Do Smoking Bans Improve Neonatal Health?

Evaluation of Population-Level Tobacco Control Interventions and Health Outcomes: A Systematic Review and Meta-Analysis

Importance

Smoking causes considerable noncommunicable diseases, perinatal morbidity, and mortality.

Objective

To investigate the associations of population-level tobacco-control policies with health outcomes.

Data Sources

PubMed, EMBASE, Web of Science, Cumulated Index to Nursing and Allied Health Literature, and EconLit were searched from inception to March 2021 (updated on 1 March 2022). References were manually searched.

Study Selection

Studies reporting on associations of population-level tobacco control policies with health-related outcomes were included. Data were analyzed from May to July 2022.

Data Extraction and Synthesis

Data were extracted by 1 investigator and cross-checked by a second investigator. Analyses were conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline.

Main Outcomes and Measures

The primary outcomes were respiratory system disease (RSD), cardiovascular disease (CVD), cancer, mortality, hospitalization, and health care utilization. The secondary outcomes were adverse birth outcomes, such as low birth weight and preterm birth. Random-effects meta-analysis was used to estimate pooled odds ratios (ORs) and 95% CIs.

Results

Of 4952 records identified, 144 population-level studies were included in the final analysis; 126 studies (87.5%) were of high or moderate quality. The most frequently reported policies were smoke-free legislation (126 studies), followed by tax or price increases (14 studies), multicomponent tobacco control programs (12 studies), and a minimum cigarette purchase age law (1 study). Smoke-free legislation was associated with decreased risk of all CVD events (OR, 0.90; 95% CI, 0.86-0.94), RSD events (OR, 0.83; 95% CI, 0.72-0.96), hospitalization due to CVD or RSD (OR, 0.91; 95% CI, 0.87-0.95), and adverse birth outcomes (OR, 0.94; 95% CI, 0.92-0.96). These associations persisted in all sensitivity and subgroup analyses, except for the country income category, for which a significant reduction was only observed in high-income countries. In meta-analysis, there was no clear association of tax or price increases with adverse health outcomes. However, for the narrative synthesis, all 8 studies reported statistically significant associations between tax increases and decreases in adverse health events.

Conclusions and Relevance

In this systematic review and meta-analysis, smoke-free legislation was associated with significant reductions in morbidity and mortality related to CVD, RSD, and perinatal outcomes. These findings support the need to accelerate the implementation of smoke-free laws to protect populations against smoking-related harm.

Municipal smoke-free laws and preterm birth

BACKGROUND

Smoking during pregnancy and prenatal secondhand smoke exposure increase the risk of preterm birth. As Kentucky has the second highest rate of smoking in the United States and no statewide smoke-free law, an examination of the effect of municipal smoke-free legislation on preterm birth is warranted.

OBJECTIVE

This study used state-level live birth data and county-level municipal smoke-free legislation status to assess the association between the presence and strength of smoke-free laws and the likelihood of preterm birth. Moreover, this study hypothesized that pregnant persons living in counties with comprehensive municipal smoke-free laws prohibiting smoking inside all workplaces and enclosed public places would exhibit a lower likelihood of preterm birth than those living in counties with weak or moderate laws (ie, smoke-free laws with exemptions that do not cover all workplaces and enclosed public places) or no smoke-free law.

STUDY DESIGN

Using live birth data from the Kentucky Office of Vital Statistics with birth years ranging from 2004 to 2020, a total of 894,372 live births were recorded that indicated that a childbearing person was between the ages of 18 and 49 years and a resident of Kentucky; these live births formed the sample for the study. Municipal ordinances implemented during a given calendar year were coded in the model as present starting with the following calendar year, as the birth records were time deidentified except for the year of birth. This lagged law convention maximized the likelihood that pregnant persons included in the study were exposed to the smoke-free policy for at least a portion of their pregnancy. Multilevel logistic regression was used to assess the effect of smoke-free ordinances on the likelihood of preterm birth, with personal- and county-level variables included as potential covariates and pregnant persons nested within the county of residence. Data analysis was conducted using SAS (version 9.4; SAS Institute, Cary, NC), with an alpha level of .05.

RESULTS

Nearly all personal-level variables were associated with preterm birth status. Personal factors associated with an increased likelihood of preterm birth included being older (relative to 18-24 years old; odds ratios [95% confidence intervals]: 1.02 [1.01-1.04] and 1.27 [1.24-1.31] for ages 25-34 and 35-49 years, respectively); having a history of preterm birth (odds ratio, 4.65; 95% confidence interval, 4.53-4.78); and smoking before pregnancy (odds ratio, 1.14; 95% confidence interval, 1.12-1.16). Pregnant persons living in counties with comprehensive laws were 9% less likely to have a preterm birth than those living in counties without a smoke-free ordinance (odds ratio, 0.91; 95% confidence interval, 0.89-0.94; P<.001). There was no difference in the likelihood of preterm birth between those living in counties with moderate or weak laws and those unprotected by any smoke-free ordinance in their county of residence.

CONCLUSION

This study demonstrated that comprehensive municipal smoke-free laws are associated with reduced risk of preterm birth and that moderate or weak smoke-free laws are not. The findings have major implications for public health policy and underscore the potential influence of healthcare providers' advocacy for strong smoke-free policies, prohibiting smoking in all workplaces (including restaurants, bars, and casinos), to support healthy pregnancies.

Association of smoke-free laws with preterm or low birth weight deliveries-A multistate analysis

OBJECTIVE

To assess the association between the change in statewide smoke-free laws and the rate of preterm or low birth weight delivery hospitalizations.

DATA SOURCE

2002-2013 Healthcare Cost and Utilization Project State Inpatient Databases.

STUDY DESIGN

Quasi-experimental difference-in-differences design. We used multivariate logistic models to estimate the association between the change in state smoke-free laws and preterm or low birth weight delivery hospitalizations. The analyses were also stratified by maternal race/ethnicity to examine the differential effects by racial/ethnic groups.

DATA COLLECTION/EXTRACTION METHODS

Delivery hospitalizations among women aged 15-49 years were extracted using the International Classification of Diseases, Ninth Revision, and Diagnosis-Related Group codes.

PRINCIPAL FINDINGS

Non-Hispanic black mothers had a higher rate of preterm or low birth weight delivery hospitalization than other racial/ethnic groups. Overall, there was no association between the change in smoke-free laws and preterm or low birth weight delivery rate. Among non-Hispanic black mothers, the change in statewide smoke-free laws was associated with a 0.9-1.9 percentage point (P < .05) reduction in preterm or low birth weight delivery rate beginning in the third year after the laws took effect. There was no association among non-Hispanic white mothers. A decline in the black-white disparity of 0.6-1.6 percentage points (P < .05) in preterm or low birth weight delivery rates was associated with the change in state smoke-free laws.

CONCLUSION

The change in state smoke-free laws was associated with a reduction in racial/ethnic disparities in preterm or low birth weight delivery hospitalizations in selected US states.

The effect of outdoor smoking ban: Evidence from Korea

To address exposure to secondhand smoke, which is highly prevalent in Korea, local governments have implemented smoking bans at open public places (parks, bus stops, and school zones) since 2011. Exploiting temporal and spatial variation in the implementation dates of these bans, this study estimates their causal effects on individual smoking behavior. The individual-level longitudinal data from the 2009-2017 Korean Labor and Income Panel Study are linked to the smoking ban legislation information from the National Law Information Center. I find robust evidence that outdoor smoking bans increased the probability of making a quit attempt by 16%. This effect appears immediately after a ban goes into effect and lasts for three or more years. People who spend more time outdoors are more likely to change smoking behavior. I also find heterogeneity in effects across the amount of monetary penalty. Whereas the policy change did not affect the prevalence of smoking overall, higher penalties had stronger impacts on reducing the intensity of smoking and increasing the propensity to try to quit.

The impact of anti-tobacco legislation on birth weight in Peru

Background

Tobacco exposure remains a significant issue for public health, especially for pregnant women. It increases the risk for premature labor, low birth weight and small for gestational age (SGA), among other effects. To reduce these risks, many countries have enacted public policies to curb tobacco exposure. Peru enacted anti-tobacco laws that forbid smoking in public places, require prevention text and images in products and publicity, along with restriction of sales to adults. We evaluated the effect of the implementation of this law on newborn outcomes: birth weight, prematurity and SGA.

Methods

This was a quasi-experimental study that utilized data from the Peruvian Live Birth Registry. Children born to mothers from urban areas were the intervention group, while children born to mothers from rural areas were considered the control group. Only singletons with information on birth weight and gestational age, born to mothers aged 12 to 49 years were included in the study. In addition, newborns with birth weights greater than + 4 standard deviations (SD) or less than - 4 SD from the gestational age-specific mean were excluded. To measure the effect of legislation on birth weight we performed a difference in differences analysis.

Results

A total of 2,029,975 births were included in the analysis. After adjusting for characteristics of the mother and the child, and contextual variables, the anti-tobacco law in Peru reduced the incidence of prematurity by 30 cases per 10,000 live births (95% CI: 19 to 42).

Conclusions

The reform had negligible effects on overall birth weights and on the incidence of SGA. This modest result suggests the need for a more aggressive fight against tobacco, prohibiting all types of advertising and promotion of tobacco products, among others measures.

Effects of national smoke-free legislation on the rates of preterm births and low birthweights in Taiwan

This study evaluated the effects of partial and complete island-wide smoking bans on perinatal outcomes in Taiwan. Trends were determined in the yearly prevalence rates for preterm births and low birth weight (LBW) for a 1978 to 1997 pre-ban period, a 1998 to 2008 Phase 1 partial ban period, and a 2009 to 2016 Phase 2 complete ban period. Poisson regression with a yearly time-series model was employed to determine alterations in trends in prevalence rates for preterm births and LBW. Compared with pre-ban period, the rate ratio (RR) for Phase 1 preterm births was 0.969 (95% confidence interval [CI] = 0.968-0.971) and Phase 2 0.995 (95% CI = 0.992-0.998). The Phase 1 RR LBW fell 0.4% (95% CI = 0.2%-0.5%), but Phase 2 RR rose 1.7% (95% CI = 1.4%-2.1%). Data indicated that the risk of preterm births and LBW in Taiwan was reduced significantly after implementation of the smoking ban. These findings are in agreement with growing evidence suggesting that smoke-free legislation exerted a beneficial health effect on pregnant women and their newborn infants.

Effect of tobacco control policies on perinatal and child health: a systematic review and meta-analysis

BACKGROUND

Tobacco smoking and smoke exposure during pregnancy and childhood cause considerable childhood morbidity and mortality. We did a systematic review and meta-analysis to investigate whether implementation of WHO's recommended tobacco control policies (MPOWER) was of benefit to perinatal and child health.

METHODS

We searched 19 electronic databases, hand-searched references and citations, and consulted experts to identify studies assessing the association between implementation of MPOWER policies and child health. We did not apply any language restrictions, and searched the full time period available for each database, up to June 22, 2017. Our primary outcomes of interest were perinatal mortality, preterm birth, hospital attendance for asthma exacerbations, and hospital attendance for respiratory tract infections. Where possible and appropriate, we combined data from different studies in random-effects meta-analyses. This study is registered with PROSPERO, number CRD42015023448.

FINDINGS

We identified 41 eligible studies (24 from North America, 16 from Europe, and one from China) that assessed combinations of the following MPOWER policies: smoke-free legislation (n=35), tobacco taxation (n=11), and smoking cessation services (n=3). Risk of bias was low in 23 studies, moderate in 16, and high in two. Implementation of smoke-free legislation was associated with reductions in rates of preterm birth (-3·77% [95% CI -6·37 to -1·16]; ten studies, 27 530 183 individuals), rates of hospital attendance for asthma exacerbations (-9·83% [-16·62 to -3·04]; five studies, 684 826 events), and rates of hospital attendance for all respiratory tract infections (-3·45% [-4·64 to -2·25]; two studies, 1 681 020 events) and for lower respiratory tract infections (-18·48% [-32·79 to -4·17]; three studies, 887 414 events). Associations appeared to be stronger when comprehensive smoke-free laws were implemented than when partial smoke-free laws were implemented. Among two studies assessing the association between smoke-free legislation and perinatal mortality, one showed significant reductions in stillbirth and neonatal mortality but did not report the overall effect on perinatal mortality, while the other showed no change in perinatal mortality. Meta-analysis of studies on other MPOWER policies was not possible; all four studies on increasing tobacco taxation and one of two on offering disadvantaged pregnant women help to quit smoking that reported on our primary outcomes had positive findings. Assessment of publication bias was only possible for studies assessing the association between smoke-free legislation and preterm birth, showing some degree of bias.

INTERPRETATION

Smoke-free legislation is associated with substantial benefits to child health. The majority of studies on other MPOWER policies also indicated a positive effect. These findings provide strong support for implementation of such policies comprehensively across the world.

FUNDING

Chief Scientist Office Scotland, Farr Institute, Netherlands Lung Foundation, Erasmus MC.

Smoke-free legislation and child health

In this paper, we aim to present an overview of the scientific literature on the link between smoke-free legislation and early-life health outcomes. Exposure to second-hand smoke is responsible for an estimated 166 ,000 child deaths each year worldwide. To protect people from tobacco smoke, the World Health Organization recommends the implementation of comprehensive smoke-free legislation that prohibits smoking in all public indoor spaces, including workplaces, bars and restaurants. The implementation of such legislation has been found to reduce tobacco smoke exposure, encourage people to quit smoking and improve adult health outcomes. There is an increasing body of evidence that shows that children also experience health benefits after implementation of smoke-free legislation. In addition to protecting children from tobacco smoke in public, the link between smoke-free legislation and improved child health is likely to be mediated via a decline in smoking during pregnancy and reduced exposure in the home environment. Recent studies have found that the implementation of smoke-free legislation is associated with a substantial decrease in the number of perinatal deaths, preterm births and hospital attendance for respiratory tract infections and asthma in children, although such benefits are not found in each study. With over 80% of the world’s population currently unprotected by comprehensive smoke-free laws, protecting (unborn) children from the adverse impact of tobacco smoking and SHS exposure holds great potential to benefit public health and should therefore be a key priority for policymakers and health workers alike.