The Whitehall Studies investigated
social determinants of health
The social determinants of health (SDOH) are the economic and social conditions that influence individual and group differences in health status. They are the health promoting factors found in one's living and working conditions (such as the d ...
, specifically the
cardiovascular
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
disease prevalence and
mortality rate
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of de ...
s among British
civil servant
The civil service is a collective term for a sector of government composed mainly of career civil servants hired on professional merit rather than appointed or elected, whose institutional tenure typically survives transitions of political leaders ...
s. The initial prospective
cohort study
A cohort study is a particular form of longitudinal study that samples a cohort (a group of people who share a defining characteristic, typically those who experienced a common event in a selected period, such as birth or graduation), performing ...
, the Whitehall I Study,
examined over 17,500 male civil servants between the ages of 20 and 64, and was conducted over a period of ten years, beginning in 1967. A second cohort study, the Whitehall II Study,
was conducted from 1985 to 1988 and examined the health of 10,308 civil servants aged 35 to 55, of whom two thirds were men and one third women. A long-term follow-up of study subjects from the first two phases is ongoing.
The studies, named after the
Whitehall
Whitehall is a road and area in the City of Westminster, Central London. The road forms the first part of the A roads in Zone 3 of the Great Britain numbering scheme, A3212 road from Trafalgar Square to Chelsea, London, Chelsea. It is the main ...
area of
London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
and originally led by
Michael Marmot
Sir Michael Gideon Marmot (born 26 February 1945) is Professor of Epidemiology and Public Health at University College London. He is currently the Director of The UCL Institute of Health Equity. Marmot has led research groups on health inequa ...
, found a strong association between grade levels of civil servant employment and mortality rates from a range of causes: the lower the grade, the higher the mortality rate. Men in the lowest grade (messengers, doorkeepers, etc.) had a mortality rate three times higher than that of men in the highest grade (administrators). This effect has since been observed in other studies and named the "status syndrome".
Whitehall I
The first Whitehall Study compared mortality of people in the highly stratified environment of the
British Civil Service
His Majesty's Home Civil Service, also known as His Majesty's Civil Service, the Home Civil Service, or colloquially as the Civil Service is the permanent bureaucracy or secretariat of Crown employees that supports His Majesty's Government, which ...
. It showed that among British civil servants, mortality was higher among those in the lower grade when compared to the higher grade. The more senior one was in the employment hierarchy, the longer one might expect to live compared to people in lower employment grades.
The first of the Whitehall studies, or Whitehall I, found higher
mortality rate
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of de ...
s due to all causes for men of lower employment grade. The study also revealed a higher mortality rate specifically due to
coronary heart disease
Coronary artery disease (CAD), also called coronary heart disease (CHD), ischemic heart disease (IHD), myocardial ischemia, or simply heart disease, involves the reduction of blood flow to the heart muscle due to build-up of atherosclerotic pla ...
for men in the lower employment grade when compared to men in higher grades.
The initial Whitehall study found lower grades, and thus
status
Status (Latin plural: ''statūs''), is a state, condition, or situation, and may refer to:
* Status (law)
** City status
** Legal status, in law
** Political status, in international law
** Small entity status, in patent law
** Status conference ...
, were clearly associated with higher prevalence of significant risk factors. These risk factors include
obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...
, smoking, reduced
leisure
Leisure has often been defined as a quality of experience or as free time. Free time is time spent away from business, work, job hunting, domestic chores, and education, as well as necessary activities such as eating and sleeping. Leisure ...
time, lower levels of physical activity, higher prevalence of underlying illness, higher
blood pressure
Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...
, and shorter height. Controlling for these risk factors accounted for no more than forty percent of differences between civil service grades in
cardiovascular disease
Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, h ...
mortality
Mortality is the state of being mortal, or susceptible to death; the opposite of immortality.
Mortality may also refer to:
* Fish mortality, a parameter used in fisheries population dynamics to account for the loss of fish in a fish stock throug ...
. After controlling for these risk factors, the lowest grade still had a
relative risk
The relative risk (RR) or risk ratio is the ratio of the probability of an outcome in an exposed group to the probability of an outcome in an unexposed group. Together with risk difference and odds ratio, relative risk measures the association bet ...
of 2.1 for cardiovascular disease mortality compared to the highest grade.
Whitehall I was carried out by the Department of Medical Statistics & Epidemiology at the
London School of Hygiene & Tropical Medicine
The London School of Hygiene and Tropical Medicine (LSHTM) is a public research university in Bloomsbury, central London, and a member institution of the University of London that specialises in public health and tropical medicine.
The inst ...
and published in 1987. The Whitehall Study papers are available to view at the School's archives.
Whitehall II
Twenty years later, th
Whitehall II studydocumented a similar gradient in morbidity in women as well as men. The name ''Whitehall II'' was derived from the previous Whitehall study. The Whitehall Studies revealed this social gradient for a range of different diseases: heart disease, some cancers, chronic lung disease, gastrointestinal disease, depression, suicide, sickness absence, back pain and general feelings of ill-health. A major challenge, and a reason for the importance of these studies, was to understand the causes of this social distribution of so many disorders.
Whitehall II is a longitudinal,
prospective cohort study
A prospective cohort study is a longitudinal cohort study that follows over time a group of similar individuals (cohorts) who differ with respect to certain factors under study, to determine how these factors affect rates of a certain outcome. F ...
of 10,308 women and men, all of whom were employed in the London offices of the British Civil Service at the time they were recruited to the study in 1985. The Study is led by Professor Mika Kivimaki at University College London. The initial data collection included a clinical examination and self-report questionnaire. Since then, twelve waves of data collection have been completed: phase 1 (1984-1985; age 35 to 55), phase 2 (1989-1990), phase 3 (1991-1993), phase 4 (1995-1996), phase 5 (1997-1999), phase 6 (2001), phase 7 (2002-2004), phase 8 (2006), phase 9 (2007-2009), phase 10 (2011), phase 11 (2012-2013), phase 12 (2015-2016). The thirteenth wave began in February 2019. Researchers are continuing to collect further data and samples from the cohort.
Research continues to explore the pathways and mechanisms through which social position influences health. The research group aims to build a
causal model
In the philosophy of science, a causal model (or structural causal model) is a conceptual model that describes the causal mechanisms of a system. Causal models can improve study designs by providing clear rules for deciding which independent va ...
leading from social position through psychosocial and behavioural pathways to pathophysiological changes, sub-clinical markers of disease, functional change, and clinical disease.
The Whitehall II study began as a study of working age people and investigated the relationships between work, stress, and health. Whitehall II found that the way work is organised, the work climate, social influences outside work, influences from early life, and health behaviours all contribute to the social gradient in health. As participants in this study continue through adult life, the research focuses on inequalities in health and functioning in an aging population. With an increasingly large population of older citizens in the UK, there is an urgent need to identify the causes of social inequalities and to study the long-term effects of previous circumstances on people's ability to function and stay healthy during retirement. Researchers in the Whitehall II team are also considering the role of social inequalities in relation to
dementia
Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...
risk.
Data sharing
The Whitehall II team have a
data sharing
Data sharing is the practice of making data used for scholarly research available to other investigators. Many funding agencies, institutions, and publication venues have policies regarding data sharing because transparency and openness are consid ...
policy, allowing researchers from other institutions to use data from the Whitehall II cohort. There is a slightly different data sharing policy for projects that involve genetic information. This policy suggests that the team are engaging with the
open access movement
Open access (OA) is a set of principles and a range of practices through which research outputs are distributed online, free of access charges or other barriers. With open access strictly defined (according to the 2001 definition), or libre op ...
, a social movement which is gaining momentum in academia.
International impact
The social gradient in health is not a phenomenon confined to the British Civil Service. Throughout the developed world, wherever researchers have had data to investigate, they have observed the social gradient in health. In order to address inequalities in health, it is necessary both to understand how social organisation affects health, and to find ways to improve the conditions in which people work and live.
Michael Marmot
Sir Michael Gideon Marmot (born 26 February 1945) is Professor of Epidemiology and Public Health at University College London. He is currently the Director of The UCL Institute of Health Equity. Marmot has led research groups on health inequa ...
chaired the World Health Organization's Commission on Social Determinants of Health (CSDH), which was established in 2005 and launched its final report in August 2008.
The Commission sought to engage with policy makers, global institutions, and civil society on the issues around health inequalities within and between countries, the social determinants of health, and act to address those issues. The CSDH acted as a catalyst for change, working with countries, academics, and civil society to bring health inequalities to the fore in the national policy dialogue. The overarching goals of the CSDH were to improve population health, to reduce health inequities, and to reduce disadvantages due to ill health.
Health risks associated with disparities of wealth and power
By design, the Whitehall studies have been focused upon a single set of related occupations, where the people within each occupational grade tend to be socially similar, yet clear social distinctions between grades are inherent. The studies were designed in this manner as an attempt to avoid certain research drawbacks associated with generalized
social class
A social class is a grouping of people into a set of Dominance hierarchy, hierarchical social categories, the most common being the Upper class, upper, Middle class, middle and Working class, lower classes. Membership in a social class can for ...
groupings—drawbacks that otherwise would result from the diversity of occupations within social classes—which in turn would tend to reduce the objectivity of any analysis.
The primary health risks under investigation in the Whitehall studies include cardiovascular function, smoking, car ownership,
angina
Angina, also known as angina pectoris, is chest pain or pressure, usually caused by ischemia, insufficient blood flow to the Cardiac muscle, heart muscle (myocardium). It is most commonly a symptom of coronary artery disease.
Angina is typical ...
, leisure and hobbies,
ECG
Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...
measurements, and
diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
.
High blood pressure at work was associated with greater "job stress," including "lack of skill utilization," "tension," and "lack of clarity" in tasks assigned. The higher blood pressure among the lowest grade servants was found to be related to the highest job stress score, whereas blood pressure at home was not related to job stress level.
According to Whitehall study researchers, "a steep inverse association between social class, as assessed by grade of employment, and mortality from a wide range of diseases" has been demonstrated. Summing up the moral of the Whitehall studies, the researchers concluded that "more attention should be paid to the social environments, job design, and the consequences of income inequality."
Explanations and implications
Subjects of Whitehall II in the lowest employment grades were more likely to have many of the established risk factors of coronary heart disease (CHD): a propensity to smoke, lower height-to-weight ratio, less leisure time, and higher blood pressure. However, even after normalizing for those factors, the lower employment grades were still at greater risk for a heart attack; another factor was at work.
Some have pointed to cortisol, a hormone produced by the body as a response to stress. An effect of cortisol release is a reduction in the immune system's efficacy through lymphocyte manipulation. One theory explaining the connection between immune-efficiency and CHD is that infectious pathogens, such as
herpes
Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected.
Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold s ...
or
Chlamydia
Chlamydia, or more specifically a chlamydia infection, is a sexually transmitted infection caused by the bacterium ''Chlamydia trachomatis''. Most people who are infected have no symptoms. When symptoms do appear they may occur only several wee ...
, are at least partially responsible for coronary diseases. Therefore, a body with a chronically suppressed immune system will be less able to prevent CHD.
A study of the
cortisol
Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone.
It is produced in many animals, mainly by the ''zona fasciculata'' of the adrenal cortex in the adrenal gland ...
awakening response (the difference between cortisol levels upon awakening and thirty minutes later) further supports the significance of cortisol. Workers showed no significant difference in cortisol levels upon awakening, regardless of socioeconomic position. However, the lower employment grades showed significantly higher levels thirty minutes later, particularly if it was a workday. Researchers concluded that to be caused by chronic stress and its anticipation.
This seems counter-intuitive: one usually thinks of those with the most decision-making responsibility as the ones with the most stressful lives. One theory is that the lower one is on the chain of command, the less control one has over his or her life. Not having to take orders on how to perform a task, or when to do it, results in lower heart rate, stress hormones, and blood pressure than being told how and when to perform it.
This theory, however, is not without its detractors. A Finnish study conducted a cohort study similar to Whitehall, but with greater analysis of the worker's stress. The study determined that decision autonomy was not a significant contributing factor to coronary heart disease, but that lack of predictability in the workplace was a significant factor. In the Finnish study, "predictability" was defined as high stability of work and lack of unexpected changes, and was found to correlate closely to employment grade.
Others argue that because there is a strong correlation between low employment grade and domestic stress, stress from a lack of control at work cannot be the whole story. In this line of reasoning, the size of one's paycheck alone could significantly contribute to overall stress. Those with fewer resources have a harder time making ends meet, a situation that can be a tremendous source of chronic anxiety.
Adding to the controversy is the disagreement over the cortisol explanation in the first place. The theory is based on a pathogenic contribution to coronary heart disease and the stressed body's inability to fight it. Follow-up studies on the Whitehall II cohort failed to demonstrate a correlation between pathogen burden and socioeconomic status, whereas other studies in different parts of the world have.
An alternative to the cortisol explanation is that self-esteem is the major contributing factor and that the link between professional achievement and self-esteem accounts for the health gradient. The study supporting this view correlated low self-esteem in test subjects with greater reductions in heart rate variability and higher heart rates in general—both established coronary heart disease risk factors—while performing stressful tasks.
Currently there is no universally-accepted cause for the phenomenon brought to light by the Whitehall studies. Clearly, stress is associated with a higher risk of coronary heart disease, but so are many other non-traditional factors. Furthermore, “stress” seems to be too nonspecific. There are different kinds of stress in one's day-to-day life and each kind could contribute differently. Vaananen, et al., are making great headway in this regard by researching which components of stress are responsible and which are not.
Regardless of the exact reason why coronary heart disease is more prevalent in lower employment grades, the results of the Whitehall studies have significantly changed the way some doctors approach the evaluation of heart disease risk. By recognizing the effects of psychosocial stressors on the body, in addition to the traditional risk factors, physicians can offer a better assessment of a patient's health.
Direction
Professor Sir Michael Marmot of the Department of Epidemiology and Public Health at
University College London
, mottoeng = Let all come who by merit deserve the most reward
, established =
, type = Public research university
, endowment = £143 million (2020)
, budget = ...
initiated the Whitehall II study. It is now directed by Professor Mika Kivimaki. Marmot was the commissioner of the
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
's Commission on Social Determinants of Health.
Further reading
Social/Economic Status and Disease (journal article on Whitehall I study)
See also
*
Robert Sapolsky Research on Stress
References
{{Reflist, 2
External links
- Whitehall Study web site
Statistics.gov.uk- 'Whitehall Study' (statistical database)
- 'Cohort Profile: The Whitehall II Study'
WorkHealth.org- 'The Whitehall Study' (summary), Michael Marmot
- 'Selected Abstracts from the Whitehall II Study', Marmot, ''et al.''
British medical research
1967 establishments in the United Kingdom
Civil Service (United Kingdom)
Cohort studies
Epidemiological study projects
1967 in science