Table 1
Summary risk estimates of studies evaluating the risk of oral, pharyngeal or oesophageal cancer in current and former BQ-T users.
| SITE OF CANCER | PRODUCT AND TYPE OF USERS | SUMMARY RISK RATIO | 95% CI | EGGER’S/BEGG’S TEST FOR PUBLICATION BIAS (P VALUE) |
|---|---|---|---|---|
| Oral cancer | Current BQ-T user | 7.89 | 3.90–15.98 | 0.02 |
| Former BQ-T user | 5.61 | 2.24–14.04 | ||
| Pharyngeal cancer | Current BQ-T user | 4.81 | 2.05–11.30 | 1.00 |
| Former BQ-T user | 2.50 | 1.43–4.38 | ||
| Oesophageal cancer | Current BQ-T user | 2.42 | 1.25–4.69 | 0.81 |
| Former BQ-T user | 2.64 | 1.87–3.72 |
Figure 1
Forest plot and meta-RR (random effect) of the effect of BQ-T cessation on oral cancer risk (A – former users, B – current users).
Figure 2
Forest plot and meta-RR (random effect) of the effect of BQ-T cessation on pharyngeal cancer risk (A – former users, B – current users).
Figure 3
Forest plot and meta-RR (random effect) of the effect of BQ+T cessation on oral cancer risk (A – former users, B – current users).
Table 2
Summary risk estimates of studies evaluating the risk of oral cancer in current and former BQ+T users.
| STUDIES INCLUDED | PRODUCT AND TYPE OF USERS | SUMMARY RISK RATIO | 95% CI | ||
|---|---|---|---|---|---|
| Overall | Ref 13–19 | Current BQ+T user | 6.29 | 3.83–10.33 | |
| Former BQ+T user | 6.87 | 4.10–11.52 | |||
| By Gender | Males | Ref 14–17, 19 | Current BQ+T user | 3.60 | 2.55–5.08 |
| Former BQ+T user | 3.96 | 2.99–5.25 | |||
| Females | Ref 14,15,19 | Current BQ+T user | 13.11 | 3.64–47.22 | |
| Former BQ+T user | 21.29 | 7.41–61-17 | |||
| Studies with cofounder adjustment | Ref 13,15,16,18,19 | Current BQ+T user | 6.29 | 3.83–10.33 | |
| Former BQ+T user | 9.02 | 5.32–15.29 | |||
| Dropping cohort studies (problematic definition of “cessation”) | 15-18 | Current BQ+T user | 7.27 | 3.40-15.50 | |
| Former BQ+T user | 6.53 | 3.16–13.49 | |||
| Case control studies with confounder adjustment and reasonable definition of “former” user | Ref 15,16 | Current BQ+T user | 9.61 | 2.77–33.30 | |
| Former BQ+T user | 7.63 | 2.57–22.63 | |||
| Duration of cessation | Ref 15,16 | Former user <10 years | 1.21 | 0.90–1.63 | |
| Former user >10 years | 0.72 | 0.48–1.07 | |||
Figure 4
Forest plot and meta-RR (random effect) of the effect of BQ+T cessation duration on Oral cancer. (A) Former users <10yrs and (B) Former users >10yrs.