Int. J. Epidemiol. (April 2006) 35 (2): 330-336. doi: 10.1093/ije/dyi295 First published online: January 4, 2006
Is it exposure to cigarette smoke or to smokers which increases the risk of meningococcal disease in teenagers?
Pietro G Coen1,*,
Joanna Tully1,
James M Stuart2,
Deborah Ashby3,
Russell M Viner4 and
Robert Booy1
+ Author Affiliations
1Academic Department of Child Health, Queen Mary, University of London, Royal London Hospital, UK
2Health Protection Agency South West, The Wheelhouse, Bonds Mill, Stonehouse, Gloucestershire GL10 3RF, UK
3Centre for Environmental Preventive Medicine, Queen Mary's Barts and the London School of Medicine and Dentistry, University of London, UK
4Department of Paediatrics, Royal Free and University College Medical School, University College London, UK
*Corresponding author. Hospital Epidemiologist, Infection Control Office, Department of Microbiology, The Windeyer Institute of Medical Sciences, University College London Hospitals NHS Trust, 46 Cleveland Street, London W1T 4JF, UK. E-mail: []
Accepted November 22, 2005.
Abstract
Background Passive smoking appears to increase the risk of meningococcal disease (MD) in adolescents. Whether this effect is attributable to exposure to cigarette smoke or contact with smokers is unknown.
Methods We conducted a prospective population-based case?control study with age, sex matched-controls in 1:1 matching. Participants were 15?19 year old with MD recruited at hospital admission in six regions (65% of the population of England) from January 1999 through June 2000, and their matched controls. Data on potential risk factors were gathered by confidential interview, including seven passive smoking variables. Factor analysis was performed to assess the dimensionality of the passive smoking exposure variables. The data were analysed with univariate and multivariate conditional logistic regression.
Results 144 case?control pairs were recruited (51% male; median age 17.6). Factor analysis identified two independent factors representing passive smoking (P < 0.01), one associated with ?exposure to smoke?, the other with ?smoker contact?. Only smoker contact was a significant risk factor for MD (OR = 1.8; 95% CI 1.0?3.3; P = 0.05). In multivariate analysis this factor was still associated with MD independently of potential confounders such as active smoker status and household crowding.
Conclusion Contact with smokers is associated with increased risk of MD in adolescents. This is more likely to be due to higher carriage rates in smokers than to exposure to smoke and emphasizes the importance of public health measures to stop smoking. In epidemiological studies that assess risk from passive smoking, exposure to smoke should be differentiated where possible from contact with smokers.
Published by Oxford University Press on behalf of the International Epidemiological Association ? The Author 2006; all rights reserved.
