Consequences of China's special send-down movement on infectious disease control in rural areas: a natural experiment

China's send-down movement in the 1960s and 1970s, as a natural experiment, provides a unique opportunity to investigate the relationship between peers' dissemination of health literacy, community health workers, and infectious disease control in areas with weak health systems and inadequate human resources. To address the lack of studies on the health effects of the send-down movement, this study examined the associations between prenatal exposure to the send-down movement and infectious diseases in China.

We analyzed 188,253 adults born in 1956-1977 with rural hukou who participated in the Second National Sample Survey on Disability in 2006 across 734 counties of China. Difference-in-difference models were used to detect the effect of the send-down movement on infectious diseases. Infectious diseases were ascertained by using the combination of self- or family members' reports and on-site medical diagnosis of disabilities attributed to infectious disease by experienced specialists. The density of the relocated urban sent-down youth or "sent-down youths" (SDYs) in each county defined the intensity variable of the send-down movement.

Individuals in SDY-receiving areas with increased intensity of prenatal exposure to the send-down movement had a decreased probability of infectious diseases (β = -0.0362, 95% CI: 0.0591, -0.0133) after controlling for a set of regional and cohort characteristics. This association was stronger in counties with more prevalent infectious diseases prior to the send-down movement (β = -0.0466, 95% CI: 0.0884, -0.0048) than in those with less prevalence (β = -0.0265, 95% CI: 0.0429, -0.010). No substantial differences were found across sex-specific groups or by strictness of send-down movement implementation. On average, prenatal exposure to the send-down movement corresponded to a decrease in the probability of infectious diseases in rural areas by 19.70%.

For areas with weak health systems, strengthening community health workers and promoting health literacy may be two key points to address the burden of infectious diseases. Increasing education and primary health care through peer-to-peer dissemination may contribute to the reduction of infectious disease prevalence.