Relationship of cigarette smoking and snuff dipping to plasma fibrinogen, fibrinolytic variables and serum insulin. The Northern Sweden MONICA Study.

The influence of cigarette smoking and use of smokeless tobacco on plasma fibrinogen level, fibrinolytic variables, glucose tolerance and serum insulin was studied in a randomly selected population sample consisting of 604 men and 662 females between 25 and 64 years. Subjects were grouped according to tobacco habits as follows: regular smokers (> 1 cig/day), ex-smokers, snuff dippers, and non-tobacco users. An oral glucose tolerance test was performed on 54% of the participants. Tissue plasminogen activator (tPA) activity and plasminogen activator inhibitor type 1 (PAI-1) activity were used to study fibrinolysis. Men who smoked had 0.34 g/l (95% CI 0.17 to 0.49) higher fibrinogen level than non-tobacco users and numbers of cigarettes smoked correlated with plasma fibrinogen levels (r = 0.21, P = 0.006). Female smokers had significantly higher fibrinogen levels than ex-smokers but the difference compared with non-smokers was not significant. Snuff dipping did not affect fibrinogen levels. We found no relationship between tPA activity, PAI-1 activity and tobacco use. Post-load plasma glucose was lower in women who smoked, otherwise no influence of tobacco use on glucose levels was seen. Lower post-load insulin levels (-8.8 mU/ml, 95% CI -2.4 to -16.3) than in non-smokers were also found in women who smoked. This was only partially explained by a lower body mass index in smokers. We conclude that cigarette smoking is associated with increased fibrinogen levels, unaltered fibrinolysis, normal glucose tolerance and insulin levels. The use of smokeless tobacco, as moist oral snuff, does not appear to affect these potential cardiovascular risk factors.