Life Course Trajectories of Body Mass Index and Risk of Cancer in Adulthood: Systematic Review and Meta-Analysis.

OBJECTIVE

This systematic review and meta-analysis aimed to identify common life-course body mass index (BMI) trajectories (childhood/adulthood to adulthood) and their impact on risk of cancer overall and cancer at different sites in adulthood.

METHODS

Observational studies were identified that assessed the association of BMI trajectories with cancer risks from databases published in English. The pooled effect sizes were estimated using a random-effects model.

FINDINGS: A total of 24 eligible studies were included in the meta-analysis. Transitioning from normal weight to obesity was significantly associated with an increased risk of colorectal cancer (effect size [ES] = 1.170, 95% CI: 1.096, 1.245), pancreatic cancer (ES = 1.337, 95% CI: 1.247, 1.426), kidney cancer (ES = 2.122, 95% CI: 1.619, 2.624), and liver cancer (ES = 1.777, 95% CI: 1.261, 2.293), compared to those in the stable normal weight trajectory. No significant difference in the risk of breast or prostate cancer was observed when comparing various BMI trajectories to a stable normal BMI trajectory.

CONCLUSION

The findings suggest that lifetime BMI trajectories influence cancer risk, with a transition from normal BMI to higher levels associated with an increased risk of cancer. The impact varied by trajectory and cancer type. Further studies are needed to confirm these findings.