Retrospective Cohort Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 28, 2015; 21(32): 9607-9613
Published online Aug 28, 2015. doi: 10.3748/wjg.v21.i32.9607
Comparison of effects of obesity and non-alcoholic fatty liver disease on incidence of type 2 diabetes mellitus
Wei-Dong Li, Kun-Fa Fu, Gui-Mei Li, Yan-Shu Lian, Ai-Min Ren, Yun-Jue Chen, Jin-Rong Xia
Wei-Dong Li, Jin-Rong Xia, Department of Gastroenterology, Zhongda Hospital, School of Medicine, Southeast University, Nanjing 210009, Jiangsu Province, China
Kun-Fa Fu, Jiangsu Provincial Geriatric Hospital, Nanjing 210010, Jiangsu Province, China
Gui-Mei Li, Department of Pathology, 81st Hospital of the People’s Liberation Army, Nanjing, 210002, Jiangsu Province, China
Yan-Shu Lian, Department of Preventive Medicine, Jiankang Vocational College, Nanjing 210036, Jiangsu Province, China
Ai-Min Ren, Physical Examination Center, Nanjing Branch, Jiangsu Armed Police General Hospital, Nanjing 210028, Jiangsu Province, China
Yun-Jue Chen, Occupational Health Management Center, Nanjing Hospital of Occupational Disease Control, Nanjing 210042, Jiangsu Province, China
Author contributions: Li WD, Fu KF, Ren AM, Chen YJ, Li GM and Xia JR contributed to the experimental design, data collection, and data collation; Li WD wrote and revised the manuscript; Lian YS analyzed the data; all authors read and approved the final version to be published.
Conflict-of-interest statement: The authors disclose no conflicts of interest in this study.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at xjr049540@163.com.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Jin-Rong Xia, Chief Physician, Associate Professor, Department of Gastroenterology, Zhongda Hospital, School of Medicine, Southeast University, No. 87 Dingjia Qiao Road, Nanjing Gulou District, Nanjing 210009, Jiangsu Province, China. xjr049540@163.com
Telephone: +86-25-83262831 Fax: +86-25-83272356
Received: January 12, 2015
Peer-review started: January 13, 2015
First decision: April 24, 2015
Revised: May 25, 2015
Accepted: June 15, 2015
Article in press: June 16, 2015
Published online: August 28, 2015
Processing time: 228 Days and 0.7 Hours
Abstract

AIM: To compare and analyze the effects of obesity and non-alcoholic fatty liver disease (NAFLD) on the incidence of type 2 diabetes mellitus (T2DM) in Chinese subjects.

METHODS: In 2008, a population of 4847 subjects was randomly sampled from 17 medical units for enrollment in this cohort study. Baseline information was obtained via a questionnaire on general information, physical examination (height, weight, and blood pressure), laboratory tests (triglycerides, total cholesterol, fasting blood glucose, alanine aminotransferase (ALT), uric acid, and creatinine), B-mode ultrasound, and ECG screening. The incidence of T2DM after four years of follow-up was calculated. Numeric variable data was tested for normality, with the data expressed as mean ± SD. Kaplan-Meier analysis was performed to calculate the cumulative incidence. The Cox proportional hazards model was used to analyze the relative risk (RR) of different body mass index (BMI) levels and NAFLD on T2DM, as well as analyzing the RR adjusted for age, sex, blood pressure, lipids, transaminases, uric acid, and creatinine.

RESULTS: A total of 4736 (97.71%) subjects completed 4-year follow-up, with a median follow-up time of 3.85 years, totaling 17223 person-years. 380 subjects were diagnosed with T2DM, with a cumulative incidence of 8.0%. The cumulative incidence of T2DM in the NAFLD and control groups was 17.4% vs 4.1% (P < 0.001), respectively, while the incidence in overweight and obese subjects was 11.0% vs 15.8% (P < 0.001), respectively. The incidence of T2DM increased with an increase in baseline BMI. Cox regression analysis showed that the risk of T2DM in the NAFLD group (RR = 4.492, 95%CI: 3.640-5.542) after adjustment for age, sex, blood pressure, lipids, ALT, uric acid, and creatinine was 3.367 (2.367-4.266), while the value (RR, 95%CI) in overweight and obese subjects after adjustment for age, sex, BMI, blood pressure, lipids and other factors was 1.274 (0.997-1.629) and 1.554 (1.140-2.091), respectively. Stratification of three BMI levels (BMI < 24 kg/m2, 24 kg/m2≤ BMI < 28 kg/m2, BMI ≥ 28 kg/m2) showed that the risk of T2DM in the NAFLD group was significantly higher than that in the control group (RR = 3.860, 4.049 and 3.823, respectively).

CONCLUSION: Compared with BMI, NAFLD could be better at forecasting the risk of T2DM in Chinese subjects, and may be a high risk factor for T2DM, independent of overweight/obesity.

Keywords: Non-alcoholic fatty liver disease; Type 2 diabetes; Cohort study; Incidence

Core tip: A population of 4847 Chinese subjects was randomly sampled from 17 medical units for enrollment in this cohort study with a 4-year follow-up. The effects of obesity and non-alcoholic fatty liver disease (NAFLD) were compared and analyzed on the incidence of type 2 diabetes mellitus (T2DM). Compared with body mass index, NAFLD could be better at forecasting the risk of T2DM in Chinese subjects, and may be a high risk factor for T2DM, independent of overweight/obesity.