Unawareness of Hepatitis B Virus Infection confers on Higher Rate of Metabolic Syndrome: A Community-based Study

The objective of this study was to determine whether awareness of hepatitis B virus (HBV) serostatus was discordant with metabolic syndrome (MetS) among people with chronic HBV infection. We conducted a community-based study in four Taiwanese districts. A total of 3493 adult participants were recruited. Participants who were hepatitis B surface antigen (HBsAg) seropositive and had self-reported HBV infection were considered aware of hepatitis B (aHB); those who denied a history of HBV infection were considered unaware of hepatitis B (uaHB). Among the 454 participants who were HBsAg seropositive, 275 (60.6%) were aHB and 179 (39.3%) were uaHB. Hypertriglyceridemia showed significant inverse association with HBsAg seropositive, especially among those who were aHB. Insulin resistance was significantly, positively associated with HBsAg seropositive, especially among participants who were uaHB. Those who were uaHB had a higher risk of central obesity, hyperglycemia, insulin resistance, and MetS than those who were aHB (odds ratio = 2.33, 1.64, 2.15, 1.85, respectively, all p < 0.05). The association among the prevalence of MetS, its individual components and HBsAg seropositivity varies according to awareness of HBV infection. It is important to recognize an individual’s risk for MetS, especially who were unaware of HBV infection.

awareness of HBV serostatus were not reported in these studies. The awareness of HBV serostatus may vary considerably among different samples, depending on the age, education level, urban residence, and family history of liver disease 11 . More importantly, when the relationship between chronic HBV infection and MetS is studied, a behavioral mechanism, in addition to the potential biological mechanism, should be examined. Hence, the objective of this community-based study was to determine whether awareness of HBV serostatus was discordant with MetS and its individual component among people with CHB.

Results
After excluding participants who were antibody to HCV (anti-HCV) positive (n = 143), had a history of cancer (n = 125), or had incomplete data on the MetS survey (n = 17), hepatitis B surface antigen (HBsAg) or anti-HCV tests (n = 10), or did not answer to the question of HBV infection (n = 23), 3,493 participants were included in the analysis. The prevalence of MetS was 31.6%. Participants with MetS were older, had less formal education, exercised less, and were more likely to live in a rural area, smoke, and alcohol consumption than those without MetS (Table 1). Among the participants with MetS, 14% had elevated aspartate aminotransferase (AST), 22% had elevated alanine aminotransferase (ALT), 39.2% had elevated γ-glutamyltranspeptidase (GGT), and 78.3% had fatty liver. Participants with MetS were more likely to have significant fibrosis (AST-to-platelet ratio index (APRI) > 0.5) and advanced fibrosis (APRI > 1.0) of the liver compared with those without MetS (11.8% vs 6.4%, p < 0.001; and 1.5% vs. 0.7%, p = 0.036, respectively). The area under receiver operating characteristic curves of homeostatic model assessment -insulin resistance (HOMA-IR) for MetS diagnosis was 0.797(95% confidence interval: 0.781-0.812). The optimal cut-off for the diagnosis of MetS was 1.905 (sensitivity: 68.6%, specificity: 77.3%). IR was defined as HOMA-IR ≥ 1.9.
Among the 454 participants who were HBsAg seropositive, 275 (60.6%) were aware of hepatitis B (aHB) and 179 (39.3%) were unaware of hepatitis B (uaHB). The proportion who were HBsAg positive did not differ between participants with and without MetS (12.2% vs. 13.3%, p = 0.563). The proportion who self-reported a history of HBV infection was lower in participants with MetS than in those without it (7.5% vs. 10.7%, p = 0.003). MetS was not related to APRI level among HBsAg seropositive participants. Compared with participants who were aHB, those who were uaHB were older, more likely to live in a rural area, had less formal education, and were less likely to have a family history of liver disease (Table 2).
Comparison of HBV carriers who were and were not aware of their HBV serostatus. The relationship between HBV awareness and MetS among the HBsAg seropositive participants is shown in Table 5. After adjusting for age and sex, the aOR of having MetS was 1.85 (95% CI 1.20-2.83) in uaHB compared with aHB. When each metabolic component was analyzed separately, the aOR of having central obesity, hyperglycemia, and HOMA-IR ≥ 1.9 were significantly higher among uaHB compared with aHB participants (aOR = 2.33, 95% CI 1.56-3.49; aOR = 1.64, 95% CI 1.08-2.49; and aOR = 2.15, 95% CI 1.45-3.20, respectively). Being uaHB was not significantly associated with elevated blood pressure, hypertriglyceridemia, hypercholesterolemia, high LDL-C level, low high-density lipoprotein cholesterol (HDL-C) level, fatty liver, or elevated AST, ALT or APRI levels.

Discussion
In this community-based cross-sectional study, the association between MetS and awareness of HBV serostatus was examined. The prevalence of MetS was not associated with HBsAg seropositivity. The prevalence of MetS was lower among participants who were aHB and higher among participants who were uaHB compared with HBsAg seronegative participants. This difference may explain the conflicting results of published studies. It suggests that the complex relationship between metabolic disorder and CHB is explained by not only biomedical (e.g., genetics, biological process), but also by biosocial (e.g., sex, race/ethnicity, education) and psychosocial (e.g., physical activity, diet intake, smoking) variables.
A significant inverse association between HBsAg seropositivity and hypertriglyceridemia was observed in this study. This finding is consistent with previous studies conducted among different ethnic groups 6,7,9,[12][13][14][15][16] . A potential mechanism is inhibition of the secretion of apolipoprotein B 17 , an essential component for the formation of very-low-density lipoprotein (VLDL) and LDL-C, by HBV X protein. The increase in HBV X protein contributes to lower levels of VLDL, a triglyceride-rich particle, and a consequent reduction in the serum triglyceride level 18 . A similar association was evident between aHB, but not uaHB, and hypertriglyceridemia. HBV awareness has implications for lipid profile changes in HBV carriers, and its mechanism needs further exploration.
IR is the principal pathophysiological mechanism that leads to MetS. However, the effect of chronic HBV infection on human insulin sensitivity and hyperglycemia is not consistent in the literature. HBsAg seropositive patients had higher HOMA-IR levels than controls in a study from Korea 19 . However, no significant association between chronic HBV infection and the HOMA-IR level was reported in a study from Taiwan 20 . A recent meta-analysis of HBV infection and risk of type 2 diabetes mellitus (DM), revealed that HBV itself might not be pro-diabetic 21 . Another meta-analysis showed a significantly higher prevalence of DM in the HBV-infected group than in the control group in the Asia-Pacific region 22 . In our study, HBsAg seropositive participants, particularly those who were uaHB, had a higher risk of IR compared with controls. Interestingly, aHB was not related to IR, and those participants had an even lower risk of hyperglycemia than controls. When studying the relationship between chronic HBV infection and IR, we suggest the influence of HBV awareness should be considered.
To the best of our knowledge, the impact of awareness of HBV serostatus on the risk of MetS has never been previously studied. ATP III, the National Heart, Lung and Blood Institute and the American Heart Association identified specific underlying risk factors for MetS, including obesity, physical inactivity, atherogenic diet, cigarette smoking, and family history of premature coronary heart disease 23,24 . Other well-defined factors beyond the clinical criteria that define MetS, such as patients' knowledge, attitudes, and behaviors, may contribute to the development of MetS and diseases for which it is a predisposing condition 5 . Compared with participants who were aHB, those who were uaHB had a higher risk of obesity, hyperglycemia, IR, and MetS in our study. Although our cross sectional data cannot address the questions of causality, we suppose biosocial and psychosocial factors may explain potential pathogenic mechanisms. The level of education was not associated with MetS in the National Health and Nutrition Examination Survey (NHANES) cohort 25 . However, among African-American females and males, more formal education (at least high school graduation) was associated with reduced risk of MetS, compared with lower educational status 26 . Our study revealed that participants who were aHB had more formal education and were more likely to have a family history of liver disease. The educational level may influence dietary choices, physical activity, and stress levels. In theory, they would have better medical knowledge and pay more attention to their health status. This population was mostly likely to embrace lifestyle changes and achieve good medical compliance and adherence. In addition to socioeconomic status, rural-urban differences may play a role in the prevalence of MetS in developing nations 27 , but these associations are not consistent. In Korea, the age and sex adjusted prevalence of MetS was higher in rural than in urban communities 28 . In the present study, participants living in rural areas were more likely to have MetS compared with those living in urban areas. This may be attributed to the difference in accessibility of medical services and public awareness. Rural residents are less likely than urban residents to obtain certain preventive healthcare services 29 . Furthermore, socioeconomically disadvantaged older people in rural areas face personal, community, and healthcare barriers that limit their access to primary care 30 . We found that participants who were uaHB, compared to those who were aHB, were older and more likely to live in a rural area. They have higher risk of obesity and MetS probably because they receive less medical information and use less medical resources to improve their health.
Analysis of the NHANES III showed that type II DM and IR are independent predictors of overall mortality among people with CHB 31 . Excess BMI and MetS is a significant risk factor for the development of cirrhosis, HCC and intrahepatic cholangiocarcinoma [32][33][34] . It is reasonable to predict that people who are uaHB have a higher risk of liver fibrosis, cirrhosis, and HCC. People who are uaHB are more likely to be diagnosed at a later stage and antiviral therapy is delayed. Active screening programs and increased disease awareness are vital for preventing CHB disease progression.
The present study has several limitations. First, the study examined cross-sectional data; therefore, we could not conclude that a causal relationship existed between awareness of HBV serostatus and lower risk of the metabolic disorder. We suggested that individuals' perceived threat and knowledge of and attitude toward the disease, along with their accessibility to medical resources determine this causality. Our postulation needs further prospective and longitudinal follow up study to validate. Second, we did not evaluate the time period of hepatitis B awareness and relevant lifestyle changes, such dietary habits, in the present study. A comprehensive behavioral assessment and a longitudinal follow-up study would be required to clarify the etiology. Third, we did not measure hepatitis B e-antigen serostatus and hepatitis B viral load to analyze different groups' metabolic profile. A dose-response relation between viral replication and metabolic disorder may help establish causality. Instead, we found that no association was observed between MetS and the degrees of liver fibrosis among HBV carriers.
In conclusion, this community-based study indicated that the association among the prevalence of MetS, its individual components and HBsAg seropositivity varies according to awareness of HBV infection. Hypertriglyceridemia showed significant inverse association with HBsAg seropositivity, especially among those who were aHB. IR was significantly, positively associated with HBsAg seropositivity, especially among participants who were uaHB. Moreover, those who were uaHB had a higher risk of obesity, hyperglycemia, IR, and MetS than those who were aHB. In addition to an urgent need to promote awareness of HBV and the treatment of eligible patients, it is important to recognize an individual's risk for MetS and provide interventions with specific management strategies.

Methods
Study population. We conducted a community-based cross-sectional study from August 2013 to August 2015 in four Taiwanese districts (Wan-li, Gong-liao, Rul-fan, and An-le). Three districts were rural townships on the northeastern seaboard, and one was urban. Adult participants (≥30 years old) were recruited from the community by public service announcements, talks to community groups, and notices in clinics. Written informed consent was obtained from each of the participants. The study was conformed to the ethical guidelines of the Declaration of Helsinki, and was performed with the approval of the ethical committee of the Keelung Chang Gung Memorial Hospital.  Clinical evaluation and laboratory tests. The data related to alcohol consumption, smoking history, physical activity, family history, and medical history were obtained by a structured in-person interview that was administered by trained nurses, research assistants, and medical students. Heavy alcohol consumption was defined as alcohol intake >30 g daily in males and >20 g daily in females 35 . Normal consumption (light to moderate alcohol intake) was defined as a history of alcohol consumption but no heavy alcohol consumption. Blood pressure, height, weight, and waist circumference were measured with the subjects wearing light clothes and no shoes. BMI was calculated as weight in kilograms divided by the square of the height in meters. The BMI cutoffs suggested by the Department of Health in Taiwan were used. These cutoffs were used to create normal HBsAg(+) vs HBsAg(−) uaHB vs HBsAg(−) aHB vs HBsAg(−) OR (95% CI) P-value aOR (95% CI) P-value OR (95% CI) P-value aOR (95% CI) P-value OR (95% CI) P-value aOR (95% CI) P-value   (18.5 ≤ BMI < 24), overweight (24 ≤ BMI < 27) and obese (BMI ≥ 27) categories. All participants were asked to fast overnight (≥8 hours) before blood sample collection. Blood tests included liver biochemistry, glucose, lipid profile, HBsAg, and anti-HCV. The APRI was used to assess liver fibrosis. The APRI was calculated as follows: = × APRI AST(/upper limit of normal) 100/platelet count(10 /L) 9 APRI thresholds of 0.5 and 1.0 resulted in sensitivity and specificity values of 70.0% and 60.0%, 50.0% and 83.0% for significant fibrosis and advanced fibrosis, respectively 36 . Since IR is one of the key mechanisms for MetS development, we assessed IR using the HOMA-IR score 37 . The HOMA-IR score was calculated by the following formula: m HOMA IR Fasting plasma insulin ( U/L) fasting plasma glucose (mmol/L)/ 22 5 Some communities were selected for hepatic ultrasonography examination based on the availability of public facilities. An ultrasonography scoring system, which included assessment of the liver surface, liver parenchyma, hepatic vessels, and spleen size, was developed to evaluate the degree of hepatic fibrosis 38 . The degree of hepatic steatosis was graded as none, mild, moderate, or severe based on the discrepancy of echogenicity between the liver and kidneys, the degree of posterior attenuation, and the visibility of the vessels 39 . After ultrasonography, the presence of cirrhosis and/or fatty liver was recorded. A total of 1,066 (30.5%) participants received abdominal ultrasonography.
Hepatitis B awareness and metabolic syndrome. All participants were asked whether they had ever been infected with HBV. Participants who were HBsAg seropositive and had self-reported HBV infection were considered aHB. Participants who were HBsAg seropositive and denied a history of HBV infection were considered uaHB.
A race-specific waist circumference threshold, based on the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria 23,40,41 was utilized to prevent distortions in MetS prevalence. According to the ATP III criteria, MetS was defined as the presence of at least three of the following five traits: central obesity (based on the Asian waist circumference cut-offs, males: >90 cm, females: >80 cm); blood pressure ≥130/85 mm Hg or drug treatment for essential hypertension; serum HDL-C level <40 mg/dL in males or <50 mg/dL in females or drug treatment for low HDL-C; serum triglycerides level ≥150 mg/dL or drug treatment for elevated triglycerides; and fasting plasma glucose level ≥100 mg/dL or drug treatment for DM. Statistical analysis. Continuous variables were expressed as mean ± standard deviation. Statistical comparisons between groups of patients were performed using the t-test for continuous variables and Pearson chi-square test for categorical variables. Receiver operating characteristics (ROC) analysis with maximization of the Youden index (sensitivity + specificity − 1) was used to establish the optimal cut-off for HOMA-IR to predict MetS. We conducted unadjusted and multivariate adjusted logistic regression analyses to determine if HBV awareness was associated with odds of MetS and its individual components. Database manipulation and analyses were performed using SPSS, version 19 (SPSS Inc., Chicago, IL, USA). The odds ratio (OR), adjusted OR (aOR), 95% confidence interval (CI), and p-values were calculated. A p-value < 0.05 was considered statistically significant. The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.