In utero and childhood exposure to the Great Chinese Famine and risk of cancer in adulthood: the Kailuan Study

The risk of cancer in adulthood can be influenced by exposure to environmental factors (e.g., food shortage and stress) in early life. This study compared the risk of cancer morbidity and mortality between Chinese adults who were or were not exposed to the Great Chinese Famine (1959–1961) in utero or during early childhood. The Kailuan Study participants (n = 101,095) were classified into 5 famine exposure groups by birth year collected at study baseline (2006–2007): after 1961 (unexposed), 1959–1961 (in utero exposed), 1956–1958 (infancy and early childhood exposed, aged 0.1–2.9 y), 1953–1955 (childhood exposed, aged 3.0–5.9 y), and before 1953 (exposed, aged 6+ y). They were further classified by the severity of famine exposure. Cancer and cancer mortality cases from 2006 to 2016 were confirmed by reviewing medical records. Cox proportional hazard models were computed, adjusting for sex, socioeconomic status, and other time-varying cancer-related covariates. During a median follow-up of 10.0 y, we identified 3560 incident cancer cases and 1749 cancer deaths. Famine exposure at all ages was positively associated with the risk of cancer morbidity and mortality (P < 0.001 for all, compared with unexposed). Severe exposure to famine in early childhood, but not other ages, had a higher risk of composite cancer events [adjusted HR = 2.04 (95% CI: 1.47, 2.84) for 0.1–2.9 y; and 1.61 (95% CI: 1.15, 2.25) for 3.0–5.9 y], relative to the less severely exposed groups of the same age range. When cancer morbidity and mortality were studied separately, similar patterns were observed. In utero and early childhood exposures to famine, especially severe famine, were associated with a higher risk of cancer morbidity and mortality in adulthood. Awareness should be raised regarding the long-term effect of early life nutritional status. Trial registration number: ChiCTR-TNRC-11001489 (http://www.chictr.org.cn/showprojen.aspx?proj=8050).