Smoking prevalence among U.S. national samples of pregnant women

Prevalence of Cigarette Smoking, E-cigarette Use, and Dual Use Among Urban and Rural Women During the Peripartum Period, PRAMS 2015-2020

OBJECTIVES

Evidence has emerged on the health dangers of electronic cigarette (e-cigarette) use among pregnant women and neonates. We examined whether rural residence is a risk factor for smoking and e-cigarette use among women during the peripartum period in the United States.

METHODS

This study was based on pooled cross-sectional 2015-2020 data from the Pregnancy Risk Assessment Monitoring System. The outcome was exclusive smoking, exclusive e-cigarette use, and use of both products (ie, dual use) versus use of neither tobacco product by women with live infants aged 2 to 6 months. We examined rural-urban differences in outcome by using univariate and multivariable multinomial logistic regressions with post hoc contrasts and marginal analyses, adjusting for complex survey design and nonresponse.

RESULTS

During the peripartum period, 5.0% of women were smoking combustible cigarettes, 5.0% were using e-cigarettes, and 1.9% were using both tobacco products. The crude prevalence of e-cigarette use was 1.1 percentage point higher, and the adjusted prevalence was 0.8 percentage points lower for rural versus urban women (P < .001 for both). Among rural women, 6.7% (95% CI, 6.3%-7.1%) smoked combustible cigarettes exclusively and 2.6% (95% CI, 2.3%-2.8%) used both products, as compared with 4.5% (95% CI, 4.4%-4.8%) and 1.7% (95% CI, 1.6%-1.8%) of urban women, respectively, adjusting for sociodemographic and health-related characteristics.

CONCLUSIONS

Maternal sociodemographic and health-related characteristics differed by combustible smoking versus e-cigarette use during the peripartum period. The effect of residence on e-cigarette use was significantly confounded by sociodemographic and health-related characteristics, resulting in clinically comparable prevalence of e-cigarette use in rural and urban mothers with live infants aged 2 to 6 months.

Trends in Smoking Before, During, and After Pregnancy in the United States from 2000 to 2020: Pregnancy Risk Assessment Monitoring System

Objectives: This study used 2000-2020 Pregnancy Risk Assessment Monitoring System data to estimate trends in smoking before, during, and after pregnancy, as well as quitting smoking during pregnancy. Materials and Methods: Weighted prevalence and 95% confidence intervals (CIs) were calculated by year for each smoking-related measure. Annual percent change (APC) and average annual percent change (AAPC) in prevalence were estimated using Joinpoint regression to characterize trends over time. Results: Between 2000 and 2020, significant decreases in the prevalence of smoking before (23.0% to 14.0%; AAPC = -2.3% [95% CI = -2.9% to -1.7%]), during (13.2% to 6.5%; AAPC = -3.4% [95% CI = -4.0% to -2.7%]), and after pregnancy (18.9% to 8.8%; AAPC = -3.6% [95% CI = -4.3% to -2.9%]) were observed. For each measure, the fastest declines occurred largely throughout the 2010s (before: APC = -5.5% [2012-2020]; during: APC = -5.1% [2009-2020]; and after: APC = -6.4% [2012-2020]). The proportion of people who quit smoking during pregnancy significantly increased from 43.2% in 2000 to 53.7% in 2020 (AAPC = 1.0%; 95% CI = 0.2%-1.9%); however, Joinpoint regression detected relatively no change in quitting during pregnancy between 2010 and 2020 (APC = 0.0%; 95% CI = -0.4% to 0.5%). Conclusions: The prevalence of smoking before, during, and after pregnancy has reduced dramatically in the United States between 2000 and 2020, with the fastest declines occurring throughout the second decade of the twenty-first century. However, prevention and cessation efforts are still needed since approximately half of people who smoked before pregnancy continue to smoke during pregnancy.

Addressing the smoking-hypertension paradox in pregnancy: insight from a multiethnic US birth cohort

Background

Smoking during pregnancy has been associated with reduced risk of a spectrum of hypertensive (HTN) disorders, known as the "smoking-hypertension paradox."

Objective

We sought to test potential epidemiologic explanations for the smoking-hypertension paradox.

Methods

We analyzed 8510 pregnant people in the Boston Birth Cohort, including 4027 non-Hispanic Black and 2428 Hispanic pregnancies. Study participants self-reported tobacco, alcohol, cannabis, opioids, or cocaine use during pregnancy. We used logistic regression to assess effect modification by race/ethnicity, and confounding of concurrent substances on hypertensive disorders or prior pregnancy. We also investigated early gestational age as a collider or competing risk for pre-eclampsia, using cause-specific Cox models and Fine-Gray models, respectively.

Results

We replicated the paradox showing smoking to be protective against hypertensive disorders among Black participants who used other substances as well (aOR: 0.61, 95% CI: 0.41, 0.93), but observed null effects for Hispanic participants (aOR: 1.14, 95% CI: 0.55, 2.36). In our cause-specific Cox regression, the effects of tobacco use were reduced to null effects with pre-eclampsia (aOR: 0.81, 95% CI: 0.63, 1.04) after stratifying for preterm birth. For the Fine-Gray competing risk analysis, the paradoxical associations remained. The smoking paradox was either not observed or reversed after accounting for race/ethnicity, other substance use, and collider-stratification due to preterm birth.

Conclusions

These findings offer new insights into this paradox and underscore the importance of considering multiple sources of bias in assessing the smoking-hypertension association in pregnancy.

Effect of Vitamin C Supplementation for Pregnant Smokers on Offspring Airway Function and Wheeze at Age 5 Years: Follow-up of a Randomized Clinical Trial

Importance

Vitamin C supplementation (500 mg/d) for pregnant smokers has been reported to increase offspring airway function as measured by forced expiratory flow (FEF) through age 12 months; however, its effects on airway function at age 5 years remain to be assessed.

Objective

To assess whether vitamin C supplementation in pregnant smokers is associated with increased and/or improved airway function in their offspring at age 5 years and whether vitamin C decreases the occurrence of wheeze.

Design, Setting, and Participants

This study followed up the Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function (VCSIP) double-blind, placebo-controlled randomized clinical trial conducted at 3 centers in the US (in Oregon, Washington, and Indiana) between 2012 and 2016. Investigators and participants remain unaware of the treatment assignments. Forced expiratory flow measurements at age 5 years were completed from 2018 to 2021.

Interventions

Pregnant smokers were randomized to vitamin C (500 mg/d) or placebo treatment.

Main Outcomes and Measures

The primary outcome was the prespecified measurement of FEF between 25% and 75% expired volume (FEF25-75) by spirometry at age 5 years. Secondary outcomes included FEF measurements at 50% and 75% of expiration (FEF50 and FEF75), forced expiratory volume in 1 second (FEV1), and occurrence of wheeze.

Results

Of the 251 pregnant smokers included in this study, 125 (49.8%) were randomized to vitamin C and 126 (50.2%) were randomized to placebo. Of 213 children from the VCSIP trial who were reconsented into this follow-up study, 192 (90.1%) had successful FEF measurements at age 5 years; 212 (99.5%) were included in the analysis of wheeze. Analysis of covariance demonstrated that offspring of pregnant smokers allocated to vitamin C compared with placebo had 17.2% significantly higher mean (SE) measurements of FEF25-75 at age 5 years (1.45 [0.04] vs 1.24 [0.04] L/s; adjusted mean difference, 0.21 [95% CI, 0.13-0.30]; P < .001). Mean (SE) measurements were also significantly increased by 14.1% for FEF50 (1.59 [0.04] vs 1.39 [0.04] L/s; adjusted mean difference, 0.20 [95% CI, 0.11-0.30]; P < .001), 25.9% for FEF75 (0.79 [0.02] vs 0.63 [0.02] L/s; 0.16 [95% CI, 0.11-0.22]; P < .001), and 4.4% for FEV1 (1.13 [0.02] vs 1.09 [0.02] L; 0.05 [95% CI, 0.01-0.09]; P = .02). In addition, offspring of pregnant smokers randomized to vitamin C had significantly decreased wheeze (28.3% vs 47.2%; estimated odds ratio, 0.41 [95% CI, 0.23-0.74]; P = .003).

Conclusions and Relevance

In this follow-up study of offspring of pregnant smokers randomized to vitamin C vs placebo, vitamin C supplementation during pregnancy resulted in significantly increased airway function of offspring at age 5 years and significantly decreased the occurrence of wheeze. These findings suggest that vitamin C supplementation for pregnant smokers may decrease the effects of smoking in pregnancy on childhood airway function and respiratory health.

Trial Registration

ClinicalTrials.gov Identifier: NCT03203603.

Patterns and Trends in Use of Electronic Nicotine Delivery Systems Before and During Pregnancy: Pregnancy Risk Assessment Monitoring System, United States, 2016-2019

INTRODUCTION

This study used 2016-2019 Pregnancy Risk Assessment Monitoring System data to estimate prevalence of electronic nicotine delivery system (ENDS) use around pregnancy, changes in ENDS use and cigarette smoking from before to during pregnancy, and trends in these behaviors over time.

METHODS

ENDS and cigarette use during the 3 months before and the last three months of pregnancy were measured. Weighted prevalence estimates and 95% confidence intervals were estimated for outcomes overall and ENDS use by maternal characteristic for 2016-2019; logistic regression tested for differences in ENDS use by maternal characteristic and for linear trends in ENDS and cigarette use before and during pregnancy. Analyses were completed in 2021.

RESULTS

In 2019, 4.3% (N = 98,050) of women used ENDS before and 1.3% (N = 28,811) used ENDS during pregnancy. Most exclusive ENDS users (82.2%) and exclusive cigarette smokers (55.0%) stopped use during pregnancy. Among dual users, 46.3% stopped use during pregnancy while 20.2% continued dual use and 24.9% smoked cigarettes exclusively. Few dual users (8.6%) and exclusive cigarette smokers (0.5%) reported using ENDS exclusively during pregnancy. From 2016-2019, exclusive ENDS use increased and exclusive cigarette smoking decreased both before and during pregnancy.

CONCLUSIONS

ENDS use during pregnancy is low but increased since 2016. Less than one-half of dual ENDS and cigarettes users quit during pregnancy; few dual users or exclusive cigarette smokers switched to exclusive ENDS use during pregnancy. Continued surveillance of ENDS and other tobacco use during pregnancy is critical to inform public health activities that protect maternal and child health.

Maternal Smoking and Congenital Heart Defects, National Birth Defects Prevention Study, 1997-2011

OBJECTIVES

To assess associations between maternal smoking and congenital heart defects (CHDs) in offspring.

STUDY DESIGN

We performed a retrospective case-control study using data for cases of CHD (n = 8339) and nonmalformed controls (n = 11 020) from all years (1997-2011) of the National Birth Defects Prevention Study. Maternal self-reported smoking 1 month before through 3 months after conception was evaluated as a binary (none, any) and categorical (light, medium, heavy) exposure. Multivariable logistic regression was used to estimate aOR and 95% CIs. Stratified analyses were performed for septal defects according to maternal age, prepregnancy body mass index, and maternal race/ethnicity.

RESULTS

Multiple CHDs displayed modest associations with any level of maternal periconceptional smoking independent of potential confounders; the strongest associations were for aggregated septal defects (OR, 1.5; 95% CI, 1.3-1.7), tricuspid atresia (OR, 1.7; 95% CI, 1.0-2.7), and double outlet right ventricle (DORV) (OR, 1.5; 95% CI, 1.1-2.1). Tricuspid atresia and DORV also displayed dose-response relationships. Among heavy smokers, the highest odds were again observed for tricuspid atresia (aOR 3.0; 95% CI, 1.5-6.1) and DORV (aOR 1.5; 95% CI, 1.1-2.2). Heavy smokers ≥35 years old more frequently had a child with a septal defect when compared with similarly aged nonsmokers (aOR 2.3; 95% CI, 1.4-3.9).

CONCLUSIONS

Maternal periconceptional smoking is most strongly associated with septal defects, tricuspid atresia, and DORV; the risk for septal defects is modified by maternal age.

Smoking status: A tacit screen for postpartum depression in primary care settings

BACKGROUND

Universal screening for postpartum depression (PPD) remains an unachieved national priority. A tacit screen that requires no additional resources for administration can help to achieve this priority. We examine the predictive utility of using smoking as a tacit screen for PDD. We first establish smoking is a valid proxy for more prominent psychosocial determinants of PPD and is a predictor for PPD.

METHODS

We analyzed PRAMS data (2012-2015; N=134,435). Time of smoking was categorized as nonsmoker, during the prenatal period, the postpartum, or continuously; PPD was assessed using two PHQ-2 style questions.

RESULTS

Compared to nonsmokers, women who smoked only during the prenatal period (OR: 1.41; 95% CI: 1.06 - 1.86), only during the postpartum (OR: 1.33; 95% CI: 1.18 - 1.49), and continuously throughout both periods (OR: 1.54; 95% CI: 1.41 - 1.69) were more likely to experience PPD. Smoking assessed at a prenatal visit (SN: 0.90, SP: 0.21), postpartum visit (SN: 0.86, SP: 0.25), or assessed at both visits (SN: 0.90, SP: 0.19) performed relatively well as a tacit screen for PPD, performing better among unmarried women (SN: 0.75 - 0.81; SP: 0.29 - 0.36).

LIMITATIONS

In this study, the criterion of positivity used was PRAMS' adapted version of the PHQ-2. This tacit screen may perform differently relative to a clinical diagnosis.

CONCLUSIONS

Time of smoking predicts risk of PPD and can be used to tacitly screen for PPD with reasonable accuracy without requiring any additional time in settings with limited resources for routine screening of PPD.

An examination of how e-cigarette/cigarette use during adolescence is associated with future use during the third trimester of pregnancy

Background: Adolescent e-cigarette use has increased, as has e-cigarette use during pregnancy, yet little is known about how these types of tobacco/nicotine (cigarettes/e-cigarettes) use during adolescence are associated with tobacco/nicotine use during the third trimester of pregnancy among young adults. Methods: National longitudinal data (2013-2018) from the Population Assessment of Tobacco and Health (PATH) study were used. Young adults ages 18-20 who indicated past-year pregnancy made up the analytic sample (N = 246). Logistic regression was used to evaluate the association between history of past 30-day use of cigarettes/e-cigarettes during adolescence (i.e., 14-17) and later use during the third trimester of pregnancy among young women (i.e., 18-20). Results: Within the sample of young women who indicated a pregnancy during the past year, 18.9% indicated smoking cigarettes and 4.2% indicated using e-cigarettes during their last trimester. Cigarette smoking in adolescence (wave 1 or 2) was associated with cigarette use during the last trimester (aOR = 4.76, 95% CI = 1.36, 16.6); however, e-cigarette use during adolescence was not associated with either cigarette or e-cigarette use during the third trimester of pregnancy. Conclusions: Tobacco/nicotine prevention in early adolescence has implications for preventing tobacco/nicotine-related harms during pregnancy among young adults. Intervention programs and clinicians informed about various types of tobacco/nicotine are needed to address tobacco/nicotine cessation among adolescents to prevent consequences of tobacco/nicotine use during pregnancy.

Smartphone-based financial incentives to promote smoking cessation during pregnancy: A pilot study

Cigarette smoking during pregnancy increases risk for pregnancy complications, growth restriction, and other adverse health outcomes. The most effective intervention for reducing smoking during pregnancy is financial incentives contingent on biochemically-verified smoking abstinence. The present study examined the efficacy of a smartphone-based intervention whereby smoking monitoring and incentive delivery occurred remotely using a mobile app. If efficacious, this remote intervention would allow pregnant women residing in geographically remote areas to benefit from incentives-based cessation interventions. Sixty U.S. pregnant smokers were recruited between May 2018 to May 2019 via obstetrical clinics, Women, Infants, and Children (WIC) offices, and Facebook. Participants were assigned sequentially to one of two treatments: best practices alone (N = 30) or best practices plus financial incentives (N = 30). Outcomes were analyzed using repeated measures analysis based on generalized estimating equations (GEE). Seven-day point prevalence abstinence rates were greater in the incentives versus best practices arms early- (46.7% vs 20.0%, OR = 3.50, 95%CI = 1.11,11.02) and late-antepartum (36.7% vs 13.3%, OR = 3.76, 95%CI = 1.04,13.65), and four- (36.7% vs 10.0%, OR = 5.21, 95%CI = 1.28,21.24) and eight-weeks postpartum (40.0% vs 6.7%, OR = 9.33, 95%CI = 1.87,46.68), although not at the 12- (23.3% vs 10.0%, OR = 2.74, 95%CI = 0.63,11.82) or 24-week (20.0% vs 6.7%, OR = 3.50, 95%CI = 0.65,18.98) postpartum assessments likely due to this pilot study being underpowered for discerning differences at the later assessments, especially 24-weeks postpartum which was three months after treatment completion. These results support the efficacy of this remote, incentives-based intervention for pregnant smokers. Further research evaluating its efficacy and cost-effectiveness in a well-powered, randomized controlled trial appears warranted.

Decreasing smoking during pregnancy: Potential economic benefit of reducing sudden unexpected infant death

Sudden Unexpected Infant Death (SUID) remains the leading cause of death among U.S. infants age 1-12 months. Extensive epidemiological evidence documents maternal prenatal cigarette smoking as a major risk factor for SUID, but leaves unclear whether quitting reduces risk. This Commentary draws attention to a report by Anderson et al. (Pediatrics. 2019, 143[4]) that represents a breakthrough on this question and uses their data on SUID risk reduction to delineate potential economic benefits. Using a five-year (2007-11) U.S. CDC Birth Cohort Linked Birth/Infant Death dataset, Anderson et al. demonstrated that compared to those who continued smoking, women who quit or reduced smoking by third trimester decreased the adjusted odds of SUID risk by 23% (95% CI, 13%-33%) and 12% (95% CI, 2%-21%), respectively. We applied these reductions to the U.S. Department of Health and Human Services' recommended value of a statistical life in 2020 ($10.1 million). Compared to continued smoking during pregnancy, the economic benefits per woman of quitting or reducing smoking are $4700 (95% CI $2700-$6800) and $2500 (95% CI, $400-$4300), respectively. While the U.S. obtained aggregate annual economic benefits of $0.58 (95% CI, 0.35-0.82) billion from pregnant women who quit or reduced smoking, it missed an additional $1.16 (95%CI 0.71-1.60) billion from the women who continued smoking. Delineating the health and economic impacts of decreasing smoking during pregnancy using large epidemiological studies like Anderson et al. is critically important for conducting meaningful economic analyses of the benefits-costs of developing more effective interventions for decreasing smoking during pregnancy.