Smoking cigarettes was associated with an increased risk for type 2 diabetes in individuals who were positive for hepatitis B surface antigen, but not significant for patients positive for hepatitis C virus infection antibodies, according to results from a community-based cohort study.
“Although the prevalence of smoking has decreased in developed countries, it is rapidly increasing in developing countries and is highest in the Asia-Pacific region,” Chong-Shan Wang, MD, MPH, director of the A-Lein Community Health Center, and assistant professor, Institute of Public Health, National Yang-Ming University, Taiwan, and colleagues wrote. “It is important to elucidate whether smoke increases the risk for type 2 diabetes in the individuals in HBV or HCV infection because comorbidities of type 2 diabetes and viral hepatitis will enhance the progression into terminal liver diseases.”
Between 1997 and 2004, the researchers studied the risk for incidence of diabetes in a cohort of 3,539 adults with hyperendemic HBV and HCV in southern Taiwan. Of these patients, 68.6% were seronegative, 17.3% were positive for HCV antibodies (anti-HCV; n = 612), 11.8% were positive for hepatitis B surface antigen (HBsAg; n = 417) and 2.4% had HBV/HCV coinfection (n = 85). Among these, 74.8% had never smoked cigarettes (n = 2,646), 4.8% were former smokers (n = 171), 12.7% smoked less than 1 pack per day (n = 451) and 7.7% smoked more than one pack per day (n = 271).
A total of 423 individuals developed diabetes. Univariate analyses showed that patients who were anti-HCV-positive (incidence rate ratio = 2.3; 95% CI, 1.3-2.1) or had HBV/HCV coinfection (IRR = 2.3; 95% CI, 1.3-3.6) were more likely to develop diabetes compared with seronegative patients.
Patients who smoked more than one pack per day were more likely to develop diabetes compared with those who never smoked (IRR = 1.5; 95% CI, 1.04-2). A multiple Cox proportional hazards model analysis using different viral hepatitis statuses showed smoking levels were strong predictors for diabetes with a dose–response relationship for type 2 diabetes in patients who were HBsAg-positive and light smokers (HR = 3.8; 95% CI, 1.2-12.3) and heavy smokers (HR = 4.4; 95% CI, 1.5-13.3).
A cumulative hazard function test showed that the more a patient smoked, the greater the cumulative incidence rate of diabetes was among HBsAg-positive patients (P = .03 by log-rank test).
Heavy smoking was a moderate predictor of type 2 diabetes in seronegative individuals (HR = 1.7). However, was not a predictor for those who were anti-HCV-positive, despite the fact they were more likely to experience insulin resistance and type 2 diabetes.
“This finding implies that active smoking might produce different risks for type 2 diabetes in the individuals with different viral hepatitis statuses,” the researchers wrote.
Further analyses showed that patients aged older than 65 years, who frequently consumed alcohol, had a BMI greater than 25, had less than 9 years of education or smoked more than 1 pack per day were more likely to develop diabetes (P < .05).
The researchers concluded: “We strongly recommend that persons who are HBsAg-positive avoid smoking to prevent the development of type 2 diabetes and further progression into advanced liver disease or cardiovascular diseases.” – by Melinda Stevens
Disclosure: Healio.com/Hepatology was unable to confirm relevant financial disclosures at the time of publication.