Occasional smoking in a study of premenopausal women

Ovarian function and cigarette smoking

Cigarette smoking has been implicated in reproductive outcomes including delayed conception, but mechanisms underlying these associations remain unclear. One potential mechanism is the effect of cigarette smoking on reproductive hormones; however, studies evaluating associations between smoking and hormone levels are complicated by variability of hormones and timing of specimen collection. We evaluated smoking among women participating in the BioCycle Study, a longitudinal study of menstrual cycle function in healthy, premenopausal, regularly menstruating women (n = 259). Fertility monitors were used to help guide timing of specimen collection. Serum levels of oestradiol, progesterone, follicle-stimulating hormone (FSH), luteinising hormone (LH) and total sex-hormone binding globulin (SHBG) across phases of the menstrual cycle were compared between smokers and non-smokers. We observed statistically significant phase-specific differences in hormone levels between smokers and non-smokers. Compared with non-smokers, smokers had higher levels of FSH in the early follicular phase and higher LH at menses after adjusting for potential confounding factors of age, race, body mass index, parity, vigorous exercise, and alcohol and caffeine intake through inverse probability of treatment weights. No statistically significant differences were observed for oestradiol, progesterone or SHBG. These phase-specific differences in levels of LH and FSH in healthy, regularly menstruating women who are current smokers compared with non-smokers reflect one mechanism by which smoking may influence fertility and reproductive health.

Reaching young adult smokers through the internet: comparison of three recruitment mechanisms

INTRODUCTION

While young adults have the highest prevalence of cigarette smoking of any adult age group, studies of tobacco and other substance use have reported challenges in recruiting this age group. The Internet may be a useful tool for reaching young adult smokers. The present study compared three Internet-based recruitment methods for young adult smokers to complete a survey about tobacco and other substance use: Craigslist advertisements, other Internet advertisements, and E-mail invitations through a survey sampling service.

METHODS

Recruitment campaigns invited young adults aged 18-25 years who had smoked at least one cigarette in the past 30 days to complete an online survey. Recruitment methods were compared across recruitment numbers, costeffectiveness, and demographic and smoking characteristics of recruited participants.

RESULTS

In 6 months, 920 people gave online consent to determine eligibility to complete the survey, of which 336 (36.5%) were eligible, and 201 (59.8%) completed the survey. While Internet advertisements yielded the largest proportion of recruited participants and completed surveys overall, Craigslist and sampling strategies were more successful at targeting young adult smokers who went on to complete the survey and were more costeffective. Participants differed in demographic and substance use characteristics across the three recruitment mechanisms.

DISCUSSION

We identified success at reaching young adults who have smoked cigarettes recently through the Internet, though costs, participant eligibility, proportion of completed surveys, and respondent characteristics differed among the three methods. A multipronged approach to Internet recruitment is most likely to generate a broad diverse sample of young adult smokers.

Cigarette smoking and effects on hormone function in premenopausal women

Cigarette smoke contains compounds that are suspected to cause reproductive damage and possibly affect hormone activity; therefore, we examined hormone metabolite patterns in relation to validated smoking status. We previously conducted a prospective study of women of reproductive age (n = 403) recruited from a large health maintenance organization, who collected urine daily during an average of three to four menstrual cycles. Data on covariates and daily smoking habits were obtained from a baseline interview and daily diary, and smoking status was validated by cotinine assay. Urinary metabolite levels of estrogen and progesterone were measured daily throughout the cycles. For the present study, we measured urinary levels of the pituitary hormone follicle-stimulating hormone (FSH) in a subset of about 300 menstrual cycles, selected by smoking status, with the time of transition between two cycles being of primary interest. Compared with nonsmokers, moderate to heavy smokers (>/= 10 cigarettes/day) had baseline levels (e.g., early follicular phase) of both steroid metabolites that were 25-35% higher, and heavy smokers (>/= 20 cigarettes/day) had lower luteal-phase progesterone metabolite levels. The mean daily urinary FSH levels around the cycle transition were increased at least 30-35% with moderate smoking, even after adjustment. These patterns suggest that chemicals in tobacco smoke alter endocrine function, perhaps at the level of the ovary, which in turn effects release of the pituitary hormones. This endocrine disruption likely contributes to the reported associations of smoking with adverse reproductive outcomes, including menstrual dysfunction, infertility, and earlier menopause.