METHODS: A literature search was conducted across databases including PubMed, Embase, Web of Science, and Cochrane on October 20, 2023. The included studies reported the number of pregnant women and the count of those who were dual users. Quality assessment was undertaken using the JBI tool. The pooled prevalence of dual use was determined via a random-effects model. All statistical analyses were executed using R software, version 4.3.
PROSPERO: CRD42023486020.
RESULTS: Eighteen studies were analyzed, encompassing 5,983,363 pregnant women. The meta-analysis indicated an overall prevalence of 4.6% (95% CI: 2.0-10.3) for dual users with significant heterogeneity (I2 = 100%). Subgroup analysis based on the country showed a prevalence of 4.9% (95% CI: 2.0 to 11.6) for USA and 8.1% (95% CI: 0.00 to 1.00) for UK. Meta-regression revealed reduction of prevalence of dual use from 2019 to 2023. A potential publication bias was indicated by the LFK index and the Doi plot.
CONCLUSION: The dual consumption of e-cigarettes and traditional tobacco in pregnant women is a significant health concern, with a notable prevalence. Given the established risks of tobacco smoking during pregnancy and the uncertainties surrounding e-cigarettes, more comprehensive research and public health interventions are urgently needed to address this issue.
DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: A cross-sectional analysis of adult (≥ 18 years) current smokers and ex-smokers from 14 countries participating in the ITC Project. Data from the most recent survey questionnaire for each country were included, which spanned the period 2013-17. Countries were categorized into four groups based on regulations governing NVP sales and marketing (allowable or not), and level of enforcement (strict or weak where NVPs are not permitted to be sold): (1) most restrictive policies (MRPs), not legal to be sold or marketed with strict enforcement: Australia, Brazil, Uruguay; (2) restrictive policies (RPs), not approved for sale or marketing with weak enforcement: Canada, Malaysia, Mexico, New Zealand; (3) less restrictive policies (LRPs), legal to be sold and marketed with regulations: England, the Netherlands, Republic of Korea, United States; and (4) no regulatory policies (NRPs), Bangladesh, China, Zambia. Countries were also grouped by World Bank Income Classifications. Country-specific weighted logistic regression models estimated adjusted NVP prevalence estimates for: awareness, ever/current use, and frequency of use (daily versus non-daily).
FINDINGS: NVP awareness and use were lowest in NRP countries. Generally, ever- and current use of NVPs were lower in MRP countries (ever-use = 7.1-48.9%; current use = 0.3-3.5%) relative to LRP countries (ever-use = 38.9-66.6%; current use = 5.5-17.2%) and RP countries (ever-use = 10.0-62.4%; current use = 1.4-15.5%). NVP use was highest among high-income countries, followed by upper-middle-income countries, and then by lower-middle-income countries.
CONCLUSIONS: With a few exceptions, awareness and use of nicotine vaping products varied by the strength of national regulations governing nicotine vaping product sales/marketing, and by country income. In countries with no regulatory policies, use rates were very low, suggesting that there was little availability, marketing and/or interest in nicotine vaping products in these countries where smoking populations are predominantly poorer. The higher awareness and use of nicotine vaping products in high income countries with moderately (e.g. Canada, New Zealand) and less (e.g. England, United States) restrictive policies, is likely due to the greater availability and affordability of nicotine vaping products.