Exposure to tobacco smoke and validation of smoking status during pregnancy in the MIREC study

Smoking cessation and relapse-prevention interventions tailored for expectant and new fathers: protocol of a systematic review and network meta-analysis

INTRODUCTION

Exposure of pregnant women and newborns to secondhand smoke (SHS) can lead to adverse maternal and neonatal health outcomes. Among expectant and new fathers, who are the main source of SHS exposure for pregnant women, new mothers and babies, smoking rates remain high. A partner's pregnancy potentially constitutes a critical period where expectant and new fathers are motivated to quit smoking. However, there is no consensus on the optimal form and delivery of smoking cessation and relapse-prevention interventions. We present a systematic review and network meta-analysis protocol that aims to synthesise and evaluate the effectiveness of smoking cessation and relapse-prevention interventions tailored for this population.

METHODS AND ANALYSIS

To identify relevant studies, we will conduct a comprehensive search, in English and Chinese, of 10 electronic databases. The review will include randomised and quasi-randomised controlled trials that compare behavioural interventions (tailored and non-tailored) with/without the addition of pharmacotherapy with usual care, a minimal or placebo control for assisting expectant and new fathers to quit smoking and prevent smoking relapse. The primary outcome of interest is the self-reported and/or biochemically verified smoking abstinence at ≥1-month follow-up. Two reviewers will independently screen, select and extract relevant studies, and perform a quality assessment. Disagreements will be resolved by a consensus or third-party adjudication. The Cochrane Risk of Bias tool V.2 will be used to assess the risk of bias in the included studies. We will obtain the results of the systematic review through pooled quantitative analyses using a network meta-analysis. Sensitivity and subgroup analyses will be performed.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review of published data. The findings will be disseminated via peer-reviewed publication.

PROSPERO REGISTRATION NUMBER

CRD42022340617.

Effects of Maternal Cigarette Smoking on Trace Element Levels and Steroidogenesis in the Maternal-Placental-Fetal Unit

This study evaluates the interaction of toxic elements cadmium (Cd) and lead (Pb) due to exposure from cigarette smoking, essential elements, and steroidogenesis in the maternal-placental-fetal unit. In a cohort of 155 healthy, postpartum women with vaginal term deliveries in clinical hospitals in Zagreb, Croatia, samples of maternal blood/serum and urine, placental tissue, and umbilical cord blood/serum were collected at childbirth. The biomarkers determined were concentrations of Cd, Pb, iron (Fe), zinc (Zn), copper (Cu), and selenium (Se), and steroid hormones progesterone and estradiol in maternal and umbilical cord blood and the placenta. Three study groups were designated based on self-reported data on cigarette smoking habits and confirmed by urine cotinine levels: never smokers (n = 71), former smokers (n = 48), and active smokers (n = 36). Metal(loid)s, steroid hormones, urine cotinine, and creatinine levels were analyzed by ICP-MS, ELISA, GC-MS, and spectrophotometry. Cigarette smoking during pregnancy was associated with increased Cd levels in maternal, placental, and fetal compartments, Pb in the placenta, and with decreased Fe in the placenta. In active smokers, decreased progesterone and estradiol concentrations in cord blood serum were found, while sex steroid hormones did not change in either maternal serum or placenta. This study provides further evidence regarding toxic and essential metal(loid) interactions during prenatal life, and new data on sex steroid disruption in cord serum related to cigarette smoking. The results indicate that umbilical cord sex steroid levels may be a putative early marker of developmental origins of the future burden of disease related to harmful prenatal exposure to cigarette smoke.

Robust tobacco smoking self-report in two cohorts: pregnant women or men and women living with or without HIV

Understanding the true burden of tobacco smoking on adverse pregnancy outcomes is critical in generating appropriate interventions to improve outcomes. Self-reporting of human behaviour that is associated with stigma is associated with underreporting in general and may bias the impact of smoking in studies; however, self-reporting is frequently the most practical method of gleaning this information. The objective of this study was to evaluate concordance between self-reported smoking and concentrations of plasma cotinine, a biomarker of smoking, among participants enrolled in two related HIV cohorts. A total of 100 pregnant women (76 living with HIV [LWH] and 24 negative controls) in their third trimester, and 100 men and non-pregnant women (43 LWH and 57 negative controls) were included. Among all participants, 43 pregnant women (49% LWH and 25% negative controls) and 50 men and non-pregnant women (58% LWH and 44% negative controls) were self-reported smokers. The odds of discordance between self-reported smoking and cotinine levels were not significantly different between self-reported smokers and non-smokers, nor between pregnant women and others, but were significantly increased, regardless of self-reported status, among people LWH compared to negative controls. The overall concordance between plasma cotinine and self-reported data among all participants was 94% with a sensitivity and specificity of 90% and 96%, respectively. Taken together, these data demonstrate that participant surveying in a non-judgemental context can lead to accurate and robust self-report smoking data among both persons LWH and not, including in the context of pregnancy.

Individual, Independent, and Joint Associations of Toxic Metals and Manganese on Hypertensive Disorders of Pregnancy: Results from the MIREC Canadian Pregnancy Cohort

BACKGROUND

Toxic metals, such as lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg), may be associated with a higher risk of gestational hypertension and preeclampsia, whereas manganese (Mn) is an essential metal that may be protective.

OBJECTIVES

We estimated the individual, independent, and joint associations of Pb, Cd, As, Hg, and Mn on the risk of developing gestational hypertension and preeclampsia in a cohort of Canadian women.

METHODS

Metal concentrations were analyzed in first and third trimester maternal blood (n=1,560). We measured blood pressure after 20 wk gestation to diagnose gestational hypertension, whereas proteinuria and other complications defined preeclampsia. We estimated individual and independent (adjusted for coexposure) relative risks (RRs) for each doubling of metal concentrations and examined interactions between toxic metals and Mn. We used quantile g-computation to estimate the joint effect of trimester-specific exposures.

RESULTS

Each doubling of third trimester Pb (RR=1.54; 95% CI: 1.06, 2.22) and first trimester blood As (RR=1.25; 95% CI: 1.01, 1.58) was independently associated with a higher risk of developing preeclampsia. First trimester blood As (RR=3.40; 95% CI: 1.40, 8.28) and Mn (RR=0.63; 95% CI: 0.42, 0.94) concentrations were associated with a higher and lower risk, respectively, of developing gestational hypertension. Mn modified the association with As such that the deleterious association with As was stronger at lower concentrations of Mn. First trimester urinary dimethylarsinic acid concentrations were not associated with gestational hypertension (RR=1.31; 95% CI: 0.60, 2.85) or preeclampsia (RR=0.92; 95% CI: 0.68, 1.24). We did not observe overall joint effects for blood metals.

DISCUSSION

Our results confirm that even low blood Pb concentrations are a risk factor for preeclampsia. Women with higher blood As concentrations combined with lower Mn in early pregnancy were more likely to develop gestational hypertension. These pregnancy complications impact maternal and neonatal health. Understanding the contribution of toxic metals and Mn is of public health importance. https://doi.org/10.1289/EHP10825.

Secondhand smoke exposure is associated with the risk of hypertensive disorders of pregnancy: the Japan Environment and Children's Study

Hypertensive disorders of pregnancy (HDP) are associated with poor maternal and neonatal prognoses. Although several studies have indicated an effect of secondhand smoke (SHS) exposure on HDP, such evidence is lacking in Japan. Therefore, we analyzed data from the Japan Environment and Children's Study, a large-scale epidemiological investigation, to elucidate a possible link between SHS exposure and HDP risk. Data were obtained from the all-birth fixed datasets and included information on 104,062 fetuses and their parents. SHS exposure was assessed in terms of the frequency (rarely, 1-3, or 4-7 days/week) and the daily duration of exposure (<1, 1-2, or ≥2 h(s)/day). Modified Poisson regression model analyses were performed with adjustment for known risk factors for HDP. Additionally, the population attributable fractions (PAFs) of SHS exposure and maternal smoking to HDP prevalence were estimated. The relative risks of developing HDP among individuals with SHS exposures of 4-7 days/week and ≥2 h/day were 1.18 and 1.27 (95% confidence interval: 1.02-1.36 and 0.96-1.67), respectively, compared to the reference groups (rare exposure and <1 h/day). The PAFs for the risk of HDP due to SHS exposure and perinatal smoking were 3.8% and 1.8%, respectively. Japanese women with greater exposure to SHS have a higher risk of HDP after adjustment for possible confounding factors; thus, relevant measures are required to reduce SHS exposure to alleviate HDP risk. The association between second-hand smoking exposure and hypertensive disorders of pregnancy risk was analyzed using the JECS data. The relative risks in 4-7 days/week and ≥2 h/day of SHS exposures were 1.18 and 1.27, respectively. The PAFs due to SHS exposure and maternal smoking were 3.80% and 1.81%, respectively.

Maternal Folate Status and the Relation between Gestational Arsenic Exposure and Child Health Outcomes

Gestational arsenic exposure adversely impacts child health. Folate-mediated 1-carbon metabolism facilitates urinary excretion of arsenic and may prevent arsenic-related adverse health outcomes. We investigated the potential for maternal folate status to modify associations between gestational arsenic exposure and child health. We used data from 364 mother-child pairs in the MIREC study, a prospective pan-Canadian cohort. During pregnancy, we measured first trimester urinary arsenic concentrations, plasma folate biomarkers, and folic acid supplementation intake. At age 3 years, we evaluated twelve neurodevelopmental and anthropometric features. Using latent profile analysis and multinomial regression, we developed phenotypic profiles of child health, estimated covariate-adjusted associations between arsenic and these phenotypic profiles, and evaluated whether folate status modified these associations. We identified three phenotypic profiles of neurodevelopment and three of anthropometry, ranging from less to more optimal child health. Gestational arsenic was associated with decreased odds of optimal neurodevelopment. Maternal folate status did not modify associations of arsenic with neurodevelopmental phenotypic profiles, but gestational arsenic was associated with increased odds of excess adiposity among those who exceed recommendations for folic acid (>1000 μg/day). However, arsenic exposure was low and folate status was high. Gestational arsenic exposure may adversely impact child neurodevelopment and anthropometry, and maternal folate status may not modify these associations; however, future work should examine these associations in more arsenic-exposed or lower folate-status populations.

The effect of health education on second-hand smoke knowledge and exposure among pregnant women in Jordan: A quasi-experimental study

Second-Hand Smoke (SHS) is a significant health issue. For non-smoker pregnant women, SHS exposure can lead to harmful consequences on the fetus. This study aimed to examine the effectiveness of a health education program in decreasing SHS exposure and increasing pregnant women's knowledge of its harmful effects. A quasi-experimental (pretest-posttest control group) design and the second-hand exposure questionnaire (SS-A) were used. A convenience sample of 136 pregnant Jordanian women from the antenatal clinic was recruited and assigned to an intervention group (n = 70) and a control group (n = 66). The intervention group received a health education program, while the control group received the usual antenatal care. The data were collected from October to December 2018. The results revealed that the highest exposure to SHS was in the home setting, with an average of 8.7 ± 2.21 hours daily for both groups. After the educational program, there were significantly lower scores of exposure and a higher score of knowledge in the intervention group, compared to the control group (p < 0.001). There was also a significant decrease in the scores of exposure and a significant increase in the score of knowledge of the intervention group from pretest to posttest (p < 0.001). The study provides evidence about the importance of a program to educate pregnant women about the negative impact of SHS. Nurses need to assess SHS exposure and provide health education for pregnant women.

Predictors of Secondhand Smoke Exposure During Pregnancy in Costa Rica, the Dominican Republic, and Honduras

INTRODUCTION

Secondhand smoke (SHS) exposure poses risks to pregnant women and children. Though smoking among pregnant women in many low- and middle-income countries is low, exposure to SHS might be higher. We examined the prevalence and predictors of SHS among pregnant women from Costa Rica, the Dominican Republic, and Honduras.

METHODS

Postpartum women 18+ years old who completed pregnancy in past 5 years were surveyed in health care and community settings.

RESULTS

Data for 1,081 women indicated low tobacco use (1.0%-3.7%), frequent exposure to active smokers (29.0%-34.0%), often being close enough to breathe others' smoke (49.4%-66.5%), and most having smoke-free home policies (70.8%-76.2%). Women reporting unintended pregnancy (adjusted odds ratio [aOR]: 1.44, 95% confidence interval [CI] 1.03, 2.00) and alcohol consumption (aOR: 1.92, 95% CI 1.34, 2.77) were more likely to be close enough to breathe others' smoke. Women with health problems during pregnancy (aOR: 1.48 95% CI 1.07, 2.06) were more likely to have home smoking policies. Tobacco use was associated with all SHS exposure outcomes.

CONCLUSIONS

SHS exposure was high during pregnancy; women with higher risk variables, that is, tobacco use, alcohol consumption, and unintended pregnancy were more likely to be exposed. Addressing SHS exposure in pregnancy in low- and middle-income countries can improve maternal health outcomes in vulnerable populations.

IMPLICATIONS

The study results suggest a cluster of multiple risk factors associated with a high prevalence of exposure to SHS among pregnant women in LIMCs from Latin America and Caribbean Region. Interventions, regulations, and policies need to address specific high-risk factors to change behaviors and improve maternal and child health outcomes especially in vulnerable populations.

The Association Between Second-hand Smoke Exposure and Psychiatric Distress Among Naturally Pregnant Women and Pregnant Women After Assisted Reproductive Technology Treatment: a Birth Cohort Study

Second-hand smoke (SHS) has been shown to be associated with psychiatric distress in pregnant women spontaneously conceived (SC), but this has never been investigated in pregnant women with assisted reproductive technology (ART) treatment. This study aimed to investigate and compare the associations of SHS with psychiatric distress among SC and ART pregnant women. Participants (1467 SC and 857 ART women) were from the sub-study of Chinese National Birth Cohort (CNBC) in Anhui Province. SHS was assessed by the self-reported questionnaire. The symptoms of depression, anxiety, stress, and poor sleep quality were assessed using CES-D, SAS, CPSS, and PSQI questionnaire. Multivariable linear regression was used to determine the association between SHS and psychiatric distress in each trimester. In SC women, SHS (yes or no) was associated with depression and anxiety symptoms in the 3rd trimester (β = 0.90, 95% CI 0.07-1.73 for depression and β = 1.21, 95% CI 0.39-2.04 for anxiety) and stress symptom and poor sleep quality in both the 2nd and 3rd trimesters (β = 0.85, 95% CI 0.20-1.49 in the 2nd trimester and β = 0.69, 95% CI 0.07-1.32 in the 3rd trimester for stress, and β = 1.32, 95% CI 0.68-1.96 in the 2nd trimester and β = 1.38, 95% CI 0.64-2.11 in the 3rd trimester for poor sleep quality). By contrast, in ART women, SHS was associated with depression and stress symptoms in the 1st trimester (β = 1.97, 95% CI 0.59-3.35 for depression and β = 1.18, 95% CI 0.24-2.12 for stress) and poor sleep quality throughout the pregnancy (β = 0.64, 95% CI 0.22-1.06 in the 1st trimester, β = 0.77, 95% CI 0.35-1.18 in the 2nd trimester, and β = 0.99, 95% CI 0.50-1.48 in the 3rd trimester, respectively). Our findings indicate a universal and detrimental effect of SHS on psychiatric health among both SC and ART pregnant women. However, the SHS impact may be more substantial at the early stage of pregnancy for ART women and at later stages for SC women. This implies the importance of reducing SHS exposure during pregnancy and the necessary to be aware of the difference in the effect of SHS on psychiatric distress between SC and ART women.

Perinatal smoking exposure and risk of asthma in the first three years of life: A prospective prebirth cohort study

BACKGROUND

There is limited evidence on the association between prenatal smoking exposure and the risk of asthma in children. The aim of this prebirth cohort study was to investigate the association between prenatal and postnatal tobacco smoke exposure and the risk of asthma in Japanese children.

METHODS

Study subjects were 1304 mother-child pairs. Information on the variables under study was obtained using repeated questionnaires that were completed by mothers, first prior to delivery, then shortly after birth and subsequently around 4, 12, 24, and 36 months after delivery. Ever asthma was defined as a maternal report of physician-diagnosed asthma at any time since birth. Current asthma was defined as the use of asthma medication at the time of the sixth survey.

RESULTS

Logistic regression models revealed that maternal active smoking, either before pregnancy or during pregnancy, was not associated with the risk of ever asthma or current asthma. Further, no association was observed between postnatally living with at least one household smoker and the risk of asthma. Among children whose mothers are never smokers, maternal second-hand smoke (SHS) exposure at work and/or at home during pregnancy increased the risk of ever asthma and current asthma in children; adjusted odds ratio (95% confidence intervals) for ever asthma and current asthma were 2.41 (1.13-5.05) and 4.82 (1.68-13.43), respectively.

CONCLUSIONS

Our findings suggest that maternal SHS exposure during pregnancy might be associated with an increased risk of ever asthma and current asthma in young children whose mothers have never smoked.

Determination of Urinary Cotinine Cut-Off Concentrations for Pregnant Women in the Japan Environment and Children's Study (JECS)

Few studies have assessed the accuracy of self-reported questionnaires to determine smoking habits relative to urinary biomarkers. This study investigated urinary cotinine cut-off concentrations distinguishing active, passive and non-smokers among pregnant women who participated in the Japan Environment and Children's Study, a nationwide birth cohort study. Pregnant participants with measured urinary cotinine concentrations (UCCs) and who completed self-reported questionnaires on smoking status were included (n = 89,895). The cut-off values (COVs) for active and passive smokers were calculated by fitting mixed normal distribution functions to UCCs. The sensitivity and specificity of the questionnaires were subsequently evaluated. The median (interquartile range) UCC was 0.24 (0.083-0.96) µg/g-creatinine, with the detection rate of 89%. The COV for distinguishing active smokers from passive and non-smokers was 36.8 µg/g-creatinine. When this COV was considered to represent the true condition, the questionnaire had a sensitivity of 0.523, a specificity of 0.998, a positive predictive value (PPV) of 0.967 and a negative predictive value (NPV) of 0.957. The COV for distinguishing passive smokers from non-smokers was 0.31 µg/g-creatinine, with the questionnaire having a sensitivity of 0.222, a specificity of 0.977, a PPV of 0.868 and an NPV of 0.644. As many as 78% of passive smokers might be misclassified as non-smokers.