Is it just a cure? Re-evaluating the effects of prenatal exposure to the Great Chinese Famine on the risk of infectious diseases in adulthood.

BACKGROUND

Very limited studies focused on the early-life adversities on infectious diseases. Taking the Great Chinese famine as a natural experiment, this study re-evaluated the long-term effect of prenatal famine exposure on infectious diseases by using nationally representative data.

METHODS

Using difference-in-difference (DID) models, we analyzed 215,216 adults who participated in the Second National Sample Survey on Disability in 2006 across 734 counties of China to detect the effects of prenatal exposure to the Great Chinese Famine on the risk of infectious diseases in adulthood. Infectious diseases were ascertained by using the combination of self-reports or family members' reports and on-site medical diagnosis by experienced specialists, and the severity of famine was measured by the cohort size shrinkage index (CSSI) at the county level.

RESULTS

All DID estimates of the effects of famine on the probability of infectious diseases were insignificant, with a coefficient of 0.0007 (-0.0024, 0.0026) for all participants and coefficients of 0.0001 (-0.0041, 0.0043) and -0.0002 (-0.0036, 0.0033) for males and females, respectively. That is, the famine cohort dwelling in regions with a greater intensity of famine had similar levels of infectious disease risks than the cohorts with post-famine prenatal exposure experience in less affected famine regions. Furthermore, there were no significant famine and post-famine cohort differences in the DID estimates by examining the variations in subgroups with different types of infectious diseases (trachoma, poliomyelitis, tuberculosis, maternal infections and other infectious diseases).

CONCLUSION

No significant impact of prenatal exposure to the Chinese famine was observed on the risk of infectious diseases in adulthood. Famine survivors may be "cured" by the famine and were resilient to adverse environments in their life course because selective mortality may weaken the association between adverse prenatal exposure and later health.