Британдық мемет қызметкерлерінің денсаулығы: Әлеуметтік факторлар мен аурулар

Health study of British civil servants
The Whitehall Studies investigated social determinants of health, specifically the cardiovascular disease prevalence and mortality rates among British civil servants. The initial prospective cohort study, the Whitehall I Study,

The first Whitehall Study compared mortality of people in the highly stratified environment of the British Civil Service. 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 rates due to all causes for men of lower employment grade. The study also revealed a higher mortality rate specifically due to coronary heart disease for men in the lower employment grade when compared to men in higher grades. The initial Whitehall study found lower grades, and thus status, were clearly associated with higher prevalence of significant risk factors. These risk factors include obesity, smoking, reduced leisure time, lower levels of physical activity, higher prevalence of underlying illness, higher blood pressure, and shorter height. Controlling for these risk factors accounted for no more than forty percent of differences between civil service grades in cardiovascular disease mortality. After controlling for these risk factors, the lowest grade still had a relative risk 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 and published in 1987. The Whitehall Study papers are available to view at the School's archives.

The Whitehall II team have a data sharing 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, a social movement which is gaining momentum in academia.

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 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.

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 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, leisure and hobbies, ECG measurements, and diabetes. 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."

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 or Chlamydia, 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 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.

Professor Sir Michael Marmot of the Department of Epidemiology and Public Health at University College London initiated the Whitehall II study. It is now directed by Professor Mika Kivimaki. Marmot was the commissioner of the World Health Organization's Commission on Social Determinants of Health.