The Whitehall studies followed two cohorts of British civil servants over several decades and found a strong and steep gradient between higher occupational category and a range of mental and physical health outcomes. Much of the literature on Whitehall focuses on how social status in adulthood predicts occupational prestige and autonomy, which are plausible mechanisms that could transmit stress and lead to worse health. These mechanisms, Michael Marmot argues, are more important than the role that health plays in determining social position.
In a 2011 paper (here as a 2010 working paper), Anne Case and Christina Paxson take a different approach to the Whitehall data. They make three observations that I believe should be garnering more attention.
First, they argue that the study is not ideally set up to study the impact of early health on adult health:
“We find that, because the population from which this cohort was drawn consisted almost exclusively of white collar civil servants, the Whitehall II sample is not well suited for quantifying the importance of childhood conditions for the population as a whole. Children from poor backgrounds who find white collar positions in Whitehall are different in many dimensions from other poor children, and these differences lead to a systematic underestimate of the impact of early-life health and circumstances on later-life health and social status.” (Pg. 2)
They quantify the potential bias in a clever way. They take the two largest cohort studies from the general population in Britain: the NCDS 1958 Cohort and the BCS 1970 cohort, and examine how much socioeconomic status in childhood (measured by father’s occupational category) predicts adults height, first in a full sample and then in a sample restricted only to social servants. If social servants from low-status fathers have some unobserved differences that compensate for early health disadvantages, then we would expect the association to be weaker between parental education and height. Indeed, this is what they find.
Second, focusing on the Whitehall II cohort, they show that childhood socioeconomic status (father’s occupational status, and family car ownership during childhood) has a lasting impact in adulthood both on initial occupational category, and also on subsequent promotions. Not surprisingly, much of this effect is mediated through education. Importantly, however, they find that early health exerts a strong independent effect on these same outcomes (captured by height and whether the person was ever hospitalized before age 16). These are important results, especially since as the above results indicate, the Whitehall study is likely to be positively selected.
Third, these early health effects also exert an independent effect on adult health. For example, in regressions that control for a variety of current and previous characteristics, spending time in the hospital as a child is associated with a 7 percentage point lower likelihood of being in “excellent” or “very good” health as an adult. Controlling for current occupational grade does not dampen the association between child health and adult health. To try to disentangle whether occupational grade is high because health is good, or whether health is good because occupational grade is high, they also estimate regression models predicting current health on future occupational grade using earlier waves of the survey. Future grade is unlikely to cause current health, but they find that current health does predict future grade. Moreover, in fixed effect models, they find that current health is a much stronger predictor of future promotion than any previous occupational grades.
The authors conclude: “despite the downward biases that are likely to result from selection into Whitehall II, we still find evidence that health in childhood influences occupational status in adulthood. Adults who had better childhood health—as measured by adult height and hospitalizations in childhood—start at higher grades in the civil service, and are promoted to higher grades after they enter the civil service. The association between height and occupational status in adulthood is robust to controls for education, implying that childhood health does not operate solely through its effects on educational attainment” (Pg. 22).
If we take this study seriously, and I believe we should, it invites serious reconsideration of the apparent finding in Whitehall that occupational status causes health in adulthood. This does not mean that inequality in social status does not matter. To the contrary, the Case and Paxson results highlight the centrality of early life health exposures on late life outcomes. This is a different causal mechanism, and would result in a greater focus on interventions focused on poor children than on promoting greater workplace equality later in life as a means for improving adult health.