Low intelligence during childhood has repeatedly been linked to an increased risk of cardiovascular morbidity and mortality in old age. Studies suggest that part of this increase in risk may arise from a long-term cumulative exposure to cardiovascular risk factors that are more likely to arise in these people early and then persist across the lifecourse. How early this divergence in risk factors occurs, however, remains unclear, as does the extent by which any observed associations may be explained by upstream socioeconomic factors.