Acute and long-term estradiol kinetics in smoking postmenopausal women

Cigarette smoking and hormones

PURPOSE OF REVIEW

The purpose is to provide a summary of the effects of cigarette smoking on steroid hormone metabolism and how it affects female fertility.

RECENT FINDINGS

Components of tobacco smoke such as polycyclic aromatic hydrocarbons lead to transcriptional upregulation of a number of genes, including members of the cytochrome P450 (CYP) family, in particular CYP1B1 and CYP1A1. In humans, CYP1A1 and CYP1A2 are the primary enzymes catalyzing the 2-hydroxylation of estradiol. This pathway shunts available estrogen away from the more estrogenically potent 16α-hydroxylation to the production of catechol estrogens, mainly 2 and 4 hydroxyestradiol.

SUMMARY

Smoking has multiple effects on hormone secretion and metabolism. These effects are mainly mediated by the pharmacological action of tobacco alkaloids (nicotine and its metabolite cotinine). A strong body of evidence indicates that the negative effects of cigarette smoking on fertility compromises nearly every system involved in the reproductive process.

Impact of smoking on estrogenic efficacy

Depending on the type, duration and intensity of cigarette smoking, the efficacy of endogenous and exogenous estrogen can be reduced or completely cancelled. Not only does smoking diminish the beneficial effects of estrogen on hot flushes and urogenital symptoms and its positive effects on lipid metabolism, but smoking also can reduce estrogen's ability to prevent osteoporosis and perhaps also cardiovascular diseases. This is mainly caused by dose-dependent elevated hepatic clearance, partially in conjunction with lower estrogen levels, and has been demonstrated so far only with oral estrogen applications. Compensation for the failure of therapeutic action should not be made by increasing the dose in smokers since this might result in the production of potentially mutagenic estrogen metabolites associated with a higher risk of breast cancer. Since the favorable effects of estrogens seem to be not lost in smokers when estrogens are applied transdermally, this route should be preferred in smokers. The most important conclusion from the data presented is that the effects of smoking are very complex and dependent on a multiplicity of factors, so that different types of clinically relevant negative effects must be expected. Women who continue to smoke despite all warnings should be informed that smoking, in addition to all its other negative effects, can also jeopardize the success of hormone replacement therapy.

Women and Smoking: The Effect of Gender on the Epidemiology, Health Effects, and Cessation of Smoking

Smoking is still the leading cause of premature morbidity and mortality. This paper examines new research on gender differences and the epidemiology of smoking, smoking-related morbidity and mortality, and factors that affect smoking cessation. The rate of decline in the prevalence of smoking has been slowing, especially among adolescent girls. New research suggests that, compared with men, women may be more susceptible to smoking-related morbidity and mortality. Gender-related barriers to smoking cessation include weight gain, sex hormones, and mood. Furthermore, the sensory aspects of smoking may have more of an effect on smoking treatment for women than for men. We discuss new studies that examine smoking-cessation interventions that may be particularly beneficial for women, including exercise (as an adjunct intervention), very low nicotine content cigarettes, and a variety of pharmacotherapy. Further research is needed to identify and target the gender-specific needs of smokers.