A number of studies have shown that obesity is implicated in the susceptibility to several cancers. However, the association between obesity and cholangiocarcinoma remains unclear. This meta-analysis aimed to quantitatively assess the association between overweight or obesity and the incidence of cholangiocarcinoma. A literature search was performed for cohort and case-control studies published from 1996 to 2013 using PubMed, Cochrane, and EMBASE databases. Studies were included if they reported odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) of cholangiocarcinoma with respect to obesity or overweight. Normal weight, overweight, and obesity were defined when the body mass index (BMI) was 18.5-24.9, 25-29.9, and ≥ 30 kg/m(2), respectively. Excess body weight was defined as BMI ≥ 25 kg/m(2). Ten studies met the inclusion criteria, which included five cohort and five case-control studies. Compared with normal weight, being overweight (pooled OR 1.30, 95 % CI 1.13-1.49), obesity (pooled OR 1.52, 95 % CI 1.13-1.89), and excess body weight (pooled OR 1.37, 95 %CI 1.22-1.55) were significantly associated with cholangiocarcinoma. The funnel plot revealed no evidence for publication bias. Obesity is associated with the increased risk of cholangiocarcinoma, which needs to be confirmed by long-term cohort studies.

IntroductionA number of studies have shown that diabetes mellitus is implicated in susceptibility to several cancers. However, the relationship between diabetes and cholangiocarcinoma remain unclear.AimTo quantitatively assess the relationship between diabetes and incidence of cholangiocarcinoma in cohort and case-control studies.Material and methodsA literature search was performed for entries from 1996 to 2014 using the PubMed and EMBASE databases. Studies were included if they reported odds ratios (OR) and corresponding 95% CI of cholangiocarcinoma with respect to diabetes mellitus.ResultsTwenty studies met the inclusion criteria, which included fifteen case-control studies and five cohort studies from Asia (n = 11), the United States (n = 5), and Europe (n = 4). Compared with individuals without diabetes, the pooled OR of cholangiocarcinoma was 1.74 (95% CI: 1.62–1.87, p = 0.568 for heterogeneity) for patients with diabetes, ICC (summary RR, 1.93; 95% CI: 1.65–2.25; p = 0.037 for heterogeneity), and ECC (summary RR, 1.66; 95% CI: 1.39–1.98; p = 0.001 for heterogeneity). The funnel plot revealed no evidence for publication bias concerning diabetes and the risk of CC (including ICC and ECC).ConclusionsThe findings from this meta-analysis suggest that diabetes may increase the risk of cholangiocarcinoma. This relationship needs to be confirmed by further follow-up studies.

Total fat consumption, particularly animal fat, increases the risk for NHL.