Carols by glow sticks: a retrospective analysis of Poisons Information Centre data

BC (before Christ), there were no risk mitigation strategies. A popular narrative could frame three wise men bringing gifts of a heavy metal and toxic essential oil products into the household of a young child, without any consideration of whether it might pose unacceptable risks and change history if it were accidentally consumed.1 BC (before consumer protection), products routinely contained undeclared toxic ingredients. BC (before childproof packaging), there were no secondary prevention measures for known toxic agents. Children were regarded as lucky if they survived the festive season without some sort of injury; be it envenomation, burns, drowning or poisoning. It is just over 50 years since poisons centres came into existence,2 along with a raft of public health injury prevention measures. It is therefore timely to ask what has replaced the annual festive season trip to the emergency department.

Poisons Information Centre (PIC) staff may not be the best people to ask. While everyone else is having fun on holidays, they are risking their health working shifts 24/7 in a poorly lit basement.3 Their usual view of the outside world is via television. However, some things are so obvious they could be seen even from outer space. The recent replacement of naked flames with safer chemiluminescent plastic rods known as glow sticks, light sticks or Cyalume (Cyalume Technologies) sticks (Box 1) has come to even our attention. Anecdotally, staff at the New South Wales Poisons Information Centre (NSWPIC) reported that these exposures cluster around weekends, holidays and the festive season. Previous studies have refuted anecdotal associations of celestial and worldly events with poisoning;4,5 we therefore felt that scientific research was required to provide an evidence base to support public health intervention.

The aim of this study was to document seasonality in glow stick exposures based on calls to Australia’s largest PIC, and to examine associations with school holidays, the festive season and summer.

Methods

Data source

Australian PICs provide round-the-clock poisoning advice free to members of the public and health care professionals who call 13 11 26.2 The NSWPIC is Australia’s largest centre, taking about 50% of the nation’s 200 000 poisoning calls annually.6 The NSWPIC takes calls from NSW, the Australian Capital Territory and Tasmania, with calls from other Australian states taken after hours on some nights as part of the national after hours roster. We searched the NSWPIC database for exposures to the substance code “Cyalume light sticks/glow toys” from 1 July 2013 to 30 June 2017. Age, sex and route of exposure were examined.

Statistical analysis

SAS 9.4 (SAS Institute) was used to analyse the data. Exposure counts per year were analysed using Poisson regression with a log link function with year as a covariate. Because daily exposure data was overdispersed, negative binomial regression was used with a log link function to determine incidence rate ratios with 95% confidence intervals for daily exposure counts. Covariates of interest were month of year (using deviation/effect coding), school holidays (defined as per NSW government school dates), holiday period (for the purposes of this study defined as 1 December to 7 January), and summer (1 December to 28 February). Owing to collinearity, models were fitted separately.

Ethics approval

This study was approved by the Sydney Children’s Hospitals Network Human Research Ethics Committee (LNR/16/SCHN/44).

Results

There were 2918 glow stick exposures over the 4-year study period. There was a negative trend with time, with a decrease of 13.0% per year (95% CI, − 16.2% to − 9.7%; P < 0.0001). The vast majority of exposures (2746 [94.1%]) occurred in children aged 14 years and younger (Box 2). Most exposures involved ingestions (eg, a child chewing on a glow bracelet), followed by ocular exposures (a splash from a burst glow stick) (Box 2). Most callers (2663 [91.3%]) were advised to stay home, with only 15 (including 13 ocular exposures) referred to hospital. The first aid for glow stick exposures is simple (Box 3), and they very rarely require any medical attention. A further 201 calls (6.9%) originated from hospitals; 1300 (44.6%) were symptomatic at the time of the call, of which 593 involved ocular exposures (66.3% of ocular exposures were symptomatic).

The Toxic Christmas Quiz (Box 4) shows that daily exposure counts for glow stick exposures have such marked peaks that they resemble an electrocardiogram. Peaks from increased exposures are evident in December, particularly on New Year’s Eve, and in January on New Year’s Day. A further peak is seen at Halloween (Box 5).

A negative binomial regression was run on calls made in 2015 and 2016 to predict daily glow stick exposures based on month of the year, school holidays, the holiday period and summer. Glow stick exposures were 4.38 times more likely in December (95% CI, 3.02–6.35; P < 0.001), when compared with the overall mean count. Statistically significant increases were also observed in October, November, January, February and March (Box 6). Glow stick exposures were 4.20 times more likely during the holiday period (95% CI, 3.42–5.15; P < 0.001), 2.52 times more likely over summer (95% CI, 2.12–3.00; P < 0.001), and 1.77 times more likely during school holidays (95% CI, 1.47–2.13; P < 0.001).

Discussion

Australian Christmas celebrations and fire bans mean “carols by candlelight” has been replaced with “carols by glow sticks”. A Google search finds hundreds of thousands more hits for “glow stick” compared with “candlelight” combined with “Australia” and “carols”. The glow stick should be an annual reminder of how much safer the world is today for children in Australia. The vast majority of calls related to accidental paediatric exposures, primarily ingestions and ocular exposures. Very few people required hospitalisation (although about 7% of calls originated from hospital), reflecting the low toxicity of these products. Of the 15 patients that the NSWPIC referred to hospital, 13 were ocular exposures, and ocular exposures were more likely to result in symptoms at the time of call.

Light has both visual and non-visual impacts on the human body and has been shown to influence mood and behaviour.7 Glow sticks emit specific, narrowband wavelengths of light (in contrast to candles). We speculate that when Australian children are under the influence of this light or simply the festive season, they try to “taste” the colour.

This study demonstrates that glow stick exposures are heavily influenced by human behaviour and are therefore largely preventable. Similarly, studies from the United States report increased glow stick exposures at Halloween,8 the Fourth of July weekend,9 and on weekends and public holidays.10 Thus, these exposures are related to recreational activities. Interestingly, Danish PICs only receive 25 calls per year regarding glow sticks,11 likely indicating better regulation of availability and usage, a lack of festive outdoor events, or a genetic insensitivity to the drug-like properties of light. We will be seeking funding to support a fact-finding delegation next winter to determine whether we can learn from their experience (parliamentarians need not apply).

Poisons centres in Australia are at their busiest in summer (with an increase in bites and stings calls), and seasonal glow stick exposures add to this burden. Although glow stick exposures are generally benign, these calls still cost centres time and resources during the busiest time of year. On average, NSWPIC staff take 50–70 calls per 8-hour shift, so the extra workload of the ∼ 50 glow stick calls on New Year’s Eve is substantial. Indeed, the NSWPIC has taken to rostering an additional staff member on New Year’s Eve. If our delegation solves this problem, another staffer could enjoy New Year’s Eve.

Cases reported here and in other studies10 indicate that acute exposures to glow sticks are relatively benign. The 2015 annual report from US poisons centres indicated that of the 17 108 exposures to glow products, there were no major outcomes or deaths.12 Despite this, we should still attempt to reduce the frequency of these events. Ocular irritation caused by glow sticks, in addition to irrigation for first aid, can be painful and traumatic for young children. Gastrointestinal upset and the burning sensation resulting from glow stick exposures can cause distress. Further, there is potential for aspiration in glow stick exposures. There is also an obstruction/foreign body hazard from the plastic casings.10 Education and prevention efforts could be targeted towards parents and children.

Active ingredients of glow sticks include anthracene, oxalates and dibutyl phthalate. While dibutyl phthalate is capable of causing severe morbidity and mortality when consumed in large quantities, it is present in minimal concentrations in glow sticks.10 Phthalates are potential endocrine disruptors; however, this risk is presumably from chronic exposure as opposed to acute poisoning.13 Labelling on Australian glow sticks is often minimal or non-existent. Perhaps labelling of phthalate content would deter parents from giving glow sticks to young children. However, this runs the risk that parents might go back to the more dangerous Paleo glow stick (candles) or the Neo glow stick (candles and flashing lights powered by button batteries, which can cause severe burns and death if ingested14). We may just have to accept that this current very low risk is part of New Year’s Eve in modern Australia. However, we call on Australian parents this festive season, as they watch children happily using glow sticks, to make a New Year’s resolution that is easily kept. Clean out the far more toxic products that are the leading cause of hospitalised and fatally poisoned children — unwanted medicines and chemicals.15-17

Box 1 – Australian children celebrating with glow sticks

Box 4 – Toxic Christmas Quiz: pick which image shows the marked periodicity in daily number of calls about glow sticks (July 2013 to June 2017) versus an electrocardiogram of a patient with poisoning over 4 seconds*

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* Bonus points if you can work out the type of poisoning.

Box 5 – Toxic Christmas Quiz solution: marked periodicity in daily number of calls about glow sticks (July 2013 to June 2017)*

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* Answer: A. Green dotted lines show Halloween, blue dotted lines indicate New Year’s Day. Bonus points: B was a patient with lithium poisoning.