are causes that are neither necessary nor sufficient. The probabilistic language is appropriate as very few factors are sufficient to cause a disease. "Smoking is a risk factor for lung cancer" implies a causal influence, but does not imply that every smoker will get lung cancer.
Other characteristics (such as age or ethnicity) may be described as risk markers or risk indicators, meaning that they are not the actual causal factor, but identify people likely to possess or experience the causal influence. Young age may be a risk indicator for motor vehicle collisions: they do not occur simply because a person is young, but because behaviours leading to collisions seem to occur more frequently among younger people.
A determinant is often presented as the 'cause of the causes' – and refers to underlying factors that gave rise to (hence explain) immediate causal factors. Determinants often operate at the societal level. Examples would include poverty, or the lack of a social safety net, or the lack of legislation to discourage smoking among young people. Determinants are useful in explaining patterns and rates of disease in populations. In a more technical expression, determinants explain the incidence rates of disease in a population, whereas risk factors predict which individuals will get sick.
Multiple factors are involved in causing any case of a disease, so it makes little sense to talk of "the cause" (link to Agent-Host-Environment). Especially for non-communicable diseases, different people may get the same disease through different pathways: the same type of cancer may be attributed to various exposures. This complexity has been pondered for centuries by philosophers, such as John Stuart Mill, and was illustrated by the epidemiologist Ken Rothman using the metaphor of "causal pies". Coloured slices in each pie represent different causal factors. Put together, the slices of a pie are sufficient to cause the disease. The different pies represent different combinations of causal factors; if one factor is necessary (such as a bacterium) it would appear in each pie. This led to the mnemonic "INUS." This stands for a causal component that is Insufficient (this factor alone will not produce the disease) but it is a Necessary component of a set of factors (the whole pie) that are together Unnecessary to cause the disease (because the disease can arise by other routes, shown by other pies) and yet the set of factors is Sufficient to cause it when they do co-occur. Quite a mouthful, but a useful way to think about parallel but independent sets of causal influences. Perhaps we should move beyond talking about finding “the” cause of a disease.
Socioeconomic status (SES) refers to a person's rank, position or esteem in society. This is an abstract concept and there are a number of possible indicators. SES may be expressed in terms of income, or level of education, type of occupation, accumulated wealth or the value of a person's house, etc.
Whatever the indicator we use, there is an almost universal tendency for people in lower socioeconomic groups to die younger and to suffer more illness during their lifetime.
In the diagram below, family income is used to represent SES. It has been adjusted to reflect the number of persons being supported and is grouped into 5 categories ('quintiles') running from poor to rich. The graph shows the years of life remaining, on average, after age 25 for people in each income category. The data were taken from a study of 2.735 million Canadians who were followed for 15 years after the 1991 Census, with deaths being recorded and linked back to the information on the census. (Tjepkema M, Wilkins R. Remaining life expectancy at age 25 and probability of survival to age 75, by socio-economic status and Aboriginal ancestry. Health Reports. 2010;22(4):1-6.)
Remaining life expectancy at age 25 in Canada by sex and income quintile, non-institutionalized population, 1991 to 2006
You will observe that, for males, people in the lowest income category will live on average to age 73 (25 + 48), while people in the richest income level can expect to live to age 80 (25 + 55): a discrepancy of 7 years. The gap is about 5 years for women.
The same study compared mortality across occupational groups. For men, the risk of dying (after adjustment for age) was more than twice as high for those who are unemployed compared to professionals. People who were visible minorities actually had lower mortality rates than the white population, but mortality among Aboriginal peoples was 1.4 times the rate in the non-Aboriginal population. Interestingly, people who only speak French have a 15% higher mortality risk than Anglophones or bilingual people.
For women, those with no paid occupation have a 50% increased risk of dying; visible minorities again fare better than the white population. However, Aboriginal women are at 1.76 times the risk of mortality (i.e., close to twice); but unilingual French speaking women have a slightly lower chance of dying.
As you read on about other health determinants, keep in mind that the majority of them are mediated by SES or can be considered facets of SES. Morbidity and mortality rates are correlated with education, income, occupation and many other factors, and these reflect broad patterns of social determinants which are the actual drivers of health.
Educational level is strongly linked to many aspects of health. For many conditions, the association is due to the broader link between socio-economic status (SES) and health; education here forms an indicator of SES. For other conditions, such as dementia, education may be an indicator of brain reserve that may enable an elderly person to function for longer despite neuronal damage.
The Canadian Facts (link) also brings up the idea of education being associated with increased power for change in the employment market and political landscape. With higher education, there is increased possibility for civic activities or engagement with politics. All in all, higher education increases an individual’s understanding of the world and their ability to influence the other social factors that impact their health.
Note: More information is included in the Child Poverty page in the Maternal and Child Health theme. If you have not yet read that page, you can do so now and consider its implications for health.
Income is the money that a person receives on a regular basis (usually as the result of employment or other investments). It is one of the most important health determinants because purchasing power drives a wide range of risk factors.
“Level of income shapes overall living conditions, affects psychological functioning, and influences health-related behaviours such as quality of diet, extent of physical activity, tobacco use, and excessive alcohol use. In Canada, income determines the quality of other social determinants of health such as food security, housing, and other basic prerequisites of health.” - The Canadian Facts
Additionally, the evenness of the distribution of wealth in society is important. Increased income equality (i.e. a smaller gap between the rich and the poor) has been shown to be a very good predictor for better health overall in that society.
Note: Click here to go to the Cultural Competency theme for a more detailed look at culture and its impact on health.
Culture refers to the shared values, understandings, assumptions and goals that guide the everyday life of a group. These are learned from earlier generations and are passed on to the succeeding generations. This shared outlook produces the typical attitudes that characterize a group, underpins their informal code of conduct and defines expectations that guide and control certain norms of behavior.
“Cultural norms” are the behaviors expected (or rejected) by culture, telling people what behaviors are appropriate.
“Cultural values” are the society’s beliefs about what is good, bad, beautiful, and what are legitimate goals in life.
Most societies identify a "mainstream" culture, and a host of subcultures. The latter may be defined in terms of age (teen culture), identity (LGBTQ culture), ethnicity (West Indian), location (street culture) or even health problems (drug culture; Alcoholics Anonymous).
Our culture influences the way we perceive virtually everything around us. This is often unconscious. Hence, culture naturally influences health, through many channels:
- Lifestyles: diet, smoking or use of drugs, patterns of exercise. These may have a positive effect on health (Mormons appear to live long because of avoiding alcohol, smoking, etc), or a negative effect;
- Attitudes toward health and illness. This includes what a person considers illness that requires treatment, and what treatments and preventive measures (vaccinations?) he or she will accept. Chinese cultures may view a sore throat in terms of imbalance between hot and cold;
- Reactions to being sick: the "Why me?" question. A person's answer (and hence how she or he handles being sick) is often guided by their cultural roots;
- Prohibitions (e.g. on using condoms) which can influence transmission of disease (here, STDs);
- Communication patterns - language but also modes of thinking. These can complicate (or enrich) your efforts to establish a therapeutic relationship and thereby cure your patient;
- Via cultural practices, either negatively (e.g., genital mutilation?) or positively (religious participation can lend group support which can promote health);
- Via the status of groups: women in some societies who have little power to insist on condom use; male 'machismo' may discourage them from seeking prompt medical attention.
If you find yourself thinking, “I don't belong to a culture”, it is potentially because you are part of the mainstream culture. Consider what advantages or disadvantages a particular cultural identity can bring with it in Canada.
Link to U Toronto program on end of life care -- module on How culture influences our thinking about dying
Culture and clinical care Pachter LM. (JAMA 1994; 271(9)). This article offers a gateway to a literature on the topic of how culture can affect how patients respond to care
War is a health determinant both in terms of direct casualties and also regarding the impact that war and conflict have on survivors, such as refugees.
In terms of casualties, Christer Ahlström at the Department of Peace and Conflict Research at Uppsala University has estimated that almost 90 percent of casualties in late 20th century wars (Iraq, Bosnia, etc.) were civilians. Estimating civilian losses is difficult: armies record deaths of their own soldiers, but not of civilians. A country ravaged by war faces huge difficulties compiling its own tally.
In terms of impact for survivors, war leads to tremendous disparity and has secondary effects on other health determinants (income, housing, education, social and physical infrastructure, water supply, etc.).
Image redrawn from Conflict as a Social Determinant of Health, adapted from Dahlgreen and Whitehead (1992).
(Source: Conflict as a Social Determinant of Health by Martin and Evans)
The Iraq Conflict
In October of 2006, GH Burnham and LF Roberts trained Iraqi volunteers who surveyed 7,868 people in 33 locations across the country. They recorded numbers of births and deaths to members of each household for a period before and then during the war. They estimated the excess mortality in Iraq to be 654,965 since the 2003 invasion — deaths that would not have been expected were it not for the war ("Mortality after the 2003 invasion of Iraq: a survey." Lancet, October 11, 2006).
Upwards of 1,000 Iraqis were dying each day during 2005-2006. The crude mortality rate progressed year by year, rising from the pre-invasion 5 per 1,000 to 7.5 in June 2005, then to 10.9, and finally to 19.8 by June 2006. Of the post-invasion deaths, 92 percent were by violence.
However, only 31 percent of violent deaths were attributed to coalition armed forces, suggesting a high level of sectarian violence and lawlessness.
In Britain, The Guardian newspaper commented: "At a time when we are celebrating our enlightened abolition of slavery 200 years ago, we are continuing to commit one of the worst international abuses of human rights of the past half-century. It is inexplicable how we allowed this to happen. It is inexplicable why we are not demanding this government's mass resignation." (March 28, 2007).
Syrian Civil War
Syria’s history is complex and many have theorized about the interplay of numerous historical events that may have led to the Syrian civil war that began in 2011. Ultimately, it was in the year 2000, with the death of Hafez Al-Assad, prime minister of Syria for 29 years, and with the rise to power of his son, Bashar Al-Assad, that the sovereignty and the economy became increasingly unstable. The Syrian population grew increasingly impatient with the government and its policies; this set the stage for the Arab Spring as it made its way from North Africa to the Middle East.
In the spring of 2011, anti-government demonstrations were held in Syria as part of the Arab Spring. While initially peaceful, the violnt government response escalated the situation and the demonstrations became rebellion. Currently (as of 2016), there have been five years of civil war in Syria, leading to one of the worst humanitarian crises of the modern age.
Estimates of the number of deaths vary. As of April 2016, the United Nations estimated 400,000 deaths in the war. Many Syrians have fled their homes to avoid the conflict. By February 2016, the United Nations reported 6.6 million Syrians had been displaced within Syria and over 4.8 million as refugees outside Syria. Refugees in neighboring countries are either living in UNHCR camps or as urban refugees. Refugee camps offer basic necessities of life, education and health care. On the other hand, those who choose to live in urban communities can work, probably illegally, and earn money. Other refugees have attempted (and are attempting) to cross the Mediterranean from Turkey to Greece. This crossing is not easy and has also taken many lives. Canada has agreed to resettle 35,000-50,000 refugees by the end of 2016.
BBC Article “Migrant crisis”
Health care includes services to promote health, prevent disease and disability, diagnose, and treat and restore health/function.
In Canada, health care coverage (that is, who pays for health services) is organized provincially through thirteen different provincial and territorial health insurance plans. While there is variation in the insurance coverage offered by each province and territory, the Canadian Health Act outlines which “medically necessary” services must be provided as insured health services in each province and territory.
These insured health services include: “hospital services provided to in-patients or out-patients (if the services are medically necessary for the purpose of maintaining health, preventing disease or diagnosing or treating an injury, illness, or disability); and medically required physician services rendered by medical practitioners.” – Health Canada
However, the Canada Health Act does not provide a list of insured services that are medically necessary and, as such, there is variation in the services that are insured by the provinces and territories. It additionally does not cover prescription drugs, home care or long-term care, vision care/prescription glasses or dental care. While provinces or territories may have some coverage for these services or treatments, most Canadians pay for these services with their personal funds (“out-of-pocket”) or with private insurance.
Canadians with below-average income are three times less likely to fill a prescription compared to above-average earners. They are also 60% less likely to get a required test or treatment due to cost.
A 2012 report by Public Health Ontario found that lowest-income households (<15,000$ annual household income) had a lower rate of having gone to the dentist in the last year compared to highest-income households (48.9%, compared to 84.1%) and the highest rate of visiting a dentist only for emergency services (43.8%, compared to 7.7% in highest-income households).
As such, it is evident that health care in the society in which an individual lives is itself a determinant of health.
Click here to go to the Health Care theme for more information.
We have covered personal health practices in separate pages, as follows:
Nutrition, Diet and Physical Activity
We also have a general discussion of health behaviours and explanatory models of these."When you ain't got no education, you sure gotta use your brains"
(Comment to a traveller by a night watchman in N. Dakota)
Updated August 2, 2017