Higher lipid peroxidation in former-smokers vs. never-smokers - study in postmenopausal women

One of the most spectacular exogenous prooxidative agents is cigarette smoking, constituting a well documented risk factor for several diseases. In turn it is suggested that hormone replacement therapy (HRT) in postmenopausal women can contribute to oxidative status. The aim of the study was to evaluate the level of oxidative damage to membrane lipids in blood serum collected from never-smokers and former-smokers. The study was performed in postmenopausal women, who were or were not HRT users.

Ninety (90) female volunteers, aged from 46 to 67 years, were enrolled. Two major groups were considered, i.e. never-smokers (n=44) and formersmokers (n=46), which were additionally subgrouped to HRT users (HRT+) and HRT non-users (HRT-). Anthropometric parameters related to obesity were also calculated. The main groups were well matched at baseline in terms of age. The level of malondialdehyde+4-hydroxyalkenals (MDA+4-HDA), as the index of LPO, was measured spectrophotometrically.

The level of LPO was higher in former-smokers than in never-smokers, regardless of HRT use. The level of LPO did constitute the only independent factor associated with past smoking in the entire examined group, as well as after stratification to HRT users and HRT non-users. LPO level was not associated with HRT treatment. No positive correlations were found between LPO level and anthropometric parameters.

Past smoking is independently associated with the increased damage to membrane lipids regardless of the use of HRT in postmenopausal women. Smoking cessation is not always associated with complete reversion of excessive oxidative damage to all biological macromolecules.