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

Association between prenatal environmental tobacco smoke exposure and preterm birth: A systematic review and meta-analysis

INTRODUCTION

The purpose of this systematic review and meta-analysis is to evaluate the global risk of preterm birth associated with passive smoking. Specifically, the study aims to examine whether passive smoking continues to impact preterm birth rates, with particular attention to the potential effects following the implementation of stricter smoking bans in recent years.

MATERIAL AND METHODS

This systematic review and meta-analysis followed PRISMA guidelines and was preregistered in PROSPERO. A comprehensive literature search was conducted in PubMed, Embase, CINAHL, and Web of Science up to February 17, 2024, using keywords related to passive smoking and preterm birth. Eligible observational studies were selected, and data were independently extracted and assessed for quality by two authors. Statistical analysis used odds ratios (ORs) and the I2 statistic for heterogeneity. Subgroup analyses and publication bias assessments were conducted. Review Manager and Stata were used for the analysis, with significance set at p < 0.05.

RESULTS

Meta-analysis showed a 21% increase in the odds of preterm birth in women exposed to environmental tobacco smoke (ETS) (OR, 1.21; 95% CI, 1.10-1.32) with significant heterogeneity (I2 = 76.2%). Stronger associations were found in cohort and cross-sectional studies, studies in Asia, larger sample sizes, and recent publications. Findings were robust across various analyses.

CONCLUSIONS

Prenatal environmental tobacco smoke exposure significantly increases preterm birth risk. Effective public health interventions, including stringent smoke-free policies, public education, and awareness campaigns, are needed to reduce environmental tobacco smoke exposure and improve maternal and infant health outcomes.

Association between long-term ambient fine particulate matter exposure and risk of postneonatal infant mortality in Taiwan

Infants and children may be potentially susceptible to harm from ambient fine particulate matter (PM2.5) pollution because of the following characteristics (1) immature immune systems (2) not yet fully developed respiratory systems (3) possess a higher absorption rate of pollutants, and (4) and daily activities may expose infants to varying levels. However, few studies have examined the possible correlation between exposure to PM2.5 and mortality in infants. Therefore, the aim of this study was to investigate the association between long-term exposure to ambient PM2.5 and post-neonatal mortality in 65 municipal areas across Taiwan. The mean annual PM2.5 levels of each municipality were categorized from 2013 to 2022 and divided into tertiles. The natural logarithm of the annual post-neonatal mortality rates per 1000 live births was assessed with respect to PM2.5 level, urbanization level, physician density, and mean annual average household income. Weighted-multiple linear regression was utilized to compute the adjusted RRs and their 95% confidence intervals (CIs). When data were not stratified by PM2.5 levels, a significant positive association was observed between long-term lifetime exposure to ambient PM2.5 and post-neonatal mortality rates after adjustment for physician density, urbanization level, and average household income. When PM2.5 levels (in tertiles) were stratified, a positive but nonsignificant trend was found in post-neonatal mortality frequency from the lowest to the highest PM2.5 category. These findings suggest that long-term exposure to PM2.5 increases the risk of post-neonatal mortality rates in Taiwan.

Association of ambient particulate matter (PM2.5) with reduced sex ratio at birth after the implementation of a rapid transit system in Taipei, Taiwan

Sex ratio at birth (SRB) is a simple, noninvasive way to monitor the reproductive health of a population. Apparently only a few studies have assessed the relationship between ambient air pollution and SRBs. The studies that investigated this relationship have yielded inconsistent results. Ambient air pollution levels, including particulate matter (PM2.5) levels, have decreased in Taipei city after a mass rapid transit (MRT) system commenced operations in 1996. The aim of this study was to determine whether the changes in levels of PM2.5 after the implementation of the MRT system in Taipei may have influenced the concurrent alterations noted in the SRB. In order to assess this potential association, annual numbers of male and female births were obtained from Taiwan's Department of Household Registration, Ministry of Interior Affairs from 1992 to 2023. Mean yearly SRBs were calculated for 4 time periods, 1992-1995, 1996-2004, 2005-2015, and 2016-2023. Linear logistic regression was employed to evaluate the variation in officially reported PM2.5 levels during those periods and alterations in the ratios. The ratios for time periods 1 to 4 were 52.61%, 52.22%, 51.78%, and 51.67%, respectively. Compared to Period 1 (pre-MRT), the odds ratios for Periods 2, 3, and 4 were 0.98 (0.97-0.99), 0.97 (0.96-0.98), and 0.96 (0.95-0.98), respectively. The trend toward the decreased SRB was found to be gradual but significant.

The impact of an online educational program to reduce second-hand exposure to smoke among nonsmoking pregnant women; a hospital-based intervention study

Background

Second-hand smoke is recognized as a public health concern, especially for pregnant women.

Objectives

To compare pregnant women's exposure and perceptions of SHS pre-and post-intervention.

Materials and methods

The study was conducted with a sample of 32 pregnant women at a tertiary university hospital in Jordan. Using a semi-structured questionnaire, researchers asked women about their knowledge, attitude and behavior regarding prenatal exposure to smoke before and after an intervention that included motivation, communication, education and counselling by using a range of media. A cotinine test was conducted to measure levels in second-hand smokers.

Results

The average maternal age was 30.88 ± 1.69 years; 68% were highly educated, 43% were employed, 37% reported not having sufficient income, and 62% did not attend for antenatal care on a regular basis. There was a significant increase in knowledge and awareness regarding second-hand smoking and its effect on pregnancy outcomes after the intervention. More than 90% of pregnant women supported a comprehensive policy in relation to smoking, and 33% of used to leave the room where others smoked. This percentage increased to 70% after the intervention. Cotinine level decreased after the intervention in 81% of cases.

Conclusions

There is an increase in knowledge and awareness regarding second-hand smoking and its effects on pregnancy outcomes after implementation of an educational intervention.

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.