The summer of 2018 was unusually warm in South-Eastern Norway (8), but we found no excess mortality among older people (over 75 years) in this period when compared to the preceding ten years. This contrasts with studies from Sweden and Finland, as well as from countries in Central and Southern Europe, which have shown excess mortality among older people related to heatwaves (4–7). There may be a number of reasons for this. First, there are relatively few deaths and thereby large confidence intervals, and the temperatures have not been as high as in heatwaves further south in Europe. We have not checked for excess mortality in smaller geographical areas or over shorter periods, caused by many consecutive days with a high mean temperature. Vest-Agder county stands out in terms of a higher number of deaths among persons older than 75 years. Most likely, this is a random finding, supported by the fact that three counties, including neighbouring Aust-Agder, had fewer deaths. We have not studied deaths in smaller population groups, for example older people living in city centres or in areas with poor living conditions. However, a study from Sweden points to little effect of socioeconomic factors (7).
Although there was no excess mortality, the heat may have given rise to increased morbidity, including for reasons such as dehydration, falls and exacerbation of chronic illness. Good family and neighbourly relations and well-functioning home-based services and health services may have counteracted increased mortality. Norway has no official alert service for extreme temperatures, but media focus with recommendations for measures may have had a positive effect. Our results provide no strong arguments for establishing an official alert service similar to what is found in other countries (10), but this may become more relevant in the future (11).
Although we failed to find any excess mortality, there is reason to study and monitor possible adverse effects of extreme temperatures on vulnerable population groups, such as older people, the chronically ill and substance abusers. In particular, there is a need for more research that can elucidate environmental, climate-related and individual factors that have a bearing on morbidity and mortality. This will be especially important since the prognoses for climate change indicate that we will see more periods with high temperatures.