Background Adult adiposity is positively associated with pancreatic cancer in Western populations. Little is known, however, about the association in China where many have lower body mass index (BMI) or about the relevance of young adulthood adiposity for pancreatic cancer in both Western and East Asian populations.
Methods The China Kadoorie Biobank (CKB) recruited 512 891 adults aged 30–79 years during 2004–2008, recording 595 incident cases of pancreatic cancer during 8-year follow-up. Cox regression yielded adjusted HRs for pancreatic cancer associated with self-reported young adulthood (mean ~25 years) BMI and with measured adulthood (mean ~52 years) BMI and other adiposity measures (eg, waist circumference (WC)). These were further meta-analysed with published prospective studies.
Results Overall, the mean BMI (SD) was 21.9 (2.6) at age 25 years and 23.7 (3.3) kg/m2 at age 52 years. Young adulthood BMI was strongly positively associated with pancreatic cancer in CKB (adjusted HR=1.36, 95% CI 1.16 to 1.61, per 5 kg/m2 higher BMI) and in meta-analysis of CKB and four other studies (1.18, 1.12 to 1.24). In CKB, there was also a positive association of pancreatic cancer with adulthood BMI (1.11, 0.97 to 1.27, per 5 kg/m2), similar in magnitude to that in meta-analyses of East Asian studies using measured BMI (n=2; 1.08, 0.99 to 1.19) and of Western studies (n=25; 1.10, 1.06 to 1.12). Likewise, meta-analysis of four studies, including CKB, showed a positive association of adulthood WC with pancreatic cancer (1.10, 1.06 to 1.14, per 10 cm).
Conclusions In both East Asian and Western populations, adiposity was positively associated with risk of pancreatic cancer, with a somewhat stronger association for young than late-life adiposity.
- young adulthood
- pancreatic cancer
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Contributors YP, CK, MVH and ZC conducted data analysis and are responsible for accuracy of the results and the decision to submit for publication. All authors were involved in study design, conduct, long-term follow-up, review and coding of disease events, interpretation of the results or writing the report.
Funding Baseline survey: Kadoorie Charitable Foundation, Hong Kong. Long-term continuation: UK Wellcome Trust (088158/Z/09/Z, 104085/Z/14/Z), Chinese Ministry of Science and Technology (2011BAI09B01, 2012-14), Chinese National Natural Science Foundation (81390541). The British Heart Foundation, UK Medical Research Council and Cancer Research UK provide core funding to the Oxford CTSU. MVH acknowledges support from the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre UK. FB acknowledges support from the BHF Centre of Research Excellence, Oxford.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Central ethnics approvals were obtained from Oxford University and the China National Centre for Disease Control and Prevention (CDC). In addition, approvals were obtained from institutional research boards at the local CDCs in the 10 regions.
Provenance and peer review Not commissioned; externally peer reviewed.
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