Since 1985, self-completion questionnaires and clinical data have been collected from the cohort every two to five years, with a high level of participation. This wealth of data has enabled Whitehall II researchers to examine the interrelationships between socio-economic biological, psychosocial, and behavioural factors. Below are some of the published key findings:
- Stress and health
Perception of the effect of stress on health is linked to risk of heart attack
Previous analyses from Whitehall II and other studies have shown that stress might have an adverse effect on people's risk of a heart attack. In this project, Whitehall II researchers have, for the first time, investigated how people's perceptions of stress might affect their health, in particular their risk of developing heart disease. We found that study members who believe stress affected their health "a lot or extremely" had double the risk of a heart attack compared to people who didn't believe stress was important in this context. After taking other biological, behavioural or psychological risk factors into account, there was still a 50% greater risk of experiencing a heart attack in those who believed stress affected their health. European Heart Journal 2013 Sep;34(34):2697-705
Does stress lead to weight gain or loss?
People have different behavioural reactions when experiencing stress, for example they might drink more alcohol or eat comfort foods. We looked at work stress and weight; those who had a tendency to be overweight were more likely to put on weight when stressed. The opposite was true for those who were a bit underweight, work stress lead to further weight loss. This was only apparent for men in the study. International Journal of Obesity (2006) 30: pp 982-987
The role of control at home
Stress and Health researchers have found that low control over work is an important factor for men's health - but not for women's. Now research suggests that low control at home may be important in predicting the women who will develop heart disease - and it's likely to be those with less money or coping mechanisms for stressful home events. It seems that home factors have a greater effect on women than on men, say the researchers. Soc Sci Med (2004) 58: 1501-1509.
- Working conditions and social status
Ageing and health inequality
A major theme of the study has been health inequalities according to social status and how they change with age. We found that physical health declined more rapidly with age in lower status groups, resulting in widening health inequalities. For example, the average physical health of a 70-year-old high status man or woman was similar to the health of a low status person 8 years younger. In mid-life this gap was only 4.5 years. As the population ages these findings become more relevant for public health policy. British Medical Journal (2007) 334: pp 990-993
Unfairness can be taken to heart
People who are often unjustly treated are at greater risk of having a heart attack or angina, even after adjusting for established coronary risk factors. People in lower socioeconomic positions and women are more likely to be exposed to everyday acts of injustice. Promoting fairness in different areas of life such as the workplace, family, and the community may contribute to a healthier society. Journal of Epidemiology and Community Health (2007) 61: pp 513-518
"Presenteeism": beware the health effects of working through illness
People who take no time off when they are actually sick have heart attacks more often than their colleagues who take time off. After analysis of over 5000 men from the Stress and Health study, researchers were able to show an effect linked to "sickness presenteeism". They looked at unhealthy men who had not previously had a heart attack. Those who worked through illness were twice as likely to have a heart attack as the men who took moderate periods of sick leave. Employers and employees take note, says the study. Am J Pub Health (2005) 95: 98-102
- Physical activity
Activity is a plus. Sitting may not be a minus
You don't necessarily have to go to the gym: moderate activity such as gardening and brisk walks reduce blood levels of markers of heart risk. Our study of data over ten years has shown that just two and a half hours of moderate physical activity per week is what it takes to get inflammatory markers into the low-risk group. Confirmation of these encouraging findings is needed to show that the benefit of physical activity is also seen in the pattern of new heart problems. Circulation 2012;126:928-33.
In another recent study, we tested the idea that physical inactivity, measured as time spent sitting, may be an independent risk factor for obesity. While more research is needed, this link was not confirmed in our analysis. American Journal of Preventive Medicine 2013;44:132-38.
Physical activity is also a mental workout
Frequent physical activity in leisure time over the years appears to have a cumulative benefit for the mind. When comparing cognitive function scores for participants doing different levels of physical activity, those doing at least two hours a week of moderate activity (for example, dancing) or vigorous activity (for example, running) scored better on cognitive function tests than those who were less active. These benefits start to emerge during mid-life and are still seen in older age. American Journal of Public Health (2005) 95: pp 2252-2258
Active outside work
There's a simple relationship between work and physical activity, say study researchers. Participants working full time did the least physical activity; those who did not work at all were most active; and part-time workers fell between. Retirement seemed to make everyone more active: those who retired but continued to work part-time were still more active than full-time workers. Higher job grades were more active - perhaps due to the expense of formal activities, the study suggests. Eur J Public Health. (2005) Jun;15(3): pp 317-22
A good diet now, a healthy heart later
Researchers from the Stress and Health study have looked at whether sticking to a healthy diet might help someone live longer in good health. The findings showed those with a healthy balanced diet reduced their risk of heart and circulatory disease, regardless of other health behaviours such as smoking. On the other hand, eating a diet consisting of fried, processed and sweet foods and red meat reduced the chances of healthy ageing. So remember, eating a balanced diet can not only help us maintain our health now, but also as we get older. American Journal of Medicine 2013 May;126(5):411-419
Good news for those with metabolic syndrome
The metabolic syndrome, previously known as syndrome X, is a potent combination of factors like central obesity and high triglyceride levels that can lead to a greatly increased risk of diabetes and heart disease.
The good news for anyone with metabolic syndrome is that researchers on the Stress and Health Study have shown that it can be reversed by sticking to a healthy diet. Diabetes Care 2010 Nov;33(11):2339-41.
- Alcohol consumption
Heavy drinking and cognitive function
It is known that heavy alcohol consumption increases the risk of several chronic diseases. However, less research exists exploring its effect on cognitive function. We found that heavy drinking during midlife was associated with decline in cognitive functioning over the next decade, as measured by tests of memory and reasoning. Men who said they drank more than four units of alcohol/day (e.g. two pints of beer a day) on average experienced memory loss similar to that typically observed in respondents six years older than them. Neurology 2014 Jan 28;82(4):332-9
Alcohol and cognitive function
Drinking alcohol may be good for the mind - within reason. Researchers analysed cognitive function scores from the Stress and Health study and compared them to the alcohol intake reported by the participants. They showed that those who drank some alcohol scored better in tests - for memory, reasoning, vocabulary and fluency - than those who drank none. The beneficial effects extended to people taking 30 drinks a week - but the results didn't include enough heavier drinkers to explore an upper limit (other research has suggested that there is a limit). On balance the researchers don't recommend higher alcohol consumption, because it is well known that excess drinking harms health (and see the study on alcohol dependence below). Am J Epidemiol (2004) 160: 240-247.
Work and alcohol dependence
A stressful work environment, in which effort is not properly rewarded, raises the risk of alcohol dependence in men of all job grades. In women, alcohol dependence was more prevalent among people in higher grades, although it was linked to "low decision latitude" - reflecting jobs with little control. The authors suggest more research is needed that explores ways in which occupational health might prevent alcohol dependence. Occup Environ Med (2004) 61: 219-224.
Sleeping only 5 hours or less a night is known to be associated with early death from heart disease. However, some people seem to thrive on a limited number of hours sleep. So what is going on? Stress and Health researchers have found it is the disrupted sleep among those of us who don't get a long night's sleep that appears to be the real culprit. Well, those of us that are insomniacs could have told you that! Sleep 2010 33:739-44
Social activities relate to better sleep quality
Continuing our cross-cultural collaborations, we studied the effects of leisure activities on sleep quality among participants in this study and a similar group in Japan. In both groups, social activities during leisure time, such as visiting friends and relatives or participating in voluntary activities, resulted in better quality of sleep. These findings support the idea that engaging in meaningful activities is a key factor for better health. Journal of Occupational Health (2005) 47: pp 384-390
Having followed our participants from middle age to older age, the Whitehall II researchers are working on identifying the key determinants of later life depression, cognitive decline, chronic disease and physical functioning at older ages. Please visit our research page for more information.