This study confirms the findings of other studies, which also show that the number of poisonings in Norway is increasing (1, 4). It emerges, however, that there are major variations associated with age groups and gender. There has been a large and welcome reduction in the number of inquiries to out-of-hours services regarding poisonings in small children.
Reimbursement claims are prepared for all contacts with out-of-hours services, and we may therefore assume that all inquiries have been registered. There is also reason to assume that the information on gender, age, home municipality, time of inquiry and fee codes is correct.
The use of diagnostic codes is fraught with more uncertainty. Different doctors may have different interpretations regarding the choice of diagnostic code. Even though formal criteria for the use of the different codes are available, some may fail to check these inclusion and exclusion criteria in their daily clinical activities. For example, we may imagine that some doctors will use the diagnostic code P19 (drug abuse) when encountering patients who have been poisoned by illicit drugs such as heroin, amphetamine and GHB. We have not included this diagnosis, since its scope is much wider than poisonings. This may have caused poisonings by illicit drugs to be underrepresented in the material.
This lack of diagnostic precision is likely to be evenly distributed through the material, and we therefore believe that the differences registered between various groups and over time still remain valid, although in a somewhat diluted form.
There is reason to believe that the large cities differ from the rest of the country in a number of ways, but out of concern for privacy we have no information on affiliations with particular municipalities in our material. We have therefore been unable to calculate contact rates for different municipalities or regions. The A&E clinics in Oslo and Bergen have separate departments that deal with patients who have been poisoned by alcohol or drugs. In other parts of the country these patients may have been brought directly to hospital and thus escaped registration in our material. Moreover, the emergency ward at the Bergen A&E clinic is part of the specialist health services and thus also excluded from our material.
We have no overview of the degree of seriousness of the registered poisonings or what subsequently happened to the patients. Most deaths from poisoning occur outside hospitals and are caused by narcotic substances, most often heroin and various combination poisonings (1, 14, 15). These types of poisonings are most often dealt with by ambulance personnel. In many cases of poisoning the patient is also admitted to hospital directly without going through the out-of-hours services. In the years 2003 – 04, the Oslo ambulance service drove 28% of the patients directly to hospital and 31% directly to the A&E clinic. Of those who were taken to the A&E clinic, 16% were admitted to hospital (5).
The Oslo A&E clinic registered a doubling of the number of poisonings (in patients older than 12 years) in the period 2003 – 08 (8). We find that the total rate of contact with out-of-hours services due to poisoning has increased by 34% over the ten-year period 2006 – 15. The slower rate of increase in our material can be explained by the strong reduction in the number of poisonings in the youngest children, but it is also likely that increasing drug abuse will have a greater impact in a large city. We found that such poisonings were overrepresented in the largest municipalities.
Another study from Oslo found that the incidence of poisoning in children younger than 15 years, registered by hospitals and out-of-hours services, decreased from 230 per 100 000 inhabitants in 1980 to 97 per 100 000 inhabitants in 2003 – 05 (9). The incidence was highest in one-year-old boys (576 per 100 000 inhabitants), but extremely low in the age group 5 – 9 years (12 per 100 000). These figures accord well with our material, which shows that the strong reduction among the youngest children has continued through the last ten years.
This trend is likely to have a number of causes: information campaigns, individual prevention under the auspices of the mother and child clinics, more safety-minded parents, childproofing of dangerous bottles and cans, foul-tasting additives, removal of poisonous products etc. For example, in the period from 1980 to 2003 – 05, a 96% reduction in tobacco poisonings was recorded in children in Oslo (9).
Many of the poisoning accidents involving small children are relatively harmless and are frequently resolved with the Poison Information Centre without any contact between the child and the health services. This can be illustrated by the numerous telephone contacts that applied to this age group. For 2004 – 06, the Poison Information Centre registered approximately 35 000 inquiries regarding chemical products, whereof 38% concerned children aged 1 – 4 years, and 86% were assessed as harmless (2). Most likely, the increasing number of inquiries to the Poison Information Centre may explain the declining number of contacts with the health services (4).
In the Oslo A&E clinic, altogether 63% of the cases of poisoning involved men, most often with overdoses of alcohol and drugs (8). In our material, men had a 30% higher contact rate in both 2006 and 2015, with alcohol as the predominant cause. In addition, we should take note of the strong increase in the rate of contact due to poisonings among the middle-aged (the age group 53 – 59 years), primarily caused by the use of alcohol among men. This age group also contained a number of recurring patients. It is well known that poisonings are most prevalent in groups with poor living conditions, especially homeless people (16, 17). Possibly, alcoholics and the homeless are overrepresented among these recurring patients.
In the Oslo A&E clinic, poisoning by a medical agent was especially prevalent among young women (8). We made the same finding. With the exception of the very youngest children, contacts because of poisoning by a medical agent occurred more frequently for women than for men, and in the age group 15 – 25 years such poisonings occurred three times more frequently in women. More than 60% of all hospitalisations due to poisoning are caused by medical agents (14), and women are overrepresented in this group, young women in particular (7, 18).
While the poisonings in infants in terms of geography and time were distributed approximately equally to other contacts with the out-of-hours services, poisonings in adolescents were strongly overrepresented at night. Similar to the Oslo A&E clinic, we also found that these poisonings occurred more frequently during weekends (8). This corroborates our impression that poisonings in adolescents are largely associated with alcohol and substance abuse.
Cases of poisoning that are dealt with as telephone contacts must be assumed to be trivial. In addition to the fact that infants were overrepresented in this group, we also found relatively many telephone contacts that involved poisonings by a medical agent. In contrast to other substances, the amount of medical agent ingested will often be known, thus making it easier to ascertain whether the dose involved was harmless.