Back to school to protect against coronary heart disease?

Public policy interventions can have profound effects on health.1 Whereas some have been highly successful (such as smoking cessation), others have actually worsened disease incidence rates. For example, widespread recommendations to avoid exposure to peanuts at a young age paradoxically led to a higher incidence of peanut allergy in children.2 Selecting which policies to implement is often difficult, particularly for social science based reforms. As large randomised experiments are usually not feasible, policy makers are often left wringing their hands over limited evidence from observational epidemiology.

Increased years of education has been repeatedly associated with a decreased risk of coronary heart disease (CHD).3 However, this association may simply be an artefact of confounding, whereby factors associated with longer education, such as socioeconomic status, lead to a spurious association between education and CHD. As CHD is the most common cause of death worldwide,4 efforts to increase educational attainment may have major health benefits if the association is causal.

Tillmann and colleagues (doi:10.1136/bmj.j3849) used mendelian randomisation to try to clarify the nature of the association between education and CHD and help to inform public policy.5 Mendelian randomisation …