Influence of smoking on hormone secretion in obese and lean female smokers

Smoke, alcohol and drug addiction and female fertility

BACKGROUND

Considerable interest has been gathered on the relevant impact of preventable factors, including incorrect lifestyle and unhealthy habits, on female fertility. Smoking, alcohol and addictive drugs consumption represent a major concern, given the broad range of diseases which might be favored or exacerbated by these dependable attitudes. Despite the well-characterized effects of prenatal exposure on pregnancy outcomes and fetus health, a substantial proportion of women of reproductive age is still concerned with these habits. At present, the impact of smoke, alcohol and addictive drugs on women fertility, and, particularly, the specific targets and underlying mechanisms, are still poorly understood or debated, mainly due to the scarcity of well-designed studies, and to numerous biases.

OBJECTIVE

The current review will provide a comprehensive overview of clinical and experimental studies in humans and animals addressing the impact of smoke, alcohol and addictive drugs on female fertility, by also embracing effects on ovary, oviduct, and uterus, with particular reference to primary endpoints such as ovarian reserve, steroidogenesis, ovulation and menstrual cycle, oviduct function and uterus receptivity and implantation. A brief focus on polycystic ovary syndrome and endometriosis will be also included.

METHODS

A Pubmed literature search was performed with selected keywords; articles were individually retrieved by each author. No limitation was set for publication date. Articles in languages other than English were excluded. Additional articles were retrieved from references list of selected manuscripts.

RESULTS AND CONCLUSIONS

Currently, the most consistent evidences of a detrimental effect of smoke, alcohol and addictive drugs on specific domains of the female reproductive function are provided by experimental studies in animals. Overall, clinical studies suggest that smoking is associated to decreased fertility, although causal inference should be further demonstrated. Studies addressing the effect of alcohol consumption on female fertility provide conflicting results, although the majority reported lack of a correlation. Extremely scarce studies investigated the effects of addictive drugs on female fertility, and the specific actions of selected drugs have been difficult to address, due to multidrug consumption.

Modulation of the growth hormone-insulin-like growth factor (GH-IGF) axis by pharmaceutical, nutraceutical and environmental xenobiotics: an emerging role for xenobiotic-metabolizing enzymes and the transcription factors regulating their expression. A review

The growth hormone-insulin-like growth factor (GH-IGF) axis has gained considerable focus over recent years. One cause of this increased interest is due to a correlation of age-related decline in plasma GH/IGF levels with age-related degenerative processes, and it has led to the prescribing of GH replacement therapy by some practitioners. On the other hand, however, research has also focused on the pro-carcinogenic effects of high GH-IGF levels, providing strong impetus for finding regimes that reduce its activity. Whereas the effects of GH/IGF activity on the action of xenobiotic-metabolizing enzyme systems is reasonably well appreciated, the effects of xenobiotic exposure on the GH-IGF axis has not received substantial review. Relevant xenobiotics are derived from pharmaceutical, nutraceutical and environmental exposure, and many of the mechanisms involved are highly complex in nature, not easily predictable from existing in vitro tests and do not always predict well from in vivo animal models. After a review of the human and animal in vivo and in vitro literature, a framework for considering the different levels of direct and indirect modulation by xenobiotics is developed herein, and areas that still require further investigation are highlighted, i.e. the actions of common endocrine disruptors such as pesticides and phytoestrogens, as well as the role of xenobiotic-metabolizing enzymes and the transcription factors regulating their expression. It is anticipated that a fuller appreciation of the existing human paradigms for GH-IGF axis modulation gained through this review may help explain some of the variation in levels of plasma IGF-1 and its binding proteins in the population, aid in the prescription of particular dietary regimens to certain individuals such as those with particular medical conditions, guide the direction of long-term drug/nutraceutical safety trials, and stimulate ideas for future research. It also serves to warn athletes that using compounds touted as performance enhancing because they promote short-term GH release could in fact be detrimental to performance in the long-run.

Pre-Analytic Considerations for the Proper Assessment of Hormones of the Hypothalamic-Pituitary Axis in Epidemiological Research

There is growing epidemiological interest in hormones as predictors of chronic diseases. The correct handling and analysis of hormones can be cumbersome, and great care must be taken in these processes in order to gain the most information possible. Given differences in sampling, processing, and stability of the various hormonal assays, we sought to provide a comprehensive review to aid future epidemiological research. We have coupled a thorough literature search with our own analytical experience to outline common laboratory problems one must consider in analyzing the hormones of the hypothalamic-pituitary axis. In addition, we describe the benefits and limitations of using alternative media--including urine, saliva, and blood spots on filter paper--to measure endocrine hormones in epidemiological studies.

Cigarette smoking and the risk of goitre and thyroid nodules amongst parous women

OBJECTIVES

To clarify the mechanisms by which smoking is associated to toxic and nontoxic goitre and thyroid nodules.

DESIGN

Cohort study.

SETTING

Sweden.

SUBJECTS

A cohort of 874,507 parous women identified through the Medical Birth Registry, with smoking behaviour assessed through self-reported information at the first pre-natal visit, and follow-up between 1983 and 1997.

MAIN OUTCOME MEASURES

Hospital diagnoses of toxic and nontoxic goitre and thyroid nodules, identified by record-linkage with the national Inpatient Registry. Cox regression was employed to estimate the hazard ratio (HR) of smokers compared with nonsmokers and the corresponding 95% confidence limits (CL).

RESULTS

There was a significantly increased risk of goitre and nodules amongst smokers. The positive association was stronger for toxic (age adjusted HR = 1.94, CL = 1.74-2.16) than for nontoxic goitre and nodules (age-adjusted HR = 1.26; CL = 1.14-1.38). There was generally no clear risk trend with regard to amount smoked (below and above 10 cigarettes per day). Elevated body mass attenuated these associations, whilst being born in Swedish areas of endemic goitre enhanced the association with nontoxic goitre and nodules.

CONCLUSIONS

Smoking enhances the risk of thyroid goitre and nodules requiring hospital admission. Iodine deficiency and body weight are likely to be important modifiers of the risk of thyroid hyperplastic diseases amongst smokers.

Smoking and the risk of endometrial cancer: results from the Nurses' Health Study

An inverse association between smoking and endometrial cancer has generally been observed, primarily among current smokers. To assess this association, we analyzed data from the prospective Nurses' Health Study. From 1976 to 2000, 702 cases of invasive endometrial cancer were identified during 1.8 million person-years of follow-up. Smoking status was assessed in 1976 and updated every 2 years. Cox proportional hazards models were used to calculate multivariate relative risks (RRs), controlling for endometrial cancer risk factors. Compared to never smokers, the multivariate RR of endometrial cancer was significantly lower among both current smokers (RR = 0.63; 95% CI = 0.50-0.79) and past smokers (RR = 0.73; 95% CI = 0.62-0.87). When additionally adjusting for body mass index (BMI), the RR for current smokers was attenuated (RR = 0.72; 95% CI = 0.57-0.90), but the RR for past smokers did not change. Risk was lower among women who smoked 35 or more cigarettes a day (RR = 0.60; 95% CI = 0.39-0.91) and among those who smoked for 40 or more years (RR = 0.63; 95% CI = 0.45-0.87). Tests for trend, which excluded never smokers, were not statistically significant for any of the smoking variables analyzed. These data indicate that both current and past smoking are associated with a lower risk of endometrial cancer. The findings provide insight into disease etiology and suggest that the influence of smoking on endometrial cancer risk occurs even in early adulthood, is long-lasting, and may not be attributed solely to short-term hormonal modulation.

Association of body mass index, age, and cigarette smoking with serum testosterone levels in cycling women undergoing in vitro fertilization

OBJECTIVE

[1] To examine the effects of body mass index (BMI), age, cigarette smoking, cause of infertility, and use of oral contraceptives on baseline serum testosterone (T), and [2] to examine associations between baseline serum T and IVF outcomes such as pre-hCG serum E(2), number of oocytes retrieved, oocyte fertilization rate, and pregnancy outcome in regularly cycling women.

DESIGN

Prospective, cohort study.

SETTING

Three IVF programs in eastern Massachusetts.

PATIENT(S)

Four hundred twenty-five regularly cycling women planning to undergo IVF. Women with polycystic ovary syndrome, ovulatory infertility, or irregular cycles were excluded from this study.

INTERVENTION(S)

Collection of epidemiological data and baseline serum in women undergoing IVF.

MAIN OUTCOME MEASURE(S)

Baseline serum total T, sex hormone binding globulin (SHBG), and calculation of free androgen index.

RESULT(S)

Body mass index >26 kg/m(2) was associated with a significant increase in serum T (P<.01) and free androgen index (P<.0001). Serum T decreased significantly throughout the fourth decade of life (P<.03). A history of cigarette smoking >10 pack years was associated with increased serum T (P<.01). A diagnosis of endometriosis was associated with decreased serum T. Serum T correlated positively with pre-hCG serum E(2) and number of oocytes retrieved. However, serum T did not significantly influence fertilization or pregnancy rates.

CONCLUSION(S)

In cycling infertile women, increasing BMI and cigarette smoking are associated with increased serum T. Advancing age and endometriosis are associated with decreased serum T.

Chromium picolinate may favorably influence the vascular risk associated with smoking by combating cortisol-induced insulin resistance

Smoking promotes insulin resistance and other features - excepting hypertension - of the insulin resistance syndrome; these effects appear to reflect chronic nicotine exposure. The adverse impact of smoking on insulin function may be a prominent mediator of the excess vascular risk associated with smoking. Although the mechanistic basis of nicotine-induced insulin resistance remains to be clarified, increased secretion of ACTH and cortisol seems likely to play an important role in this regard. It is therefore intriguing to note that supplemental chromium picolinate has been reported to have a rapid and substantial favorable impact on glycemic control in patients with corticosteroid-induced diabetes. In dexamethasone-treated rats, high doses of this compound have been shown to markedly improve insulin sensitivity. Thus, if these initial reports are confirmable, ample intakes of bioactive chromium may have the potential to reverse the negative influence of corticosteroids on insulin signaling. Such an effect might have utility not only for smokers, but for others in whom chronic up-regulation of the hypothalamic-pituitary-adrenal axis compromises vascular health. The impact of chromium picolinate on smoking- or nicotine-induced insulin resistance merits study.

Acute effects of nicotine on serum glucose insulin growth hormone and cortisol in healthy smokers

Cigarette smoking impairs glucose tolerance and alters serum levels of hormones involved in glucose metabolism, but the role of nicotine in such hormonal alterations is not well understood. In order to isolate the effects of transdermal nicotine on serum glucose, insulin, growth hormone, and cortisol in smokers, we conducted a randomized double-blind placebo-controlled cross-over study involving 34 healthy volunteer smokers between 18 and 55 years of age. Administration of a 14-mg transdermal nicotine patch resulted in nonsignificantly lowered fasting quantitative insulin-sensitivity index (P =.11) and a nonsignificant 9.3-mg/dL mean increase in serum glucose levels during a 75-g oral glucose tolerance test (OGTT) at time 60 minutes (P =.12). There were no substantial differences between groups in the areas under the curve (AUCs) for glucose (P =.33) or insulin (P =.79) during the OGTT. Levels of insulin and cortisol also were not significantly altered by nicotine. A secondary finding observed in the overall study group (primarily in females) was that nicotine caused a 29% median decrease in serum growth hormone (P =.02). We conclude that nicotine patches may lead to mild hyperglycemia and lowered insulin sensitivity. Further research is needed to determine the clinical implications of the unexpected finding that nicotine decreased growth hormone levels in female smokers.

Stress and body shape: stress-induced cortisol secretion is consistently greater among women with central fat

OBJECTIVE

Excessive central fat puts one at greater risk of disease. In animal studies, stress-induced cortisol secretion has been shown to increase central fat. The objective of this study was to assess whether women with central fat distribution (as indicated by a high waist-to-hip ratio [WHR]), across a range of body mass indexes, display consistently heightened cortisol reactivity to repeated laboratory stressors.

METHODS

Fifty-nine healthy premenopausal women, 30 with a high WHR and 29 with a low WHR, were exposed to consecutive laboratory sessions over 4 days (three stress sessions and one rest session). During these sessions, cortisol and psychological responses were assessed.

RESULTS

Women with a high WHR evaluated the laboratory challenges as more threatening, performed more poorly on them, and reported more chronic stress. These women secreted significantly more cortisol during the first stress session than women with a low WHR. Furthermore, lean women with a high WHR lacked habituation to stress in that they continued to secrete significantly more cortisol in response to now familiar challenges (days 2 and 3) than lean women with a low WHR.

CONCLUSIONS

Central fat distribution is related to greater psychological vulnerability to stress and cortisol reactivity. This may be especially true among lean women, who did not habituate to repeated stress. The current cross-sectional findings support the hypothesis that stress-induced cortisol secretion may contribute to central fat and demonstrate a link between psychological stress and risk for disease.