RISK FACTORS The effects of waterpipe tobacco smoking on health outcomes: a systematic review

Results Twenty-four studies were eligible for this review. Based on the available evidence, waterpipe tobacco smoking was significantly associated with lung cancer [odds ratio (OR)1⁄4 2.12; 95% confidence interval (CI) 1.32–3.42], respiratory illness (OR1⁄4 2.3; 95% CI 1.1–5.1), low birth-weight (OR1⁄4 2.12; 95% CI 1.08–4.18) and periodontal disease (OR1⁄4 3–5). It was not significantly associated with bladder cancer (OR1⁄4 0.8; 95% CI 0.2–4.0), nasopharyngeal cancer (OR1⁄4 0.49; 95% CI 0.20–1.23), oesophageal cancer (OR1⁄4 1.85; 95% CI 0.95–3.58), oral dysplasia (OR1⁄4 8.33; 95% CI 0.78–9.47) or infertility (OR1⁄4 2.5; 95% CI 1.0–6.3) but the CIs did not exclude important associations. Smoking waterpipe in groups was not significantly associated with hepatitis C infection (OR1⁄4 0.98; 95% CI 0.80–1.21). The quality of evidence for the different outcomes varied from very low to low.