Nonalcoholic fatty liver disease is a risk factor for type 2 diabetes in middle-aged Japanese men.
OBJECTIVE
To determine the association between nonalcoholic fatty liver disease and the risk for development of diabetes.


METHODS
We conducted an observational cohort study in male workers > or = 40 years old in a Japanese company from 1997 to 2005. We excluded workers with alcohol intake > or = 20 g/day and those with impaired glucose tolerance by a 75-g oral glucose tolerance test. The remaining 3,189 workers were classified into fatty liver (FL) and non-FL group based on the findings of abdominal ultrasonography. Both groups were followed for the development of diabetes. Hazard ratio (HR) was determined in Cox proportional hazard analysis. A nested case-control study was conducted to determine the odds ratio (OR).


RESULTS
The average age of participants was 48.0 years at the entry, and the average follow-up period was 4.0 years. The incidence of diabetes in the FL group was 2,073 per 100,000 person-years (65 cases), whereas 452 per 100,000 person-years (44 cases) in the non-FL group. The age- and BMI-adjusted HR of diabetes associated with FL was 5.5 (95% CI 3.6-8.5, P < 0.001). In the nested case-control analysis, the OR adjusted for age and BMI was 4.6 (3.0-6.9, P < 0.001).


CONCLUSIONS
Nonalcoholic fatty liver disease significantly increases the risk of diabetes in middle-aged Japanese men.
University of Occupational and Environmental Health, Department of Gastroenterology and Metabolism,1-1 Iseigaoka, Yahatanishi-ku Kitakyushu 807-8555, Japan.
Michihiko
M
Shibata
Yasuyuki
Y
Kihara
Masashi
M
Taguchi
Mitsuo
M
Tashiro
Makoto
M
Otsuki
D016022:Case-Control Studies; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005234:Fatty Liver / Q000150:complications* / Q000453:epidemiology; D005500:Follow-Up Studies; D018149:Glucose Intolerance; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D015995:Prevalence; D016016:Proportional Hazards Models; D012307:Risk Factors