Effects of water-pipe smoking on lung function: a systematic review and meta-analysis.

ABSTRACT

BACKGROUND: Although common in many Middle Eastern countries, water-pipe tobacco smoking, commonly known as water-pipe smoking (WPS), is increasingly popular in Western cultures. The primary objective of this study was to systematically review the effects of WPS on lung function. The secondary objective was to compare the effects of WPS and cigarette smoking on lung function. METHODS: We conducted a systematic review using the approach of the Cochrane Collaboration to search for, select, and abstract studies. We conducted two separate meta-analyses comparing water-pipe smokers with nonsmokers, and water-pipe smokers with cigarette smokers for each of three spirometric measurements (FEV1, FVC, and FEV1/ FVC). We used the standardized mean difference (SMD) to pool the results. RESULTS: Six cross-sectional studies were eligible for this review. Compared with no smoking, WPS was associated with a statistically significant reduction in FEV1 (SMD = -0.43; 95% CI, -0.58 to -0.29; equivalent to a 4.04% lower FEV1%), a trend toward lower FVC (SMD = -0.15; 95% CI, -0.34 to 0.04; equivalent to a 1.38% reduction in FVC%), and lower FEV1/ FVC (SMD = -0.46; 95% CI, -0.93 to 0.01; equivalent to a 3.08% lower FEV1/ FVC). Comparing WPS with cigarette smoking, there was no statistically significant difference in FEV1, FVC, and FEV1/ FVC. The six studies suffered from methodologic limitations. CONCLUSIONS: WPS negatively affects lung function and may be as harmful as cigarette smoking. WPS, therefore, is likely to be a cause of COPD.