Obesity and hepatitis B infection are associated with increased risk of metabolic syndrome in university freshmen

Objective: To investigate the prevalence of metabolic syndrome and its associated risk factors in a cohort of university freshmen. Design: A cross-sectional study in a university health center in North Taiwan. Subjects: A total of 8226 students (mean age: 19.2+/-2.3 years) receiving pre-entrance health examinations and lifestyle questionnaires during the 2005-2006 academic year were recruited. Measurements: A fasting plasma glucose, lipids, uric acid and hepatitis B serology were measured for each subject. The prevalence of metabolic syndrome and its individual components were examined using the America Heart Association and National Heart Lung Blood Institute criteria. The risk factors for metabolic syndrome were identified using a multivariate logistic regression analysis. Results: The prevalence of overweight, obesity and metabolic syndrome was 12.7% (17.0% in men and 7.6% in women), 13.0% (18.4% in men and 6.4% in women) and 4.6% (6.4% in men and 2.4% in women). The risk for metabolic syndrome increased with an increase of body mass index and plasma uric acid level, and decreased with the vigorous physical activity and current alcohol drinking. Furthermore, as compared to subjects with seroprotective titers from hepatitis B vaccination (anti-HBs(+) and anti-HBc(-)), those without protective titers of anti-HBs after vaccination or without hepatitis B infection (anti-HBs(-) and anti-HBc(-)) had 34% higher risk for metabolic syndrome, and those with natural infection of hepatitis B (anti-HBc(+)) had 58% higher risk for metabolic syndrome. Conclusions: Overweight, obesity and metabolic syndrome were more common among men than women in university freshmen. Hepatitis B vaccination with anti-HBs(+) was associated with a lower risk of metabolic syndrome as compared to anti-HBs(-). However, hepatitis B infection presented with anti-HBc(+) was associated with a higher risk of metabolic syndrome. The interplay between hepatitis B infection, hepatitis B vaccination and metabolic syndrome needs further investigation.