Lingering prenatal effects of the 1918 influenza pandemic on cardiovascular disease

Abstract

Prenatal exposure to the 1918 influenza pandemic (Influenza A, H1N1 subtype) is associated with ⩾20% excess cardiovascular disease at 60 to 82 years of age, relative to cohorts born without exposure to the influenza epidemic, either prenatally or postnatally (defined by the quarter of birth), in the 1982-1996 National Health Interview Surveys of the USA. Males showed stronger effects of influenza on increased later heart disease than females. Adult height at World War II enlistment was lower for the 1919 birth cohort than for those born in adjacent years, suggesting growth retardation. Calculations on the prevalence of maternal infections indicate that prenatal exposure to even uncomplicated maternal influenza may have lasting consequences later in life. These findings suggest novel roles for maternal infections in the fetal programming of cardiovascular risk factors that are independent of maternal malnutrition.

Fig. 1

US influenza deaths by month and periods of pregnancy, birth, and infancy for birth cohorts. Influenza deaths, redrawn from Almond and Mazumder25 (top), with schema for pregnancy and birth in the corresponding year and birth quarter (bottom).

Fig. 2

Cardiovascular disease (1982–1996) and mean height (1941–1942) by birth year: (a) National Health Interview Surveys (NHIS) of 1982–1996 (USA), shown as unadjusted, or adjusted for cohort trend and year for sample aged 60 to 82 years. (b) Male height at ages 19 to 27 years, by birth year at enlistment in 1941 and 1942; from the National Archives and Records Administration (numbers of registrants in parenthesis).