Identifying health inequalities: the Whitehall study

DAISY PAYLING: Can you tell me a bit about Whitehall Study and when and why it was set up?

CHRIS OLVER: It was a health survey, which was conducted on male middle aged civil servants from 1967 to 1970, looking for signs of cardiovascular disease and other risk factors. The reason it was set up was cardiovascular disease was seen as the major killer of people within that age group, not just in the UK, but across the globe.

DAISY PAYLING: How did they conduct the study?

CHRIS OLVER: They conducted the study by inviting the participants to complete a self-questionnaire, which I have an example here, and also to undergo various medical tests, looking into blood pressure, cholesterol levels, and also echocardiograms and x-rays. The questionnaires were designed to pick up information about their cardiovascular history, but also included questions on their smoking habits, their former smoking habits if they were ex-smokers, and also their medical history. So what did they expect to find?

DAISY PAYLING: Well, the interesting thing about the civil service is that the employment grades are really clearly stratified. So they expected to find that the higher status jobs, which were presumed to have a high level of stress attached to them, would lead to a higher risk of cardiovascular disease and mortality. What they actually found was the direct opposite of that. So lower status jobs had a higher risk of heart disease. And more than that, they found a social gradient. So the lower you were in the hierarchy, the higher your risk of heart disease on a sliding scale.

CHRIS OLVER: Oh, OK. Was it just heart disease?

DAISY PAYLING: No, it was all major causes of deaths– so strokes, renal disease, cancers, not just heart disease.

CHRIS OLVER: How did it help our understanding of health inequalities?

DAISY PAYLING: Well, it gave researches a more nuanced perspective on the relationship between socioeconomic status and health. So previously, researchers had thought about health inequalities as the understanding that the poorest people in society would have poor health outcomes, but that everybody else would be reasonably OK. But this understanding that there was a gradient took away the black and white thinking. And it meant that we needed to think about health inequalities as a sliding scale from poorest to richest in society. The study really highlighted the importance of the socioeconomic status of the participants and how socioeconomic status affected health outcomes. So by looking at the ways that individual risk factors–

CHRIS OLVER: Such as smoking?

DAISY PAYLING: Yeah– affected health, it sort of partitioned those different risk factors groups and looked, for example, at smokers. And then even within groups of smokers, the social gradient still existed, which really highlighted the fact that even within those different behavioural choices that people make, it’s the socioeconomic status that really is the major–

CHRIS OLVER: It’s completely fundamental, yeah.

DAISY PAYLING: Yeah, the real key thing in determining people’s health.

CHRIS OLVER: So with the original study, of course, there was only one or two sort of questions which really brought out the gradient– essentially that one question with the civil service grade. So in terms of the follow up study, it was necessary to redesign the study to focus more on the social and psychological aspects underlying the gradient.

DAISY PAYLING: Yeah. So because Whitehall 1 showed this, the existence of this gradient, and that wasn’t what they were expected to find, then Whitehall 2, which was the follow up study, which started in the 1980s, really wanted to investigate the social gradient further, and so asked a lot more questions about–

CHRIS OLVER: And it’s still going on today.

DAISY PAYLING: It is still going on today, yes.