There is considerable evidence that early life exposures influence later blood pressure¹ and the disease end point most strongly associated with blood pressure—haemorrhagic stroke—is also related to indicators of early life adversity.² In particular, the number of siblings that a person had was positively associated with haemorrhagic stroke risk.² A small case-control study found that an infant or perinatal death in one or more siblings was associated with increased risk of stroke.³ Both haemorrhagic stroke⁴ and blood pressure⁵ declined across the 20th century in developed countries, and both show cohort effects, such that each subsequent birth cohort has lower haemorrhagic stroke risk and lower levels of blood pressure than previous birth cohorts.⁵ Across countries infant mortality rates 70 years ago correlate strongly with current stroke mortality.⁶ One early life factor that would be related to all these indicators of early life exposure is infant diarrhoea. We postulate that severe dehydrating diarrhoea in infancy is associated with higher subsequent blood pressure.

METHODS AND RESULTS

The …