Drug metabolism and variability

Reproductive factors, hormone use, and risk for lung cancer in postmenopausal women, the Nurses' Health Study

BACKGROUND

There is increasing evidence suggesting that female hormones may play a significant role in lung cancer development. We evaluated the associations between reproductive factors, exogenous hormone use, and lung cancer incidence in the Nurses' Health Study.

METHODS

We assessed age at menopause, age at menarche, type of menopause, parity, age at first birth, postmenopausal hormone (PMH) use, and past oral contraceptive use in 107,171 postmenopausal women. Cox models were used to estimate the hazard ratios for each exposure, adjusting for smoking and other covariates.

RESULTS

We identified 1,729 lung cancer cases during follow-up from 1984 to 2006. Menopause onset before 44 years of age (hazard ratio, 1.39; 95% confidence interval, 1.14-1.70) and past oral contraceptive use for >5 years (hazard ratio, 1.22; 95% confidence interval, 1.05-1.42) were associated with increased lung cancer risk. These associations were strongest in current smokers and small cell histology. In never smokers, increased parity was associated with decreased risk among parous women (P trend = 0.03), whereas in current smokers, older age at first birth was associated with increased risk (P trend = 0.02). PMH use was not associated with overall lung cancer incidence. However, nonsignificant results of increased risk in adenocarcinoma were seen with current PMH use.

CONCLUSIONS

Our findings suggest female hormones may influence lung carcinogenesis, although the effect is likely modest, varied by histologic subtype, and altered by smoking.

IMPACT

Further investigation of the pathophysiology of female hormones in lung cancer subtypes and their interaction with smoking will lead to better understanding of lung carcinogenesis.

The influence of smoking on uterine bleeding during sequential oral hormone therapy

OBJECTIVE

To study the influence of smoking on uterine bleeding patterns during sequentially administered oral hormone therapy (HT).

METHODS

Using a post-hoc strategy, we included four sequential oral HT groups from two studies. The therapies consisted of estradiol from days 1 to 28 (estradiol or estradiol valerate) and progestogen (levonorgestrel or gestodene) on days 17-28. A total of 111 healthy, early postmenopausal women (38 smokers and 73 non-smokers) followed for 2 years were included in the analyses. Uterine bleeding data were collected from bleeding calendars.

RESULTS

On the regimen containing levonorgestrel, smoking women had a cyclical bleeding significantly earlier than non-smoking women (about 2 days' difference). Moreover, smoking women had significantly longer bleeding than non-smoking women (about 1 day in difference). This was in contrast to the three regimens containing gestodene, where smoking seemed to have far less influence on uterine bleeding.

CONCLUSIONS

On a regimen containing levonorgestrel, smokers exhibit an earlier and longer uterine bleeding than do non-smokers. This is in contrast to regimens containing gestodene, where smoking women are less likely to differ from non-smoking women with regard to bleeding. This indicates that smoking influences progestogen metabolism, and that this influence may vary with different progestogens. Further studies are needed.

Effects of alcohol and cigarette smoking on change in serum estrone levels in postmenopausal women randomly assigned to fixed doses of conjugated equine estrogens with or without a progestin

OBJECTIVE

To determine the effects of alcohol and smoking on serum estrone levels among women assigned to hormone therapy.

DESIGN

We analyzed the data from 676 participants in the Postmenopausal Estrogen/Progestin Interventions study.

RESULTS

Those who consumed more than 5.5 g of alcohol daily demonstrated greater rises in serum estrone than those who drank less (>0 to < or =5.5 g/d) (P = 0.07) and those who were abstinent (P = 0.09). Current smokers had lesser gains in serum estrone compared with former smokers (P < 0.0001) and never smokers (P < 0.0001).

CONCLUSIONS

Alcohol consumption augmented and smoking diminished serum estrone levels achieved while women were taking hormone therapy.