Association between atherosclerotic diseases and carboxyhaemoglobin levels in tobacco smokers.

In a cross-sectional study carboxyhaemoglobin (COHb) levels in tobacco smokers were found to provide a better indication of a person's risk of having developed certain atherosclerotic diseases, including ischaemic heart disease, than the smoking history. In the age group 30-69 years a person with a COHb level of 5% or more was found to be 21 times (lower 95% confidence limit 3.3 times) as likely to be affected by these diseases as another person of the same age and sex with similar smoking history and current smoking habits but with a COHb level of less than 3%.