Cigarette smoking and male reproduction

Testosterone deficiency and the aging male

Testosterone deficiency (TD), also known as male hypogonadism, is a complex syndrome encompassing physical, biochemical, and social aspects that increasingly affects the aging population. TD has been analyzed over recent decades, with an enhanced focus on etiologies relating to aging males. There is debate whether testosterone decline leading to hypogonadism is directly and primarily related to age-specific processes or if it is the subsequent result of accumulating comorbidities throughout a lifetime. Several studies have been done to further characterize this distinction. Chronic comorbidities that have commonly been associated with TD include hypertension (HTN), cardiovascular disease (CVD), diabetes mellitus (DM), obesity, metabolic syndrome (MetS), chronic kidney disease (CKD), and tobacco use. Although clear associations between hypogonadism and aging have been biochemically demonstrated, many large studies have illustrated the concomitant effects of highly prevalent chronic diseases and social behaviors in aging men. Given the significant impact of hypogonadism on the physical and mental health of men, this paper aims to delve into these studies and further define the complex relationship of testosterone deficiency in the aging male.

Leader emergence and affective empathy: A dynamic test of the dual-hormone hypothesis

Personal distress is a building block of empathy, yet has received scant attention in studies of individual differences in leadership. We investigate whether the effect of leader emergence on men's distress is influenced by their personalized power motive (p Power) and changes in their testosterone (T) and cortisol (C) levels. In an experiment involving 96 males, p Power modulated the direction and intensity of T change in emergent leaders, with high p-Power leaders showing a more positive T change compared to their low p-Power counterparts. We also conducted a dynamic test of the dual-hormone hypothesis in which participants' changes in T and C interacted to produce differences in personal distress. Contrary to expectations, positive changes in T were associated with increased distress at negative changes in C. Given that high T and low C are associated with leadership, we explain these findings and question the assumption that personal distress represents a shortcoming in leaders.

Effects of nonsteroidal anti-inflammatory drug (NSAID) use upon male gonadal function: A national, population-based study

Recent data have suggested that short-term NSAID use induces a state of compensated hypogonadism. Our aim was to investigate the association between chronic, regular NSAID use and compensated hypogonadism in a large, nationally representative cohort, the US National Health and Nutrition Examination Survey (NHANES) database. Men 20-80 years who answered the analgesic use questionnaire and underwent hormonal testing were included. Multivariable regression was utilised to determine the relationship between NSAID use and serum testosterone (T), anti-Mullerian hormone (AMH) and T:AMH ratio. Among 3,749 men, 505 (13.5%) reported regular NSAID use and 3,244 (86.5%) did not. Regular users had lower T (440.7 ± 27.0 vs. 557.0 ± 24.9 ng/dl, p = .005) and albumin (43.8 ± 0.2 vs. 45.1 ± 0.1, p < .001) compared to nonregular users. On multivariable analysis, only active smoking was significantly associated with T, AMH and T:AMH ratio (p < .001, p = .036 and p = .005 respectively). Regular NSAID use was not associated with T, AMH or T:AMH ratio (p = .523, p = .974, and p = .872 respectively). In this nationally representative sample of US men, regular and chronic NSAID use was not associated with alterations in T or compensated hypogonadism. These data should reassure patients and clinicians regarding the safety of NSAID use with respect to the risk of alteration in the hypothalamic-pituitary-gonadal axis.

The effects of competition and implicit power motive on men's testosterone, emotion recognition, and aggression

A contribution to a special issue on Hormones and Human Competition. We investigated the effects of competition on men's testosterone levels and assessed whether androgen reactivity was associated with subsequent emotion recognition and reactive and proactive aggression. We also explored whether personalized power (p Power) moderated these relationships. In Study 1, 84 males competed on a number tracing task and interpreted emotions from facial expressions. In Study 2, 72 males competed on the same task and were assessed on proactive and reactive aggression. In both studies, contrary to the biosocial model of status (Mazur, 1985), winners' testosterone levels decreased significantly while losers' levels increased, albeit not significantly. Personalized power moderated the effect of competition outcome on testosterone change in both studies. Using the aggregate sample, we found that the effect of decreased testosterone levels among winners (compared to losers) was significant for individuals low in p Power but not for those with medium or high p Power. Testosterone change was positively related to emotion recognition, but unrelated to either aggression subtype. The testosterone-mediated relationship between winning and losing and emotion recognition was moderated by p Power. In addition, p Power moderated the direct (i.e., non-testosterone mediated) path between competition outcome and emotion recognition and both types of aggression: high p-Power winners were more accurate at deciphering others' emotions than high p-Power losers. Finally, among high p-Power men, winners aggressed more proactively than losers, whereas losers aggressed more reactively than winners. Collectively, these studies highlight the importance of implicit power motivation in modulating hormonal, cognitive, and behavioral outcomes arising from human competition.

Associations of lead and cadmium with sex hormones in adult males

Heavy metal exposures are ubiquitous in the environment and their relation to sex hormones is not well understood. This paper investigates the associations between selected heavy metals (lead and cadmium) and sex hormones (testosterone, free testosterone, estradiol, free estradiol) as well as other major molecules in the steroid biosynthesis pathway (androstanedione glucuronide and sex-hormone binding globulin (SHBG)). Blood lead and cadmium were selected as biomarkers of exposure, and tested for associations in males using National Health and Nutritional Examination Survey (NHANES) data from 1999-2004. After adjustment for age, race, body mass index, smoking status, diabetes and alcohol intake, blood lead was positively associated with testosterone and SHBG while blood cadmium was positively associated with SHBG. After controlling for additional heavy metal exposure, the associations between lead and testosterone as well as cadmium and SHBG remained significant. Furthermore, the association between blood lead and testosterone was modified by smoking status (P for interaction=0.011), diabetes (P for interaction=0.021) and blood cadmium (P for interaction=0.029). The association between blood cadmium and SHBG levels was modified by blood lead (P for interaction=0.004). This study is the most comprehensive investigation to date regarding the association between heavy metals and sex hormones in males.

CDK14 expression is down-regulated by cigarette smoke in vivo and in vitro

In this study, DNA arrays have been employed to monitor gene expression patterns in testis of mice exposed to tobacco smoke for 24 weeks and compared to control animals. The results of the analysis revealed significant changes in expression of several genes that may have a role in spermatogenesis. Cdk14 was chosen for further characterization because of a suggested role in the testis and in regulation of Wnt signaling. RT-PCR analysis confirmed down regulation of Cdk14 in mice exposed to cigarette smoke (CS). Cdk14 is expressed in all testicular cells; spermatogonia- and Sertoli-derived cell lines treated with cigarette smoke extract (CSE) in vitro showed down-regulation of CDK14 mRNA and protein levels as well as down-regulation of β-catenin levels. CS-induced down-regulation of CDK14 mRNA and protein levels was also observed in several lung epithelium-derived cell lines including primary normal human bronchial epithelial cells (NHBE), suggesting that the effect is not restricted to the testis. Similar to testicular cells, CS-induced down-regulation of CDK14 in lung cells correlated with decreased levels of β-catenin, a finding suggesting impaired Wnt signaling. In the lungs, CDK14 was localized to the alveolar and bronchial epithelium.

Association of serum α-tocopherol with sex steroid hormones and interactions with smoking: implications for prostate cancer risk

BACKGROUND

Vitamin E may protect against prostate cancer, possibly only in smokers and, we hypothesize, through altered sex steroid hormones. A controlled trial in smokers showed that sex hormone levels were inversely associated with baseline serum α-tocopherol and decreased in response to vitamin E supplementation. The vitamin E-hormone relation is understudied in non-smokers.

METHODS

Serum sex steroid hormones and α-tocopherol were measured for 1,457 men in NHANES III. Multivariable-adjusted geometric mean hormone concentrations by α-tocopherol quintile were estimated.

RESULTS

We observed lower mean testosterone, estradiol, and SHBG concentrations with increasing serum α-tocopherol (Q1 = 5.5 and Q5 = 4.6 ng/ml, p-trend = 0.0007; Q1 = 37.8 and Q5 = 33.1 pg/ml, p-trend = 0.02; Q1 = 38.8 and Q5 = 30.6 pg/ml, p-trend = 0.05, respectively). Interactions between serum α-tocopherol and exposure to cigarette smoke for total testosterone, total estradiol, and SHBG were found with the inverse relation observed only among smokers.

CONCLUSIONS

Results from this nationally representative, cross-sectional study indicate an inverse association between serum α-tocopherol and circulating testosterone, estradiol, and SHBG, but only in men who smoked. Our findings support vitamin E selectively influencing sex hormones in smokers and afford possible mechanisms through which vitamin E may impact prostate cancer risk.

Evaluation of the effects of cigarette smoking on testosterone levels in adult men

INTRODUCTION

Cigarette smoking is highly prevalent among men. Many studies have evaluated the effect of cigarette smoking on levels of male reproductive hormones; however, the findings still remain controversial.

AIM

To evaluate the influence of cigarette smoking on serum levels of total testosterone (TT), free testosterone (FT), bioavailable testosterone (BT), sex hormone-binding globulin (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH).

METHODS

A total of 255 men (90 smokers and 165 nonsmokers), aged 30 to 70 years, were investigated. Weight and height were obtained and body mass index (BMI) was calculated. Also, waist circumference and hip circumference were measured and waist-to-hip ratio was obtained. Fasting blood samples were drawn for determination of plasmatic glucose levels and serum levels of total cholesterol, high-density lipoprotein cholesterol (HDL-c), triglycerides, albumin, prolactin, TT, SHBG, LH, and FSH. The values of low-density lipoprotein cholesterol (LDL-c) were determined by Friedwald equation and the values of FT and BT were calculated from TT, SHBG, and albumin. Statistical significance was set at P < or = 0.05.

MAIN OUTCOME MEASURES

The influence of smoking on levels of TT, FT, and BT.

RESULTS

No significant difference was observed in the mean values of TT (P = 0.580), FT (P = 0.869), BT (P = 0.933), SHBG (P = 0.279), LH (P = 0.573), and FSH (P = 0.693) in the different levels of pack-years when compared to nonsmokers. Moreover, after multivariate logistic regression, no association between increased pack-years of smoking and increased odds ratio for occurrence of low hormones and SHBG levels was observed.

CONCLUSION

In this study, smokers and nonsmokers had similar mean values of androgens, gonadotropins and SHBG. However, it is necessary to standardize pack-years of smoking in order to elucidate the influence of cigarette smoking on sex hormone levels, as well as to minimize differences among studies and to confirm our results.

The effects of smoking on bone health

Osteoporotic fractures are a major public health problem in most developed countries and an increasing concern in much of the developing world. This healthcare burden will increase significantly worldwide over the next 20 years due to aging of the population. Smoking is a key lifestyle risk factor for bone loss and fractures that appears to be independent of other risk factors for fracture such as age, weight, sex and menopausal status. This review discusses the effects of smoking on bone health in pre-menopausal and post-menopausal women and men. Data from twin studies and the three main published meta-analyses are presented. Possible mechanisms by which smoking affects bone mass are reviewed. Despite smoking being a major lifestyle risk factor for osteoporosis, the mechanisms underlying smoking-associated bone loss and fracture risk remain poorly understood. The effect appears dose-dependent, and may be, at least partially, reversible. However, more work is required to confirm and characterize the reversibility of smoking-associated bone defects. Finally, strategies for quitting smoking are discussed. Encouragement of lifestyle alterations, including smoking cessation, should be a major component of any bone therapeutic programme.

Endogenous testosterone levels and smoking in men. The fifth Tromsø study

Smoking is a risk factor of coronary heart disease (CHD), while the role of testosterone in the development of CHD is controversial. The reported effects of cigarette smoking on testosterone levels in men are conflicting, and smoking may be an important confounding factor when evaluating the relationship between testosterone levels and CHD. Thus, the objective of the present study was to examine the associations of smoking status and number of cigarettes smoked per day with total and free testosterone levels in a cross-sectional population-based study of 3427 men participating in the fifth Tromsø study. Total testosterone, luteinizing hormone, follicle-stimulating hormone and sex hormone-binding globulin levels were measured with immunoassay while free testosterone levels were calculated. Waist circumference was also measured and two standardized questionnaires were completed, including smoking status and number of cigarettes smoked. The data were analysed with analysis of variance and covariance and multiple regression analysis. Smoking men had significantly higher levels of total and free testosterone compared with men who never smoked (p < 0.001 and <0.01 respectively). Both total and free testosterone levels increased significantly with increasing number of cigarettes smoked daily (p < 0.001). Smoking men had 15% higher total and 13% higher free testosterone levels compared with men who never smoked. Thus, smoking seems to be an important confounding factor when evaluating testosterone levels, and could possibly mask borderline hypogonadism.

Cerebrospinal fluid and plasma testosterone levels in post-traumatic stress disorder and tobacco dependence

BACKGROUND

Little is known about the relationship between endogenous central nervous system (CNS) testosterone and any psychiatric syndrome. The goal of this study was to screen for potential abnormalities in CNS testosterone levels in patients with post-traumatic stress disorder (PTSD) and/or tobacco dependence.

METHODS

We sampled cerebrospinal fluid (CSF) via a subarachnoid catheter over six hours and determined hourly basal CSF concentrations of testosterone in 11 combat veterans with PTSD and 12 normal volunteers. Smokers were abstinent for 11-17 h. Testosterone in CSF and matching plasma samples was assayed by radioimmunoassay.

RESULTS

A factor analysis for effects of PTSD status, smoking status and sample time revealed significant effects of PTSD or smoking status, but not time, on CSF testosterone. CSF testosterone levels were lower in individuals with PTSD as compared with normal volunteers. When divided by smoking status, abstinent smokers had mean CSF testosterone levels higher than those of non-smokers. A similar analysis of plasma testosterone revealed no significant effects of any factor on plasma testosterone.

CONCLUSIONS

These results indicate that CSF testosterone is significantly influenced by PTSD and smoking status. The exposure of the brain to altered levels of testosterone in smokers and patients with PTSD may have pathophysiologic significance in these conditions.

Prenatal effects of maternal smoking on daughters' smoking: nicotine or testosterone exposure?

OBJECTIVES

The purpose of this study was to specify the effect of prenatal fetal exposure to maternal cotinine and testosterone on daughters' smoking in adolescence and adulthood.

METHODS

Longitudinal causal models were estimated among 240 White mother-daughter pairs from the Child Health and Development Study. Mothers and daughters were reinterviewed when daughters were aged 15 to 17 years, and daughters were interviewed at 27 to 30 years of age. Blood samples were obtained from both parents during pregnancy and from adult daughters.

RESULTS

Testosterone and smoking were positively correlated among mothers during their pregnancy and among adult daughters. Maternal prenatal cotinine had no direct effect on daughters' smoking; self-reported smoking in pregnancy did have a direct effect. Smoking among daughters during adolescence was determined by maternal prenatal testosterone and self-reported maternal smoking during pregnancy and postnatally. Smoking among adult daughters reflected chronic smoking since adolescence and the continuing effect of postnatal maternal smoking. Prenatal maternal testosterone affected adult daughters' testosterone.

CONCLUSIONS

Estimates of the impact of prenatal maternal smoking depend on the measure of smoking. Prenatal testosterone exposure is a previously unrecognized risk factor for smoking among female offspring.

Predictors of sex hormone levels among the elderly: a study in Greece

This study examines the relationship between a series of epidemiologic parameters (age, height, body mass index (BMI), smoking, alcohol consumption, and coffee drinking) and serum concentrations of testosterone, estradiol, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS). Among 52 healthy, elderly Greek men, we observed that serum levels of DHEAS decreased with increasing age [19% decline per 5-year increase in age, 95% CI, -2.1-(-33.5)], obesity [48% decline for BMI >30 kg/m2 compared to <27 kg/m2, CI, -15.7-(-68.7)], and current smoking [37% decline compared to nonsmokers, CI, -9.5-(-57.2)]. Estradiol concentrations increased with increasing BMI [77.1% increase for BMI >30 kg/m2 compared to <27 kg/m2, CI, -12.0-256.3], alcohol drinking [66% increase for > or = 7 glasses/week compared to <7 glasses/week, CI, 4.4-164.4], and coffee drinking [59% increase for > or = 14 cups/week compared to > or = 14 cups/ week, CI, -0.5-155.9], and decreased among current smokers [40% decline compared to nonsmokers, CI, -64.9-0.8]. SHBG was marginally positively associated with increasing age [13% increase per 5 years, CI, -0.5-29.6]. Testosterone was significantly related only to current smoking [27% decline compared to nonsmokers, CI, -45.4-(-3.1)]. These findings suggest that several variables appear to be associated with sex steroid levels and the influence of these findings on the occurrence of hormone-related conditions warrants further exploration.

Use of a sealed minichamber for direct observation and evaluation of the in vitro effect of cigarette smoke on sperm motility

OBJECTIVE

To determine the in vitro effect of cigarette smoke on sperm motility and survival in an attempt to find a possible association with clinical studies that had pointed to the existence of such an effect in vivo.

DESIGN

Laboratory experiments in which the effect of cigarette smoke on human sperm placed in a sealed minichamber was directly observed and determined by motion analysis.

PATIENTS

High-quality fresh semen specimens were obtained from healthy donors and used for the experimental studies.

INTERVENTIONS

Various doses of filtered and nonfiltered cigarette smoke, collected by an improvised manual smoking machine, were streamed at a rate of 2 mL/s into sealed chambers containing samples of washed spermatozoa. Evaluation of the changes in sperm motility was performed in real time by direct microscopical observation and repeated determinations by the multiple exposure photography technique until their complete immobilization.

RESULTS

Streaming of 100 mL of cigarette smoke induced a dramatic drop in sperm motility, which caused sperm immobilization in about 15 minutes. This effect showed a clear dose-response relationship either with the amounts streamed or with the time during which sperm were exposed to cigarette smoke. The harmful effect was almost the same whether sperm were exposed to filtered or nonfiltered cigarette smoke. The role of carbon monoxide and hydrogen cyanide on these findings was studied separately, and it was shown that the inhibitory effect was not due to the presence of these two important components of cigarette smoke.

CONCLUSIONS

The clear evidence of the in vitro harmful effect of crude cigarette smoke on sperm motility points to the possibility that in heavy smokers certain toxic agents may reach mature spermatozoa or their precursors via the blood stream and induce their harmful effect on sperm motility in vivo.