E-Cigarette and Liquid Nicotine Exposures Among Young Children

Data from the NPDS were analyzed to investigate liquid nicotine exposures (including e-cigarette devices and liquids) among children <6 years old. The NPDS is maintained by the American Association of Poison Control Centers (AAPCC) and includes reported exposure data from the regional PCCs serving the 50 US states, District of Columbia, and several US territories. Exposure data from the PCCs are uploaded to the NPDS on a near–real time basis.²⁰ 

Federal and state legislation requiring child-resistant packaging for liquid nicotine containers was identified by using the Thomson Reuters Westlaw database.²¹ Official legislative databases for individual states were accessed for additional details as needed. A list was compiled of the effective dates for state legislation, defined as the date when it was illegal for liquid nicotine to be sold without child-resistant packaging in that state (Table 1).

Liquid nicotine exposures among children <6 years old from January 1, 2012, through April 30, 2017, were extracted from the NPDS by using the AAPCC generic codes for e-cigarette devices and liquids. In this study, we only included single-substance human exposures occurring within the 50 US states or District of Columbia with the reason “Unintentional – General.” Cases with a medical outcome of “confirmed nonexposure” or “unrelated effect” were excluded.

Liquid nicotine exposures were characterized by age and sex of the child, date of exposure, route of exposure, level of health care received, medical outcome, and “related” clinical effects. The AAPCC defines “minor effect,” “moderate effect,” and “major effect” for medical outcome as follows. “Minor effect” indicates that the individual developed some minimally bothersome signs and symptoms, typically limited to the skin or mucous membranes, which resolved quickly with no resulting disability or disfigurement. In a “moderate effect,” the individual exhibited signs or symptoms that were not life-threatening but were more pronounced, prolonged, or systemic than minor symptoms. Treatment was indicated, and the individual had no residual disability or disfigurement. In a “major effect,” the individual displayed life-threatening signs or symptoms, or symptoms that caused significant residual disability or disfigurement.²⁰ 

For this study, the 50 states and District of Columbia were dichotomized into states with and without a child-resistant packaging law for liquid nicotine containers (Table 1). States were considered to have such a law if that law went into effect before July 26, 2016, the date when the federal Child Nicotine Poisoning Prevention Act of 2015 (Public Law No. 114-116) went into effect.²² 

SPSS 24.0 (IBM Corp, Armonk, NY) and SAS Enterprise Guide 7.11 HF3 (SAS Institute, Inc, Cary, NC) were used to analyze data. Overall and state-specific exposure rates were calculated by using the July 1 US Census Bureau population estimates for children <6 years old for 2012–2016.²³ Exposure rates were only calculated for the years with 12 months of complete data (2012–2016). Trends for the monthly number of exposures were analyzed by using piecewise linear regression with breakpoints at November 2012 and January 2015. To assess the effect of the federal law for liquid nicotine child-resistant containers, only states without a similar preexisting law were included. The difference in number of exposures before and after the law was calculated for each state by using data from 9-month periods before (October 2015–June 2016) and after (August 2016–April 2017) the federal law went into effect. A paired t test was used to assess the equality of the mean number of exposures during the 9 months before and after the federal law went into effect. Statistical significance was determined by using α = .05. The institutional review board of the authors’ institution judged this study as exempt.

From January 1, 2012, to April 30, 2017, there were 8269 liquid nicotine exposures among children <6 years old reported to US PCCs. The median age of exposed children was 2.0 years (interquartile range = 1.3–2.0). The number of exposures (n = 3146) peaked at 1 year of age, and children <3 years old accounted for 83.9% (n = 6940) of exposures. Most (92.5%, n = 7649) children were exposed through ingestion and 55.3% (n = 4572) of exposures were among boys. More than one-third (35.1%, n = 2902) of exposed children were treated and/or evaluated and released, and 1.4% (n = 115) were admitted to the hospital. One-fifth of exposed children (20.3%, n = 1677) experienced a minor effect, followed by moderate effect (1.6%, n = 132) and major effect (0.1%, n = 8). One death occurred to a 1-year-old boy. One-fourth (24.6%, n = 2032) of children exposed to liquid nicotine experienced 1 or more related clinical effects. Severe clinical effects were rare, and included coma (n = 4), seizure (n = 4), respiratory arrest (n = 3), and cardiac arrest (n = 1).

For years with 12 months of complete data (2012–2016), the rate of liquid nicotine exposure was 6.4 exposures per 100 000 US children <6 years old. State-specific rates ranged from 1.6 (Washington, DC) to 22.2 (OK) (Fig 1). The overall exposure rate per 100 000 children increased by 1398.2% from 0.7 in 2012 to 10.4 in 2015, and subsequently decreased by 19.8% from 10.4 in 2015 to 8.3 in 2016 (Fig 2).

The monthly number of liquid nicotine exposures was lowest in February and July 2012 (8 exposures each month) and peaked in January 2015 (274 exposures; Fig 3). There was no significant change in the monthly number of exposures from January through November of 2012 (m = −0.3, P = .816), followed by a significant increase of 2390.1% (m = 8.6, P < .001) from November 2012 through January 2015, and then a significant decrease of 48.2% (m = −3.9, P < .001) from January 2015 through April 2017. From August 2016 (175 exposures), the first month after the federal Child Nicotine Poisoning Prevention Act went into effect, to April 2017 (142 exposures), there was an 18.9% decrease in the number of monthly liquid nicotine exposures.

Among states without a preexisting law, there was a significant difference (P = .002) in the mean number of exposures during the 9 months before compared with the 9 months after the Child Nicotine Poisoning Prevention Act of 2015 went into effect, averaging 4.4 (95% confidence interval: −7.1 to −1.7) fewer exposures per state during the 9 months after implementation of the law.

During the study period, there were >8200 exposures to liquid nicotine among children <6 years old reported to US PCCs. Although serious medical outcomes were not common, authors of previous studies have found that e-cigarette and liquid nicotine exposures more often are serious and result in health care facility admission than exposures to traditional cigarettes.^8,9 Previous reports have described the severe consequences that can occur from liquid nicotine exposure, including death.^7,–16 

The use of e-cigarettes has increased rapidly since their introduction in the United States in 2007. In 2009, 0.6% of US adults reported ever using an e-cigarette, with studies reporting increasing use.^2,24 The authors of a 2014 report indicated that 12.6% of adults had ever used an e-cigarette.²⁵ Younger adults (18–24 years old) have reported a high prevalence of e-cigarette use.²⁶ Among middle and high school students, e-cigarettes were the most commonly used tobacco product in 2016, with 4.3% and 11.3% reporting use, respectively.³ E-cigarette sales at convenience stores and other outlets grew from 2011 to 2015.²⁷ Furthermore, from 2014 to 2015, there was a 303.7% increase in e-cigarette liquid sales specifically.²⁷ Although nicotine-free products are available, 99.0% of e-cigarette products sold in the United States in 2015 contained nicotine.²⁸ 

As the use of e-cigarettes increased, so did the number of liquid nicotine exposures reported to US PCCs. The authors of 1 study reported that exposures among children <6 years old increased by 0.55 additional exposures per month between June 2010 and December 2012 and then accelerated to 6.03 additional exposures per month between January 2013 and September 2013.⁴ The authors of another study observed an ∼1500% increase in monthly e-cigarette and liquid nicotine exposures among children <6 years old from January 2012 to April 2015.⁸ Our study is the first to report a more recent reversal in this trend. In this study, the monthly number of reported liquid nicotine exposures climbed until January 2015, followed by an overall downward trend through April 2017.

In July 2014, the Child Nicotine Poisoning Prevention Act was initially introduced in the US Congress.²⁹ By mid-January 2015, at the peak of the children’s exposures, state legislation in New York, Minnesota, Vermont, and Illinois requiring child-resistant packaging for liquid nicotine containers had gone into effect. Fourteen additional states (Table 1) soon followed before the federal law’s effective date.²² During the 9 months after the effective date (July 26, 2016) of the federal law, there was an overall decrease of 18.9% in the monthly number of liquid nicotine exposures. Among states that had not previously enacted a similar state law, there was a significant decrease in the mean number of liquid nicotine exposures among children <6 years old when comparing the 9 months before and after the federal law. Although the federal law may have contributed to this decline, its impact is uncertain because of a number of potentially confounding factors and the lack of a comparison group. The frequency of exposures had been decreasing before its enactment. Various factors likely contributed to the observed decrease, including state legislation requiring child-resistant packaging; efforts by public health professionals, clinicians, and child safety advocates to inform child caregivers of the risk of liquid nicotine exposures; and widespread media attention. State legislation may have influenced child exposures even in states without liquid nicotine packaging laws because manufacturers may have begun to distribute child-resistant containers throughout the United States rather than produce different products for states with and without these requirements.

We were unable to detect differences in monthly liquid nicotine exposures before and after enactment of individual state legislation requiring child-resistant packaging for liquid nicotine containers because of the small number of exposures in individual states. Other factors also may have washed out the effects of these laws, such as continued presence of previously-purchased non–child-resistant containers in children’s homes. In addition, manufacturers and retailers were aware of the impending implementation dates of these state laws and may have begun to distribute child-resistant liquid nicotine containers before these dates.

Although child-resistant packaging requirements for liquid nicotine containers have been established, more comprehensive requirements could further reduce the likelihood of serious poisonings. Flow restrictors effectively limit young children’s ability to empty the contents of liquid medicine bottles.³⁰ Applying this technology to liquid nicotine bottles could limit the dose ingested by children who gain access to these bottles. Additionally, the Child Nicotine Poisoning Prevention Act only applies to liquid nicotine bottles and does not address the packaging or design of e-cigarette devices themselves. Chambers in refillable e-cigarette devices in which the liquid nicotine is held are another source of exposure. Child-resistant chambers in e-cigarette devices could help prevent liquid nicotine exposure among young children.

Liquid nicotine comes in a variety of candy, fruit, dessert, and other flavors that may be attractive to young children. By 2014, there were 7764 unique flavors found across all e-cigarette brands.³¹ The majority of exposures in this study occurred through ingestion, which is associated with the exploratory behavior common among young children, but also may be influenced by the attractiveness of liquid nicotine flavors, scents, and packaging to a young child. For instance, a bestselling e-liquid sold at an online site is named “Fruit Hoops” and has packaging that features images of colorful cereal.³² The American Academy of Pediatrics and other health organizations have called on the US Food and Drug Administration (FDA) to ban the use of flavors and attractive labeling for liquid nicotine.³³ 

E-cigarette liquid can be purchased at different nicotine concentrations, typically varying from 0 to 36 mg/mL.³⁴ Concentrated nicotine solutions, such as 60 mg/mL, are also available to consumers, who can then dilute and mix their own e-cigarette liquids.^16,34 A young child can easily ingest a lethal dose in 1 swallow.⁶ In 1 case report, a 15 month-old child died after ingesting a dose of 4.1 mg/kg of liquid nicotine.¹⁰ The 1 death in our study was previously reported.⁷ Fatalities from liquid nicotine poisonings could be prevented by limiting the volume and concentration of liquid nicotine packaged in containers to a sublethal dose for an average young child. This approach has been used for >50 years for such products as children’s aspirin.³⁵ 

Future research should be conducted to assess the effect of flow restrictors, flavoring, labeling, concentration, and other product-related factors on liquid nicotine exposure and outcome rates among young children.

The FDA passed a final rule on May 10, 2016, deeming all tobacco products, including e-cigarettes and liquid nicotine refill containers, under its authority. This required all e-cigarette products that went into market after February 15, 2007, to apply for FDA approval and also established several requirements that had to be implemented by varying deadlines.³⁶ However, in May 2017, the FDA announced delays in enforcement of future compliance deadlines for several of these requirements. Additionally, in July 2017, the FDA revealed a new regulatory plan that includes extending premarket review for e-cigarettes to August 2022 and seeking public comment on regulation of “kid-appealing flavors in e-cigarettes.”³⁷ In addition, the US Department of Justice has requested extensions in lawsuits that have challenged the FDA’s authority to enforce its deeming rule.³⁸ The final outcome of these actions will determine the FDA’s future role in regulating e-cigarettes and liquid nicotine.

This study has several limitations. Exposure calls to PCCs are voluntary; therefore, the NPDS underestimates the true incidence of exposures to liquid nicotine nationwide. NPDS data may not be representative of the entire spectrum of liquid nicotine exposures because of potential reporting bias. Exposures reported to PCCs do not necessarily represent ingestion, poisonings, or overdoses because exposures are not generally confirmed with definitive laboratory testing. Information provided to PCCs is by self-report, which cannot be completely verified by the PCCs or AAPCC. Differentiation of liquid nicotine exposures due to e-cigarette devices versus e-cigarette liquids was uncertain, thus limiting the ability to assess the impact of child-resistant packaging laws that only apply to e-cigarette liquid containers. Although calls to PCCs regarding liquid nicotine exposures have decreased since January 2015, the relationship of this decline with child-resistant packaging legislation is only an association; there are many other factors that may have influenced exposures and call rates. Despite these limitations, the NPDS is a comprehensive data source useful for investigating liquid nicotine exposures in the United States.

Liquid nicotine can pose a serious poisoning risk for young children. The frequency of liquid nicotine exposures among children <6 years old has decreased since January 2015, which may, in part, be attributable to adoption of child-resistant packaging laws for liquid nicotine containers and greater public awareness of the risks associated with these products. Additional measures, including child-resistant e-cigarette devices, use of flow restrictors on liquid nicotine containers, and regulations on e-cigarette liquid flavoring, labeling, and concentrations, could further reduce the incidence of these exposures and the likelihood of serious medical outcomes when exposures do occur.

AAPCC

American Association of Poison Control Centers

e-cigarette

electronic cigarette

FDA

Food and Drug Administration

NPDS

National Poison Data System

PCC

poison control center