Gender differences in the relation between fibrinogen, tissue-type plasminogen activator antigen and markers of insulin resistance: Effects of smoking

A stronger positive association between fibrinogen or tissue-type plasminog en activator antigen (tPA-ag) and fasting insulin is observed in women than in men. We investigated whether this effect could be explained by a differ ence in smoking habits. The relations between markers for insulin resistance [fasting insulin and i nsulin resistance as estimated by the homeostasis model assessment (HOMA-IR )] and fibrinogen and tPA-ag were examined cross-sectionaly in 4976 (582 fo r tPA-ag) subjects from the D.E.S.I.R, (Data from an Epidemiological Study on the Insulin Resistance syndrome) study. The modifying effect of smoking habits were evaluated. Seventeen percent of women and 27% of men were smokers. Fibrinogen concentr ations were higher in smokers than in non-smokers, in men only. Female smok ers had lower concentrations of tPA-ag than non-smokers. In both women and men, fibrinogen was positively associated with fasting insulin [women: beta = 0.33 mg/U (95% confidence interval: 0.29, 0.37); men: beta = 0.15 mg/U ( 0.11, 0.19)] and with HOMA-IR [women: beta = 0.17 mu g/mu U mol/l (0.15, 0. 19); men: beta = 0.06 (0.04. 0.08)]. For tPA-ag these associations were for insulin beta = 0.76 mg/U (0.54, 0.98) and beta = 0.89 mg/U (0.67, 1.11), a nd for HOMA-IR beta = 0.47 mu g/mu U mol/l (0.33, 0,61) and beta = 0.45 mu g/mu U mol/l (0.33, 0.57), women and men respectively. The associations of fibrinogen and tPA-ag with insulin and HOMA-IR were sharply reduced in male smokers compared to male non-smokers, however the strength of the associat ions in male non-smokers did not reach that in women. Fibrinogen and tPA-ag are independetly related with markers of insulin resi stance with the relation with fibrinogen being stronger in women than in me n. The strong modifying effect of smoking habits does not completely explai n this gender difference.