The effect of passive smoking and breast feeding on serum antioxidant vitamin (A, C, E) levels in infants

Role of genetics and the environment in the etiology of congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a congenital malformation characterized by failure of diaphragm closure during embryonic development, leading to pulmonary hypoplasia and pulmonary hypertension, which contribute significantly to morbidity and mortality. The occurrence of CDH and pulmonary hypoplasia is theorized to result from both abnormalities in signaling pathways of smooth muscle cells in pleuroperitoneal folds and mechanical compression by abdominal organs within the chest cavity on the developing lungs. Although, the precise etiology of diaphragm maldevelopment in CDH is not fully understood, it is believed that interplay between genes and the environment contributes to its onset. Approximately 30% of patients with CDH possess chromosomal or single gene defects and these patients tend to have inferior outcomes compared with those without genetic associations. At present, approximately 150 gene variants have been linked to the occurrence of CDH. The variable expression of the CDH phenotype in the presence of a recognized genetic predisposition can be explained by an environmental effect on gene penetrance and expression. The retinoic acid pathway is thought to play an essential role in the interactions of genes and environment in CDH. However, apart from the gradually maturing retinol hypothesis, there is limited evidence implicating other environmental factors in CDH occurrence. This review aims to describe the pathogenesis of CDH by summarizing the genetic defects and potential environmental influences on CDH development.

The etiology of congenital diaphragmatic hernia: the retinoid hypothesis 20 years later

Congenital diaphragmatic hernia (CDH) is a severe birth defect and a major cause of neonatal respiratory distress. Impacting ~2-3 in 10,000 births, CDH is associated with a high mortality rate, and long-term morbidity in survivors. Despite the significant impact of CDH, its etiology remains incompletely understood. In 2003, Greer et al. proposed the Retinoid Hypothesis, stating that the underlying cause of abnormal diaphragm development in CDH was related to altered retinoid signaling. In this review, we provide a comprehensive update to the Retinoid Hypothesis, discussing work published in support of this hypothesis from the past 20 years. This includes reviewing teratogenic and genetic models of CDH, lessons from the human genetics of CDH and epidemiological studies, as well as current gaps in the literature and important areas for future research. The Retinoid Hypothesis is one of the leading hypotheses to explain the etiology of CDH, as we continue to better understand the role of retinoid signaling in diaphragm development, we hope that this information can be used to improve CDH outcomes. IMPACT: This review provides a comprehensive update on the Retinoid Hypothesis, which links abnormal retinoic acid signaling to the etiology of congenital diaphragmatic hernia. The Retinoid Hypothesis was formulated in 2003. Twenty years later, we extensively review the literature in support of this hypothesis from both animal models and humans.

Is maternal cigarette or water pipe use associated with stopping breastfeeding? Evidence from the Jordan population and family health surveys 2012 and 2017-18

Background

Maternal smoking is suspected to have negative impacts on breastfeeding, such as decreasing the quantity of breast milk, and reducing vitamin and fat concentrations in the milk in the late lactation period. Cigarette and water pipe tobacco products are widely used in Jordan. We aimed to estimate the association between use of different tobacco products and the rates of current breastfeeding.

Methods

Data from Jordan’s Population and Family Health Surveys 2012 and 2017–18 were examined. Last-born, living children, aged < 25 months, from singleton births, ever breastfed, and living with their mother were included. The key outcome variables were the current breastfeeding (during last 24 h) and tobacco usage status [water pipe tobacco (hookah or narghile) and/or cigarette tobacco]. Complex sample multivariate logistic regression analysis was used to evaluate the association of the current breastfeeding with maternal smoking status.

Results

Overall, 6726 infants were included in the study. The current breastfeeding rate in infants aged 0–6 months was 87%, compared with 43.9% in infants aged 12–17 months and 19.4% in infants aged 18–24 months. Overall, 4.4% had mothers who smoked cigarettes, 5.4% smoked water pipe, and 1.6% both cigarettes and water pipe. The proportion of breastfed infants in non-smoking mothers was 57.7% and, those in smoke water pipe, cigarette and both tobacco products were 55.4, 44.9, and 51.0% respectively. Univariate analysis revealed that women cigarette smokers had a lower odds ratio (OR) for current breastfeeding (OR 0.60, 95% Confidence Interval [CI] 0.39, 0.92). Multivariate analysis revealed that maternal cigarette smoking was associated with a lower odds ratio for current breastfeeding compared with mothers who smoked neither water pipe nor cigarettes (AOR 0.51, 95% Cl 0.30, 0.87).

Conclusions

These results indicate that maternal smoking is associated with termination of breastfeeding, suggesting that structured training should be organized for healthcare professionals, expectant mothers and the general public about the association between maternal smoking and cessation of lactation.

Tobacco Metabolites and Caffeine in Human Milk Purchased via the Internet

BACKGROUND

Chemicals inhaled or ingested by mothers can be present in their milk. Our objective was to determine levels of nicotine, cotinine, and caffeine in human milk purchased via the Internet.

MATERIALS AND METHODS

We purchased human milk (n=102) via the Internet and abstracted seller advertisements for information volunteered about tobacco and caffeine use. Nicotine, cotinine, and caffeine levels in the milk were quantified by mass spectrometry according to published protocols.

RESULTS

No sellers indicated smoking in their advertisement. Many of the milk samples (58%) had detectable nicotine or cotinine; four (4%) of the samples had nicotine or cotinine levels high enough to indicate active smoking. Twelve (12%) sellers said in their advertisements that they specifically limit (4%) or avoid (8%) caffeine entirely. Five (5%) of the samples had caffeine levels consistent with consuming at least 1 cup of coffee 2 hours prior to milk expression. Detectable amounts of caffeine were found in almost all of the samples (97%).

CONCLUSIONS

In 102 milk samples, we detected evidence of active smoking, secondhand smoke exposure, and almost ubiquitous caffeine consumption. Buyers of human milk on the Internet should be aware that advertisements do not always include accurate information as to what substances may be present. Sellers may misrepresent their health behaviors or be unaware of lifestyle factors that can lead to exposure to nicotine and caffeine.

Brief intervention to preteens and adolescents to create smoke-free homes and cotinine results: a randomized trial

BACKGROUND

Little research has focused on brief and practical strategies for addressing environmental tobacco smoke exposure through interventions focused explicitly on creating a smoke-free home.

METHODS

We used a two-group (intervention and control groups) repeated-measures randomized controlled trial design. Families were randomized to the intervention (n = 176) or control (n = 176) condition after the baseline interview, with outcome assessments for reported and urine cotinine measures at 2 (post-intervention), 6 (follow-up) and 12 (follow-up) months.

RESULTS

Baseline urinary cotinine levels of both groups were not statistically significantly different (P > 0.05); however, post-intervention urinary cotinine levels were significantly different at 2, 6 and 12 months after start of the study (P < 0.001).

CONCLUSION

As a physician-based brief intervention, our intervention was effective. Clinical providers might offer feedback and brief interventions to preteens and adolescents. Because of the ease of intervention on delivery, this intervention has the potential to have significant impact if widely disseminated.

Obesity and endocrine dysfunction programmed by maternal smoking in pregnancy and lactation

Obesity is a global epidemic, and maternal smoking has been shown to be associated with the development of childhood obesity. Overall, approximately 40% of children worldwide are exposed to tobacco smoke at home. It is well known that environmental changes within a critical window of development, such as gestation or lactation, can initiate permanent alterations in metabolism that lead to diseases in adulthood, a phenomenon called programming. It is known that programming is based on epigenetic alterations (changes in DNA methylation, histone acetylation, or small interfering RNA expression) that change the expression pattern of several genes. However, little is known concerning the mechanisms by which smoke exposure in neonatal life programs the adipose tissue and endocrine function. Here, we review several epidemiological and experimental studies that confirm the association between maternal nicotine or tobacco exposure during gestation or lactation and the development of obesity and endocrine dysfunction. For example, a positive correlation was demonstrated in rodents between increased serum leptin in the neonatal period and exposure of the mothers to nicotine during lactation, and the further development of leptin and insulin resistance, and thyroid and adrenal dysfunction, in adulthood in the same offspring. Thus, a smoke-free environment during the lactation period is essential to improving health outcomes in adulthood and reducing the risk for future diseases. An understanding of the pathophysiological mechanisms underlying the effects of smoking on programming can provide new insights into therapeutic strategies for obesity.

Maternal periconceptional exposure to cigarette smoking and alcohol consumption and congenital diaphragmatic hernia

BACKGROUND

Congenital diaphragmatic hernia (CDH) is a major birth defect that occurs when abdominal organs herniate through a diaphragmatic opening into the thoracic cavity and is associated with high mortality (>50%). The etiology of CDH is not well understood.

METHODS

Using data from the National Birth Defects Prevention Study, we examined associations between CDH and maternal periconceptional exposure (1 month before through the third month of pregnancy) to cigarette smoking and alcohol. Interview reports of exposures were provided by mothers of CDH (n = 503) and unaffected control (n = 6703) infants delivered from October 1997 through December 2005. Any exposure (yes/no), as well as quantity (average number of cigarettes or drinks), type (active/passive smoking; beer, wine, distilled spirits), and duration (e.g., number of months exposed) were examined. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated for all CDH cases combined, selected subtypes (Bochdalek, Morgagni, not otherwise specified), and phenotypes (infants with/without additional major birth defects).

RESULTS

The aOR for any smoking was nonsignificantly elevated for all CDH cases combined. Odds of any smoking was significant for isolated Bochdalek CDH (aOR, 1.9; 95% CI, 1.2-3.0). The aORs associated with all measures of alcohol consumption were near unity for each CDH category examined. Stratification of smoking exposure by alcohol consumption and stratification of alcohol consumption by smoking exposure did not appreciably change the aORs.

CONCLUSIONS

These findings identified periconceptional smoking exposure as a potential risk factor for CDH. Future studies need to confirm our findings and explore possible pathways accounting for the teratogenic effect of smoking.