A study examining the changes in cancer survival over the past 40 years has revealed that the difference in mortality between the married and never married, particularly between married and never married men, has increased. Håkon Kravdal from the University of Oslo and Dr Astri Syse from the Cancer Registry of Norway examined survival data from patients diagnosed with cancer between 1970 and 2007 and compared this to their marital status – married, never married, divorced/separated, or widowed. Results showed that the unmarried have a greater risk of mortality regardless of age, education, site of tumour, time since diagnosis, and cancer stage. Furthermore, over the 40 years examined during the study, the effect of never having been married on mortality increased from 18% to 35% for men and from 17% to 22% for women. The researchers conclude that there is no obvious explanation for the increasing disadvantage among the never-married. However Dr Syse suggests, "The differences in survival between unmarried and married people with cancer could possibly be explained by better general health at time of diagnosis or better adherence to treatment regimes and follow ups.”