cosmic rays, ct scans and education: additional factors that might influence longevity and mortality in norway

It has previously been reported that differences in life expectancy can be linked to income. in norway, a registry-based study that included all norwegian residents aged ≥ 40 years (2005-2015) was performed. this study showed substantial and increasing gaps in life expectancy by income level during the interval between 2005-2015. compared to the united states, the largest life expectancy differences were for individuals in the lower to middle part of the income distribution, although differences were observed at all income levels. despite its undeniable strengths and although this paper can be considered as a significant contribution to this field, it has some shortcomings. the first shortcoming of this study is due to ignoring the effects of population exposures to natural and man-made ionizing and non-ionizing radiation on life expectancy. another shortcoming arises from ignoring the strong impact of education on lifestyle. in summary, what is observed in this study might be at least to some extent, due to education-related changes in lifestyle and not necessarily income (despite the mutual links between education and income).