Smoking after menopause may increase sex hormone levels

Brand JS. J Clin Endocrinol Metab. 2011;doi:10.1210/jc.2011-1165.

Issue: November 2011

Postmenopausal women who smoke cigarettes have higher androgen and estrogen levels than nonsmokers. The highest sex hormone levels are in heavy smokers, researchers reported in a recent study.

“The observed increase in sex hormone levels with cigarette use suggests that tobacco smoke, apart from its direct toxic and carcinogenic effects, may also influence chronic disease risk through hormonal mechanisms,” Judith Brand, MSc, of University Medical Center Utrecht in the Netherlands, said in a press release issued by The Endocrine Society. “The good news is that the effect of cigarette smoking appears reversible, as an almost immediate reduction in sex hormone levels was seen in women who quit using cigarettes.”

Relationship between smoking, sex hormones

The cross-sectional study included more than 2,000 postmenopausal women aged 55 to 81 years who were included in the Norfolk population of the European Prospective Investigation into Cancer. Women were categorized as current, former or never smokers, based on patient self-reports of cigarette use. All women were at least 1 year postmenopausal and were not currently using hormone therapy.

Researchers found that current smokers had higher circulating levels of androgens and estrogens, including testosterone (19% to 37% higher), free testosterone (19% to 34% higher), 17-hydroxyprogesterone (17% to 22% higher), androstenedione (2% to 23% higher), sex hormone-binding globulin (SHBG; 6% to 10% higher) and estradiol (2% to 15% higher). Additionally, current smoking habit was associated with a larger difference in sex hormone levels than lifetime cigarette exposure as measured by pack-years. For former smokers who quit within 1 to 2 years after menopause, sex hormone levels were similar to those of nonsmokers.

“The almost immediate lower levels with smoking cessation may indicate that hormone-related disease risks could potentially be modified by changing smoking habits,” the researchers wrote in the study.

An association between BMI, smoking status and sex hormone levels was also apparent. The researchers found smoking-related increases in SHBG levels restricted to lean women, as well as increases in free estradiol and free testosterone that were stronger in overweight women.

Future implications

Further research is needed to determine the biological mechanisms by which smoking affects sex hormone levels in postmenopausal women, the researchers said.

“Obviously, quitting smoking has major health benefits such as prevention of cancer, respiratory and heart diseases,” Brand said. “Our research suggests that smoking cessation may have additional effects by modifying hormone-related disease risks, but this was not the subject of the present study and requires further investigation.”

Disclosure: The researchers report no relevant financial disclosures.

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