Does diabetes mellitus with or without gallstones increase the risk of gallbladder cancer? Results from a population-based cohort study.
BACKGROUND
Previous studies have suggested that diabetes mellitus (DM) is a risk factor for gallbladder cancer; however, it remains unclear whether DM with or without gallstones increases the risk of gallbladder cancer. The aim of this study was to evaluate the risk factors for gallbladder cancer, including sex, hypertension, hyperlipidemia, gallstones, and DM.


METHODS
The study cohort consisted of 214,179 subjects newly diagnosed with diabetes (cases) collected from the claims data of the Health Insurance Program of Taiwan from 2000 to 2001 who were retrospectively enrolled. The control group consisted of 206,860 subjects without diabetes, matched with the cases for sex, age, and index year. The subjects were followed up until the end of 2008. The effects of the risk factors on the incidence of gallbladder cancer were evaluated with Cox's proportional hazard regression models.


RESULTS
The risk of gallbladder cancer was higher in the DM group than in the non-DM group, with a hazard ratio (HR) of 1.53 [95 % confidence interval (CI) 1.22-1.90]. Gallstones were also a risk factor for gallbladder cancer, with an HR of 2.52 (95 % CI 1.11-5.73). DM and gallstones were synergistic risk factors for gallbladder cancer (p < 0.0001), with an HR of 5.37 (95 % CI 3.17-9.10) for subjects with both diseases in relation to those with neither of these conditions.


CONCLUSIONS
In the present long-term cohort study, DM with or without gallstones increased the risk of gallbladder cancer. Gallstones were independently related to gallbladder cancer, and DM and gallstones were synergistic risk factors for gallbladder cancer.
School of Chinese Medicine, China Medical University, Taichung, Taiwan.
Hsueh-Chou
HC
Lai
Shih-Ni
SN
Chang
Che-Chen
CC
Lin
Ching-Chou
CC
Chen
Jen-Wei
JW
Chou
Cheng-Yuan
CY
Peng
Shih-Wei
SW
Lai
Fung-Chang
FC
Sung
Yu-Fen
YF
Li
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D005706:Gallbladder Neoplasms / Q000453:epidemiology / Q000209:etiology*; D042882:Gallstones / Q000150:complications* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult