Smoking by any smoker in the household and the risk of invasive meningococcal disease: subgroup analysis by methodological quality. Squares indicate the odds ratio and bars represent 95% confidence intervals (CI). Odds ratios more than one indicate smoke exposure in the household increases the risk of invasive meningococcal disease in children.
Murray et al. BMC Public Health 2012 12:1062 doi:10.1186/1471-2458-12-1062