Letters to the editor

OVERVIEW

Please submit letters for the editor's consideration within three weeks of receipt of Clinical Medicine. Letters should ideally be limited to 350 words, and sent by email to: clinicalmedicine{at}rcplondon.ac.uk

A review of the health effects of smoking shisha

Editor – We read with interest the review on the health effects of smoking shisha (Clin Med 2015;15:263–66): an important and under-appreciated topic. We wish to highlight the development of chronic obstructive pulmonary disease (COPD) as a further important long-term consequence of shisha smoking on the respiratory system.

Persistent airway inflammation may lead to poorly reversible airflow obstruction (COPD), chronic sputum production (chronic bronchitis) and breakdown of the alveolar membranes (emphysema). The most important aetiological factors are cigarette smoke and biomass exposure. Like cigarette smoke, shisha smoke can act as the necessary inflammatory stimulus and there is a misconception that water ‘filters’ the smoke.

In support of this, a Lebanese study estimating the national COPD burden found it to be twice as prevalent in exclusive shisha smokers compared to non-smokers.¹ COPD prevalence was significantly positively correlated with number of water-pipe years. Among the subjects with the greatest exposure, those with 40 water-pipe years, there was a 37.2% prevalence of COPD.¹ The BREATHE study was a large cross-sectional study surveying 62000 people in eleven Middle-Eastern countries. Data were collected on respiratory symptoms and smoking. A significant association was observed between chronic bronchitis and shisha use (corrected for concurrent cigarette use).² Elsewhere it has been shown that there is a strong dose-relationship between shisha smoke exposure and prevalence of chronic bronchitis.³ In Chinese water-pipe smokers (a variant on the Middle-Eastern pipe where the tobacco is lit directly instead of using coals) the rate of radiologically diagnosed emphysema was higher than in cigarette smokers or non-smokers.⁴

These clinical data are supported by animal models: chronic airway inflammation with eventual airflow limitation typical of COPD has been demonstrated using water-pipe smoke in mice. Mice exposed to shisha smoke for 30 minutes per day for five days develop neutrophilic inflammation of their airways and an increase in tumor necrosis factor-alpha and interleukin-6 present in broncho–alveolar lavage fluid.⁵

As COPD is set to become the third leading cause of death worldwide by 20206 it is essential for all physicians to recognise shisha smoking as an increasingly important cause of COPD, to ask about shisha exposure, and to warn patients of the risks to their health including COPD.