Poisoning incidence and living conditions
The incidence of poisonings by substances of abuse was higher, the poorer the living conditions. This is in line with previous findings among patients treated for acute poisoning in hospitals in Oslo (11), but our study showed a clearer association. One possible explanation could be that our material consisted of poisonings by substances of abuse, whereas the hospital study included cases related to substance abuse as well as attempted suicides, and thus included a wider panorama of toxic agents. Most likely, the known association between acute poisonings and poor living conditions (4, 5) is strengthened by the negative consequences of long-term substance abuse (18).
The association between poor health and low socioeconomic status can be explained by influence, in which poor living conditions cause poor health, as well as by selection, in which poor health increases the risk of having poor living conditions (19, 20), for example through exclusion from the labour market. It has also been demonstrated that a high degree of social inequality in a society is alone a factor that contributes to poorer public health (21).
In our material, the incidence of poisoning by substances of abuse was higher in the older age groups, the poorer the living conditions in the living conditions group (Table 3). This phenomenon could be due to selection, meaning that persons with risky substance-abuse behaviour over time end up in districts with poor living conditions, where housing is cheaper and the density of municipal housing is higher (9). However, this phenomenon could also be caused by influence – an effect of poor living conditions over time. Similarly, the falling incidence with higher age in living conditions group I could be an effect of good living conditions over time, but may also have been caused by selection if persons with risky substance-abuse behaviour tend to move out of the district.
It is conceivable that patients who come from a wealthier background are cared for at home by their resourceful next of kin, while patients from a poorer background are picked up on the street and brought to the casualty clinic. On the other hand, it is also imaginable that people living in poor conditions are more habituated to substance-abuse behaviour and their threshold to seeking help may therefore be higher. We are not aware of any studies about this, but we deem it unlikely that this would change the main findings in our study.
The highest incidences of acute poisoning by substances of abuse were found in the central districts (St. Hanshaugen, Gamle Oslo, Grünerløkka, Sagene and Frogner). Most likely, this is due to the fact that social and demographic conditions in the central city districts, in addition to living conditions, have an effect on the incidence of poisoning by substances of abuse. For example, these districts have a considerable proportion of childless couples and young adults (9, 16).
There was no difference in incidence between the living conditions groups among persons younger than 36 years. Weekend binge drinking is common among youth and young adults in Oslo (14), and it may appear that such behaviour is associated with this age group across the variety of living conditions in the districts.
Of all districts, St. Hanshaugen had the highest incidence, which may be related to the fact that many housing programmes for substance abusers are located there. Many of the residents are registered at the address of their housing programme, but not all.
The districts of Søndre Nordstrand, Stovner and Grorud all have relatively poor living conditions, but nevertheless had relatively low incidences of poisoning within their living conditions groups (II and III). The Alna district had the lowest poisoning incidence in living conditions group III. These districts have the city’s highest proportion of non-western immigrants, approximately 40 % of the inhabitants (22). Many of the non-western immigrants are Muslims, who tend to be associated with less frequent substance abuse (23). Similar findings were also made in the previous study of patients treated in hospitals (11).