Objectives: Emerging evidences have explored the association between famine exposure during early life and cancer risk in adulthood, but the results remain controversial and inconsistent. This study aimed to provide a comprehensive evidence on the relation of famine exposure to later cancer risk.
Design: Systematic review and meta-analysis.
Methods: Relevant reports published up to March, 2022 were identified by searching PubMed, Embase, Web of sciences and Medline databases. Pooled relative ratios (RRs) with 95% confidence intervals (CIs) were used to evaluate the effect famine exposure on cancer risk.
Results: Totally, 18 published articles with 6,061,147 subjects were included in this study. Compared with unexposed group, early life famine exposure dramatically increased the risk of cancer in adulthood (RR=1.13, 95% CI: 1.04-1.22). The pooled RRs were different in terms of sex, exposure severity, exposure period, famine type, study design type and cancer location. A remarkably elevated risk for cancer was discerned in women exposed to famine (RR=1.09, 95% CI: 1.00-1.18), severe exposure (RR=1.12, 95% CI: 1.02-1.22) and adolescence exposure (RR=1.76, 95% CI: 1.02-2.50), Chinese famine exposure (RR=1.55, 95% CI: 1.29-1.82) and cohort studies (RR=1.28, 95% CI: 1.13-1.42). Moreover, a significant association of early-life famine exposure with increased risk of breast (RR=1.16, 95% CI: 1.05-1.27) and stomach cancers (RR=1.89, 95% CI: 1.24-2.54) was observed.
Conclusion: This meta-analysis suggests that exposure to famine during early life may increase the risk of cancer in adulthood. The above-mentioned association is pronounced in women exposed to famine, severe exposure, adolescence exposure, Chinese famine, cohort studies, breast and stomach cancers. It is essential for decision-makers to take targeted measures for improving population awareness regarding the long-term effect of early life nutritional status.
Keywords: Famine exposure; cancer; early life; meta-analysis; systematic review.