Propensity score analysis of the association between maternal exposure to second-hand tobacco smoke and birth defects in Northwestern China

Previous studies have suggested that maternal active smoking can increase the risk of birth defects, but evidence on second-hand tobacco smoke (SHS) is limited. We aimed to assess the association between maternal exposure to SHS and birth defects in a Chinese population. The data were based on a large-scale cross-sectional survey conducted in Shaanxi Province, China. Considering the characteristics of survey design and the potential impact of confounding factors, we adopted propensity score matching (PSM) to match the SHS exposure group and the non-exposure group to attain a balance of the confounders between the two groups. Subsequently, conditional logistic regression was employed to estimate the effect of SHS exposure on birth defects. Furthermore, sensitivity analyses were conducted to verify the key findings. After nearest neighbor matching of PSM with a ratio of 2 and a caliper width of 0.03, there were 6,205 and 12,410 participants in the exposure and control group, respectively. Pregnant women exposed to SHS were estimated to be 58% more likely to have infants with overall birth defects (OR = 1.58, 95% CI: 1.30–1.91) and 75% more likely to have infants with circulatory system defects (OR = 1.75, 95% CI: 1.26–2.44). We also observed that the risk effect of overall birth defects had an increasing trend as the frequency of exposure increased. Additionally, sensitivity analyses suggested that our results had good robustness. These results indicate that maternal exposure to SHS likely increases the risk of overall birth defects, especially circulatory system defects, in Chinese offspring.

Secondhand Smoke Exposure in Lao People’s Democratic Republic: Results From the 2015 National Adult Tobacco Survey

Objectives: Second-hand smoke (SHS) exposure causes >600,000 deaths annually worldwide, however, information regarding SHS exposure in Lao People’s Democratic Republic (Lao PRD) is limited; we report SHS exposure prevalence at home, inside workplaces, and indoor public spaces in Lao PDR.Methods: Data were from the 2015 Lao National Adult Tobacco Survey, a nationally representative sample of 7,562 participants aged ≥15 years recruited through a stratified 2-stage cluster sampling approach.Results: 88.3% (83.9% of non-smokers) reported SHS exposure at home and 63.0% (54.0% of non-smokers) at workplaces. Among non-smokers, women had greater exposure at home than men (86.6 vs. 77.0%). Lower education levels were associated with exposure at home or the workplace. 99.2% reported SHS exposure at any public place; specifically for restaurants/food stores 57.7%, government offices 56.2%, public transport 31.6%, and health care facilities 11.7%.Conclusion: SHS exposure at home and workplace in Lao PDR is among the highest in South-East Asia. Comprehensive smoke-free policies at government-owned workplaces and facilities, stricter enforcement of these smoke-free policies, and strategies to encourage smoke-free environments at homes and in public places are urgently needed.

Association Between Second Hand Smoke (SHS) Exposure In Pregnant Women And Their Socioeconomic Status (SES) And Its Interaction With Age: A Cross-Sectional Study In Urban Areas

Background: The high rate of second hand smoke (SHS) exposure puts pregnant women at risk of various harms and identify relevant influence factors are vital for primary prevention. The study aimed to explore the effect of individual socioeconomic status (SES) on exposure to SHS exposure among pregnant women.Methods: A total of 678 non-smoker pregnant women from 14 communities of Hengyang city, Hunan province of China were recruited in this survey. A self-designed structural questionnaire was used to collect variables. Exposure to SHS was defined as self-reported smoking habit of spouse/partner. The individual SES consisted of martial status, educational attainment, employment and per-capita monthly income.Results: There were 238 (35.1%) participants suffered from SHS exposure during pregnancy. After adjusted for confounding variables, compared to the pregnant women who were employed, others were unemployed were more likely to suffer from SHS exposure (OR= 1.697; 95%CI: 1.102-2.614). Similarly, those women who had high school or technical secondary school education level were associated with SHS exposure compared with college or above education attachment (OR: 1.577, 95%CI: 1.020-2.437). The interaction effects between age and junior middle school or below educational attainment (OR: 1.131, 95%CI: 1.015-1.261), unstable marriage (OR: 1.380, 95%CI: 1.075-1.772) on SHS exposure was detected.Conclusion: Exposure to SHS was very common among pregnant women. Those pregnant women of low level of SES should considered as key population to implement public health intervention. Pregnant women of unstable martial status with older age were more likely to SHS exposure.

Elastin degradation markers are elevated in never-smokers with past history of prolonged exposure to secondhand tobacco smoke and are inversely associated with their lung function

Background- Prolonged past exposure to secondhand tobacco smoke (SHS) in never-smokers is associated with occult obstructive lung disease and abnormal lung function, in particular reduced diffusing capacity. Previous studies have shown ongoing SHS exposure to be associated with increased elastin degradation markers (EDM) desmosine and isodesmosine. Research Question- Are EDM levels elevated in persons with remote history of SHS exposure, and are those levels associated with reduced lung function? Study Design and Methods- We measured the plasma levels of EDM from 193 never-smoking flight attendants with history of remote but prolonged SHS exposure in aircraft cabin and 103 nonsmoking flight attendants or sea-level control participants without history of cabin SHS exposure, and examined those levels versus their lung function with adjustment for covariates. The cabin SHS exposure was estimated based on airline employment history and dates of smoking ban enactment. EDM plasma levels were quantified by high-performance liquid chromatography and tandem mass spectrometry. Results- The median [interquartile range; IQR] plasma EDM level for all participants was 0.30 [0.24 to 0.36] ng/mL with a total range of 0.16 to 0.65 ng/mL. Plasma EDM levels were elevated in those with history of exposure to cabin SHS compared to those not exposed (0.33±0.08 vs. 0.26±0.06 ng/mL; age- and sex-adjusted P<0.001). In those with history of cabin SHS-exposure, higher EDM levels were associated with lower diffusing capacity (parameter estimate (PE) [95%CI]=4.2 [0.4 to 8.0] %predicted decrease per 0.1 ng/mL increase in EDM; P=0.030). Furthermore, EDM levels were inversely associated with FEV1, FEV1/FVC, and FEF25-75 (PE [95%CI]=5.8 [2.1 to 9.4], 4.0 [2.2 to 5.7], and 12.5 [5.8 to 19.2]% predicted decrease per 0.1 ng/mL increase in EDM, respectively) (P<0.001).

The association of workplace smoke-free policies on individual smoking and quitting-related behaviours

Background Our study aims to provide information about workplace smoke-free (SF) policy coverage in mainland China and to assess the relationship between workplace SF policies and secondhand smoke (SHS) exposure, current smoking, smoking harm awareness and quitting intention among smokers. Method Data from the 2018 Asia Best Workplace Mainland China programme were used to address these aims. This cross-sectional study included 14,195 employees from the 2018 survey and 14,953 employees from the 2019 survey. Logistic regression with year-fixed effects was applied to these data. The dependent variables were SHS exposure, smoking or smoking harm awareness. The explanatory variable was the SF workplace policy. Results A total of 21,275 participants (73.0%) reported working under SF policies. The overall prevalence of smoking and SHS exposure were 20.3% and 52.5%, respectively. The workplace SF policy was significantly associated with lower SHS exposure (OR: 0.48, 95% CI: 0.45–0.51), lower current smoking employees (OR: 0.81, 95% CI: 0.76–0.87) and higher awareness of smoking harm (OR: 1.76, 95% CI: 1.61–1.91). However, workplace SF policy was not significantly associated with quitting intention (OR: 0.99, 95% CI: 0.84–1.16). Conclusion Our study identified that although most companies had established workplace SF policies, the overall prevalence of SHS exposure remained very high. Workplace SF policy is associated with lower SHS exposure, lower overall current smoking and higher awareness of smoking harm. These findings provide valuable evidence to promote such policies in all workplaces.

Exposure to second-hand smoke during early life and subsequent sleep problems in children: a population-based cross-sectional study

Background Previous studies have revealed that current secondhand smoke exposure showed highly suggestive evidence for increased risk of simultaneous sleep problems in children. Data on the associations between early-life exposure to SHS with subsequent sleep problems in children were scarce. We aimed to evaluate the associations of early-life SHS exposure with sleep problems in children. Methods In this cross-sectional study, children were recruited from elementary and middle schools in Liaoning Province, China between April 2012 and January 2013. We assessed early-life SHS exposure (pregnancy and the first 2 years of life) via questionnaires. Sleep problems and different types of sleep-related symptoms were measured based on the validated tool of the Sleep Disturbance Scale for Children (SDSC). Generalized linear mixed models were applied to estimate the associations of early-life SHS exposure with sleep problems. Results We included a total of 45,562 children (22,657 [49.7%] males; mean [SD] age, 11.0 [2.6] years) and 6167 of them (13.5%) were exposed to early-life SHS during both pregnancy and the first 2 years of life. Compared with unexposed counterparts, children exposed to early-life SHS had higher total T-scores of SDSC (β = 4.32; 95%CI: 4.06, 4.58) and higher odds of increased sleep problems (OR = 2.14; 95%CI: 1.89, 2.42). When considering different sleep-related symptoms, the associations between early-life SHS exposure and symptom of sleep-wake transition disorders (i.e., bruxism) were the strongest in all analyses. Conclusions Early-life SHS exposure was associated with higher odds of global sleep problems and different sleep-related symptoms in children aged 6–18 years. Our findings highlight the importance to strengthen efforts to support the critical importance of maintaining a smoke-free environment especially in early life.

Tobacco Smoke Exposure and Urinary Cadmium in Women from Northern Mexico

Cadmium (Cd), a carcinogenic metal also related to reproductive and cardiovascular diseases, is contained in tobacco and elevated concentrations of it in humans have been consistently associated with first-hand tobacco smoke; however, there is scarce and inconclusive evidence of the relationship between Cd and secondhand smoke (SHS) exposure. Our aim was to evaluate the association between exposure to tobacco, both active and SHS, with urinary Cd concentrations in Mexican women. In a cross-sectional analysis that included 998 women living in northern Mexico, we measured the concentration of creatinine-adjusted urinary Cd (µg-cadmium/g-creatinine) using inductively coupled plasma triple quadrupole (ICP-QQQ) in tandem mass spectrometry mode (MS/MS). We gathered tobacco smoking information through an in-person interview and formed seven groups: non-smokers without SHS exposure; non-smokers with SHS exposure; ex-smokers without SHS exposure <1 year of quitting; ex-smokers without SHS exposure ≥1 year of quitting, ex-smokers with SHS exposure <1 year of quitting; ex-smokers with SHS exposure ≥1 year of quitting and current smokers. The interview also yielded sociodemographic characteristics. We used linear multivariable regression models to estimate the association between Cd concentrations and tobacco smoke exposure. Compared to non-smokers without SHS exposure, we found higher Cd concentrations in ex-smokers with SHS exposure <1 year of quitting and current smokers (adjusted geometric means 0.51 vs. 1.01 and 0.69 µg-cadmium/g-creatinine, respectively). Our results do not support a conclusion that SHS exposure is a source of Cd body burden.

Second-Hand Smoke Exposure inside the House and Adverse Birth Outcomes in Indonesia: Evidence from Demographic and Health Survey 2017

Objectives: Second-hand Smoke (SHS) during pregnancy among non-smoking women associates with mortality and morbidity risks in their infants. However, little is known about the SHS inside the house and the adverse birth outcomes. This study aims to assess the prevalence, level, and frequency of SHS exposure inside the house and investigate their associations with birth outcomes. Methods: We use the Indonesian Demographic and Health Survey (IDHS) 2017, a large-scale nationally representative survey. Women aged 15 to 49 years who had given birth in the last five years before the study and their husbands were interviewed (n=19,935). Three dependent variables included Low Birth Weight (LBW), size at birth, and birth weight. Results: Seventy-eight percent of mothers exposed to SHS inside home, of whom 7.2% had LBW children. Compared to non-SHS exposure mothers, those exposed to SHS were younger, had first birth before 20 years old, married, lower educated, non-worker, lived in rural, grand multipara, had pollution from cooking fuel, cook in a separate building, had higher risk of delivering lower birth weight (aOR=1.16, 95% CI: 1.02, 1.33), and smaller baby (aOR=1.51, 95%CI: 1.35, 1.69), even after the controlling for the covariates. We identified the inverted U-shaped association for SHS exposure frequency. Similar risk was also observed among mothers exposed with SHS on a daily basis compared to those who are not exposed. Conclusion: Exposure to SHS inside home was significantly associated with LBW and size at birth. Given the high smoking prevalence, relevant policy and health promotion are needed.

Maternal Secondhand Smoke Exposure Enhances Macrosomia Risk Among Pregnant Women Exposed to PM2.5: A New Interaction of Two Air Pollutants in a Nationwide Cohort

Background: Fine particulate matter (PM2.5) is one of the most common outdoor air pollutants, and secondhand smoking (SHS) is an important source of inhalable indoor air pollution. Previous studies were controversial and inconsistent about PM2.5 and SHS air pollutants on neonatal birth weight outcomes, and no studies assessed the potential interactive effects between PM2.5 and SHS on birth weight outcomes.Purpose: To investigate the interaction between gestational PM2.5 and SHS air pollution exposure on the risk of macrosomia among pregnant women and examine the modifying effect of SHS exposure on the association of PM2.5 air pollution and birth weight outcomes during pregnancy.Methods: Research data were derived from the National Free Preconception Health Examination Project (NFPHEP), which lasted 3 years from January 1, 2010, to December 31, 2012. At least 240,000 Chinese women from 220 counties were enrolled in this project. PM2.5 exposure concentration was obtained using a hindcast model specific for historical PM2.5 estimation from satellite-retrieved aerosol optic depth. Different interaction models about air pollution exposure on birth weight outcomes were established, according to the adjustment of different confounding factors and different pregnancy stages. The establishment of interaction models was based on multivariable logistic regression, and the main confounding factors were maternal age at delivery and pre-pregnancy body mass index (BMI) of participants. SHS subgroups analysis was conducted to further confirm the results of interaction models.Results: In total, 197,877 participants were included in our study. In the full-adjusted interaction model, maternal exposure to PM2.5 was associated with an increased risk of macrosomia in whole, the first-, second-, and third trimesters of pregnancy (p &lt; 0.001). The interactive effect was statistically significant between maternal exposure to PM2.5 and SHS on the risk of macrosomia in the whole (interaction p &lt; 0.050) and the first-trimester pregnancy (interaction p &lt; 0.050), not in the second (interaction p &gt; 0.050) or third trimester (interaction p &gt; 0.050) of pregnancy. The higher frequency of SHS exposure prompted the stronger interaction between the two air pollutants in the whole pregnancy and the first-trimester pregnancy.Conclusions: In the whole and first-trimester pregnancy, maternal exposure to SHS during pregnancy enhanced the risk of macrosomia among pregnant women exposed to PM2.5 air pollutants, and the interaction became stronger with the higher frequency of SHS exposure.