Maternal smoking and body composition of the newborn

EDC mixtures during pregnancy and body fat at 7 years of age in a Swedish cohort, the SELMA study

BACKGROUND

Some endocrine disrupting chemicals (EDC), are "obesogens" and have been associated with overweight and obesity in children. Daily exposure to different classes of EDCs demands for research with mixtures approach.

OBJECTIVES

This study evaluates the association, considering sex-specific effects, between prenatal exposure to EDC mixture and children's body fat at seven years of age.

METHODS

A total of 26 EDCs were assessed in prenatal urine and serum samples from first trimester in pregnancy from 737 mother-child pairs participating in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study. An indicator for children's "overall body fat" was calculated, using principal component analysis (PCA), based on BMI, percent body fat, waist, and skinfolds measured at seven years of age. Weighted quantile sum (WQS) regression was used to assess associations between EDC mixture and children's body fat.

RESULTS

Principal component (PC1) represented 83.6 % of the variance, suitable as indicator for children's "overall body fat", with positive loadings of 0.40-0.42 for each body fat measure. A significant interaction term, WQS*sex, confirmed associations in the opposite direction for boys and girls. Higher prenatal exposure to EDC mixture was borderline significant with more "overall body fat" for boys (Mean β = 0.20; 95 % CI: -0.13, 0.53) and less for girls (Mean β = -0.23; 95 % CI: -0.58, 0.13). Also, higher prenatal exposure to EDC mixture was borderline significant with more percent body fat (standardized score) for boys (Mean β = 0.09; 95 % CI: -0.04, 0.21) and less for girls (Mean β = -0.10 (-0.26, 0.05). The chemicals of concern included bisphenols, phthalates, PFAS, PAH, and pesticides with different patterns for boys and girls.

DISCUSSION

Borderline significant associations were found between prenatal exposure to a mixture of EDCs and children's body fat. The associations in opposite directions suggests that prenatal exposure to EDCs may present sex-specific effects on children's body fat.

Maternal nutrition during mid-pregnancy and children's body composition at 7 years of age in the SELMA study

Optimal nutrition during pregnancy is vital for both maternal and child health. Our objective was to explore if prenatal diet is associated with children's height and body fat. Nutrient intake was assessed through a FFQ from 808 pregnant women and summarised to a nutrition index, 'My Nutrition Index' (MNI). The association with children's height and body fat (bioimpedance) was assessed with linear regression models. Secondary analysis was performed with BMI, trunk fat and skinfolds. Overall, higher MNI score was associated with greater height (β = 0·47; (95 % CI 0·00, 0·94), among both sexes. Among boys, higher MNI was associated with 0·15 higher BMI z-scores, 0·12 body fat z-scores, 0·11 trunk fat z-scores, and larger triceps, and triceps + subscapular skinfolds (β = 0·05 and β = 0·06; on the log2 scale) (P-value < 0·05). Among girls, the opposite associations were found with 0·12 lower trunk fat z-scores, and smaller subscapular and suprailiac skinfolds (β = -0·07 and β = -0·10; on the log2 scale) (P-value < 0·05). For skinfold measures, this would represent a ± 1·0 millimetres difference. Unexpectedly, a prenatal diet in line with recommended nutrient intake was associated with higher measures of body fat for boys and opposite to girls at a pre-pubertal stage of development.

Prenatal exposures to mixtures of endocrine disrupting chemicals and sex-specific associations with children's BMI and overweight at 5.5 years of age in the SELMA study

BACKGROUND

Prenatal exposure to mixtures of endocrine disrupting chemicals (EDC) has the potential to disrupt human metabolism. Prenatal periods are especially sensitive as many developmental processes are regulated by hormones. Prenatal exposure to EDCs has inconsistently been associated with children's body mass index (BMI) and obesity. The objective of this study was to investigate if prenatal exposure to a mixture of EDCs was associated with children's BMI and overweight (ISO-BMI ≥ 25) at 5.5 years of age, and if there were sex-specific effects.

METHODS

A total of 1,105 mother-child pairs with complete data on prenatal EDCs concentrations (e.g., phthalates, non-phthalate plasticizers, phenols, PAH, pesticides, PFAS, organochlorine pesticides, and PCBs), children's measured height and weight, and selected covariates in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study were included in this analysis. The mixture effect of EDCs with children's BMI and overweight was assessed using WQS regression with 100 repeated holdouts. A positively associated WQS index with higher BMI and odds of overweight was derived. Models with interaction term and stratified weights by sex was applied in order to evaluate sex-specific associations.

RESULTS

A significant WQS*sex interaction term was identified and associations for boys and girls were in opposite directions. Higher prenatal exposure to a mixture of EDCs was associated with lower BMI (Mean β = -0.19, 95%CI: -0.40, 0.01) and lower odds of overweight (Mean OR = 0.72, 95%CI: 0.48, 1.04) among girls with borderline significance. However, the association among boys did not reach statistical significance. Among girls, the possible chemicals of concern were MEP, 2-OHPH, BPF, BPS, DPP and PFNA.

CONCLUSION

Prenatal exposure to a mixture of EDCs was associated with lower BMI and overweight among girls, and non-significant associations among boys. Chemicals of concern for girls included phthalates, non-phthalate plasticizers, bisphenols, PAHs, and PFAS.

Does maternal smoking in pregnancy explain the differences in the body composition trajectory between breastfed and formula-fed infants?

Growth patterns are known to differ between breastfed and formula-fed infants, but little is known about the relative impact of maternal smoking in pregnancy v. feeding mode on growth trajectory in infancy. We conducted a secondary analysis of a trial, the Tolerance of Infant Goat Milk Formula and Growth Assessment trial involving 290 healthy infants, to examine whether smoking in pregnancy modified the association between feeding mode and body composition of infants. Fat mass (FM) and fat-free mass (FFM) were estimated at 1, 2, 3, 4, 6 and 12 months of age using bioimpedance spectroscopy. Formula-fed infants (n 190) had a higher mean FFM at 4 months (mean difference (MD) 160 g, 95 % CI 50·4, 269·5 g, P < 0·05)) and 6 months (MD 179 g, 95 % CI 41·5, 316·9 g, P < 0·05) compared with the breastfed infants (n 100). Sub-group analysis of breastfed v. formula-fed infants by maternal smoking status in pregnancy showed that there were no differences in the FM and FFM between the breastfed and formula-fed infants whose mothers did not smoke in pregnancy. Formula-fed infants whose mothers smoked in pregnancy were smaller at birth and had a lower FM% and higher FFM% at 1 month compared with infants of non-smoking mothers regardless of feeding mode, but the differences were not significant at other time points. Adequately powered prospective studies with an appropriate design are warranted to better understand the relative impact of maternal smoking, feeding practice and the growth trajectory of infants.

Oxidative stress and mitochondrial dysfunction in parafacial respiratory group induced by maternal cigarette smoke exposure in rat offspring

Cigarette smoke (CS) exposure negatively affects neurodevelopment. We established a CS exposure rat model to determine how maternal CS exposure induces oxidative stress and mitochondrial dysfunction in parafacial respiratory group (pFRG) essential to central chemoreceptive regulation of normal breathing. Pregnant rats were exposed to CS during gestational days 1-20, and the offspring were studied on postnatal day 2. Our data showed that maternal CS exposure resulted in elevated accumulation of ROS, which left a footprint on DNA and lipid with increases in 8-hydroxy-2'-deoxyguanosine and malondialdehyde contents. Furthermore, maternal CS exposure induced decreases in manganese superoxide dismutase, catalase and glutathione reductase activities as well as reduction in glutathione content in pFRG in the offspring. Moreover, maternal exposure to CS led to mitochondrial ultrastructure changes, mitochondrial swelling, reduction in ATP generation, loss of mitochondrial membrane potential and increase in mitochondrial DNA copy number. These findings suggest that maternal exposure to CS alters normal development of pFRG that is critical for normal respiratory control.

Fetal exposure to maternal active and secondhand smoking with offspring early-life growth in the Healthy Start study

BACKGROUND

Previous studies have modeled the association between fetal exposure to tobacco smoke and body mass index (BMI) growth trajectories, but not the timing of catch-up growth. Research on fetal exposure to maternal secondhand smoking is limited.

OBJECTIVES

To explore the associations between fetal exposure to maternal active and secondhand smoking with body composition at birth and BMI growth trajectories through age 3 years.

METHODS

We followed 630 mother-child pairs enrolled in the Healthy Start cohort through age 3 years. Maternal urinary cotinine was measured at ~ 27 weeks gestation. Neonatal body composition was measured using air displacement plethysmography. Child weight and length/height were abstracted from medical records. Linear regression models examined the association between cotinine categories (no exposure, secondhand smoke, active smoking) with weight, fat mass, fat-free mass, and percent fat mass at birth. A mixed-effects regression model estimated the association between cotinine categories and BMI.

RESULTS

Compared to unexposed offspring, birth weight was significantly lower among offspring born to active smokers (-343-g; 95% CI: -473, -213), but not among offspring of women exposed to secondhand smoke (-47-g; 95% CI: -130, 36). There was no significant difference in the rate of BMI growth over time between offspring of active and secondhand smokers (p = 0.58). Therefore, our final model included a single growth rate parameter for the combined exposure groups of active and secondhand smokers. The rate of BMI growth for the combined exposed group was significantly more rapid (0.27 kg/m² per year; 95% CI: 0.05, 0.69; p < 0.01) than the unexposed.

CONCLUSIONS

Offspring prenatally exposed to maternal active or secondhand smoking experience rapid and similar BMI growth in the first three years of life. Given the long-term consequences of rapid weight gain in early childhood, it is important to encourage pregnant women to quit smoking and limit their exposure to secondhand smoke.

Testing the programming of temperament and psychopathology in two independent samples of children with prenatal substance exposure

Prenatal programming models have rarely been applied to research on children with prenatal substance exposure, despite evidence suggesting that prenatal drug exposure is a form of stress that impacts neurodevelopmental outcomes and risk for psychopathology. Utilizing data from two longitudinal multisite studies comprising children prenatally exposed to substances as well as a nonexposed comparison group (Maternal Lifestyle Study, n = 1,388; Infant Development, Environment, and Lifestyle study, n = 412), we tested whether early phenotypic indicators of hypothesized programming effects, indexed by growth parameters at birth and infant temperament, served as a link between prenatal substance exposure and internalizing and externalizing behavior at age 5. Latent profile analysis indicated that individual differences in reactivity and regulation for infants prenatally exposed to substances was best characterized by four temperament profiles. These profiles were virtually identical across two independent samples, and demonstrated unique associations with adjustment difficulties nearly 5 years later. Results of path analysis using structural equation modeling also showed that increased prenatal substance exposure was linked to poorer growth parameters at birth, profiles of temperamental reactivity in infancy, and internalizing and externalizing behavior at age 5. This pathway was partially replicated across samples. This study was among the first to link known individual-level correlates of prenatal substance exposure into a specific pathway to childhood problem behavior. Implications for the developmental origins of a child's susceptibility to psychopathology as a result of intrauterine substance exposure are discussed.

Feeding practices and nutritional status of HIV-exposed and HIV-unexposed infants in the Western Cape

Background

Optimal infant- and young child-feeding practices are crucial for nutritional status, growth, development, health and, ultimately, survival. Human breast milk is optimal nutrition for all infants. Complementary food introduced at the correct age is part of optimal feeding practices. In South Africa, widespread access to antiretrovirals and a programme to prevent mother-to-child transmission of HIV have reduced HIV infection in infants and increased the number of HIV-exposed uninfected (HEU) infants. However, little is known about the feeding practices and nutritional status of HEU and HIV-unexposed (HU) infants.

Objective

To assess the feeding practices and nutritional status of HIV-exposed and HIV-unexposed (HU) infants in the Western Cape.

Design

Prospective substudy on feeding practices nested in a pilot study investigating the innate immune abnormalities in HEU infants compared to HU infants. The main study commenced at week 2 of life with the nutrition component added from 6 months. Information on children's dietary intake was obtained at each visit from the caregiver, mainly the mother. Head circumference, weight and length were recorded at each visit. Data were obtained from 6-, 12- and 18-month visits. World Health Organization feeding practice indicators and nutrition indicators were utilised.

Setting

Tygerberg Academic Hospital, Western Cape. Mothers were recruited from the postnatal wards.

Subjects

Forty-seven mother-infant pairs, 25 HEU and 22 HU infants, participated in this nutritional substudy. Eight (17%) infants, one HU and seven HEU, were lost to follow-up over the next 12 months. The HEU children were mainly Xhosa (76%) and HU were mainly mixed race (77%).

Results

The participants were from poor socio-economic backgrounds. In both groups, adherence to breastfeeding recommendations was low with suboptimal dietary diversity. We noted a high rate of sugar- and salt-containing snacks given from a young age. The HU group had poorer anthropometric and nutritional indicators not explained by nutritional factors alone. However, alcohol and tobacco use was much higher amongst the HU mothers.

Conclusion

Adherence to breastfeeding recommendations was low. Ethnicity and cultural milieu may have influenced feeding choices and growth. Further research is needed to understand possible reasons for the poorer nutritional and anthropometric indicators in the HU group.

Quantity and timing of maternal prenatal smoking on neonatal body composition: the Healthy Start study

OBJECTIVE

To examine the dose-dependent and time-specific relationships of prenatal smoking with neonatal body mass, fat mass (FM), fat-free mass (FFM), and FM-to-FFM ratio, as measured by air-displacement plethysmography (PEA POD system).

STUDY DESIGN

We analyzed 916 mother-neonate pairs participating in the longitudinal prebirth cohort Healthy Start study. Maternal prenatal smoking information was collected in early, middle, and late pregnancy by self-report. Neonatal body composition was measured with the PEA POD system after delivery. Multiple general linear regression models were adjusted for maternal and neonatal characteristics.

RESULTS

Each additional pack of cigarettes smoked during pregnancy was associated with significant decreases in neonatal body mass (adjusted mean difference, -2.8 g; 95% CI, -3.9 to -1.8 g; P < .001), FM (-0.7 g; 95% CI, -1.1 to -0.3 g; P < .001), and FFM (-2.1 g; 95% CI, -2.9 to -1.3 g; P < .001). Neonates exposed to prenatal smoking throughout pregnancy had significantly lower body mass (P < .001), FM (P < .001), and FFM (P < .001) compared with those not exposed to smoking. However, neonates of mothers who smoked only before late pregnancy had no significant differences in body mass (P = .47), FM (P = .43), or FFM (P = .59) compared with unexposed offspring.

CONCLUSION

Exposure to prenatal smoking leads to systematic growth restriction. Smoking cessation before late pregnancy may reduce the consequences of exposure to prenatal smoking on body composition. Follow-up of this cohort is needed to determine the influence of catch-up growth on early-life body composition and the risk of childhood obesity.

Effects of Occupational Tobacco Exposure on Foetal Growth, among Beedi Rollers in Coastal Karnataka

INTRODUCTION

Though there is ample evidence on adverse effects of tobacco exposure caused by smoking during pregnancy on foetal outcomes, there is lack of studies done on the effects of exposure caused by transdermal absorption, as is seen among beedi rolling women. Therefore, this study was planned, to assess the effect of maternal exposure to tobacco, in the form of beedi-rolling, on the birth weight and other neonatal anthropometric measurements.

MATERIALS AND METHODS

A cross sectional study with controls was conducted, with 102 beedi rollers forming the study group and an equal number of matched controls (control group) (total 204). Data was collected by using a pre-tested questionnaire and anthropometric examinations of the neonates were carried out within 48 hours of their births.

RESULTS

Mean birth weight of the newborns was 2.66 (SD=0.32) among those who were born to beedi rolling women and it was 2.63 (SD=0.38) kg among the control group. Crown heel length was 48.09 centimeters (SD=1.93) in the study group and it was 48.12 cm (SD=1.92) in the control group. Beedi rolling beyond the 7(th) month of gestation and for more than six hours per day was associated with a small but insignificant decline in birth weight and crown heel length.

CONCLUSION

Beedi-rolling was found to be relatively safe during pregnancy but it could produce adverse effects if it was continued into the third trimester and for longer durations. This study can make the beedi rollers as well as their employers aware of harmful over-exposure to beedi rolling and help them in preventing it.

Effects of maternal tobacco-smoke exposure on fetal growth and neonatal size

Exposure to tobacco smoke, through both active and passive measures, has a significant impact on women's health, including effects on the cardiovascular, pulmonary and reproductive systems. Of particular interest is the effect of smoking on pregnancy outcomes. One crucial outcome that has been linked to the subsequent development of both neonatal and adult disease is intrauterine or fetal growth restriction. In this article, we will summarize the effects of smoking on newborn size and fetal growth. We will review evidence showing that tobacco consumption during pregnancy leads to a reduction in birthweight, largely through affecting specific anthropometric measures and newborn body composition. We will highlight the role of genetic susceptibility to these effects and discuss how smoking cessation prior to the third trimester results in a reduction in the risk of fetal growth restriction.

Prenatal substance abuse: short- and long-term effects on the exposed fetus

Prenatal substance abuse continues to be a significant problem in this country and poses important health risks for the developing fetus. The primary care pediatrician's role in addressing prenatal substance exposure includes prevention, identification of exposure, recognition of medical issues for the exposed newborn infant, protection of the infant, and follow-up of the exposed infant. This report will provide information for the most common drugs involved in prenatal exposure: nicotine, alcohol, marijuana, opiates, cocaine, and methamphetamine.

The impact of intrauterine tobacco exposure on the cerebral mass of the neonate based on the measurement of head circumference

The objective of the study was to assess cerebral mass, based on head circumference measurements in neonates exposed to tobacco smoke in utero, and to determine the relative proportions of the cerebral and body mass. The study included 147 neonates born in the period 2003-2004 at the Princess Anna Mazowiecka University Hospital and admitted to the Neonatal and Intensive Care Department of the Medical University in Warsaw. Subjects were divided into three groups on the basis of maternal status as active, passive, or nonsmokers determined by maternal urinary cotinine concentration and a questionnaire. Neonates whose mothers were active smokers throughout the whole period of pregnancy had a lower head circumference and in consequence a lower cerebral mass significantly more frequently when compared with those whose mothers were nonsmokers, P= 0.002. (Median difference in cerebral mass was 48.27 g.) The risk of lower cerebral mass was 3.9 (1.4-10.8, CI 95%) in the group of neonates whose mothers actively smoked cigarettes during pregnancy. A negative correlation was seen between cerebral mass and maternal urinary cotinine concentration (correlation coefficient r=-23, P= 0.006). The ratio of the cerebral to body mass was similar for neonates in all three groups. Active smoking during pregnancy had a negative effect on the cerebral mass of the neonate, however no such effect was observed in neonates whose mothers were passive smokers. The deficiency in cerebral mass increased with greater smoking intensity. Active smoking by the mother during pregnancy inhibits the growth of the brain as well as that of the body mass of the neonate.

Maternal active smoking and newborn body composition

OBJECTIVE

Maternal smoking during pregnancy is associated with a reduction in birth size but very few studies have collated changes in neonatal anthropometry. Our aims were both to assess body composition differences by anthropometry between new-borns from smoking mothers and those from non-smoking mothers, and to show whether these differences affect proportional body mass distribution.

METHODS

Caucasian mothers and their full term singleton new-borns (N=1216) were selected during 2009. A structured questionnaire was completed regarding obstetric and demographic data, as well as tobacco consumption. Women were categorized, according to their smoking habits, into a non-smoking group (never smoked or stopped smoking prior to pregnancy) and a smoking group (smoked throughout pregnancy).

RESULTS

22.1% of mothers smoked during pregnancy (median: 6 cigarettes/day, range: l-40). Smoking mothers were significantly younger than non-smoking mothers but there were no differences regarding other aspects which could affect infant weight. Infants from non-smoking mothers were heavier, longer, and body circumferences were all larger than those from smoking mothers (p<0.001), but the Ponderal Index showed no statistical differences. Skinfold thicknesses were significantly lower in new-borns from smoking mothers but these differences were less evident than those from body size. Subcutaneous fat distribution did not show statistical differences between the two groups. After gestational age, to smoke during gestation is the second main determinant of birth weight.

CONCLUSIONS

Smoking during pregnancy involves a generalized reduction of most axiological parameters as a result of proportionate fetal growth impairment. In those infants born from mothers who smoked during gestation, neonatal lean body mass appears to be more affected than body fat, and distribution of subcutaneous fat is not different.

Maternal use of nicotine replacement therapy during pregnancy and offspring birthweight: a study within the Danish National Birth Cohort

Smoking is a well-established risk factor for fetal growth restriction and other adverse pregnancy outcomes, and nicotine may be one of the chemical compounds that drive these associations. Nicotine replacement therapy (NRT) is a smoking cessation aid, which can facilitate smoking cessation. It is, however, unknown whether NRT used during pregnancy impairs fetal growth. The aim of this study was to estimate the association between the use of NRT during pregnancy and offspring birthweight. The study population consisted of 72 761 women enrolled in the Danish National Birth Cohort between 1996 and 2002. Information on NRT and potential confounders was obtained from two computer-assisted telephone interviews conducted in the second and third trimesters, respectively. Multiple linear regression in a multilevel model was used to estimate the association between NRT use and birthweight adjusted for gestational age and potential confounders. The adjusted analyses showed no significant association between the duration of NRT use and birthweight (b = 0.25 g per week of NRT use [95% CI -2.31, 2.81]) and neither was the type of NRT product (patch, gum, inhaler) associated with reduced birthweight. However, simultaneous use of more than one NRT product was associated with reduced birthweight (b = -10.73 g per week of NRT use [95% CI -26.51, 5.05]), although the association was not statistically significant. The results of this study suggest that maternal use of NRT in pregnancy does not seriously affect birthweight, but there could be a negative effect on birthweight associated with simultaneous use of more than one type of NRT product.

Gender, smoking during pregnancy and gestational age influence cord leptin concentrations in newborn infants

BACKGROUND

Low birth weight (BW), small head circumference, reduced length, increased preterm births and neuro-endocrine dysfunctions are among known consequences of smoking during pregnancy. Few studies have linked leptin to clinical features of growth restriction associated with maternal smoking and explored interaction with other determinants of size at birth, such as gender.

METHODS

Cord serum leptin concentrations were measured in 1215 term infants born to Caucasian mothers at completion of uneventful pregnancy. Serum concentrations were related to BW, gestational length, gender and maternal smoking and interaction with other determinants of size at birth evaluated.

RESULTS

Smoking was more frequent in younger (P<0.001) and shorter mothers (P=0.03) from lower socio-economic groups (SEGPs) (P<0.001). Infants born to smokers were lighter (190 g less), shorter and with smaller head circumference. Cord serum leptin concentrations were higher in girls (9.8 s.d. 7.6 ng/ml) than in boys (7.05 s.d. 5.8 ng/ml) (P<0.001). Boys were heavier (BW 3.52 s.d. 0.49 kg) than girls (3.39 s.d. 0.44 kg) (P<0.001), but girls had greater skinfold thickness measurements (sub-scapular and quadriceps skinfold thicknesses 5.5 s.d. 1.6 mm and 7.6 s.d. 1.9 mm respectively; boys 5.3 s.d. 1.6 vs 7.24+/-1.90 mm, P<0.001 respectively). Multivariate analyses showed gender (P<0.001), BW SDS (P<0.001), gestational length (P<0.001) and maternal smoking (P<0.042) as factors that influenced umbilical cord serum leptin concentrations in newborns.

CONCLUSION

Maternal smoking restrains foetal growth through placental vascular effects, and likely also via associated effects on leptin metabolism. More studies are needed to determine the influence that maternal smoking may have on placental syncytiotrophoblast and foetal adipose tissue.

Gender differences among hardcore smokers: an analysis of the tobacco use supplement of the current population survey

BACKGROUND

Despite significant declines in smoking rates in the United States, a substantial percentage of adults continue to smoke. Improved understanding of current smokers and their contact with sources of cessation support future tobacco control efforts. Recent evidence suggests that hardcore smokers, established smokers without a history of quit attempts, have less contact with cessation support. Although gender is among the major factors that influence smoking cessation, no research is available on gender differences among hardcore smokers.

METHODS

Demographic, environmental, and smoking-related characteristics of female hardcore smokers and male hardcore smokers and other female smokers were examined. Data from 17,777 smokers from the 2003 Current Population Survey Tobacco Use Supplement were analyzed.

RESULTS

Compared with female hardcore smokers, male hardcore smokers were more likely to have contact with smoking restrictions at work (OR = 1.69) and at home (OR = 1.45). Compared with female hardcore smokers, female other smokers were more likely to have seen a healthcare provider during the past year who advised them to quit smoking (OR = 1.39) and more likely to have smoking restrictions at work (OR = 1.25) and at home (OR = 2.32)). Measures of nicotine dependence suggested that female hardcore smokers were less dependent than male hardcore smokers but more dependent than other female smokers.

CONCLUSIONS

The sociodemographic and healthcare access variations in tobacco use identified in our analyses have significant public health implications and underscore the vital need for clinical and scientific advances in tobacco use prevention and control efforts.

[The effects of tobacco on children]

INTRODUCTION

Smoking remains an important topic. It is estimated that at present half the children born in France have been, or will be, exposed to the toxic effects of passive smoking. This paper aims to review the evidence of the effects of passive smoking, both intra and extra-uterine.

STATE OF THE ART

Extra-uterine passive smoking is implicated in numerous respiratory (asthma, allergy, infections...) and non respiratory diseases (neoplastic, dental, ophthalmic, digestive, cardio-vascular and infective). Intra-uterine exposure is even more dangerous and leads to abnormalities of the pregnancy (placental abnormalities, prematurity...), of the foetus (behavioural problems, malformations) and long term problems for the unborn child. Passive smoking is responsible for pulmonary morphological abnormalities (pulmonary hypoplasia, reduction in elasticity, increased deposition of collagen and alteration of alveolar structure) and functional disorders (reduced compliance, increased airways resistance, bronchial hyperreactivity). Finally it causes a disturbance of respiratory control, promoting all the factors responsible for sudden cot death.

CONCLUSIONS

The ill effects of passive smoking fully justify efforts to inform and persuade the medical profession of its duty to fight this scourge.

Course of growth during the first 6 years in children exposed in utero to tobacco smoke

OBJECTIVES

Postnatal growth in children exposed in utero to tobacco smoke is not well understood. This study investigated growth during the first 6 years in children whose mothers smoked during pregnancy.

MATERIALS AND METHODS

Weight, length, and head circumference were measured annually for 6 years in 100 children in each group of smoking (study) and nonsmoking (control) mothers.

RESULTS

Weight and head circumference were significantly smaller in the neonates whose mothers smoked >or=15 cigarettes/day, but the difference disappeared by 3 years of life. Length was significantly smaller in the study neonates at birth, followed by increasing divergence from normality up to 2 years, when the mean difference of children whose mothers smoked >or=15 cigarettes/day from control children was -3.4 cm (p <or= 0.0001). Subsequently, they manifested catch-up growth ,and the difference from the controls at 3, 4, 5, and 6 years was -2.5 cm (p <or= 0.0001), -2.2 cm (p = 0.005), -2.1 cm (p = 0.013), and -1.9 cm (p = 0.055), respectively.

DISCUSSION

The delayed growth was related to smoking per se and appeared to be independent of several confounding factors. At birth, there was a significant negative correlation between the number of cigarettes smoked per day and the growth parameters studied; it remained significant up to the 6 year only for length.

CONCLUSION

Length exhibits the most persistent growth delay of the parameters studied, but catch-up growth occurs after the second year of life, and thus, intrauterine exposure to tobacco smoke seems to have no permanent effect on children's growth.

Impact of parental smoking on diabetes, hypertension and the metabolic syndrome in adult men and women in the San Antonio Heart Study

AIMS/HYPOTHESIS

In the San Antonio Heart Study (SAHS) we investigated the effects of exposure to parental smoking on diabetes, hypertension and the metabolic syndrome in adult offspring aged 25-64 years.

SUBJECTS, MATERIALS AND METHODS

In a retrospective cohort study the parental smoking status during childhood, obtained through a postal questionnaire, determined a person's exposure status. Logistic regression models were used to calculate odds ratios for diabetes, hypertension and the metabolic syndrome at the baseline SAHS examination in relation to parental smoking status. All models were adjusted for age, sex, ethnicity, education years, personal smoking status (current, former or never-smoker), BMI and, in the case of diabetes, a family history of diabetes.

RESULTS

Of the 2,371 participants who returned the mailing, 44.5, 5.4, 20.0 and 30.1% reported that their father, mother, both or neither parent smoked, respectively. Participants reporting that both parents smoked were 1.60 (95% CI: 0.95-2.69) times more likely to have diabetes, 1.55 (95% CI: 1.05-2.28) times more likely to have hypertension, and 1.46 (95% CI: 1.01-2.10) times more likely to have the metabolic syndrome than participants reporting that neither parent smoked during their childhood. Odds ratios, after limiting the population to younger participants (i.e. <or=50 years) to reduce survivor bias, were 2.53 (95% CI: 1.21-5.31), 1.29 (95% CI: 0.78-2.16), and 1.41 (95% CI: 0.89-2.22) for diabetes, hypertension and the metabolic syndrome, respectively.

CONCLUSIONS/INTERPRETATION

These results provide evidence that early exposure to parental smoking may be associated with an increased risk of diabetes and perhaps hypertension and the metabolic syndrome.

Assessing newborn body composition using principal components analysis: differences in the determinants of fat and skeletal size

Background

Birth weight is a composite of skeletal size and soft tissue. These components are likely to have different growth patterns. The aim of this paper is to investigate the association between established determinants of birth weight and these separate components.

Methods

Weight, length, crown-rump, knee-heel, head circumference, arm circumference, and skinfold thicknesses were measured at birth in 699 healthy, term, UK babies recruited as part of the Exeter Family Study of Childhood Health. Corresponding measurements were taken on both parents. Principal components analysis with varimax rotation was used to reduce these measurements to two independent components each for mother, father and baby: one highly correlated with measures of fat, the other with skeletal size.

Results

Gestational age was significantly related to skeletal size, in both boys and girls (r = 0.41 and 0.52), but not fat. Skeletal size at birth was also associated with parental skeletal size (maternal: r = 0.24 (boys), r = 0.39 (girls) ; paternal: r = 0.16 (boys), r = 0.25 (girls)), and maternal smoking (0.4 SD reduction in boys, 0.6 SD reduction in girls). Fat was associated with parity (first borns smaller by 0.45 SD in boys; 0.31 SD in girls), maternal glucose (r = 0.18 (boys); r = 0.27 (girls)) and maternal fat (r = 0.16 (boys); r = 0.36 (girls)).

Conclusion

Principal components analysis with varimax rotation provides a useful method for reducing birth weight to two more meaningful components: skeletal size and fat. These components have different associations with known determinants of birth weight, suggesting fat and skeletal size may have different regulatory mechanisms, which would be important to consider when studying the associations of birth weight with later adult disease.

Pharmacological treatment for pregnant women who smoke cigarettes

Smoking has been associated with several concerns in pregnancy including miscarriage, preterm delivery and stillbirth. Unfortunately, approximately 12% of the pregnant population continue to smoke cigarettes, suggesting a need for additional therapy beyond behavioural change. This paper reviews the literature on the use of nicotine replacement therapy and bupropion (Zyban^®) in the pregnant human population, the pharmacokinetics of nicotine in the pregnant woman, and current guidelines for smoking cessation for pregnant patients. There are currently four studies that have investigated the use of nicotine patch, three for nicotine gum, and registry and preliminary reports for bupropion. These studies did not show any adverse pregnancy outcomes with the use of pharmacological aid for smoking cessation. All the nicotine replacement therapy studies, with the exception of one randomized-controlled nicotine patch trial had small sample sizes and looked at short-term use of drug in the third trimester. Two studies have examined the pharmacokinetics of nicotine in the pregnant woman. The results from these studies reveal greater nicotine metabolism in pregnant individuals who continue to smoke during pregnancy. Current guidelines from several organizations uniformly recommend that Nicotine Replacement Therapy should be considered if non-pharmacological therapies have been unsuccessful. Bupropion is recommended in pregnancy if the benefits outweigh the risks. There is a need for further studies on the safety and effectiveness of Nicotine Replacement therapy and bupropion in pregnancy. However, considering the current research and guidelines, pharmacological cessation aids should be considered if non-pharmacological therapies have not been effective.

Growth up to 2 years in relationship to maternal smoking during pregnancy

Smoking during pregnancy causes intrauterine growth retardation, but the subsequent growth of these children is not well understood. Two hundred four newborns of mothers who smoked during pregnancy and 204 control neonates were studied. Children were re-examined at 1 and 2 years. Newborns of mothers who smoked 1-9 cigarettes/day had similar anthropometric parameters with the controls. Significant retardation in weight, length, and head circumference was present in the newborns whose mothers smoked > or = 10 cigarettes/day. At follow-up, in children of smoking mothers the retardation of weight improved, head circumference remained stable, and length retardation increased even in children whose mothers smoked < 10 cigarettes/day.

Perinatal bone turnover in term human neonates and the influence of maternal smoking

Bone turnover in neonates appears independently of the comparably low maternal bone turnover, but there is only sparse information on the effect of the in utero environment on fetal bone turnover. Postnatally, the resuming growth velocity and alterations in mineral homeostasis affect neonatal bone turnover. This study evaluated the relationship of bone marker concentrations to maternal and fetal auxological variables as well as maternal smoking and assessed the short-term change in bone markers during the first days of life. Serum markers of bone formation [osteocalcin and bone-specific alkaline phosphatase (BALP)] and bone resorption (C-terminal telopeptide of type I collagen) were measured in cord blood and at discharge (median d 3) in 69 healthy term neonates. Concentrations of BALP were significantly lower in neonates of smokers (n = 16) compared with nonsmokers (n = 53), both at birth (p = 0.013) and at discharge (p = 0.036). Both cord osteocalcin and BALP were negatively related to maternal weight and maternal body mass index. Maternal smoking and pregnancy weight gain were the predictors of cord BALP (r2 = 0.24; p < 0.001), whereas the mode of delivery best predicted cord C-terminal telopeptide of type I collagen levels (r2 = 0.19; p < 0.001). C-terminal telopeptide of type I collagen and osteocalcin increased significantly (p < 0.001) from birth to discharge, whereas BALP levels did not change significantly during the same period. Our results suggest that maternal smoking during pregnancy and maternal obesity may have a negative impact on fetal bone formation. The significant increase of osteocalcin and C-terminal telopeptide of type I collagen may result either from an increase in bone turnover or altered renal clearance.

Fetal origins of obesity

The worldwide epidemic of obesity continues unabated. Obesity is notoriously difficult to treat, and, thus, prevention is critical. A new paradigm for prevention, which evolved from the notion that environmental factors in utero may influence lifelong health, has emerged in recent years. A large number of epidemiological studies have demonstrated a direct relationship between birth weight and BMI attained in later life. Although the data are limited by lack of information on potential confounders, these associations seem robust. Possible mechanisms include lasting changes in proportions of fat and lean body mass, central nervous system appetite control, and pancreatic structure and function. Additionally, lower birth weight seems to be associated with later risk for central obesity, which also confers increased cardiovascular risk. This association may be mediated through changes in the hypothalamic pituitary axis, insulin secretion and sensing, and vascular responsiveness. The combination of lower birth weight and higher attained BMI is most strongly associated with later disease risk. We are faced with the seeming paradox of increased adiposity at both ends of the birth weight spectrum-higher BMI with higher birth weight and increased central obesity with lower birth weight. Future research on molecular genetics, intrauterine growth, growth trajectories after birth, and relationships of fat and lean mass will elucidate relationships between early life experiences and later body proportions. Prevention of obesity starting in childhood is critical and can have lifelong, perhaps multigenerational, impact.

Growth from birth onwards of children prenatally exposed to drugs: a literature review

Reductions in birth weight and length have been independently attributed to prenatal exposure to alcohol, cigarettes and cocaine. While pregnant women often use multiple substances, studies have not consistently controlled for exposure to other agents or other important differences in maternal lifestyle associated with the use of these substances. Despite these difficulties, the preponderance of evidence suggests that prenatal alcohol and cocaine independently reduce birth measurements. This review synthesizes the scientific literature focusing on prenatal exposures and the relationship to child growth. First examined are studies that investigated the link between prenatal exposures and birth weight and length, followed by the effects of these substances on childhood growth. Studies vary in the number of subjects, cohort characteristics, measurement of exposure and control for potential confounders. Differences in sample characteristics and size, as well as degree of statistical control for potential confounders and the examination of moderating characteristics, have led to differing conclusions regarding the long-term effect of prenatal substance exposure on growth. Large-scale, well-designed studies are needed to clearly examine the unique contribution of both varying prenatal exposures and the magnitude and timing of these exposures on childhood growth deficits.

High rates of infant macrosomia: a comparison of a Canadian native and a non-native population

The Cree of James Bay have the highest ever reported mean birth weight and a high prevalence of infant macrosomia. This study was designed to examine independent risk factors for infant macrosomia among the Cree, to compare these to risk factors among non-Native Canadians and to determine if ethnic differences persist after adjusting for differences in the distribution of other risk factors. Macrosomia was defined as birth weight >90(th) percentile for gestational age of a reference population. Independent determinants of macrosomia were examined in 385 Cree and 5644 non-Native women. The potential effect of ethnicity (Cree vs. non-Native) was determined after statistically adjusting for age, parity, pregravid weight, height, net rate of weight gain, gestational diabetes mellitus (GDM) and smoking status. The prevalence of macrosomia among the Cree was 34.3% vs. 11.1% among non-Natives. Although GDM significantly increased the risk for macrosomia among the Cree (odds ratio: 4.46, 95% CI: 2.24-9.26), it was not a significant risk factor among non-Natives (odds ratio: 1.15, 95% CI: 0.79-1.65). The risk for infant macrosomia remained elevated among the Cree compared with non-Natives after adjusting for other risk factors (odds ratio: 3.64, 95% CI: 2.69-4.90). In conclusion, the Cree have a high prevalence of macrosomia despite controlling for important differences in pregravid weight and GDM. Some of this variation may be due to genetic differences in fetal growth. The differential impact of GDM on macrosomia in the two ethnic groups may be due to differences in treatment strategies for GDM.

Does smoking by pregnant women influence IQ, birth weight, and developmental disabilities in their infants? A methodological review and multivariate analysis

Neuropsychologists are asked frequently to address the issue of the cause of a variety of central nervous system problems that may affect higher cortical function. One such issue is the relationship of maternal smoking to adverse reproductive outcomes involving neocortical insult including mental retardation, learning disabilities, attention-deficit hyperactivity disorder, and other insults that may be related to prolonged hypoxic states in utero. The instant paper develops the issue of causation as a scientific inquiry, reviews several traditional, applicable models, and critiques these models. An additional model of motility is proposed and discussed. The issue of the relationship of maternal smoking to adverse reproductive outcomes is then addressed from a review perspective along with new empirical analyses, the latter demonstrating that researchers tend to draw causal conclusions independent of whether the respective design of their studies would support conclusions about the causation of an event. Causal conclusions in the absence of causal designs have often lead to incomplete and incorrect conclusions. It is necessary to match conclusions not only to the outcomes of a research project but also to its design and accompanying limitations.

Factors affecting newborn bone mineral content: in utero effects on newborn bone mineralization

Several factors have been found recently to have a significant impact on newborn bone mineral content (BMC) and developing fetal bone. Recently we showed that maternal vitamin D deficiency may affect fetal bone mineralization. Korean winter-born newborn infants had extremely low serum 25-hydroxyvitamin D (25-OHD), high serum cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker), and markedly lower (8 %) total body BMC than summer-born newborn infants. Infant total body BMC was positively correlated with cord serum 25-OHD and inversely correlated with ICTP, which was also negatively correlated with vitamin D status. In three separate studies on North American neonates we found markedly lower (8-12 %) BMC in summer newborn infants compared with winter newborn infants, the opposite of the findings for Korean neonates. The major reason for the conflicting BMC results might be the markedly different maternal vitamin D status of the North American and Korean subjects. Recently, we found evidence of decreased bone formation rates in infants who were small-for-gestational age (SGA) compared with infants who were appropriate-for-gestational age; we reported reduced BMC, cord serum osteocalcin (a marker of bone formation) and 1,25-dihydroxyvitamin D (the active metabolite of vitamin D), but no alterations in indices of fetal bone collagen metabolism. In theory, reduced utero-placental blood flow in SGA infants may result in reduced transplacental mineral supply and reduced fetal bone formation. Infants of diabetic mothers (IDM) have low BMC at birth, and infant BMC correlated inversely with poor control of diabetes in the mother, specifically first trimester maternal mean capillary blood glucose concentration, implying that factors early in pregnancy might have an effect on fetal BMC. The low BMC in IDM may be related to the decreased transplacental mineral transfer. Cord serum ICTP concentrations were higher in IDM than in control subjects, implying increased intrauterine bone resorption. BMC is consistently increased with increasing body weight and length in infants. Race and gender differences in BMC appear in early life, but not at birth. Ethanol consumption and smoking by the mother during pregnancy affect fetal skeletal development.

Growth from birth to early adolescence in offspring prenatally exposed to cigarettes and marijuana

Weight, height, and head circumference were examined in children from birth to early adolescence for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing longitudinal study. The negative association between growth measures at birth and prenatal cigarette exposure was overcome, sooner in males than females, within the first few years, and by the age of six, the children of heavy smokers were heavier than control subjects. Pre and postnatal environmental tobacco smoke did not have a negative effect upon the growth parameters; however, the choice of bottle-feeding or shorter duration of breast-feeding by women who smoked during pregnancy appeared to play an important positive role in the catch-up observed among the infants of smokers. Prenatal exposure to marijuana was not significantly related to any growth measures at birth, although a smaller head circumference observed at all ages reached statistical significance among the early adolescents born to the heavy marijuana users.

The relationship in neonates between clinically measured head circumference and brain volume estimated from head CT-scans

OBJECTIVE

To determine if the frontal-occipital head circumference correlates with brain volume on CT and to investigate correlations between the volumes of different brain subdivisions in live neonates.

METHODS

Records were studied from 27 neonates with anatomically normal head CT-scans which were ordered for clinical reasons, and which were performed at Johns Hopkins Hospital. Clinical data were abstracted from medical records. Brain volumes were estimated by digitizing the structures of interest on each slice of head CT-scans.

RESULTS

In this sample of 27 infants with a mean birth weight of 3000.4 +/- 668 g, mean head circumference of 33.5 +/- 1.8 cm, and mean gestational age of 37 weeks and 4 days +/- 24 days, the mean of total brain volume was 333.0 +/- 78.3 ml. The correlation between clinically measured head circumference and total brain volume was 0.55 (P < 0.003). Regression of total brain volume on head circumference and its second and third powers accounted for 43% of the variation in total brain volume. Other predictor variables, namely infant race, sex, gestational age, and maternal age, were not significant in this regression once head circumference was included. The slope of the cubic function of head circumference as a predictor of brain volume was greatest below the mean head circumference of 33.5 cm. Brain volume leveled off at head circumferences greater than the mean.

CONCLUSION

Head circumference is a powerful predictor of total brain volume in the neonate: below the approximate head-circumference mean of 33.5 cm, smaller head circumference indicates smaller total brain volume.

A theory of technophysio evolution, with some implications for forecasting population, health care costs, and pension costs

We argue that over the past 300 years human physiology has been undergoing profound environmentally induced changes made possible by numerous advances in technology. These changes, which we call technophysio evolution, increased body size by over 50%, and greatly improved the robustness and capacity of vital organ systems. Because technophysio evolution is still ongoing, it is relevant to forecasts of longevity and morbidity and, therefore, to forecasts of the size of the elderly population and pension and health care costs.