Abstract
Studies using cotinine levels to define smokers have generally failed to detect an association between smoking and multiple sclerosis (MS). Using a Swedish population-based case-control study, we show that associations in relation to MS risk and progression differ considerably depending on how smoking is measured. The risk of conversion into secondary progressive disease was increased among smokers when self-reported smoking history, but not presumed cotinine levels, was used to define smokers. Defining smoking by cotinine levels without distinguishing between different sources of nicotine may lead to severely biased estimates of the association between smoking and both MS risk and progression.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.