Elevated risk of nicotine dependence among sib-pairs discordant for maternal smoking during pregnancy: evidence from a 40-year longitudinal study

Multigenerational association between smoking and autism spectrum disorder: findings from a nationwide prospective cohort study

Animal studies have shown that exposure to cigarette smoke during pregnancy can induce neurobehavioral anomalies in multiple subsequent generations. However, little work has examined such effects in humans. We examined the risk of grandchild autism spectrum disorder (ASD) in association with grandmother's smoking during pregnancy, using data from 53 562 mothers and grandmothers and 120 267 grandchildren in Nurses' Health Study II. In 1999, Nurses' Health Study II participants with children reported on their mothers' smoking. Grandchildren's ASD diagnoses were reported by the mothers in 2005 and 2009. Among grandmothers, 13 383 (25.0%) smoked during pregnancy, and 509 (0.4%) grandchildren were diagnosed with ASD. The adjusted odds ratio for ASD for grandmother smoking during pregnancy was 1.52 (95% CI, 1.06-2.20). Results were similar with direct grandmother reporting in 2001 of her smoking during pregnancy from the Nurses' Mothers Cohort Study subgroup (n = 22 167 grandmothers, n = 49 917 grandchildren) and were stronger among grandmothers who smoked ≥15 cigarettes per day during pregnancy (adjusted odds ratio = 1.93 [95% CI, 1.10-3.40]; n = 1895 grandmothers, n = 4212 grandchildren). Results were similar when we adjusted for mother's smoking during pregnancy. There was no association with grandfather's smoking as reported by the grandmother. Our results suggest a potential persistent impact of gestational exposure to environmental insults across 3 generations.

Maternal smoking during pregnancy, offspring smoking, adverse childhood events, and risk of major depression: a sibling design study

BACKGROUND

Evidence of a biologically plausible association between maternal smoking during pregnancy (MSP) and the risk of depression is discounted by null findings from two sibling studies. However, valid causal inference from sibling studies is subject to challenges inherent to human studies of MSP and biases particular to this design. We addressed these challenges in the first sibling study of MSP and depression conducted among adults past the peak age for the onset of depression, utilizing a prospectively collected and biologically validated measure of MSP and accounting for non-shared as well as mediating factors.

METHODS

We fit GEE binomial regression models to correct for dependence in the risk of depression across pregnancies of the same mother. We also fit marginal structural models (MSM) to estimate the controlled direct effect of MSP on depression that is not mediated by the offspring's smoking status. Both models allow the estimation of within- and between-sibling risk ratios.

RESULTS

The adjusted within-sibling risk ratios (RR_W) from both models (GEE: RR_W = 1.97, CI 1.16-3.32; MSM: RR_W = 2.08, CI 1.04-4.17) evinced an independent association between MSP and risk of depression. The overall effects from a standard model evinced lower associations (GEE: RR_T = 1.12, CI 0.98-1.28; MSM: RR_T = 1.18, CI 1.01-1.37).

CONCLUSIONS

Based on within-sibling information free of unmeasured shared confounders and accounting for a range of unshared factors, we found an effect of MSP on the offspring's risk of depression. Our findings, should they be replicated in future studies, highlight the importance of considering challenges inherent to human studies of MSP and affective disorders.

Prenatal nicotine alters development of the laterodorsal tegmentum: Possible role for attention-deficit/hyperactivity disorder and drug dependence

As we cycle between the states of wakefulness and sleep, a bilateral cholinergic nucleus in the pontine brain stem, the laterodorsal tegmentum (LDT), plays a critical role in controlling salience processing, attention, behavioral arousal, and electrophysiological signatures of the sub- and microstates of sleep. Disorders involving abnormal alterations in behavioral and motivated states, such as drug dependence, likely involve dysfunctions in LDT signaling. In addition, as the LDT exhibits connectivity with the thalamus and mesocortical circuits, as well as receives direct, excitatory input from the prefrontal cortex, a role for the LDT in cognitive symptoms characterizing attention-deficit/hyperactivity disorder (ADHD) including impulsivity, inflexibility, and dysfunctions of attention is suggested. Prenatal nicotine exposure (PNE) is associated with a higher risk for later life development of drug dependence and ADHD, suggesting alteration in development of brain regions involved in these behaviors. PNE has been shown to alter glutamate and cholinergic signaling within the LDT. As glutamate and acetylcholine are major excitatory mediators, these alterations would likely alter excitatory output to target regions in limbic motivational circuits and to thalamic and cortical networks mediating executive control. Further, PNE alters neuronal development and transmission within prefrontal cortex and limbic areas that send input to the LDT, which would compound effects of differential processing within the PNE LDT. When taken together, alterations in signaling in the LDT are likely to play a role in negative behavioral outcomes seen in PNE individuals, including a heightened risk of drug dependence and ADHD behaviors.

Accessing specialist support to stop smoking in pregnancy: A qualitative study exploring engagement with UK-based stop smoking services

Objectives

Specialist stop smoking services can be effective for supporting women with smoking cessation during pregnancy, but uptake of these services is low. A novel theoretical approach was used for this research, aiming to identify barriers to and facilitators of engaging with specialist smoking cessation support using the Theoretical Domains Framework (TDF).

Methods

Semi‐structured interviews and a focus group (n = 28) were carried out with pregnant women who smoke/recently quit smoking, midwives and Stop Smoking in Pregnancy advisors from two local authority commissioned services in the UK. Inductive thematic analysis was used to code interview transcripts and deductive thematic analysis used to match emerging themes to TDF domains.

Results

Themes corresponded to seven domains of the TDF: Knowledge: Knowledge of available services for pregnant smokers; Environmental context and resources: Uptake of referral to cessation services by pregnant smokers; Social Influences: Smoking norms and role of others on addressing smoking in pregnancy; Beliefs about Capabilities: Confidence in delivering and accepting pregnancy smoking cessation support; Beliefs about Consequences: Beliefs about risks of smoking in pregnancy and role of cessation services; Intentions: Intentions to quit smoking during pregnancy; Emotions: Fear of judgement from healthcare professionals for smoking in pregnancy.

Conclusions

These novel findings help to specify factors associated with pregnant women’s engagement, which are useful for underpinning service specification and design by public health commissioners and service providers. Addressing these factors could help to increase uptake of cessation services and reduce rates of smoking in pregnancy.

Prenatal Tobacco Exposure and the Risk of Tobacco Smoking and Dependence in Offspring: a Systematic Review and Meta-Analysis

BACKGROUND

There is some compelling, though not comprehensive, epidemiological evidence which suggests an association between prenatal tobacco exposure and tobacco smoking/dependence in offspring. We conducted a systematic review and meta-analysis to identify the magnitude and consistency of associations reported between prenatal tobacco exposure and subsequent tobacco smoking/dependence in offspring.

METHODS

Using the PRISMA guideline, we systematically searched PubMed, SCOPUS, EMBASE and Psych-INFO to identify relevant studies. The methodological quality of all identified studies was checked by the Newcastle-Ottawa Scale. Inverse variance weighted random effects meta-analysis was used to estimate pooled risk ratio (RR) and 95 % confidence intervals (CI). We stratified outcomes by tobacco smoking initiation, lifetime tobacco smoking, current tobacco smoking and tobacco dependence. We further performed subgroup and leave-one-out sensitivity analyses. The protocol of this review was registered in the PROSPERO.

RESULTS

Twenty-six cohort and one case-control study were included in the final meta-analysis. We found elevated pooled risks of tobacco smoking initiation [RR = 2.08, (95 % CI: 1.18-3.68)], ever tobacco smoking [RR = 1.21, (95 % CI: 1.05-1.38)], current tobacco smoking [RR = 1.70, (95 % CI: 1.48-1.95)] and tobacco dependence [RR = 1.50, (95 % CI: 1.31-1.73)] in offspring exposed to maternal prenatal tobacco use compared to non-exposed. We also noted higher risk estimate of current tobacco smoking in offspring exposed to heavy prenatal tobacco smoking [RR = 1.68, (95 % CI: 1.26-2.23)] when compared to prenatal exposure to lighter tobacco use [RR = 1.39, (95 % CI: 1.09-1.78)]. There was no association observed between paternal smoking during pregnancy and tobacco smoking in offspring.

CONCLUSION

Offspring exposed to maternal prenatal tobacco smoking are at an increased risk of tobacco smoking/dependence, indicating that tobacco smoking cessation during gestation may be imperative to reduce these risks in offspring.

Perinatal Navigator Approach to Smoking Cessation for Women With Prevalent Opioid Dependence

Women who smoke during pregnancy face psychosocial barriers to cessation, and women with opioid use disorder (OUD) face amplified barriers. We pilot tested a Perinatal Wellness Navigator (PWN) program for a group of high-risk perinatal women (N = 50; n = 42 with OUD) that consisted of (a) one-on-one tobacco treatment, (b) comprehensive assessment of cessation barriers, and (c) linkage to clinical/social services. Outcome measures were assessed at baseline and postintervention. Participants smoked 10 fewer cigarettes per day (p = .05) at postintervention and were less dependent on nicotine (p < .01). Mean postnatal depression scores (p = .03) and perceived stress (p = .03) decreased postintervention. Participants received at least one referral at baseline (n = 106 total), and 10 participants received an additional 18 referrals at postintervention to address cessation barriers. The PWN program was minimally effective in promoting total tobacco abstinence in a high-risk group of perinatal women, but participants experienced reductions in cigarettes smoked per day, nicotine dependence, stress, and depression.

Trajectories of pre- and postnatal co-use of cannabis and tobacco predict co-use and drug use disorders in adult offspring

Co-use of cannabis and tobacco is increasingly common among women and is associated with tobacco and cannabis dependence and poorer cessation outcomes. However, no study has examined maternal patterns of co-use over time, or the impact of maternal co-use on co-use and drug problems in adult offspring. Pregnant women (M age = 23, range = 18-42; 52% African American, 48% White) were asked about substance use during each trimester of pregnancy, and at 8 and 18 months, 3, 6, 10, 14, 16, and 22 years postpartum. We examined patterns of any maternal cigarette and cannabis use during pregnancy and the postpartum years. As young adults (M age = 22.8 years, range = 21-26), 603 offspring completed the Diagnostic Interview Schedule (DIS). Growth mixture modeling (GMM) was used to identify four maternal trajectories through 16 years postpartum: (1) no co-use (66%), (2) decreasing co-use (16%), (3) postpartum-only co-use (11%), and (4) chronic co-use (7%). Offspring whose mothers were in the decreasing co-use group (co-users primarily during prenatal and preschool periods) were more likely to be co-users than the offspring of non-co-users. Offspring whose mothers were chronic co-users of cigarettes and cannabis were more than twice as likely to have a drug use disorder than young adults whose mothers were not co-users. The results of this study highlight the heterogeneity in maternal co-use of tobacco and cannabis over time, with some women quitting during pregnancy but resuming co-use in the postpartum, and other women co-using during pregnancy but desisting co-use over time. Maternal trajectories of co-use were associated with inter-generational transfer of risk for substance use and dependence in adult offspring.

Prenatal tobacco and marijuana co-use: Impact on newborn neurobehavior

Tobacco and marijuana are some of the most common prenatal substance exposures worldwide. The social acceptability and political landscape of marijuana and its potency have changed dramatically in the last two decades leading to increased use by pregnant women. Despite evidence for increasing marijuana use and high rates of co-use of tobacco (TOB) and marijuana (MJ) during pregnancy, the impact of prenatal exposure to each substance is typically studied in isolation. We investigated the influence of co-exposure to TOB and MJ on infant neurobehavioral development over the first postnatal month. Participants were 111 mother-infant pairs from a low-income, diverse sample (Mean age = 25 ± 5; 54% minorities). TOB and MJ use were assessed by Timeline Followback interview with biochemical confirmation. Three groups were identified: (a) prenatal MJ + TOB, (b) prenatal TOB only, (c) controls. Newborn neurobehavior was assessed at seven time points over the first postnatal month using the NICU Network Neurobehavioral Scale. MJ + TOB-exposed infants showed decreased ability to self-soothe (Self-regulation) and attend to stimuli (Attention), and increased need for examiner soothing (Handling) and low motor activity (Lethargy) versus unexposed infants. Despite low levels of MJ use in MJ + TOB co-users, co-exposure was associated with nearly double the impact on infant self-soothing and need for examiner soothing versus TOB-exposure alone. Effects of MJ + TOB co-exposure appeared more pronounced for daughters than for sons. Although results are preliminary, they highlight additional risk from dual exposure to MJ + TOB vs. TOB exposure alone, particularly for daughters. Results also highlight the critical importance of investigating prenatal exposures in concert and the need for intervention efforts to address MJ co-use in pregnant TOB users.

Impact of maternal prenatal smoking on fetal to infant neurobehavioral development

Despite recent emphasis on the profound importance of the fetal environment in "programming" postnatal development, measurement of offspring development typically begins after birth. Using a novel coding strategy combining direct fetal observation via ultrasound and actocardiography, we investigated the impact of maternal smoking during pregnancy (MSDP) on fetal neurobehavior; we also investigated links between fetal and infant neurobehavior. Participants were 90 pregnant mothers and their infants (52 MSDP-exposed; 51% minorities; ages 18-40). Fetal neurobehavior at baseline and in response to vibro-acoustic stimulus was assessed via ultrasound and actocardiography at M = 35 weeks gestation and coded via the Fetal Neurobehavioral Assessment System (FENS). After delivery, the NICU Network Neurobehavioral Scale was administered up to seven times over the first postnatal month. MSDP was associated with increased fetal activity and fetal limb movements. Fetal activity, complex body movements, and cardiac-somatic coupling were associated with infants' ability to attend to stimuli and to self-regulate over the first postnatal month. Furthermore, differential associations emerged by MSDP group between fetal activity, complex body movements, quality of movement, and coupling, and infant attention and self-regulation. The present study adds to a growing literature establishing the validity of fetal neurobehavioral measures in elucidating fetal programming pathways.

Prenatal exposures to tobacco and cannabis: Associations with adult electronic cigarette use

INTRODUCTION

Prenatal exposures to tobacco and cannabis are associated with combustible cigarette use. This study evaluated pathways from these prenatal exposures to adult electronic cigarette use. We tested whether there were indirect effects of these prenatal exposures via childhood behavior dysregulation, early tobacco use, and adolescent tobacco dependence.

METHODS

Telephone interviews were conducted with 427 adult offspring (22-33 years old) from 3 prenatal cohorts with trimester-specific data on exposures to tobacco, alcohol, and cannabis. The offspring were 59% Black and 41% White (61% female). Prenatal exposures included quantity/frequency of tobacco, alcohol, and cannabis use by mothers during the first trimester. Using logistic regression and structural equation modeling, we examined the effects of gestational exposures on adult electronic cigarette use via early cigarette use (prior to age 14), controlling for covariates of combustible and electronic cigarette use.

RESULTS

There were no effects of childhood behavioral dysregulation on electronic cigarette use. However, there was a significant indirect effect of prenatal exposures to tobacco and cannabis on electronic cigarette use via early adolescent combustible cigarette use and adolescent risk for tobacco dependence.

CONCLUSIONS

One implication of these findings is that the inter-generational risk for tobacco use conferred via gestational exposures to tobacco and cannabis generalizes to novel products such as electronic cigarettes. These results have implications for public health, as more women use cannabis and co-use cigarettes and cannabis during pregnancy.

Prenatal nicotine exposure alters postsynaptic AMPA receptors and glutamate neurotransmission within the laterodorsal tegmentum (LDT) of juvenile mice

Despite dissemination of information regarding the harm on fetal development of smoking while pregnant, the number of pregnancies associated with nicotine exposure appears to have stagnated. Presence of nicotine during neural formulation is associated with a higher susceptibility of drug dependence, suggesting an altered development of neurons in circuits involved in saliency and motivation. The laterodorsal tegmental nucleus (LDT) plays a role in coding stimuli valence via afferents to mesolimbic nuclei. Accordingly, alterations in development of neural mechanisms in the LDT could be involved in vulnerability to drug dependency. Therefore, we examined the effect of prenatal nicotine exposure (PNE) on glutamatergic functioning of LDT neurons in mouse brain slices using whole-cell, patch clamp concurrent with fluorescence-based calcium imaging. PNE was associated with larger amplitudes of AMPA-induced currents, and greater AMPA-mediated rises in intracellular calcium. AMPA/NMDA ratios and the AMPA-current rectification index were lower and higher, respectively, consistent with changes in the functionality of AMPA receptors in the PNE, which was substantiated by a greater inhibition of evoked and spontaneous glutamatergic synaptic events by a selective inhibitor of GluA2-lacking AMPA receptors. Paired pulse ratios showed a decreased probability of glutamate release from presynaptic inputs, and fluorescent imaging indicated a decreased action potential-dependent calcium increase associated with PNE. When taken together, our data suggest that PNE alters LDT glutamatergic functioning, which could alter output to mesolimbic targets. Such an alteration could play a role in altered coding of relevancy of drug stimuli that could enhance risk for development of drug dependency.

Association Between Maternal Smoking During Pregnancy and Severe Mental Illness in Offspring

IMPORTANCE

Several recent population-based studies have linked exposure to maternal smoking during pregnancy to increased risk of severe mental illness in offspring (eg, bipolar disorder, schizophrenia). It is not yet clear, however, whether this association results from causal teratogenic effects or from confounding influences shared by smoking and severe mental illness.

OBJECTIVE

To examine the association between smoking during pregnancy and severe mental illness in offspring, adjusting for measured covariates and unmeasured confounding using family-based designs.

DESIGN, SETTING, AND PARTICIPANTS

This study analyzed population register data through December 31, 2013, for a cohort of 1 680 219 individuals born in Sweden from January 1, 1983, to December 31, 2001. Associations between smoking during pregnancy and severe mental illness in offspring were estimated with adjustment for measured covariates. Cousins and siblings who were discordant on smoking during pregnancy and severe mental illness were then compared, which helped to account for unmeasured genetic and environmental confounding by design.

EXPOSURES

Maternal self-reported smoking during pregnancy, obtained from antenatal visits.

MAIN OUTCOMES AND MEASURES

Severe mental illness, with clinical diagnosis obtained from inpatient and outpatient visits and defined using International Classification of Diseases codes for bipolar disorder and schizophrenia spectrum disorders.

RESULTS

Of the 1 680 219 offspring included in the analysis, 816 775 (48.61%) were female. At the population level, offspring exposed to moderate and high levels of smoking during pregnancy had greater severe mental illness rates than did unexposed offspring (moderate smoking during pregnancy: hazard ratio [HR], 1.25; 95% CI, 1.19-1.30; high smoking during pregnancy: HR, 1.51; 95% CI, 1.44-1.59). These associations decreased in strength with increasing statistical and methodologic controls for familial confounding. In sibling comparisons with within-family covariates, associations were substantially weaker and nonsignificant (moderate smoking during pregnancy: HR, 1.09; 95% CI, 0.94-1.26; high smoking during pregnancy: HR, 1.14; 95% CI, 0.96-1.35). The pattern of associations was consistent across subsets of severe mental illness disorders and was supported by further sensitivity analyses.

CONCLUSIONS AND RELEVANCE

This population- and family-based study failed to find support for a causal effect of smoking during pregnancy on risk of severe mental illness in offspring. Rather, these results suggest that much of the observed population-level association can be explained by measured and unmeasured factors shared by siblings.

Prenatal tobacco exposure, maternal postnatal nicotine dependence and adolescent risk for nicotine dependence: Birth cohort study

AIMS

The goals of this study are to determine if there is (a) a threshold effect for prenatal tobacco exposure (PTE) on adolescent risk for nicotine dependence, and (b) an additive effect of PTE and maternal postnatal nicotine dependence on adolescent risk for nicotine dependence.

METHODS

Pregnant women were recruited in their 4th or 5th gestational month and asked about cigarette use during the first trimester. Mothers reported on third trimester cigarette use at delivery. Sixteen years post-partum, mothers and offspring reported on current levels of cigarette use (N=784). Nicotine dependence was assessed in both using a modified Fagerström questionnaire.

RESULTS

Based on the results of a threshold analysis for PTE, four groups were created: threshold PTE only (10+ cigarettes per day), maternal nicotine postnatal dependence with no-low PTE (0-<10 cigarettes per day), threshold PTE+maternal postnatal nicotine dependence, and a referent group with no-low PTE and no maternal postnatal nicotine dependence. Adolescents in the PTE-only group and the PTE+maternal postnatal nicotine dependence group were significantly more likely to be at risk for nicotine dependence than the offspring from the referent group. However, there was no evidence for an additive effect of maternal postnatal nicotine dependence, and maternal nicotine dependence was not a significant predictor of adolescent risk for nicotine dependence in regression models including prenatal tobacco exposure.

CONCLUSIONS

Bivariate analysis revealed a threshold effect for PTE of 10 cigarettes per day. In multivariate analysis, PTE remained significantly related to risk for offspring nicotine dependence, after controlling for maternal postnatal nicotine dependence and other covariates associated with adolescent cigarette use.

Are digital interventions for smoking cessation in pregnancy effective? A systematic review protocol

BACKGROUND

Behavioural support for smoking cessation in pregnancy can be effective; however, many pregnant women face barriers to seeking support to stop smoking. Some digital interventions have been found to be effective for smoking cessation in the general population and may be effective for supporting cessation in pregnancy due to their flexibility and the potential for personalisation. To date, there is limited evidence of the effectiveness of digital interventions for smoking cessation in pregnancy. This review aims to assess the following: (1) whether digital interventions are effective at promoting smoking cessation among pregnant women; (2) which behaviour change techniques (BCTs) or combinations of BCTs are associated with the effectiveness of digital interventions for smoking cessation in pregnancy; and (3) whether the number of BCTs used is associated with the effectiveness of digital interventions for smoking cessation in pregnancy.

METHODS

This review will include digital interventions delivered largely through computer (PC or laptop), video/DVD, mobile phone (including smartphones) or portable handheld device (e.g. tablet, iPad) and include websites, mobile or tablet applications and SMS text messages. Interventions must be randomised or quasi-randomised controlled trials aimed at women who smoke in pregnancy, with smoking cessation as a measured outcome (preferably the latest available point prevalence smoking status measure taken during pregnancy, biochemically verified if available). Electronic bibliographic databases will be searched to identify suitable studies indexed in the following: Academic Search Complete, ASSIA, CINAHL, The Cochrane Library, EMBASE, Medline, PsycINFO, Scopus, and Web of Science. The search strategy will include key words and database-specific subject headings relating to 'pregnancy' and 'smoking' and synonyms for the terms 'digital' and 'randomised controlled trial'. Where required and where possible, the first and second authors will independently code interventions and control groups for BCTs. If data allows, meta-analyses will be used to assess intervention effectiveness and the effectiveness of BCTs.

DISCUSSION

This systematic review will provide a detailed synthesis of the effectiveness of current research using digital interventions for smoking cessation in pregnancy, to build on the evidence base and guide the development of future research in this area.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016036201.

Maternal smoking during pregnancy and offspring's tobacco dependence. A study of exposure-discordant sibling pairs

BACKGROUND

Prenatal exposure to maternal smoking has previously been linked to tobacco dependence, but confounding from genetic and early-environmental factors is of concern. The aim of this study was to clarify if maternal smoking during pregnancy may affect the onset and manifestations of tobacco dependence after taking such factors into account.

METHODS

The study is based on a matched cohort of 1538 siblings discordant for prenatal exposure to maternal smoking, who participated in a survey conducted in 2010 in Sweden. Analyses were based on pairs where both siblings had been daily smokers (193 pairs) or snus users (173 pairs) at some time in their life. Participants were 19-27 years old at the time of participation. Outcomes were tobacco dependence measured with the Cigarette Dependence Scale (CDS-12) in smokers and with the adapted Smokeless Tobacco Dependence Scale (STDS-12) in snus users, and previous quit attempts. Exposure to maternal smoking during pregnancy was retrieved from the Swedish Medical Birth Register.

RESULTS

There was no difference in dependence scores in exposure-discordant siblings (mean difference 0.36 on CDS-12 [95% confidence interval: -1.23 to 1.95] and 0.61 on STDS-12 [95% confidence interval: -1.20 to 2.43]). Neither did the siblings differ with regard to previous quit attempts.

CONCLUSIONS

Maternal smoking during pregnancy does not appear to influence tobacco dependence in adult offspring. A potential effect of heavy maternal smoking during pregnancy cannot be excluded, but genetic and environmental influences seem to be more influential for the onset of tobacco dependence.

Geographic Variation in Maternal Smoking during Pregnancy in the Missouri Adolescent Female Twin Study (MOAFTS)

Objective

Despite well-known adverse health effects of maternal smoking during pregnancy (MSP), it is still unclear if MSP varies geographically and if neighborhood socioeconomic deprivation (SED) plays an important role in MSP. This study aims to investigate small-area geographic variation in MSP and examine the association of SED with MSP.

Methods

The Missouri Adolescent Female Twin Study (MOAFTS) is a cohort study of female like-sex twins born in Missouri to Missouri-resident parents during 1975–1985. Biological mothers completed a baseline interview in 1995–1998 and reported MSP with the twins. Residential address of the mother at birth was geocoded. We developed a census tract-level SED index using a common factor approach based on 21 area-level socioeconomic variables from the 1980 Census data. Multilevel logistic regressions estimated geographic heterogeneity (random effect) in MSP and the odds ratios (ORs, fixed effects) of neighborhood SED associated with MSP.

Results

Of 1658 MOAFTS mothers, 35.2% reported any MSP and 21.9% reported MSP beyond the first trimester. Neighborhood SED was associated with any MSP (the highest vs. the lowest quartile: OR = 1.90, 95% confidence interval [CI] = 1.40–2.57, P_trend<0.001) and MSP beyond the first trimester (OR = 1.98, 95% CI = 1.38–2.85, P_trend = 0.002) in unadjusted analyses. After adjusting for individual covariates (demographics, socioeconomic conditions, alcohol use, and parents’ cohabitation), neighborhood SED was not associated with MSP, but geographic variation still persisted in MSP (variance = 0.41, P = 0.003) and in MSP beyond the first trimester (variance = 0.82, P<0.001).

Conclusions

Neighborhood SED was associated with MSP in unadjusted analyses but this association could be explained by individual socioeconomic conditions. Nonetheless, significant geographic variation in MSP persisted and was not accounted for by differences in neighborhood SED. To develop effective interventions to reduce MSP, further studies are necessary to explore underlying reasons for its geographic variation.