Table 2 Subgroup analyses for sex-based difference in the association between smokeless tobacco use and oral cavity cancer risk
Factors | Groups | Number of cohorts | RRR and 95% CI | P value | I2 (%) |
|---|---|---|---|---|---|
Type of smokeless product | Chew | 9 | 2.09 (1.17–3.75) | 0.013 | 78.7 |
Non-chew | 3 | 0.94 (0.60–1.47) | 0.774 | 0.0 | |
Mixed | 2 | 1.51 (0.79–2.90) | 0.210 | 0.0 | |
Control definition | Hospital-based | 12 | 1.58 (1.03–2.44) | 0.037 | 70.0 |
Population-based | 2 | 3.68 (1.72–7.87) | 0.001 | 0.0 | |
Confounders adjusted | Yes | 12 | 1.75 (1.10–2.79) | 0.018 | 74.3 |
No | 2 | 1.72 (0.74–4.03) | 0.209 | 0.0 | |
Matching of control | Matched | 12 | 1.83 (1.13–2.96) | 0.013 | 74.2 |
Unmatched | 2 | 1.51 (0.79–2.90) | 0.210 | 0.0 | |
Study quality | High | 3 | 2.72 (1.57–4.71) | < 0.001 | 0.0 |
Moderate | 11 | 1.55 (0.97–2.48) | 0.066 | 72.0 |