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

Prenatal tobacco exposure on brain morphometry partially mediated poor cognitive performance in preadolescent children

Objectives

To evaluate whether prenatal tobacco exposure (PTE) is related to poorer cognitive performance, abnormal brain morphometry, and whether poor cognitive performance is mediated by PTE-related structural brain differences.

Methods

The Adolescent Brain Cognitive Development study dataset was used to compare structural MRI data and neurocognitive (NIH Toolbox®) scores in 9-to-10-year-old children with (n=620) and without PTE (n=10,989). We also evaluated whether PTE effects on brain morphometry mediated PTE effects on neurocognitive scores. Group effects were evaluated using Linear Mixed Models, covaried for socio-demographics and prenatal exposures to alcohol and/or marijuana, and corrected for multiple comparisons using the false-discovery rate (FDR).

Results

Compared to unexposed children, those with PTE had poorer performance (all p-values <0.05) on executive function, working memory, episodic memory, reading decoding, crystallized intelligence, fluid intelligence and overall cognition. Exposed children also had thinner parahippocampal gyri, smaller surface areas in the posterior-cingulate and pericalcarine cortices; the lingual and inferior parietal gyri, and smaller thalamic volumes (all p-values <0.001). Furthermore, among children with PTE, girls had smaller surface areas in the superior-frontal (interaction-FDR-p=0.01), precuneus (interaction-FDR-p=0.03) and postcentral gyri (interaction-FDR-p=0.02), while boys had smaller putamen volumes (interaction-FDR-p=0.02). Smaller surface areas across regions of the frontal and parietal lobes, and lower thalamic volumes, partially mediated the associations between PTE and poorer neurocognitive scores (p-values <0.001).

Conclusions

Our findings suggest PTE may lead to poorer cognitive performance and abnormal brain morphometry, with sex-specific effects in some brain regions, in pre-adolescent children. The poor cognition in children with PTE may result from the smaller areas and subcortical brain volumes.

Association between the second- and fourth-digit ratio and oral squamous cell carcinoma

OBJECTIVES

Using an established proxy measure of intra-utero testosterone and estrogen levels-the ratio of second- and fourth-digit lengths-we estimated its association with the oral cancer risk among a population from Southern India.

MATERIAL AND METHODS

In a hospital-based case-control study, incident oral cancer cases (N = 350) and non-cancer controls (N = 371), frequency-matched by age and sex, were recruited from two major referral hospitals in Kerala, India. Structured interviews collected information on several domains of exposure via detailed life course questionnaires. Digit lengths were measured using a ruler in a standardized manner. Unconditional logistic regression was performed to estimate the odds ratios and 95% confidence intervals.

RESULTS

Second- and fourth-digit ratio lower than 1, which indicates relatively higher intra-utero level of testosterone and lower intra-utero level of estrogen, was associated with higher oral cancer risk (OR = 1.60, 95% CI: 1.02-2.52), after accounting for several confounders.

CONCLUSION

Our findings suggest that intra-utero hormonal levels measured by second- and fourth-digit ratio are associated with oral cancer risk. Further studies in different population should confirm these results.

Maternal androgen excess increases the risk of metabolic syndrome in female offspring in their later life: A long-term population-based follow-up study

PURPOSE

Hyperandrogenic intrauterine environment may lead to the development of metabolic disorders in offspring in their later life. In this study, we aimed to determine the impact of maternal hyperandrogenism (MHA) on metabolic syndrome (MetS) risk in female offspring in their later life.

METHODS

In this cohort study conducted in Tehran, Iran, female offspring with MHA (n = 323) and without MHA (controls) (n = 1125) were selected. Both groups of female offspring were followed from the baseline to the date of the incidence of events, censoring, or end of the study period, whichever came first. We used age-scaled unadjusted and adjusted Cox regression models to assess the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between MHA and MetS in female offspring. The software package STATA was used for statistical analysis, and the significance level was set at P < 0.05.

RESULTS

We observed a higher risk of MetS (unadjusted HR (95% CI), 1.36 (1.05-1.77)), (P = 0.02) and (adjusted HR (95% CI), 1.34 (1.00-1.80)), (P = 0.05, borderline)), in female offspring with MHA, compared to controls. The results were adjusted for the potential confounders including body mass index (BMI) at baseline, net changes of BMI, physical activity, education status, and birth weight.

CONCLUSION

Our results suggest that MHA increases the risk of developing MetS in female offspring in their later life. Screening of these female offspring for MetS may be recommended.

Maternal Age and Behavior during Pregnancy Affect the 2D:4D Digit Ratio in Polish Children Aged 6–13 Years

Background: The length of the second and fourth finger calculated as a ratio (2D:4D) is a marker of prenatal exposure to sex hormones. Higher exposure to testosterone is related to a lower 2D:4D digit ratio, and inversely, higher exposure to estrogen is related to a higher 2D:4D. The digit ratio in humans (prenatally determined by sex hormone levels and androgen receptor activity) is associated with multiple biological, cognitive, and behavioral traits, as well as health in later life. The aim of this study was to verify if maternal traits during pregnancy are associated with 2D:4D among their children. Methods: We investigated 537 boys, 646 girls, and their mothers. The investigation consisted of a questionnaire and a measurement part. In the questionnaire, we included questions about maternal traits during pregnancy such as: illnesses, active and passive smoking, work activity, psychological trauma (death or serious illness of a loved one, divorce, job loss), and age. We performed length measurements of the second and fourth fingers on both hands for both study groups. Results: The GLM analysis showed that children of smoking mothers were characterized by a higher 2D:4D R as compared to their peers whose mothers did not smoke (β = 0.10, p = 0.0008). In turn, the offspring of women who worked during pregnancy exhibited lower 2D:4D R values than the children of women who did not work (β = −0.07, p = 0.0233). It should be noted, however, that the effects of those maternal factors were small, as each of them explained less than 1% of 2D:4D R in the population, adjusted for child age and sex. Pearson’s linear correlation revealed that maternal age was negatively correlated with 2D:4D R in daughters (r = −0.11, p = 0.0137), but not in sons (r = 0.02, p = 0.6908). The negative correlation of 2D:4D R with maternal age indicates that the daughters of older mothers exhibited lower values of that ratio relative to the same-age daughters of younger mothers. Conclusions: For both study groups, the right-hand digit ratio was positively correlated with maternal smoking and negatively with maternal work during pregnancy. Maternal age during pregnancy was negatively related to right hand 2D:4D only among girls.

A Pilot Study of Exposure to Nicotine in Human Pregnancy and Maternal and Fetal Testosterone Levels at Birth

Nicotine exposure in pregnant rats and sheep has shown a more than 50% increase in female fetal testosterone (FFT) levels. Increased testosterone levels have also been linked to infertility, increased anogenital distance (AGD), and reduced second to fourth digit (2D:4D) finger length ratios (FLR). In humans, we hypothesized that maternal total testosterone (MTT) levels would increase in smoking mothers and would cause increased FFT levels, increased AGD, and decreased 2D:4D FLR. This prospective study separated women expecting a female fetus into nonsmoking and smoking cohorts. Maternal cotinine (MC) was tested at 3rd trimester and delivery to assess nicotine exposure. MTT levels were drawn at delivery, and FFT levels were collected from cord blood. The AGD and 2D:4D FLRs were measured at birth. Data were analyzed using parametric and nonparametric tests. The data of 36 smokers and 28 nonsmokers were analyzed. Smoking mothers had higher parity, drug abuse history and were more likely white race. No statistical differences were seen among the primary outcomes of MTT and FFT. MTT was higher among nonsmokers versus smokers (144 versus 107 ng/dL). No correlations were noted between MC levels at delivery, MTT, and FFT levels. No statistical differences were noted among secondary outcomes of AGD and FLR. Although animal studies showed increased FFT levels after nicotine exposure, this was not seen in our human study. Placental differences in animals and humans may be at work. Our pilot study reveals a need for research on the effects of smoking in pregnancy on fetal hormones.

Estimating causal and time-varying effects of maternal smoking on youth smoking

INTRODUCTION

Maternal smoking is a well-known risk factor for youth smoking, yet whether this relationship is causal remains unresolved. This study utilizes propensity score methods for causal inference to robustly account for shared risk factors between maternal and offspring smoking.

METHODS

An 8-year longitudinal cohort of 900 adolescents in the Chicago area were followed starting from approximately age 15.6. The effects of maternal lifetime smoking (MLS) and prenatal tobacco exposure (PTE) (among participants reporting MLS) on offspring's past 30-day smoking, daily smoking status and smoking frequency were examined using logistic regression and Poisson regression after nearest-neighbor propensity matching. Age dependency of this relationship was then examined across the age range of 15-25 using time-varying effect modeling.

RESULTS

Propensity matching yielded 438 and 132 pairs for MLS and PTE study samples, respectively. MLS demonstrated significant associations with past 30-day smoking (RR 1.09; 95% CI 1.04-1.14), daily smoking (RR 1.08; 95% CI 1.05-1.12), and smoking frequency of offspring (RR 1.32; 95% CI 1.15-1.52), with stable effects across age. Among participants reporting MLS, having PTE showed significant additional effects on daily smoking (RR 1.09; 95% CI 1.02-1.17) and age-dependency that showed significance during young adulthood but not adolescence.

CONCLUSION

The relationship between maternal and offspring smoking was not fully accounted for by shared risk factors, suggesting possible causation with PTE having a delayed effect across age. Targeted prevention efforts should be made on maternal smoking-exposed adolescents to mitigate their risks of developing heavy smoking habits in adulthood.

Prenatal smoke exposure is associated with increased anogenital distance in female infants: a prospective case-control study

OBJECTIVES

To investigate the effects of maternal smoking during pregnancy on newborn infants' anogenital distance (AGD).

METHODS

Fifty-six female and sixty-four male newborn infants from mothers who smoked during pregnancy were included in this study. A control group for each sex was selected from infants whose mothers had no active or passive (in either the household or the workplace) smoke exposure before or during pregnancy. Questionnaire data on maternal demographic characteristics and information about cigarette use were collected. We assessed genital anthropometry which included AGD for both male and female neonates, and stretched penile length (SPL), penile girth for males within the first 48 h after birth. AGD measurements were also normalized according to birth weight (AGD/weight in grams), length (AGD/height in millimeters), and ponderal index [AGD/(weight in grams/height in cubic centimeters)]. Anogenital index (AGI) was calculated by dividing the AGD by cube root of birth weight.

RESULTS

In female infants, prenatal smoke exposure was associated with significantly increased weight-adjusted AGD (p=0.03). There was also a significant correlation between mothers' daily smoking rates and weight-adjusted AGD (r=0.27/p=0.03). In male infants, fetal smoke exposure was not associated with any AGD measurements, SPL and penile girth.

CONCLUSIONS

A significant increase in weight-adjusted AGD in female infants exposed to maternal smoking may be an indicator of antenatal androgen exposure and may pose a risk for short and long-term endocrine, metabolic and behavioral problems.

Postnatal Smoke Exposure Further Increases the Hepatic Nicotine Metabolism in Prenatally Smoke Exposed Male Offspring and Is Linked with Aberrant Cyp2a5 Methylation

Prenatal smoke exposure (PreSE) is a risk factor for nicotine dependence, which is further enhanced by postnatal smoke exposure (PostSE). One susceptibility gene to nicotine dependence is Cytochrome P450 (CYP) 2A6, an enzyme responsible for the conversion of nicotine to cotinine in the liver. Higher CYP2A6 activity is associated with nicotine dependence and could be regulated through DNA methylation. In this study we investigated whether PostSE further impaired PreSE-induced effects on nicotine metabolism, along with Cyp2a5, orthologue of CYP2A6, mRNA expression and DNA methylation. Using a mouse model where prenatally smoke-exposed adult offspring were exposed to cigarette smoke for 3 months, enzyme activity, mRNA levels, and promoter methylation of hepatic Cyp2a5 were evaluated. We found that in male offspring, PostSE increased PreSE-induced cotinine levels and Cyp2a5 mRNA expression. In addition, both PostSE and PreSE changed Cyp2a5 DNA methylation in male groups. PreSE however decreased cotinine levels whereas it had no effect on Cyp2a5 mRNA expression or methylation. These adverse outcomes of PreSE and PostSE were most prominent in males. When considered in the context of the human health aspects, the combined effect of prenatal and adolescent smoke exposure could lead to an accelerated risk for nicotine dependence later in life.

Prenatal smoke exposure induces persistent Cyp2a5 methylation and increases nicotine metabolism in the liver of neonatal and adult male offspring

Prenatal smoke exposure (PSE) is a risk factor for nicotine dependence. One susceptibility gene for nicotine dependence is Cytochrome P450 (CYP) 2A6, an enzyme responsible for the conversion of nicotine to cotinine and nicotine clearance in the liver. Higher activity of the CYP2A6 enzyme is associated with nicotine dependence, but no research has addressed the PSE effects on the CYP2A6 gene or its mouse homologue Cyp2a5. We hypothesized that PSE affects Cyp2a5 promoter methylation, Cyp2a5 mRNA levels, and nicotine metabolism in offspring. We used a smoke-exposed pregnant mouse model. RNA, DNA, and microsomal protein were isolated from liver tissue of foetal, neonatal, and adult offspring. Enzyme activity, Cyp2a5 mRNA levels, and Cyp2a5 methylation status of six CpG sites within the promoter region were analysed via HPLC, RT-PCR, and bisulphite pyrosequencing. Our data show that PSE induced higher cotinine levels in livers of male neonatal and adult offspring compared to controls. PSE-induced cotinine levels in neonates correlated with Cyp2a5 mRNA expression and promoter methylation at CpG-7 and CpG+45. PSE increased methylation in almost all CpG sites in foetal offspring, and this effect persisted at CpG-74 in male neonatal and adult offspring. Our results indicate that male offspring of mothers which were exposed to cigarette smoke during pregnancy have a higher hepatic nicotine metabolism, which could be regulated by DNA methylation. Given the detected persistence into adulthood, extrapolation to the human situation suggests that sons born from smoking mothers could be more susceptible to nicotine dependence later in life.

How much and why does the mum matter? Mechanisms explaining the intergenerational transmission of smoking

Offspring whose mother smokes during pregnancy have higher risk of smoking themselves. In this study, epigenetics, antisocial behaviours, and social learning were investigated as potential mechanisms of mother-to-child transmission of smoking among a population sample drawn from the Birth Cohort Study 1970. Findings on daughters showed that the direct epigenetic hypothesis was mediated by social learning mechanisms, suggesting that exposure to maternal smoking across childhood and adolescence strongly explained why the smoking habits of mother and daughter correlate. However, prenatal smoking effects on sons were only partially explained by observational learning of mother smoking habits. Our estimates provided evidence concerning the potential role also played by the child's persistent antisocial behaviours. These results were confirmed after controlling for early life circumstances and current socioeconomic conditions. Policy implications of the results are discussed.

The effects of prenatal androgen exposure on cardiac function and tolerance to ischemia/reperfusion injury in male and female rats during adulthood

AIMS

Cardiovascular diseases may originate from suboptimal intrauterine environments. We aimed to examine the effects of prenatal androgen exposure (PAE) on heart basal hemodynamic parameters and tolerance to ischemia/reperfusion (I/R) injury, in PAE adult females and males.

MAIN METHODS

Pregnant Wistar rats in the experimental group (n = 8) received 5 mg of testosterone (s.c. injection) on the 20th day of pregnancy, while controls received solvent. The hearts of adult female and male offspring were isolated and perfused in a Langendorff apparatus, values of left ventricular systolic pressure(LVSP), left ventricular developed pressure(LVDP), rate pressure product(RPP) and peak rates of positive and negative changes in left ventricular pressure(±dp/dt) were recorded using a power lab system.

KEY FINDINGS

At baseline, PAE adult males demonstrated significant higher values of LVSP, LVDP, RPP and ± dp/dt, compared to controls and PAE adult females (p < 0.05), while PAE adult females showed no significant differences compared to controls. In PAE adult males, LVSP, LVDP, RPP and ± dp/dt had significant decreasing trends per phases after I/R, compared to their controls and PAE females, while these decreasing trends were not statistically significant in PAE adult female rats vs. their controls.

SIGNIFICANCE

The impact of prenatal androgen exposure on adulthood cardiac function and tolerance to I/R is gender dependent, which may be partly explained by different cardiac effects of hyperandrogenism in males versus females. After prenatal androgen exposure, the baseline hemodynamic parameters of the hearts of adult males are increased; although they had less tolerance to I/R, findings however not observed in females.

Trajectories of pre- and postnatal co-use of cannabis and tobacco predict co-use and drug use disorders in adult offspring

Co-use of cannabis and tobacco is increasingly common among women and is associated with tobacco and cannabis dependence and poorer cessation outcomes. However, no study has examined maternal patterns of co-use over time, or the impact of maternal co-use on co-use and drug problems in adult offspring. Pregnant women (M age = 23, range = 18-42; 52% African American, 48% White) were asked about substance use during each trimester of pregnancy, and at 8 and 18 months, 3, 6, 10, 14, 16, and 22 years postpartum. We examined patterns of any maternal cigarette and cannabis use during pregnancy and the postpartum years. As young adults (M age = 22.8 years, range = 21-26), 603 offspring completed the Diagnostic Interview Schedule (DIS). Growth mixture modeling (GMM) was used to identify four maternal trajectories through 16 years postpartum: (1) no co-use (66%), (2) decreasing co-use (16%), (3) postpartum-only co-use (11%), and (4) chronic co-use (7%). Offspring whose mothers were in the decreasing co-use group (co-users primarily during prenatal and preschool periods) were more likely to be co-users than the offspring of non-co-users. Offspring whose mothers were chronic co-users of cigarettes and cannabis were more than twice as likely to have a drug use disorder than young adults whose mothers were not co-users. The results of this study highlight the heterogeneity in maternal co-use of tobacco and cannabis over time, with some women quitting during pregnancy but resuming co-use in the postpartum, and other women co-using during pregnancy but desisting co-use over time. Maternal trajectories of co-use were associated with inter-generational transfer of risk for substance use and dependence in adult offspring.

Sex Differences in the Prenatal Programming of Adult Metabolic Syndrome by Maternal Androgens

CONTEXT

Growing preclinical evidence suggests that hormonal programming by androgens in utero may contribute to cardiovascular disease risk in adult offspring. However, the effect of prenatal androgens on cardiometabolic outcomes in the human population, especially their potential differential impact on male vs female offspring, has not been well studied.

DESIGN

Adult offspring (n = 274) of mothers enrolled in the New England birth cohorts of the Collaborative Perinatal Project were assessed at ages 39 to 50. Androgen bioactivity was measured in maternal serum during the third trimester using a receptor-mediated luciferase expression bioassay. Metabolic syndrome (MetS) using Adult Treatment Panel III criteria was assessed in adult offspring. Bioactive androgens were analyzed as quartiles, with the lowest quartile (Q1) defined as the reference. Generalized estimating equations were used to evaluate the relationship of maternal bioactive androgens on offspring MetS risk overall and by sex, controlling for potential confounders and intrafamilial correlation.

RESULTS

Mean age and body mass index of adult offspring were 44.7 ± 2.6 years and 29.7 ± 6.7 kg/m2, respectively. Participants born to mothers with the highest quartile (Q4) compared with Q1 of bioactive androgens had higher risk for MetS [adjusted odds ratio (aOR): 2.53(1.07 to 6.02)]. Stratified by sex, this association was found to be significant among women [Q4 vs Q1; aOR: 4.06 (1.10 to 14.93)] but not men [Q4 vs Q1; aOR: 1.67 (0.53 to 5.26)]. Women born to mothers with the highest levels of maternal bioactive androgens also demonstrated a 4.84-fold increased odds for having hypertension [Q4 vs Q1; aOR: 4.84 (1.12 to 20.85)].

CONCLUSION

Higher levels of maternal androgens were associated with increased risk for incident MetS in adult offspring, an effect that was significant in women but not men.

Neuroendocrine and immune pathways from pre- and perinatal stress to substance abuse

Early life adversity is a documented risk factor for substance abuse and addiction. The pre- and perinatal period (i.e., from implantation, through pregnancy, to 6 months of age) is a critical period marked by high biological plasticity and vulnerability, making perinatal stress a particularly robust form of adversity. The neuroendocrine and immune systems are key mechanisms implicated in the transmission of addiction risk. We review animal and human studies that provide preliminary evidence for links between perinatal stress, neuroendocrine and immune dysregulation, and risk for substance abuse and addiction. A translational neuroscience perspective is employed to elucidate pre- and perinatally-induced biological mechanisms linked to addiction and discuss implications for prevention and intervention efforts. Significant evidence supports associations between pre- and perinatal stress and dysregulation of the hypothalamic-pituitary-adrenal axis and immune systems as well as links between neuroendocrine/immune functioning and addiction risk. More work is needed to explicitly examine the interplay between pre- and perinatal stress and neuroendocrine/immune disruptions that together heighten substance abuse risk. Future work is needed to fully understand how pre- and perinatal stress induces biological alterations to predispose individuals to higher risk for addiction. Such knowledge will strengthen theoretically-driven and empirically-supported prevention efforts for substance abuse and addiction.

The influence of smoking and cessation on the human reproductive hormonal balance

Smoking is the most widespread substance dependence in the world. Nicotine and some other components of the cigarette smoke cause various endocrine imbalances, and have negative effects on pituitary, thyroid, adrenal, testicular and ovarian functions. Here, we examined studies that describe the influence of smoking and smoking cessation on the male and female reproductive systems. We also focused on studies providing an account of differences in cessation success rates between men and women. In men, the most common effects associated with smoking are erectile dysfunction and decreasing spermiogram quality. Several groups have studied the effects of cigarette smoking on testosterone levels in men. However, the results have been conflicting. In women, nicotine has an anti-estrogen effect and increases the ratio of androgens to estrogens throughout life. Beside nicotine, other cigarette toxins also cause dysregulation of reproductive and hormonal system, and essentially influence the probability of a successful pregnancy not only in cases of assisted reproduction but also in healthy women. Tobacco addiction is one of the forms of addiction that are generally thought to be different for men and for women. Women are less successful than men in quitting smoking, and nicotine replacement therapy is less effective in female smokers. We also summarize recent studies that have indicated possible reasons.

Genetic and environmental influences on pubertal hormones in human hair across development

Puberty is a complex biopsychosocial process that can affect an array of psychiatric and medical disorders emerging in adolescence. Although the pubertal process is driven by neuroendocrine changes, few quantitative genetic studies have directly measured puberty-relevant hormones. Hair samples can now be assayed for accumulation of hormones over several months. In contrast to more conventional salivary measures, hair measures are not confounded by diurnal variation or hormonal reactivity. In an ethnically and socioeconomically diverse sample of 1286 child and adolescent twins and multiples from 672 unique families, we estimated genetic and environmental influences on hair concentrations of testosterone, DHEA, and progesterone across the period of 8-18 years of age. On average, male DHEA and testosterone were highly heritable, whereas female DHEA, progesterone, and puberty were largely influenced by environmental components. We identified sex-specific developmental windows of maximal heritability in each hormone. Peak heritability for DHEA occurred at approximately 10 years of age for males and females. Peak heritability for testosterone occurred at age 12.5 and 15.2 years for males and females, respectively. Peak heritability for male progesterone occurred at 11.2 years, while the heritability of female progesterone remained uniformly low. The identification of specific developmental windows when genetic signals for hormones are maximized has critical implications for well-informed models of hormone-behavior associations in childhood and adolescence.

Changes to Fetal Steroidogenesis Caused by Maternal Smoking

Smoking during pregnancy presents health risks for both the mother and her child. In this study we followed changes in the production of steroid hormones in pregnant smokers. We focused on changes in steroidogenesis in the blood of mothers in their 37th week of pregnancy and in mixed cord blood from their newborns. The study included 88 healthy women with physiological pregnancies (17 active smokers and 71 non-smokers). We separately analyzed hormonal changes associated with smoking according to the sex of newborns. In women with male fetuses, we found higher levels of serum cortisone, dehydroepiandrosterone (DHEA), 7α-OH-DHEA, 17-OH pregnenolone, testosterone, and androstenedione in smokers at the 37th week compared to non-smokers. In women with female fetuses, we found lower serum levels of 7β-OH-DHEA and higher androstenedione in smokers at the 37th week. We found significantly higher levels of testosterone in newborn males of smokers and higher levels of 7α-OH-DHEA in female newborns of smokers. Smoking during pregnancy induces changes in the production of steroids in both the mother and her child. These changes are different for different fetal sexes, with more pronounced changes in mothers carrying male newborns as well as in the newborn males themselves.

Is maternal periconceptional smoking associated with 2D:4D digit ratio in their children?

The 2nd--4th finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Maternal periconceptional smoking may alter the homeostasis of fetal androgens, which could in turn result in differential development of 2D:4Ds in utero. The aim of the present study was to assess the effect of maternal periconceptional smoking (i.e. 1 year before through the first trimester of pregnancy) on the 2D:4D of children within The Maternal-Infant Research on Environmental Chemicals (MIREC) study. Maternal smoking history was obtained through questionnaires during the first trimester of pregnancy in 2001 women from 10 cities across Canada. The periconceptional smoking prevalence was 12%. A follow-up study was conducted to measure growth and development up to 5 years of age in a subsample of some 800 MIREC children (MIREC-CD Plus), and digital pictures of the ventral surface of both hands were obtained in mothers and children (2–5 years). The 2D:4D was calculated as the ratio of the 2nd and 4th fingers of each hand. Boys had lower mean 2D:4Ds compared with girls in both hands. Age and maternal 2D:4D were strong determinants of the children’s 2D:4D, however, the mean 2D:4D did not differ among children whose mothers had smoked during the periconceptional period compared with those who had not, irrespective of sex. In conclusion, we did not find an association between maternal periconceptional smoking and children’s 2D:4D, although the smoking prevalence was low.

Prenatal Testosterone Exposure Decreases Aldosterone Production but Maintains Normal Plasma Volume and Increases Blood Pressure in Adult Female Rats

Plasma testosterone levels are elevated in pregnant women with preeclampsia and polycystic ovaries; their offspring are at increased risk for hypertension during adult life. We tested the hypothesis that prenatal testosterone exposure induces dysregulation of the renin-angiotensin-aldosterone system, which is known to play an important role in water and electrolyte balance and blood pressure regulation. Female rats (6 mo old) prenatally exposed to testosterone were examined for adrenal expression of steroidogenic genes, telemetric blood pressure, blood volume and Na⁺ and K⁺ levels, plasma aldosterone, angiotensin II and vasopressin levels, and vascular responses to angiotensin II and arg⁸-vasopressin. The levels of Cyp11b2 (aldosterone synthase), but not the other adrenal steroidogenic genes, were decreased in testosterone females. Accordingly, plasma aldosterone levels were lower in testosterone females. Plasma volume and serum and urine Na⁺ and K⁺ levels were not significantly different between control and testosterone females; however, prenatal testosterone exposure significantly increased plasma vasopressin and angiotensin II levels and arterial pressure in adult females. In testosterone females, mesenteric artery contractile responses to angiotensin II were significantly greater, while contractile responses to vasopressin were unaffected. Angiotensin II type-1 receptor expression was increased, while angiotensin II type-2 receptor was decreased in testosterone arteries. These results suggest that prenatal testosterone exposure downregulates adrenal Cyp11b2 expression, leading to decreased plasma aldosterone levels. Elevated angiotensin II and vasopressin levels along with enhanced vascular responsiveness to angiotensin II may serve as an underlying mechanism to maintain plasma volume and Na⁺ and K⁺ levels and mediate hypertension in adult testosterone females.

Elevated Testosterone Reduces Uterine Blood Flow, Spiral Artery Elongation, and Placental Oxygenation in Pregnant Rats

Elevated maternal testosterone levels are shown to cause fetal growth restriction, eventually culminating in sex-specific adult-onset hypertension that is more pronounced in males than in females. In this study, we tested whether uteroplacental and fetoplacental disturbances underlie fetal growth restriction and if these changes vary in male and female placentas. Pregnant Sprague-Dawley rats were injected with vehicle (n=16) or testosterone propionate (0.5 mg/kg per day from gestation day 15-19; n=16). On gestation day 20, we quantified uterine artery blood flow using microultrasound, visualized placental arterial network using x-ray microcomputed tomography, determined fetoplacental hypoxia using pimonidazole and hypoxia-inducible factor-1α, and used Affymetrix array to determine changes in placental expression of genes involved in vascular development. Plasma testosterone levels increased 2-fold in testosterone-injected rats. Placental and fetal weights were lower in rats with elevated testosterone. Uterine artery blood flow was lower, and resistance index was higher in the testosterone group. Radial and spiral artery diameter and length, the number of fetoplacental arterial branches, and umbilical artery diameter were reduced in the testosterone group. In addition, markers of hypoxia in the placentas and fetuses were elevated in the testosterone group. The magnitude of changes in placental vasculature and hypoxia was greater in males than in females and was associated with sex-specific alteration of unique sets of genes involved in angiogenesis and blood vessel morphogenesis. The results demonstrate that elevated testosterone during gestation induces a decrease in uterine arterial blood flow and fetal sex-related uteroplacental vascular changes, which may set the stage for subsequent sex differences in adult-onset diseases.

Prenatal Testosterone Exposure Leads to Gonadal Hormone-Dependent Hyperinsulinemia and Gonadal Hormone-Independent Glucose Intolerance in Adult Male Rat Offspring

Elevated testosterone levels during prenatal life lead to hyperandrogenism and insulin resistance in adult females. This study evaluated whether prenatal testosterone exposure leads to the development of insulin resistance in adult male rats in order to assess the influence of gonadal hormones on glucose homeostasis in these animals. Male offspring of pregnant rats treated with testosterone propionate or its vehicle (control) were examined. A subset of male offspring was orchiectomized at 7 wk of age and reared to adulthood. At 24 wk of age, fat weights, plasma testosterone, glucose homeostasis, pancreas morphology, and gastrocnemius insulin receptor (IR) beta levels were examined. The pups born to testosterone-treated mothers were smaller at birth and remained smaller through adult life, with levels of fat deposition relatively similar to those in controls. Testosterone exposure during prenatal life induced hyperinsulinemia paralleled by an increased HOMA-IR index in a fasting state and glucose intolerance and exaggerated insulin responses following a glucose tolerance test. Prenatal androgen-exposed males had more circulating testosterone during adult life. Gonadectomy prevented hyperandrogenism, reversed hyperinsulinemia, and attenuated glucose-induced insulin responses but did not alter glucose intolerance in these rats. Prenatal androgen-exposed males had decreased pancreatic islet numbers, size, and beta-cell area along with decreased expression of IR in gastrocnemius muscles. Gonadectomy restored pancreatic islet numbers, size, and beta-cell area but did not normalize IRbeta expression. This study shows that prenatal testosterone exposure leads to a defective pancreas and skeletal muscle function in male offspring. Hyperinsulinemia during adult life is gonad-dependent, but glucose intolerance appears to be independent of postnatal testosterone levels.

Associations between the prenatal environment and cardiovascular risk factors in adolescent girls: Internalizing and externalizing behavior symptoms as mediators

This longitudinal study examines links among adolescent internalizing and externalizing symptoms, the prenatal environment (e.g., nicotine exposure) and pre/perinatal maternal health, and cardiovascular risk factors. Girls (N=262) ages 11-17 reported internalizing and externalizing behaviors and mothers reported about the prenatal environment and maternal health during and 3 months post-pregnancy. Adolescent cardiovascular risk included adiposity, smoking, blood pressure, and salivary C-reactive protein. Internalizing symptoms mediated relations between prenatal exposures/maternal health and adiposity; externalizing symptoms mediated relations between prenatal exposures and adolescent smoking. Healthcare providers who attend to internalizing and externalizing symptoms in girls may ultimately influence cardiovascular health, especially among those with pre/perinatal risk factors.

How Smoking Cessation Influence Hormonal Levels in Postmenopausal Women?

Smoking represents the most widespread substance dependence in the world. Nicotine alters women hormonal homeostasis. Women smokers have higher testosterone and lower estradiol levels throughout life compared to non-smokers. We monitored the effect of smoking discontinuation on steroid spectrum with 25 postmenopausal women smokers. They had been examined before discontinuation of smoking and after 6, 12, 24 and 48 weeks of abstinence. Blood was collected to determine steroid spectrum (measured by GC-MS), luteinizing hormone, follicle stimulating hormone and sex hormone binding globulin (measured by IRMA). Repeated measures ANOVA model was used for evaluation of the data. In postmenopausal women, an increase in testosterone, dihydrotestosterone, dehydroepiandrosterone and other androgens occurred. Neither nicotine replacement therapy nor weight changes nor age play a role in androgen level increase. The higher androgens levels correlated with failure in smoking cessation. Women smokers have higher androgen levels, which might play a role in smoking dependence development. Women successful in smoking cessation, compared to the non-successful ones, have lower androgen levels initially and also after smoking discontinuation.

Do grandmaternal smoking patterns influence the etiology of childhood asthma?

Background:

Animal data suggest that tobacco smoke exposure of a mother when she is in utero influences DNA methylation patterns in her offspring and that there is an effect on the respiratory system, particularly airway responsiveness. The only study, to our knowledge, in humans suggests that there is a similar effect on asthma. The present study tests whether an association with respiratory problems can be confirmed in a large population study and aims to determine whether in utero exposure of the father has similar effects on his offspring.

Methods:

Information from the Avon Longitudinal Study of Parents and Children was used to compare the offspring of women and of men who had themselves been exposed to cigarette smoke in utero; separate analyses were performed for children of women smokers and nonsmokers. The outcome measures were trajectories of history of early wheezing, doctor-diagnosed asthma by age 7 years, and results of lung function and methacholine challenge tests at 8 years. A variety of social and environmental factors were taken into account; offspring sexes were examined separately.

Results:

There was no association with any outcome in relation to maternal prenatal exposure. There was some evidence of an increase in asthma risk with paternal prenatal exposure when the study mother was a nonsmoker (adjusted OR, 1.17; 95% CI, 0.97-1.41). This was particularly strong for girls (adjusted OR, 1.39; 95% CI, 1.04-1.86).

Conclusions:

We did not find that maternal prenatal exposure to her mother’s smoking had any effect on her children’s respiratory outcomes. There was suggestive evidence of paternal prenatal exposure being associated with asthma and persistent wheezing in the granddaughters.

Prenatal smoke exposure and mammographic density in mid-life

Tobacco smoke has both carcinogenic effects and anti-estrogenic properties and its inconsistent association with breast cancer risk in observational studies may be because of these competing effects across the lifecourse. We conducted a prospective study of prenatal smoke exposure, childhood household smoke exposure, and adult active smoke exposure and mammographic density, a strong intermediate marker of breast cancer risk, in an adult follow-up of existing US birth cohorts. Specifically, we followed up women who were born between 1959 and 1967 and whose mothers participated in either the Collaborative Perinatal Project (Boston and Providence sites) or the Childhood Health and Development Study in California. Of the 1134 women interviewed in adulthood (ranging in age from 39 to 49 years at interview), 79% had a screening mammogram. Cigarette smoking was reported by mothers at the time of their pregnancy; 40% of mothers smoked while pregnant. Women whose mothers smoked during pregnancy had a 3.1% (95% confidence interval (CI) = -6.0%, -0.2%) lower mammographic density than women whose mothers did not smoke during pregnancy. When we further accounted for adult body mass index and adult smoking status, the association remained (β = -2.7, 95% CI = -5.0, -0.3). When we examined patterns of smoking, prenatal smoke exposure without adult smoke exposure was associated with a 5.6% decrease in mammographic density (β = -5.6, 95% CI = -9.6, -1.6). Given the strength of mammographic density as an intermediate marker for breast cancer, the inverse associations between mammographic density and smoking patterns across the lifecourse may help explain the complex association between cigarette smoking and breast cancer risk.

Early life exposure to cigarette smoke and depressive symptoms among women in midlife

INTRODUCTION

Active cigarette smoking has consistently been associated with depression, but little is known about the association between other cigarette smoke exposures, particularly in early life, and depression. We investigated whether exposures to maternal smoking during pregnancy (MSP) and childhood secondhand smoke (SHS) are associated with depressive symptoms in midlife.

METHODS

Pregnant mothers were enrolled and were provided data on maternal smoking and other parental characteristics. Female offspring were followed through age 7 years and again in midlife (age range = 38-44 years), when they provided data on smoking history, SHS across the life course, and current depressive symptoms using the Center for Epidemiological Studies Depression Scale (CES-D).

RESULTS

Participants exposed to MSP had a higher risk for depression (risk ratio [RR] = 1.83, 95% confidence interval [CI] = 1.08, 3.09) than those without MSP exposure. Relative to those with no MSP and no childhood SHS exposures, participants with MSP and childhood SHS had more than twice the risk of depressive symptoms (RR = 2.40, 95% CI = 1.07, 5.41). Further adjustment for adult factors, particularly current smoking, substantially reduced these associations (e.g., MSP vs. no MSP exposure: RR = 1.36 [95% CI = 0.75, 2.45]).

CONCLUSIONS

Early life exposure to cigarette smoke is associated with increased risk for depression in midlife, with the association largely mediated by active smoking. These findings support a role for early life cigarette exposures in shaping smoking and depression risks in later life, and they provide some support for the direction of smoke exposure influence on depression.

Genetic and environmental influences on testosterone in adolescents: evidence for sex differences

The current study investigated genetic and environmental influences on salivary testosterone during adolescence, using data from 49 pairs of monozygotic twins and 68 pairs of dizygotic twins, ages 14-19 years (M = 16.0 years). Analyses tested for sex differences in genetic and environmental influences on testosterone and its relation to pubertal development. Among adolescent males, individual differences in testosterone were heritable (55%) and significantly associated with self-reported pubertal status (controlling for age) via common genetic influences. In contrast, there was minimal heritable variation in testosterone for females, and testosterone in females was not significantly associated with pubertal status after controlling for age. Rather, environmental influences shared by twins raised together accounted for nearly all of the familial similarity in female testosterone. This study adds to a small but growing body of research that investigates genetic influences on individual differences in behaviorally relevant hormones.

Prenatal glucocorticoids and maternal smoking during pregnancy independently program adult nicotine dependence in daughters: a 40-year prospective study

BACKGROUND

Maternal smoking during pregnancy (MSDP) is an independent risk factor for offspring nicotine dependence (ND), but mechanisms remain unknown. We investigated prenatal glucocorticoid (cortisol) and androgen (testosterone) associations with offspring ND over 40 years and the possibility that prenatal glucocorticoids and androgens would mediate links between MSDP and offspring ND.

METHODS

Participants were 1086 mother-adult offspring pairs (59% female) from the New England Family Study, a 40-year longitudinal follow-up of the Collaborative Perinatal Project. MSDP was assessed prospectively at each prenatal visit. Maternal cortisol, testosterone, and cotinine (nicotine metabolite) were assayed from third trimester maternal sera. Offspring lifetime ND was assessed via structured interview.

RESULTS

Significant bivariate associations emerged for: 1) MSDP/cotinine and lifetime ND; and 2) maternal cortisol and lifetime ND, for daughters only. In multivariate models, maternal cortisol and MSDP/cotinine remained significantly and independently associated with increased odds of lifetime ND of daughters. However, cortisol did not mediate the MSDP-lifetime ND relation. No associations emerged between maternal testosterone and offspring ND.

CONCLUSIONS

Results provide the first evidence in support of prenatal glucocorticoid programming of adult ND over 40 years in daughters only. Our study highlights two independent prenatal pathways leading to increased risk for ND in daughters: elevated prenatal glucocorticoids and MSDP/nicotine exposure. Daughter-specific effects of glucocorticoid and MSDP programming over 40 years highlight the breadth and persistence of sexually dimorphic programming effects in humans. Results do not support androgen programming of offspring ND.

The effects of smoking on steroid metabolism and fetal programming

Tobacco addiction is a serious psychosocial and health problem. A pregnant woman who smokes not only influences the maternal organism, but also passes health risks on to the unborn child. A fetus exposed to maternal smoking is not only directly influenced, but is also endangered by a wide range of diseases up to his or her adult years. The components of tobacco smoke play a significant role in the development of a number of diseases for a large proportion of the smoking population, as well as among those pregnant. This article summarizes findings regarding the impacts on the production of steroid hormones - first describing the smoking-related changes in steroidogenesis in women, and then focusing on the influence of maternal smoking on the fetus's developing steroidogenesis. We assume that if during prenatal development the fetus has already been exposed to the effect of endocrine disruptors at the time fetal steroidogenesis begins fetal programming, this exposure can have serious pathophysiological effects both in the pregnancy as well as later in life. An example of such effects might be a delay in the creation of kidney adrenal androgens, which could also be evident on the level of steroid neuroactive metabolites that may influence the individual's psychological state and lead to later addictions.

Prenatal testosterone induces sex-specific dysfunction in endothelium-dependent relaxation pathways in adult male and female rats

Prenatal testosterone (T) exposure impacts postnatal cardiovascular function, leading to increases in blood pressure with associated decreased endothelium-dependent vascular relaxation in adult females. Endothelial function in males is not known. Furthermore, which of the endothelial pathways contributes to endothelial dysfunction and if there exists sex differences are not known. The objective of this study was to characterize the relative contribution of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) to the impaired endothelium-dependent vasodilation in prenatal T-exposed adult males and females. Offspring of pregnant rats treated with T propionate or its vehicle were examined. Telemetric blood pressure levels and endothelium-dependent vascular reactivity were assessed with wire myography. Levels of nitric oxide synthase (NOS3) and Kcnn3 and Kcnn4 channel expression were examined in mesenteric arteries. Mean arterial pressure was significantly higher in T males and females than in controls. Endothelium-dependent acetylcholine relaxation was significantly lower in both T males and females. EDHF-mediated relaxation was specifically blunted in T males (Emax = 48.64% ± 3.73%) compared to that in control males (Emax = 81.71% ± 3.18%); however, NO-mediated relaxation was specifically impaired in T females (Emax = 36.01% ± 4.29%) compared with that in control females (Emax = 54.56% ± 6.37%). Relaxation to sodium nitroprusside and levcromakalim were unaffected with T-treatment. NOS3 protein was decreased in T females but not in T males. Kcnn3 expression was decreased in both T males and females compared to controls. These findings suggest that prenatal T leads to an increase in blood pressure in the adult offspring, associated with blunting of endothelial cell-associated relaxation and that the effects are sex-specific: EDHF-related in males and NO-related in females.

Prenatal cigarette smoking: Long-term effects on young adult behavior problems and smoking behavior

We examined the long-term effects of prenatal cigarette smoke exposure (PCSE) on the behavior problems and smoking behavior of 22-year-old offspring. The mothers of these offspring were interviewed about their tobacco and other drug use during pregnancy at the fourth and seventh gestational months, and at delivery. Data on the offspring are from interviews at age 22 (n=608). Behavior problems were measured by the Adult Self-Report (ASR) with the following outcome scales: total behavior problems, externalizing, internalizing, attention, anxiety/depression, withdrawn, thought, intrusive, aggression, somatic and rule breaking behavioral problems. Young adult smoking behavior was measured using self-reported average daily cigarettes, and was validated with urine cotinine. Nicotine dependence was measured with the Fagerström Tobacco and Nicotine Dependence (FTND) scale. Regression analyses tested the relations between trimester-specific PCSE and young adult's behavioral problems and smoking behavior, adjusting for demographic and maternal psychological characteristics, and other prenatal substance exposures. Exposed young adults had significantly higher scores on the externalizing, internalizing, aggression, and somatic scales of the ASR. These young adults were also more likely to have a history of arrests. Young adults with PCSE also had a higher rate of smoking and nicotine dependence. Our previous findings of the relations between PCSE and aggressive behavior in early childhood and PCSE and smoking behavior in early adolescence extend into young adulthood.

Is the intergenerational transmission of smoking from mother to child mediated by children's behavior problems?

INTRODUCTION

A previous paper used latent class analysis to assign individuals to 1 of 4 adolescent/young adult smoking trajectory classes and then established an association between maternal smoking before, during, and after pregnancy and these classes. In this paper, we examine one possible pathway for this relationship: that maternal smoking during pregnancy may set off a behavioral trajectory which increases the likelihood of problem behaviors generally, of which smoking is one manifestation.

METHODS

We used the Behavior Problems Index measure from age 8 through age 12 as a potential mediator. We used a path analysis modeling approach within a multinomial logistic regression (using Mplus) to estimate direct and indirect effects (via behavioral problems) between maternal smoking pattern and child trajectory class.

RESULTS

We found small but statistically significant indirect effects via behavioral problems from maternal smoking to child smoking trajectory for membership in all 3 smoking classes, relative to the nonsmoking trajectory, indicating partial mediation. Mediated effects were associated with maternal smoking after pregnancy, no statistically significant mediated effects were found for smoking before or during pregnancy.

CONCLUSIONS

The results provided no evidence that the effects of maternal smoking during pregnancy on child smoking trajectory are mediated by problem behavior. Effects from smoking after birth to child smoking trajectory appear to be partially mediated by problem behavior, supporting a behavioral rather than physiological effect of smoking during pregnancy but not ruling out more complex physiological pathways.

Revisiting the concepts of risk and protective factors for understanding the etiology and development of substance use and substance use disorders: implications for prevention

Over the past 20 years we have accumulated a greater knowledge and understanding of the genetic, neurobiological, and behavioral factors that may be associated with young people initiating the use of drugs and other substances and to progressing from use to abuse and dependence. This knowledge suggests that individuals may be "predisposed" to substance use disorders (SUD) and that the actual engagement in these behaviors depends on their environmental experiences from micro to macro levels. This paper summarizes this knowledge base and supports a developmental framework that examines the interaction of posited genetic, psychological, and neurobiological "predispositions" to SUD and those environmental influences that exacerbate this vulnerability.

Intergenerational relationships between the smoking patterns of a population-representative sample of US mothers and the smoking trajectories of their children

OBJECTIVES

We assessed intergenerational transmission of smoking in mother-child dyads.

METHODS

We identified classes of youth smoking trajectories using mixture latent trajectory analyses with data from the Children and Young Adults of the National Longitudinal Survey of Youth (n = 6349). We regressed class membership on prenatal and postnatal exposure to maternal smoking, including social and behavioral variables, to control for selection.

RESULTS

Youth smoking trajectories entailed early-onset persistent smoking, early-onset experimental discontinued smoking, late-onset persistent smoking, and nonsmoking. The likelihood of early onset versus late onset and early onset versus nonsmoking were significantly higher among youths exposed prenatally and postnatally versus either postnatally alone or unexposed. Controlling for selection, the increased likelihood of early onset versus nonsmoking remained significant for each exposure group versus unexposed, as did early onset versus late onset and late onset versus nonsmoking for youths exposed prenatally and postnatally versus unexposed. Experimental smoking was notable among youths whose mothers smoked but quit before the child's birth.

CONCLUSIONS

Both physiological and social role-modeling mechanisms of intergenerational transmission are evident. Prioritization of tobacco control for pregnant women, mothers, and youths remains a critical, interrelated objective.

Fetal programming of adult hypertension in female rat offspring exposed to androgens in utero

AIMS

The influence of prenatal factors on the development of arterial hypertension has gained considerable interest in recent years. We examined the effects of prenatal testosterone treatment on blood pressure in adult female rats. Further, to define the mechanisms whereby blood pressure may be raised, we examined vascular endothelial function and nitric oxide synthesis.

METHODS AND RESULTS

Testosterone propionate (0.5 mg/kg/day; SC) or vehicle was administered to pregnant Sprague-Dawley rats from gestational day 15-19. Maternal feed intake and plasma levels of steroid hormones were measured in the dams. In the female offspring, birth weight, growth rate, blood pressure, vascular reactivity, eNOS expression, and nitric oxide production were examined. In the pregnant rats, testosterone-treatment increased plasma testosterone levels by 2-fold without any significant changes in 17β-estradiol, progesterone and corticosterone levels. Testosterone-treatment did not affect maternal feed intake. The pups born to testosterone mothers were smaller in size but exhibited catch-up growth. The blood pressure in the testosterone offspring at 6 months of age was significantly higher compared to controls. Endothelium-intact mesenteric arteries from testosterone group exhibited increased contractile responses to phenylephrine, decreased vasodilation to acetylcholine and unaltered responses to sodium nitroprusside in comparison to control rats. Testosterone rats demonstrated decreased expression for eNOS, and reduced nitric oxide production.

CONCLUSIONS

Our data show that elevated plasma maternal testosterone levels: (1) causes low birth weight followed by catch-up growth and hypertension in female offspring and (2) alters endothelium-dependent vascular responses. The endothelial dysfunction is associated with decreased activity/expression of eNOS.

Developmental and environmental origins of breast cancer: DDT as a case study

More than 20 studies of serum "DDT" and breast cancer have found little support for the hypothesis that exposure influences risk of breast cancer. However, studies share common limitations including the inability to account for exposure in early life when the breast may be most vulnerable and the inability to measure exposure to the primary components of commercial DDT. This paper (1) summarizes evidence regarding critical windows of exposure for breast cancer (2) summarizes lessons learned from initial efforts to study DDT and breast cancer (3) reviews evidence from the Child Health and Development Studies (CHDS) where exposure was measured in young women using blood samples obtained during active exposure, 1-3 days after delivery and (4) suggests approaches for human studies that might advance understanding of environmental stressors in the developmental origins of disease.

Cigarette smoking and progesterone and androgen metabolites in premenopausal women

Smoking represents the most widespread substance dependence in the world. Several studies show nicotine’s ability to alter women hormonal homeostasis. Women smokers have higher testosterone and lower estradiol levels throughout life compared to women non-smokers. This negatively affects women’s reproductive function. Furthermore, alteration of neuroactive and neuroprotective steroids occurs in women smokers, and this plays an important role in the activity of the central nervous system, cognition, mental condition, and degree of substance dependence.

We monitored the effect of smoking discontinuation on steroid spectrum in 40 premenopausal women heavy smokers. These women were examined before they began to discontinue smoking, and after 6, 12, 24 and 48 weeks of abstinence. In each examination, blood was collected to determine steroid spectrum, LH, FSH, and SHBG; basic anthropometric data were also measured using GC-MS or immunoanalysis. Repeated-measures analysis of variance (ANOVA) model was used for evaluation of the data.

Given the small number of women who persisted in not smoking, only the data after 6 weeks could be analyzed. No changes were found in C21 steroids, and a slight increase in androgens occurred after the discontinuation of smoking.

Chronic smoking causes hyperandrogenism in fertile women; after smoking discontinuation, it increases further. Longer-term monitoring is necessary to show the effect of smoking discontinuation on steroid spectrum.

From the American Academy of Pediatrics: Technical report--Secondhand and prenatal tobacco smoke exposure

Secondhand tobacco smoke (SHS) exposure of children and their families causes significant morbidity and mortality. In their personal and professional roles, pediatricians have many opportunities to advocate for elimination of SHS exposure of children, to counsel tobacco users to quit, and to counsel children never to start. This report discusses the harms of tobacco use and SHS exposure, the extent and costs of tobacco use and SHS exposure, and the evidence that supports counseling and other clinical interventions in the cycle of tobacco use. Recommendations for future research, policy, and clinical practice change are discussed. To improve understanding and provide support for these activities, the harms of SHS exposure are discussed, effective ways to eliminate or reduce SHS exposure are presented, and policies that support a smoke-free environment are outlined.

Life course socioeconomic conditions, passive tobacco exposures and cigarette smoking in a multiethnic birth cohort of U.S. women

Low socioeconomic status (SES) and exposure to passive tobacco smoke are associated with increased risk of smoking in adults, but the influences of these factors in earlier life periods on adult smoking behavior are not well understood. We investigated the relationship of SES and passive tobacco exposure over the lifecourse with adult smoking status in a multiethnic cohort of U.S. women (n = 262, average age = 41.8), using prospective data on maternal smoking during pregnancy and childhood SES, and follow-up data on current smoking, adult SES and household tobacco exposure. Low adolescent and adult SES consistently increased the risk of current smoking, but most associations were not statistically significant in multivariable models. Blue collar parental occupation at birth increased the risk of smoking, particularly for current smoking relative to former smoking (odds ratio [OR] = 2.7, 95% confidence interval [CI] = 1.2-5.9). After adjusting for SES, current and former smokers were more likely than never smokers to have exposures to prenatal tobacco (OR = 4.4, 95% CI = 2.1-9.4 and OR = 2.0, 95% CI = 1.0-4.2, respectively) and adult household tobacco (OR = 2.7, 95% CI = 1.3-5.8 and OR = 2.4, 95% CI = 1.2-4.8, respectively). Our results show that early life conditions have enduring influences on women's smoking behavior in middle adulthood, even after considering similar types of conditions in later life periods.

Prenatal exposure to maternal cigarette smoking and the adolescent cerebral cortex

Smoking during pregnancy is associated with long-term consequences on offspring behavior. We measured thickness of the cerebral cortex using magnetic resonance images obtained in 155 adolescents exposed in utero to maternal smoking and compared them with 159 non-exposed subjects matched by maternal education. Orbitofrontal, middle frontal, and parahippocampal cortices were thinner in exposed, as compared with non-exposed, individuals; these differences were more pronounced in female adolescents. In exposed females, the thickness of the orbitofrontal cortex correlated negatively with a self-rated assessment of caring, one of the components of a model of positive youth development. These findings provide evidence of the long-term impact of prenatal environment on a neural substrate of cognition and social behavior.

Genes, maternal smoking, and the offspring brain and body during adolescence: design of the Saguenay Youth Study

The search for genes of complex traits is aided by the availability of multiple quantitative phenotypes collected in geographically isolated populations. Here we provide rationale for a large-scale study of gene-environment interactions influencing brain and behavior and cardiovascular and metabolic health in adolescence, namely the Saguenay Youth Study (SYS). The SYS is a retrospective study of long-term consequences of prenatal exposure to maternal cigarette smoking (PEMCS) in which multiple quantitative phenotypes are acquired over five sessions (telephone interview, home, hospital, laboratory, and school). To facilitate the search for genes that modify an individual's response to an in utero environment (i.e. PEMCS), the study is family-based (adolescent sibships) and is carried out in a relatively geographically isolated population of the Saguenay Lac-Saint-Jean (SLSJ) region in Quebec, Canada. DNA is acquired in both biological parents and in adolescent siblings. A genome-wide scan will be carried out with sib-pair linkage analyses, and fine mapping of identified loci will be done with family-based association analyses. Adolescent sibships (12-18 years of age; two or more siblings per family) are recruited in high schools throughout the SLSJ region; only children of French-Canadian origin are included. Based on a telephone interview, potential participants are classified as exposed or nonexposed prenatally to maternal cigarette smoking; the two groups are matched for the level of maternal education and the attended school. A total of 500 adolescent participants in each group will be recruited and phenotyped. The following types of datasets are collected in all adolescent participants: (1) magnetic resonance images of brain, abdominal fat, and kidneys, (2) standardized and computer-based neuropsychological tests, (3) hospital-based cardiovascular, body-composition and metabolic assessments, and (4) questionnaire-derived measures (e.g. life habits such as eating and physical activity; drug, alcohol use and delinquency; psychiatric symptoms; personality; home and school environment; academic and vocational attitudes). Parents complete a medical questionnaire, home-environment questionnaire, a handedness questionnaire, and a questionnaire about their current alcohol and drug use, depression, anxiety, and current and past antisocial behavior. To date, we have fully phenotyped a total of 408 adolescent participants. Here we provide the description of the SYS and, using the initial sample, we present information on ascertainment, demographics of the exposed and nonexposed adolescents and their parents, and the initial MRI-based assessment of familiality in the brain size and the volumes of grey and white matter.

Maternal smoking during pregnancy and possible effects of in utero testosterone: evidence from the 2D:4D finger length ratio

OBJECTIVES

Maternal smoking during pregnancy is linked to high fetal testosterone (FT), and an increased risk in offspring for autism, ADHD, conduct disorder, antisocial behaviour and criminal outcomes. The ratio of the length of the 2nd and 4th fingers (2D:4D) is thought to be negatively related to FT concentration, and is related to autism, hyperactivity, poor social behaviour, and physical aggression. We compare the 2D:4D ratio of children whose mothers smoked during pregnancy with the 2D:4D of children whose mother did not smoke.

METHOD

Cross-sectional survey in two primary schools. Questionnaires were distributed to 710 children and 546 were returned. Of these the 2nd and 4th digits of 520 children (259 females and 261 males) were measured. The main outcome measures were 2nd and 4th digit length, smoking history of mother and father.

RESULTS

Boys had lower mean 2D:4D than girls and right 2D:4D was lower than left. Among boys, those whose mother's smoked during pregnancy had lower right hand 2D:4D ratio than those whose mother did not smoke. The difference remained significant after the effects of age, height, weight and birth weight were removed. Other household smoking patterns were not associated with male offspring 2D:4D. Female offspring 2D:4D did not differ on the basis of maternal smoking.

CONCLUSIONS

Maternal smoking during pregnancy was associated with low right 2D:4D in children, but the effect was restricted to boys. A link between maternal smoking during pregnancy and 2D:4D supports a causal association between FT and such behaviours as hyperactivity and conduct disorder.

Increased nicotine self-administration following prenatal exposure in female rats

There is a significant association between maternal cigarette smoking during pregnancy and greater subsequent risk of smoking in female offspring. In animal models, prenatal nicotine exposure causes persistent alterations in cholinergic and monoaminergic systems, both of which are important for nicotine actions underlying tobacco addiction. Accordingly, the current study was conducted to determine if there is a cause-and-effect relationship between prenatal nicotine exposure and nicotine self-administration starting in adolescence. Pregnant rats were administered nicotine (6 mg/kg/day) by osmotic minipump infusion throughout gestation and then, beginning in adolescence and continuing into adulthood, female offspring were given access to nicotine via a standard operant IV self-administration procedure (0.03 mg/kg/infusion). Gestational nicotine exposure did not alter the initial rate of nicotine self-administration. However, when animals underwent one week of forced abstinence and then had a second opportunity to self-administer nicotine, the prenatally-exposed animals showed a significantly greater rate of self-administration than did the controls. Prenatal nicotine exposure causes increased nicotine self-administration, which is revealed only when the animals are allowed to experience a period of nicotine abstinence. This supports a cause-and-effect relationship between the higher rates of smoking in the daughters of women who smoke cigarettes during pregnancy and implicates a role for nicotine in this effect. Our results further characterize the long-term liabilities of maternal smoking but also point to the potential liabilities of nicotine-based treatments for smoking cessation during pregnancy.

Prediction of adolescent smoking from family and social risk factors at 5 years, and maternal smoking in pregnancy and at 5 and 14 years

AIMS

This study examines associations between maternal smoking and family, social or child risk factors when the child is aged 5 and adolescent smoking. The influence of mothers who smoke in pregnancy or continue to smoke at 14 years was also examined.

DESIGN

The Mater-University of Queensland Study of Pregnancy is a prospective cohort study.

PARTICIPANTS

Participants included 8556 women enrolled between 1981 and 1984 at their first antenatal visit. Completed questionnaires were obtained for 7223 offspring, comprising the study birth cohort. Of the 7223 eligible children a total of 4541 had information on both maternal smoking when the child was aged 5 years and adolescent smoking at 14 years.

MEASUREMENTS

Measures included maternal smoking during pregnancy and when the child was aged 5 and 14 years, child smoking at 14 years, maternal alcohol use, child behaviour problems and social and demographic variables.

FINDINGS

Adolescent smoking was predicted by a risk score at 5 years involving maternal smoking and alcohol use, non-married status, having a partner who had ever been arrested, having four or more children in the household, and child aggression at 5 years. Continued maternal smoking from 5 to 14 years was associated strongly with adolescent smoking. There was also evidence that smoking in late pregnancy may exert an independent effect on adolescent smoking.

CONCLUSIONS

The results suggest the possibility of a direct effect of prenatal smoking on adolescent smoking and highlight a set of environmental risk factors in the development of adolescent smoking. These risk factors may be used as early warning signs that intervention may be needed, and given the similarities with risk factors for other adverse childhood outcomes, the benefits of early intervention may extend beyond smoking to other problem behaviours. The possibility of being able to predict other disorders, because of these associations, also warrants further investigation.

Longitudinal analysis of the effect of prenatal nicotine exposure on subsequent smoking behavior of offspring

We explored the influence of maternal smoking during pregnancy on the likelihood of smoking among offspring in adolescence and adulthood using data from two similar British birth cohort surveys, the 1958 National Child Development Study and the 1970 British Birth Survey. Similar information was available in each cohort on maternal age at delivery, offspring sex, maternal smoking during pregnancy, parental and offspring socioeconomic status, and parental smoking at the time offspring smoking was assessed at age 16 years. Offspring smoking at 16 years and at 30/33 years were the primary outcomes of interest. Our data support an association between maternal smoking during pregnancy and an increased risk of offspring smoking later in life among female offspring but not among male offspring. Female offspring of mothers who smoked during pregnancy were more likely to smoke at 16 years than were their male counterparts. Moreover, in this same subgroup, female offspring smoking at 16 years was associated with an increased likelihood of smoking at 30/33 years. Further investigation in larger studies with greater detail of factors shaping smoking in childhood and adulthood and biochemically verified outcome measures would be desirable to clarify the relationship.

Maternal smoking during pregnancy and risk of brain tumors in the offspring. A prospective study of 1.4 million Swedish births

OBJECTIVE

Studies of the effect of maternal smoking during pregnancy on development of brain tumors in the offspring generally have found no increase in risk but most have mainly relied on retrospective exposure assessment. We conducted a prospective study on a large birth cohort in Sweden.

METHODS

Women giving birth during 1983-1997 were classified as smokers or non-smokers based on information ascertained at the first prenatal visit and recorded in the Swedish Birth Register. Follow-up of brain tumor incidence among offspring through 1997 was achieved by linkage with the Swedish Cancer Register. Hazard ratios were estimated using Cox proportional hazard regression, adjusting for demographic characteristics available in the Birth Register.

RESULTS

Brain tumors (n=480) occurred at a rate of 4.5 cases per 100,000 person-years. Children of women who smoked during pregnancy had an increased incidence of brain tumors (hazard ratio = 1.24; 95% confidence interval: 1.01-1.53). The increase in risk was similar for benign and malignant tumors, and was most apparent for astrocytoma. The effect of smoking on the occurrence of brain tumors was seen most strongly among 2-4 year-old children.

CONCLUSIONS

These results support a role for maternal smoking during pregnancy in the etiology of childhood brain tumors. Our findings should be confirmed in other prospective studies.