Prenatal exposure to passive smoking and duration of breastfeeding in nonsmoking women: Krakow inner city prospective cohort study

Risk factors for discontinuation of exclusive breast feeding within 1month: a retrospective cohort study in Japan

BACKGROUND

While breastfeeding provides benefits for infants and the mother, many women either do not breastfeed or terminate breastfeeding earlier than recommended. The aim of this analysis was to identify factors associated with early discontinuation of breastfeeding in Japanese women.

METHODS

This study used data from medical records of women delivering a singleton live birth between March 2017 and August 2019 in Iwase General Hospital, Fukushima Prefecture, Japan to assess cessation of breastfeeding by the 1-month postpartum appointment. Demographic (age at birth, and employment status), medical (parity, and physical and mental condition of the mother; and infant medical factors, such as sex, Apgar score, and jaundice, among other), and family factors (husband/partner, family members living at the same house, among others) in 734 women who had initiated breastfeeding during their delivery hospital stay were examined, and multiple logistic regression was used to determine significant predictors of early cessation of exclusive breastfeeding.

RESULTS

Bivariate analysis revealed that women who were primipara, unmarried, exposed to secondhand smoke, and employed; those who smoked before pregnancy; and those who had asthma were more likely to discontinue exclusive breastfeeding than other women. Infant factors associated with discontinuation were lower birthweight, earlier gestational age, neonatal intensive care unit admission, treatment for jaundice, or lower weight gain. Multivariable analysis revealed that primiparity, passive smoking before pregnancy, maternal employment, and neonatal jaundice therapy were associated with discontinuation of breastfeeding.

CONCLUSIONS

In particular, women whose partners smoked before pregnancy may need to be targeted for additional support for breastfeeding.

Secondhand Smoke Exposure During Pregnancy and Mothers' Subsequent Breastfeeding Outcomes: A Systematic Review and Meta-Analysis

Secondhand smoke exposure of non-smoking women during pregnancy is associated with a higher risk of adverse birth outcomes. However, the available evidence regarding the association between expectant mothers’ secondhand smoke exposure and breastfeeding outcomes remains limited. This systematic review aimed to examine associations between secondhand smoke exposure of nonsmoking women during pregnancy with the initiation, prevalence, and duration or breastfeeding compared to women who were breastfeeding and had not been exposed to secondhand smoke. Women who smoked during pregnancy were excluded. We included case-control, cross-sectional, and cohort studies with a comparison control group. Medline CINAHL, and EMBASE were searched in January 2017. After screening 2777 records we included eight prospective cohort studies. The risk of bias assessment tool for non-randomized studies indicated a high risk of outcome assessment blinding. Meta-analysis of two studies established that the odds of discontinuation of any brestfeeding before six months were significantly increased in the secondhand smoke exposed women (pooled odds = 1.07 [95%CI = 1.01, 1.14], two studies, 1382 women). Therefore, secondhand smoke might be associated with discontinuing any breastfeeding before six months. More research is necessary to understand the association between secondhand smoke and the initiation, prevalence and duration of breastfeeding.

Modifiable Individual Factors Associated with Breastfeeding: A Cohort Study in China

Breast milk is an ideal first food for infants in the initial months of life. This study aimed to identify modifiable individual factors in breastfeeding during the first six months of life in Hunan. This birth cohort study was conducted in three communities in Changsha, Hunan province. Data were collected through maternal health manuals and self-administered questionnaires during the follow-up period. To find risk factors and calculate odds ratios, generalized estimating equation models were applied. The final study included 951 mother-infant pairs. The prevalence of exclusive breastfeeding and any breastfeeding in this study was below the World Health Organization's breastfeeding goals. Infant age, passive smoking after delivery, minor postnatal depression, and feeding-bottles were shown to act negatively on both exclusive breastfeeding and any breastfeeding. In addition, cesarean delivery and delayed breastfeeding initiation had adverse effects on exclusive breastfeeding. Multiparas were less likely to continue any breastfeeding during the first few months. This study highlights the importance of screening probable maternal depression during primary care service and reducing secondhand smoke and feeding-bottle use. The results also suggest that healthcare professionals should provide more assistance and education to multiparas and mothers with cesarean delivery or delayed breastfeeding initiation.

Low-Level Prenatal Toxin Exposures and Breastfeeding Duration: A Prospective Cohort Study

Introduction Maternal exposure to tobacco smoke is associated with shortened breastfeeding duration, but few studies have examined the effects on breastfeeding outcomes of low level exposures to other toxic chemicals. Moreover, it is unclear if passive smoking is associated with duration of breastfeeding. Our objective was therefore to examine the effect of low-level prenatal exposures to common environmental toxins (tobacco smoke, lead, and phthalates) on breastfeeding exclusivity and duration. Methods We conducted an analysis of data from the Health Outcomes and Measures of the Environment (HOME) Study. Serum and urine samples were collected at approximately 16 and 26 weeks gestation and at delivery from 373 women; 302 breastfed their infants. Maternal infant feeding interviews were conducted a maximum of eight times through 30 months postpartum. The main predictor variables for this study were gestational exposures to tobacco smoke (measured by serum cotinine), lead, and phthalates. Passive smoke exposure was defined as cotinine levels of 0.015-3.0 μg/mL. Primary outcomes were duration of any and exclusive breastfeeding. Results Serum cotinine concentrations were negatively associated with the duration of any breastfeeding (29.9 weeks unexposed vs. 24.9 weeks with passive exposure, p = 0.04; and 22.4 weeks with active exposure, p = 0.12; p = 0.03 for linear trend), but not duration of exclusive breastfeeding. Prenatal levels of blood lead and urinary phthalate metabolites were not significantly associated with duration of any or exclusive breastfeeding. Conclusions Passive exposure to tobacco smoke during pregnancy was associated with shortened duration of any breastfeeding.

The relationship between husbands' health belief and environment tobacco smoke exposure among their pregnant wife

OBJECTIVE

The aim of the present study was to evaluate the relationship between health belief structures of men and environment tobacco smoke (ETS) exposure among pregnant women.

METHODS

This cross-sectional research was conducted on 120 smoking men who had pregnant wives. Data were gathered through a questionnaire that measured health belief structures related to pregnant women's exposure to cigarette's smoke including perceived susceptibility/severity, benefits, barriers and self-efficacy. Number of exposures to cigarette's smoke was defined by the number of smoked cigarettes in the presence of the pregnant wife.

RESULTS

The number of smoked cigarettes in the presence of pregnant wife had a negative relation with perceived susceptibility/severity and perceived benefits and a positive relation with perceived barriers. The number of smoked cigarettes in men had no relation with health belief constructs. Using multiple regression test showed the perceived barrier for not smoking was the strongest factor in men to anticipate the level of women's ETS exposure.

CONCLUSIONS

Results of this study showed that the level of ETS exposure among pregnant women was dependent on men's health beliefs about the ETS exposure treats among pregnant women.

Does environmental cigarette smoke affect breastfeeding behavior?

BACKGROUND:

Exposure of lactating women to environmental cigarette smoke may increase cotinine in breast milk, which in turn may reduce the volume of milk and the duration of breastfeeding.

OBJECTIVES:

To assess the relationship between exposure to environmental cigarette smoke and breastfeeding behavior.

MATERIALS AND METHODS:

This prospective cohort study was conducted on 290 mothers in Babol - Iran, who had been breastfeeding for 3–5 days after delivery. The lactating mothers were divided into two groups: those exposed to environmental cigarette smoke, and those free from smoke exposure. The study questionnaire included demographic data, information on environmental cigarette smoke, and breastfeeding behavior. Data was collected through telephone interviews at 2, 4, and 6 months of follow-up. Statistical analysis included descriptive statistics, and test of significance using Chi-square test, t-test, log-rank test, and Cox proportional hazards model.

RESULTS:

The continuation of breastfeeding for the group of exposed mothers and the unexposed group was (mean ± standard deviation) 5.57 ± 0.098 and 5.58 ± 0.109, respectively in 6 months of follow-up. There was no significant difference between the two groups (P = 0.93). The percentage of exclusive breastfeeding at 6 months in the group exposed to cigarette smoke was 65% compared to 76% of the nonexposed group. However, the difference was not statistically significant (P = 0.149).

CONCLUSIONS:

In this study, no significant association was observed between the group exposed to environmental cigarette smoke and the nonexposed group in breastfeeding behavior, although the percentage of exclusive breastfeeding at 6 months was less in the group exposed to environmental cigarette smoke. Further exploratory studies are needed.

Recent contributions of air- and biomarkers to the control of secondhand smoke (SHS): a review

Since the publication of the US Surgeon General Reports in 1996 and 2006 and the report of the California Environmental Protection Agency in 1999, many reports have appeared on the contribution of air and biomarkers to different facets of the secondhand smoke (SHS) issue, which are the targets of this review. These recent studies have allowed earlier epidemiological surveys to be biologically validated, and their plausibility demonstrated, quantified the levels of exposure to SHS before the bans in various environments, showed the deficiencies of mechanical control methods and of partial bans and the frequently correct implementation of the efficient total bans. More stringent regulation remains necessary in the public domain (workplaces, hospitality venues, transport sector, etc.) in many countries. Personal voluntary protection efforts against SHS are also needed in the private domain (homes, private cars). The effects of SHS on the cardiovascular, respiratory and neuropsychic systems, on pregnancy and fertility, on cancers and on SHS genotoxicity are confirmed through experimental human studies and through the relationship between markers and prevalence of disease or of markers of disease risk.

Activation of the aryl hydrocarbon receptor during pregnancy in the mouse alters mammary development through direct effects on stromal and epithelial tissues

Activation of the aryl hydrocarbon receptor (AHR), an environment-sensing transcription factor, causes profound impairment of mammary gland differentiation during pregnancy. Defects include decreased ductal branching, poorly formed alveolar structures, suppressed expression of milk proteins, and failure to nutritionally support offspring. AHR is activated by numerous environmental toxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and plays an as yet poorly understood role in development and reproduction. To better understand how AHR activation affects pregnancy-associated mammary gland differentiation, we used a combination of ex vivo differentiation, mammary epithelial transplantation, and AHR-deficient mice to determine whether AHR modulates mammary development through a direct effect on mammary epithelial cells (MECs) or by altering paracrine or systemic factors that drive pregnancy-associated differentiation. Studies using mutant mice that express an AHR protein lacking the DNA-binding domain show that defects in pregnancy-associated differentiation require AHR:DNA interactions. We then used fluorescence-based cell sorting to compare changes in gene expression in MECs and whole mammary tissue to gain insight into affected signaling pathways. Our data indicate that activation of the AHR during pregnancy directly affects mammary tissue development via both a direct effect on MECs and through changes in cells of the fat pad, and point to gene targets in MECs and stromal tissues as putative AHR targets.

Paternal smoking and childhood overweight: evidence from the Hong Kong "Children of 1997"

OBJECTIVE

This study examined, in a non-Western sociohistorical context, whether prenatal or postnatal secondhand smoke (SHS) exposure for children of nonsmoking mothers was associated with higher childhood BMI, and it clarified whether the observed associations were biologically mediated or socioeconomically confounded.

METHODS

A total of 6710 and 6519 children of nonsmoking mothers (N = 7924) with BMI data at approximately 7 and approximately 11 years, respectively, from a population-representative (N = 8327), Hong Kong Chinese birth cohort ("Children of 1997"), born in April or May 1997, were included in the analysis.

RESULTS

Compared with no SHS exposure, daily paternal smoking increased mean BMI z scores, but not height, at 7 years (difference: 0.10 [95% confidence interval: 0.02-0.19]) and at 11 years (difference: 0.16 [95% confidence interval: 0.07-0.26]), with adjustment for gender, birth order, socioeconomic position, mother's place of birth, breastfeeding, serious morbidity, and pubertal status.

CONCLUSIONS

Our findings, although preliminary, suggest that the association of paternal smoking with child overweight might be biologically mediated. Given the known harms of smoking, reducing SHS exposure from conception as a precautionary action for childhood overweight might be warranted.

Measuring prenatal secondhand smoke exposure in mother-baby couplets

INTRODUCTION

Pregnant women often underreport their smoking status and extent of secondhand smoke (SHS) exposure. Biomarker confirmation is the recommended method to assess smoking behaviors and SHS exposure in both mothers and infants.

OBJECTIVES

The primary aims are to (a) examine the relationship between smoking behaviors and SHS exposure in mother-baby couplets using maternal and infant hair nicotine and maternal urine cotinine analyses and (b) determine whether there is an association between maternal and infant hair nicotine samples obtained shortly after birth.

DISCUSSION

A cross-sectional study with a multiethnic sample of 210 mother-baby couplets assessing SHS exposure.

RESULTS

The level of maternal hair nicotine (MHN) was significantly different among three groups: nonsmoking, nonsmoking/passive exposed, and smoking (p < .0001), with nonsmoking and nonexposed women having the lowest level. Urine cotinine was strongly associated with self-reported smoking status (rho = .88; p < .0001). Maternal and infant hair nicotine were correlated, although MHN correlated more strongly with smoking status (rho = .46, p < .0001) than infant hair nicotine (rho = .39, p < .0001).

CONCLUSIONS

MHN was a more precise biomarker of prenatal SHS exposure than infant hair nicotine; mothers' urine cotinine was strongly correlated with self-reported smoking status.

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.