PURPOSE: To demonstrate the value of poison control data as an adjunct to national drug abuse surveys and a source of data to inform and focus prevention efforts.
METHODS: National Poison Data System (NPDS) data are collected and compiled in real time by the 60 US poison centers as callers seek guidance for poison exposures. Demographic, geographic, product, outcome, and treatment-site data for the 35453 inhalant cases reported between 1993 and 2008 were analyzed.
RESULTS: The prevalence of inhalant cases reported to US poison control centers decreased 33% from 1993 to 2008. Prevalence was highest among children aged 12 to 17 years and peaked in 14-year-olds. In contrast to national survey data showing nearly equal use of inhalants by both genders, 73.5% of NPDS inhalant cases occurred in boys, which suggests that boys may pursue riskier usage behaviors. Most cases (67.8%) were managed in health care facilities. More than 3400 different products were reported. Propellants, gasoline, and paint were the most frequent product categories. Propellants were the only product category that substantially increased over time. Butane, propane, and air fresheners had the highest fatality rates. Prevalence for all inhalants was highest in western mountain states and West Virginia, but geographic distribution varied according to product type. Gasoline was a proportionately greater problem for younger children; propellants were an issue for older children.
CONCLUSIONS: NPDS should be used to monitor inhalant abuse because it provides unique, timely, and clinically useful information on medical outcomes experienced by users, includes detailed product information (brand and formulation), and can potentially be used to identify real-time demographic, geographic, and product trends. Focusing inhalant prevention efforts on the most hazardous products and most seriously affected users may improve and facilitate strategic prevention, enabling interventions such as targeted education, product reformulation, repackaging, relabeling, or prohibition of sales of especially hazardous inhalant products to youth.
WHAT'S KNOWN ON THIS SUBJECT:
Despite declines in the late 1990s, inhalant use remains a problem, with estimated lifetime use among US teenagers ranging from 10% to 15%. Ongoing national surveys have shown usage trends, but surveillance of health hazards and products implicated has been limited.
WHAT THIS STUDY ADDS:
Poison control data should be used to monitor inhalants and focus prevention efforts on the most harmful products. Propellants have emerged as the most frequently implicated products and butane as the most lethal. Despite comparable usage by both genders, boys have more severe outcomes.
Three ongoing national surveys track substance-use trends in the United States and have shown that, despite declines in the late 1990s, inhalant use remains a problem, with estimated lifetime use among US teenagers ranging from 10% to 15%.1,–,3 The surveys include Monitoring the Future (MTF), an annual survey regarding behaviors and values that is administered to 8th-, 10th-, and 12th-graders; the National Survey on Drug Use and Health (NSDUH), an annual survey regarding drug use and mental health that is administered to US residents older than 12 years; and the Youth Risk Behavior Surveillance System (YRBSS), a nationally representative biennial survey of high school students.
The ongoing results of these 3 surveys currently guide inhalant abuse– prevention efforts. These surveys have limitations, however. Each depends on self-reporting, focuses on specific age ranges, ignores younger children, and has limited information on the specific volatile substances implicated. Two of the surveys treat all inhalants as a single class of abused substances, and the third (NSDUH) addresses only 10 product types.
The Drug Abuse Warning Network (DAWN) has also been used to monitor trends in inhalant abuse. Unlike the 3 national surveys, DAWN focuses on cases with adverse events, including inhalant-related emergency department visits from a representative sample of US hospitals and inhalant deaths reported to medical examiners.4 However, inhalants in DAWN are treated as a single class, which prevents analysis of outcomes, trends, and demographics according to product.
This study was undertaken to explore the use of US poison control data as an adjunct to national drug abuse surveys and to update a previous analysis of inhalants reported to US poison centers through 2001.5 US poison control data are collected by all 60 US poison centers by using standardized data fields and definitions, and inquiries are handled by nurse and pharmacist specialists in poison information. Data are submitted in real time to the National Poison Data System (NPDS) for compilation and analysis. Each fatality is reviewed before inclusion.
Poison control data focus on medically significant inhalant exposures and, thus, may provide an important perspective for monitoring and prevention. In addition, poison control data provide coverage of the entire US and include hospitalized and nonhospitalized patients of all ages. With >350 000 product codes, poison control data may provide more detail on specific products implicated and the ability to track emerging product trends.
Data on inhalant exposures reported to US poison centers from 1993 through 2008 were obtained from NPDS. All human cases with an exposure route of “inhalation” and exposure reason of “intentional abuse” were included. Intentional abuse was defined as “an exposure resulting from the intentional, improper or incorrect use of a substance where the victim was likely attempting to achieve a euphoric or psychotropic effect.”6 Cases were excluded if the implicated substances did not meet the National Institute on Drug Abuse definition of an inhalant: a volatile substance that is “rarely, if ever, taken by any other route of administration.”7 Examples of excluded substances are tobacco, cocaine, marijuana, methamphetamine, and pharmaceuticals formulated as pills.
Data analyzed included date of call, product implicated, age, gender, caller zip code and state, medical outcome, management site, and level of health care provided. NPDS provides 10 options for documenting medical outcome, including the following 5 definitive outcomes, all of which are a direct result or complication of the exposure, with adequate follow-up for accurate categorization:
No effect: no signs or symptoms resulted from the exposure.
Minor effect: minimally bothersome signs and symptoms, resolved rapidly without residual disability or disfigurement.
Moderate effect: more pronounced, prolonged, or systemic signs or symptoms, usually required treatment.
Major effect: life-threatening signs or symptoms or the patient manifested significant residual disability or disfigurement.
Death: a fatality occurred as a direct result or complication of the poison exposure.
Five additional medical outcomes are defined elsewhere and include not followed, nontoxic exposure; not followed, minimal clinical effects possible; unable to follow, potentially toxic exposure; unrelated effect; and confirmed nonexposure.6 Cases coded as “confirmed nonexposure” were excluded.
Prevalence rates determined for the entire study period were based on US Census Bureau July 1, 2000 (study midpoint), estimates according to single year of age or gender, as applicable.8 State-specific population estimates for each year were used to determine the average annual prevalence for each state for 2005–2008.9 The Cochran-Armitage trend test was performed to assess the significance of trends. Frequency differences in products used according to age, gender, and geographic groups were analyzed.
To compare severity according to product, a hazard index and fatality rate were calculated for each product and product category. The hazard index was defined as the number of single-substance cases with a major effect or death per 1000 single-substance cases involving the product.10 The fatality rate was defined as the number of deaths per 1000 single-substance cases involving the product. Analyses were restricted to single-substance cases to eliminate confounding clinical effects possibly attributable to other substances. If the hazard index or fatality rate differed substantially between products that were significant contributors to a product category, the product's hazard index and fatality rate were reported instead of the product-category values. Although analyses of the hazard index, fatality rate, and outcome involved only single-substance exposures, calculations of frequency according to product category included cases that were counted more than once if they involved multiple substances. Cases were reported only once for the analyses of all other variables.
Analyses, graphing, and mapping were conducted by using SAS 9.1.3 (SAS Institute, Inc, Cary, NC), Microsoft Office Excel 2007 (Microsoft Corp, Redmond, WA), and ArcGIS 9.2. (ESRI, Redlands, CA).
This study was exempted from review by The George Washington University institutional review board.
A total of 35453 inhalant-abuse cases met inclusion criteria. The mean annual prevalence of inhalant cases reported to poison control centers was 8.33 cases per million for all ages and 47.28 cases per million for 12- to 17-year-olds. The prevalence of inhalant cases for all ages decreased steadily for the first 11 years of the observation period from a peak of 11.86 cases per million in 1993 to a low of 6.51 per million in 2003 (P < .0001, Cochran-Armitage trend test). Subsequently, rates trended slightly upward to 7.92 per million in 2008 (P < .0001). For 12- to 17-year-olds there was also a significant decrease in prevalence, which decreased from 73.0 cases per million in 1993 to 33.2 cases per million in 2003 (P < .0001), but there was no significant change from 2003 onward (P = .24). (Table 3 and Figure 6, which are published as supplemental information at www.pediatrics.org/content/full/125/5/906.) Prevalence varied according to state (Fig 1), with the highest rates in western mountain states and West Virginia.
Prevalence increased with age to a peak at 14 years and then decreased steadily thereafter (Fig 2). The median age was 16 years (interquartile range: 14–22). Males comprised 73.5% of cases with known gender (1.1% unknown). For children younger than 18 years, the rate of inhalant cases was substantially higher among boys than girls, although the difference narrowed over the observation period, largely because of a more rapid decline in the rate among boys. (Supplemental Information, Fig 7.) Throughout the study period the highest prevalence rates of inhalant cases were consistently seen in 14- to 15-year-olds and the gender gap was present in each pediatric age group. (Supplemental Information, Figs 8 and 9.)
Of the cases with a definitive outcome (22 311), 0.9% (208) died, 4.5% had a major (life-threatening or disabling) outcome, 30.7% had a moderate effect, 38.4% had a minor effect, and 25.4% had no effect. Outcome was unknown for 11 980 cases and unrelated for 1162 cases.
Most cases (67.8%) were managed in a health care facility, and 71.1% of those were already there at the time poison control was consulted (unknown management site, 2.0%). The majority of patients treated in a health care facility (55.6%) were treated and released, predominantly from emergency departments; 10.2% of cases were admitted to critical care units, 6.9% to non–critical care units, 7.7% to psychiatric units, and 19.7% received an unknown level of care.
More than 200 inhalant product categories and 3410 different inhalant products were implicated. A single substance was implicated in 85% of cases, 2 substances in 11%, and 3 to 22 substances in 4%. In cases that involved more than 1 substance, alcohol (23.3% of multiple-substance cases), marijuana (12.8%), cocaine (9.9%), benzodiazepines (3.7%), and methamphetamine (2.6%) were the noninhalants most commonly used with an inhalant.
Table 1 lists the 20 most frequently implicated product categories; these categories were reported in >80% of the cases. Propellants, the largest product category, were involved in 15.6% of cases. More than half of the identified propellants were aerosol dusters (eg, computer and electronics duster sprays), and another 38.8% were fluorocarbons from products other than dusters. Gasoline was the second most frequently implicated product (13.1%), followed by paint. At least 81.8% of known paint products were aerosols. Other hydrocarbons (such as paint thinner and lighter fluid) and asphyxiants (including butane, helium, and propane) rounded out the top 5 categories.
The overall hazard index for all single-substance inhalant exposures was 29.0, and the fatality rate was 5.5 deaths per 1000 single-substance cases. Table 2 lists the hazard index and fatality rate for the 25 most frequently implicated products in single-substance exposures; these products accounted for 74% of all single-substance exposures.
The highest fatality rates were seen with butane (58.1), propane (25.9), air fresheners (21.8), and nitrous oxide (13.7). Butane also had the highest hazard index (88.7), followed by carburetor cleaners (82.5). Paint and gasoline, 2 of the most frequently implicated substances, had low fatality rates (1.6 for both) and hazard indices of 28.0 and 18.2, respectively.
The prevalence of cases that involved gasoline, paint, and other hydrocarbons have all decreased over time and currently have a rate of ∼5 cases per 10 million people (Fig 3). In contrast, cases that involved propellants, which had a steady rate throughout the 1990s, sharply increased after the year 2000 to ∼30 cases per 10 million people in 2008. Propellants had a substantially higher rate than any other product category between 2004 and 2008; the geographic emergence of propellant use is shown in Fig 4. Differences in the geographic distribution of cases involving gasoline, paint, hydrocarbons, and asphyxiants are apparent for the period between 2005 and 2008. (Supplemental Information, Figs 10–13.)
In children younger than 18 years, the products implicated differed according to gender and age. (Supplemental Information, Tables 4 and 5.) Boys comprised 72% of cases overall but accounted for 86% of the gasoline cases. Although girls comprised only 28% of the cases, they were involved in 41% of the air-freshener cases, 60% of the hair-spray cases, and 73% of the cases that involved nail products (such as nail polish and remover).
Figure 5 shows recent distributions according to age for the 7 products most frequently implicated in children. Gasoline was involved in >50% of cases among 6- to 7-year-olds but became a steadily smaller contributor in older children. Conversely, propellants become a steadily larger contributor, accounting for 38% of cases among 16- to 17-year-olds.
The frequency of exposures to pharmaceuticals and household products in NPDS parallels product market share, use, and accessibility.11 As new inhalant products are marketed and become popular, they can be expected to emerge as potential new hazards. In contrast, the severity of exposures to a particular product is often unrelated, or even inversely related, to exposure frequency; the latter finding presumably reflects concern about toxicity, which affects product purchase, use, household storage practices and prescribing. The correlation of frequency of exposure with product use suggests that the frequency of NPDS inhalant cases may mirror the frequency of inhalant use observed in national surveys, although direct comparisons are difficult because such surveys are designed to answer different questions and use different data definitions.
NPDS shows declines in cases involving 12- to 17-year-olds between 1993 and 2003 and stable rates from 2003 to 2008. Similarly, 8th-, 10th-, and 12th-graders in the MTF survey demonstrated declining use between 1995 and 2001 and subsequent modest fluctuations.2 NSDUH data also show that use of inhalants among 12- to 17-year-olds remained stable between 2002 and 2007.3,12 NPDS reported the highest prevalence for 14- to 15-year-olds, consistent with observations in the NSDUH (new users are more likely to be 14 or 15 years old13), the MTF (highest annual prevalence of inhalant use in 8th-graders compared with older students2), and the YRBSS (higher lifetime use prevalence among 9th- and 10th-graders than 11th- or 12th-graders1).
Boys accounted for 73.5% of NPDS cases with known gender, and the analysis according to product showed more girls than boys only in cases that involved hair sprays or nail products. Although the gender gap in NPDS shrank considerably from 1993 to 2008, the rate for males remained twice the rate for females. This gender gap is not typical of other types of poison control cases. In NPDS data from 1993–2008, females accounted for 50.8% of all human poison exposures reported to poison centers and 55.6% of cases that involved teenagers.14
The greater prevalence in boys in NPDS was not seen in youth in US national usage surveys. In the NSDUH (2002– 2005), 12- to 17-year-old boys and girls were equally likely to report past-year inhalant use.15 YRBSS 2007 data indicated that lifetime prevalence was actually slightly higher among high school girls than boys.1 The MTF showed similar rates for boys and girls for 8th- and 10th-graders.2 The discrepancy between NPDS and national usage surveys suggests that although inhalant use occurs with similar frequency in both genders, boys may indulge in riskier use behaviors, such as inhaling larger doses and more concentrated substances, prolonging usage episodes, selecting more hypoxic delivery methods, and using more toxic inhalants. Likewise, data from the United Kingdom have shown that mortality associated with inhalant use has consistently been disproportionately higher among males, with males accounting for 85% of all reported deaths between 1971 and 2007, despite comparable usage rates in both genders.16
As a group, inhalants, with a hazard index of 29.0 and fatality rate of 5.5 deaths per 1000 cases seem to be more dangerous than typical poison center cases, and even more dangerous than most substance-abuse cases. In 2007, the hazard index for all nonpharmaceutical exposures reported to poison centers was 2.0 and the fatality rate was 0.14; for pharmaceutical substances, the hazard index was 7.0 and fatality rate was 0.4.6 Thus, the hazard index and fatality rate were significantly greater for inhalant cases than for other pharmaceutical or nonpharmaceutical poison control cases (Pearson's χ2, P < .0001 for both measures).
Combined poison control data from 1993–2005 for all reported substance abuse by teenagers shows the comparison of inhalants to other substances of abuse. The fatality rate of 5.5 seen in this study was lower than that seen in teenaged substance abuse cases involving heroin (13.5) but higher than teenaged substance abuse cases involving methamphetamine (3.7), oxycodone (3.6), and cocaine (2.2) (NPDS, unpublished data, 2006). Butane (58.1), propane (25.9), and air fresheners (21.8) all had fatality rates higher than any of these substances of abuse. The high fatality rate associated with butane is supported by data from the United Kingdom, where gas fuels (predominantly butane) were implicated in 66% of all reported inhalant-related deaths between 1998 and 2007.16 The high fatality rate observed with inhalants, and the observation that it is disproportionately high relative to the hazard index (compared with pharmaceuticals and nonpharmaceuticals), likely reflects the occurrence of sudden death with inhalants and is troubling in the context of data showing that teenagers increasingly perceive inhalant use to be less harmful or less risky to one's health. Results from MTF indicate that the percentage of 8th- and 10th-graders who see “great risk” in using an inhalant once or twice declined steadily between 2001 and 2008.17 Lower perceived risk of using a substance often precedes an increase in use of that substance.
The prevalence of cases that involved propellants among 12- to 17-year-olds nearly doubled in the NPDS from 2002 to 2007 (from 7.6 to 14.6 cases per million population). The NSDUH also revealed a doubling in the percentage of past-year inhalant initiates reporting use of aerosol sprays other than spray paints from 2002 to 2007, which rose from 12.6% to 25.0%.12
Because poison control data are collected and analyzed in real time, NPDS has potential for use in the timely surveillance of demographic or geographic patterns of inhalant use and emerging inhalant-product hazards. These surveillance capabilities are currently deployed at the regional level by individual poison centers and nationally by the American Association of Poison Control Centers to detect chemical and bioterrorism and other public health incidents.18 Had such surveillance also been in place for inhalants, the emergence of propellants as the most commonly implicated inhalant-product category in 2001 could have been detected rapidly (Fig 3).
Because of the passive nature of data collection in NPDS,* known underreporting, and the limitations of telephone data-gathering, these results have limited generalizability. In addition, substance abusers may be even less reliable historians than the average poison center caller. Medical outcome was unknown for more than one-third of the cases in which follow-up was not adequate to definitively determine outcome. Because calculation of the hazard index and fatality rate assumed that all cases with unknown outcome did not result in a major effect or death, the hazard index and fatality rates are conservative estimates.
NPDS adds valuable information to the existing surveys used to monitor inhalant use in the United States. NPDS provides unique information on medical outcomes experienced by inhalant users, collects highly detailed product information including data on brand and formulation, has the potential to facilitate identification of real-time demographic, geographic and product trends, and can be used to signal emerging new inhalant hazards. The strength of poison control data lies in its usefulness for rapid identification of serious medical outcomes associated with different inhalant users and the various products inhaled, which focuses the public health response on the more important, medically severe inhalant-abuse scenarios and products rather than on abuse frequency. Effective prevention depends on early recognition; thus, implementation of ongoing regional and national NPDS surveillance of products implicated and exposure outcomes is essential. Through advocacy and collaborations with industry and regulatory and public health agencies, real-time detection of emerging inhalant-product hazards could lead to more rapid implementation of targeted prevention efforts such as (1) education of parents, teachers, and health professionals to facilitate early identification of inhalant users, (2) product reformulation with safer substances or noxious deterrents, (3) product repackaging to deter inhalation and access, (4) labeling changes to enhance warnings, and (5) prohibition of the sale of especially hazardous inhalant products to youth.
- Accepted December 14, 2009.
- Address correspondence to Toby L. Litovitz, MD, National Capital Poison Center, 3201 New Mexico Ave, Suite 310, Washington, DC 20016. E-mail:
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
↵* The American Association of Poison Control Centers (www.aapcc.org) maintains the national database of information logged by the 60 US poison control centers. Case records in this database are from self-reported calls; they reflect only information provided when the public or health care professionals report an actual or potential exposure to a substance (eg, an ingestion, inhalation, or topical exposure) or request information. Exposures are not necessarily poisonings or overdoses. The AAPCC is not able to completely verify the accuracy of every report made to member centers. Additional exposures may go unreported to poison control centers, and data referenced from the AAPCC should not be construed to represent the complete incidence of national exposures to any substance(s).
- MTF =
- Monitoring the Future •
- NSDUH =
- National Survey on Drug Use and Health •
- YRBSS =
- Youth Risk Behavior Surveillance System •
- DAWN =
- Drug Abuse Warning Network •
- NPDS =
- National Poison Data System
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