Body fatness at a young age and risks of eight types of cancer: systematic review and meta analysis of observational studies
K. Hidayat X. Du and B M. Shi (2018). Obes Rev.
The increased prevalence of obesity in children and adolescents worldwide is expected to potentially increase the incidence rates of early-onset cancer attributed to excess body fatness. The potential long-term impact of excess body fatness at a young age (age≤30 years) in the later development of the following conditions remain inconclusive: diffuse large B-cell lymphoma (DLBCL), oesophageal adenocarcinoma, gastric cardia cancer, hepatocellular carcinoma, multiple myeloma, pancreatic cancer, renal cell cancer and thyroid cancer. Therefore further examination of the data are required to allow development of better prevention strategies and thereby reduce future incidence of cancer attributed to excess body fatness. The authors of this study performed a comprehensive systematic literature review and meta-analysis of observational studies to explore the associations between body fatness at a young age (≤30 years) and the risks of the aforementioned cancers. Searches identified 56 articles which yielded data on 27,559 cancer cases, including 3,170 DLBCL, 1,491 oesophageal adeno-carcinoma, 1,103 gastric cardia cancer, 1,067 hepatocellular carcinoma, 3,090 multiple myeloma, 7,220 pancreatic cancer, 6,212 renal cell cancer and 4,206 thyroid cancer cases. Each 5 kg m-2 increase in body mass index at a young age was positively associated with DLBCL (relative risk [RR] 1.21, 95% confidence interval[CI] 1.09, 1.35), oesophageal adenocarcinoma (RR 1.88, 95% CI 1.37, 2.57), gastric cardia cancer (RR 1.59, 95% CI 1.15, 2.21), hepatocellular carcinoma (RR 1.31, 95% CI 1.13, 1.51), multiple myeloma (RR 1.23, 95% CI 1.15, 1.30), pancreatic cancer (RR 1.17, 95% CI 1.11, 1.24), renal cell cancer (RR 1.22, 95% CI 1.16, 1.28) and thyroid cancer (RR 1.12, 95% CI 1.07, 1.17). This study has shown that higher body fatness at a young age increases the risk of developing various types of cancer in later life. Prevention of overweight and obesity in children, adolescents and young adults should therefore be emphasised to reverse the obesity epidemic and avoid further increases in the burden of cancer attributed to excess body fatness.