Table 1. Characteristics of studies included in the meta-analysis, 2003-2014.
| References (first author, year) | Study area | Study design | No. of cases | No. of controls/cohorts | Status of controls | Mutation | Detection method | HBV genotype | Adjustment/matching variables |
|---|---|---|---|---|---|---|---|---|---|
| Qu (a), 2014 | China | NCC | 96 | 97 | CHB | Pre-S mutation | Sequence | C | Age, smoking, alcohol drinking |
| Qu (b), 2014 | China | NCC | 152 | 131 | CHB | C1653T, T1753V, A1762T/G1764A, G1896A | Sequence | C | Age, smoking, alcohol drinking |
| Sinn, 2012 | South Korea | Cohort | 24 | 195 | CHB | Pre-S mutation | Sequence | C | Age, sex, HBeAg, cirrhosis, HBV-DNA level |
| Muñoz, 2011 | China | NCC | 345 | 625 | ASC | A1762T/G1764A | Real-time polymerase chain reaction | NA | Age, cohort, screen status and screen test results |
| Kusakabe, 2011 | Japan | Cohort | 13 | 479 | ASC | C1653T, T1753V, A1762T/G1764A, G1896A | Sequence | B, C | Age, sex, body mass index, smoking, alcohol drinking, ALT, c-glutamyl transpeptidase, HBeAg, HBcAg, HBV-DNA, Genotype |
| Yuen, 2009 | Hong Kong, China | Cohort | 40 | 820 | CHB | A1762T/G1764A | Sequence | B, C | Age, gender, HBV genotype, core promoter and precore mutations, HBeAg/anti-HBe status, HBV DNA, ALT levels and LC |
| Yuan, 2009 | China | NCC | 50 | 106 | ASC | A1762T/G1764A | Real-time polymerase chain reaction | NA | Age, years between blood draw and measurement of HBV DNA double mutation, neighborhood of residence at recruitment, cigarette smoking, heavy alcohol consumption, and serum concentration of retinol |
| Sung, 2009 | Taiwan, China | NCC | 116 | 154 | ASC | A1762T/G1764A, G1896A | Sequence | A, B, C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Fang (a), 2008 | China | NCC | 33 | 33 | ASC | Pre-S mutations | Sequence | B, C | Age, sex and status of core promoter sequence, HBeAg, Anti-HBe, genotype, ALT |
| Fang (b), 2008 | China | Cohort | 61 | 2258 | ASC | C1653T, T1753V, A1762T/G1764A | Sequence | NA | Age, sex. HBeAg and abnormal ALT were not confounders in this study. |
| Yang, 2008 | Taiwan, China | Cohort | 153 | 2762 | ASC | A1762T/G1764A, G1896A, Pre-S mutation (Unpublished data) | Sequence | B, C | Age, sex, cigarette smoking, alcohol drinking, ALT level, LC, HBV DNA level, HBV genotype |
| Chou, 2008 | Taiwan, China | NCC | 132 | 204 | ASC | T1753V, A1762T/G1764A, G1896A | Sequence | A, B, C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Cao, 2008 | China | NCC | 47 | 50 | CHB | Pre S mutations | Other | NA | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Guo, 2008 | China | NCC | 58 | 71 | CHB | C1653T, T1753V, A1762T/G1764A | Sequence | B, C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Zhu, 2008 | China | NCC | 20 | 83 | CHB | A1762T/G1764A | Sequence | C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Chen, 2007 | Taiwan, China | Cohort | 7 | 141 | ASC, CHB | Pre-S deletions, G1896A | Sequence | B, C | Age, sex, ALT, total bilirubin, HBV-DNA, HBV genotypes |
| Jang, 2007 | South Korea | Cohort | 6 | 29 | ASC, CHB, LC | A1762T/G1764A | Sequence | C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Zhang, 2007 | China | NCC | 32 | 32 | CHB | A1762T/G1764A | Sequence | NA | Age sex, occupation, living environment |
| Tong, 2006 | United States | Cohort | 31 | 400 | CHB | A1762T/G1764A, G1896A | Sequence | A, B, C | OR and 95% CI calculated on the distribution of cases and controls according to the mutations. |
| Kao, 2003 | Taiwan, China | NCC | 127 | 123 | CHB | A1762T/G1764A | Sequence | B, C | Age, sex, LC, genotype |
NCC, nested case-control study; ASC, asymptomatic hepatitis B surface antigen carriers; CHB, chronic hepatitis B; LC, liver cirrhosis; HBeAg, hepatitis B e antigen; ALT, alanine aminotransferase; NA, not available; other, restriction fragment length polymorphism and polyacrylamide gel electrophoresis.