Poison control center reports: Meaningless numbers fuel misleading headlines

Nearly five years ago, headlines like, “People call poison control every 24 minutes because of dietary supplements,” “Calls to poison centers about supplements up 50%, especially among kids,” and “Dietary supplements are causing a spike in calls to poison control centers,” popped up after the publication of a study (J Med Toxicol. 2017 Sep;13(3):227-237) on dietary supplement exposures reported to U.S. poison control centers. The authors reported nearly 275,000 dietary supplement exposures reported to the National Poison Data System (NPDS) from 2000 through 2012, and an overall increase in the rate of exposures in that 13-year time period.

On the surface, the data seemed alarming; hence, the dramatic headlines. However, a closer look at the research revealed several shortcomings of the study and of poison control center data in general, compelling Safety Call International’s Rick Kingston, the National Center for Natural Products Research’s Ikhlas Khan and me to write a letter to the journal (J Med Toxicol. 2018 Mar; 14(1): 108–109) in response to the study. In that letter, we outlined the limitations and context that must be considered before drawing conclusions about the safety of dietary supplements.

A major flaw of the study was that several product categories included in the analysis involved products that are clearly outside the scope of dietary supplements. For example, homeopathic products, which are regulated by FDA as drugs, represented 36% of the “dietary supplement” dataset. Cultural medicines were also included as dietary supplements. For analyses of poison control center reports to be meaningful, they must be based on properly categorized or coded data.

The Council for Responsible Nutrition (CRN) requested that the American Association of Poison Control Centers (AAPCC) update the coding structure for dietary supplements to ensure the codes used by regional poison control centers and entered into the NPDS are consistent with the statutory and regulatory definition of dietary supplements. AAPCC representatives responded that the coding issue would be discussed at an upcoming meeting, but they made no further commitments.

While the absolute numbers reported for calls involving dietary supplement exposure in the study seemed high and were used to suggest trends, they lacked context. Without a corresponding comparison to sales data over the same period, exposure data are difficult to interpret.

This limitation of poison control data continues to be an issue. Most recently, a Centers for Disease Control and Prevention (CDC) report on melatonin exposures in children using poison control center data indicated that melatonin exposures in children increased by 530 percent during a 10-year period. What about melatonin sales? As noted in a June 8 statement from CRN, Nutrition Business Journal reported the market for melatonin increased 288 percent in the past five years alone. Also in the statement, CRN highlighted its own national consumer survey data showing the number of Americans using melatonin more than doubled from 5 percent of adults in 2012 to 11 percent of adults in 2021.

The CDC noted the year of greatest increase in reports was between 2019 and 2020 when poison control center ingestion reports increased by 37.9 percent. During that same period, melatonin sales increased by close to 40 percent, according to two different industry reports. Unavoidably, more use means more possibilities for accidental ingestion. News reporting of the increase in melatonin ingestion lacks this context and misleads parents about the potential dangers.

Media coverage about the melatonin study was also misleading in that the research was reported as a 530 percent increase in melatonin “poisoning” in children over the last decade. This misleading coverage grossly misrepresented the CDC research and raised undue alarm.

A reported ingestion to a poison control center does not mean “poisoning” or another adverse event occurred. If a parent calls a poison control center out of an abundance of care and caution about their child possibly ingesting a substance, that call gets counted as an exposure report regardless of the medical outcome. In the melatonin study, 98 percent of the reports of melatonin ingestion had an outcome of no effect or minor effect, and the overwhelming majority of children (83 percent) were completely asymptomatic. For the few reports associated with an adverse outcome, it is not possible to confirm whether the outcomes were caused by melatonin ingestion since poison control data do not include patient medical records.

When applied appropriately, poison control center data can be a useful tool to assess safety. A study on energy drink exposures reported to Texas poison control centers over a five-year period (Regul Toxicol Pharmacol. 2018 Aug;97:1-14) considered specific product types within the broad category of energy drinks, analyzed outcome severity by product type, and compared energy beverage exposures with sales data for the same period. Of the 855 documented energy drink exposures, 708 were determined to have no/minimal effects or judged as minor/not followed. Notably, the call rate to poison control centers for energy beverage exposures was 0.58 per hundred million units sold for moderate effects, and 0.053 per hundred million units sold for major effects.

The next time poison control center data are reported, look beyond the headlines, and ask these important questions: Were the appropriate data used? How many reports to the poison control center were associated with an adverse event, and of those, how many were minor effects?  Were the reports compared to sales data over the same period? Without answers to these questions, poison control center data are numbers without meaning.

Andrea Wong, Ph.D. is a toxicologist and senior vice president of scientific and regulatory affairs at the Council for Responsible Nutrition. Dr. Wong advises on emerging issues and provides scientific expertise in evaluating research relevant to the benefits and safety of ingredients and dietary supplements.