Background:
Given the increasing prevalence of e-cigarette usage and potential risks associated with non-compliant products, understanding their reporting patterns is crucial for public health regulation.

Objectives:
The aim of this study was to investigate the extent to which non-compliant electronic cigarettes, which are being sold in the European market, are being reported in relation to the prevalence of e-cigarette usage.

Methods:
We conducted a comprehensive search using the EU Rapid Information System for dangerous non-food products, commonly referred to as Rapex, to identify instances of non-compliant e-cigarettes reported between the years 2005 and 2022. This system encompasses data from 28 current and former member states of the European Union (EU-28). To determine the fraction of individuals who have ever used e-cigarettes, we accessed the latest Eurobarometer survey conducted in 2020. Additionally, we obtained population data for each country in 2020 from the World Bank. Subsequently, we computed an index for each country, namely the number of alerts per 100,000 ever e-cigarette smokers, hereafter referred to as the "alert index."

Results:
During the period from 2005 to 2022, a total of 150 alerts were recorded for violations of electronic cigarette legislation within the EU-28 region. Among the member states, Ireland exhibited the highest alert index of 4.2, followed by Bulgaria with 3.2 and Lithuania with 1.3. In 16 out of the EU-28 states, the alert index remained at 0.0 per 100,000 individuals who have ever smoked e-cigarettes. Notably, four of these 16 states, namely Italy, Germany, the United Kingdom, and Poland, were identified as the countries of origin for the reported products.

Conclusions:
In conclusion, our findings highlight the need for stricter enforcement and monitoring of non-compliant electronic cigarettes in the European market.