Across diseases, women are diagnosed later than men

'When we look across all diseases, we see a tendency that women on average are diagnosed later than men. We have looked not just at diseases, but also at the course of the patient care. Our study zooms in on the areas where the differences are most pronounced -- both for the individual diseases and for the course of the patient care. The message is that the national strategies that are established need to take a difference into account. We can no longer use the 'one size fits all' model. We are already heading in that direction with respect to personalised medicine,' says last author and Professor Søren Brunak, the Novo Nordisk Foundation Center for Protein Research.

The researchers analysed data from 6.9 million Danish people. The population was divided into two groups according to their sex. Over a 21-year period, from 1994 to 2015, the researchers have e.g. analysed the occurrence of all types of diseases, multimorbidity, where you suffer from more than one disease, and courses of patient care. They found that women on average are older when they are diagnosed compared to men. The entire sequence of the women's and men's patient care course was different and time-staggered.

In connection with ADHD, there was a difference of almost six years between the time when the two groups were diagnosed with the disease. The boys were about 14 years old, while the girls were about 20 years old. Here, according to the researchers, some studies point out that the reason for the difference is that women have a different subtype of ADHD, which manifests itself in a quiet and solitary manner as opposed to the externalising behaviour often seen in boys with ADHD.

Osteoporosis Was the Exception

Osteoporosis was one of the exceptions where women were diagnosed first. Here, women were typically diagnosed before they suffered a fracture caused by the disease, while the course for men was the opposite. They were typically not diagnosed until they turned up at the emergency room with a fracture.

Scientists do not yet know whether the differences are due to genetics, environment, diagnostic criteria or a mixture hereof. They are currently investigating this in their next step in collaboration with a research team from Finland. But they believe that there is a need to think about the sex right from the start of the research in tests with rats and mice.

'It has been surprising to see that there is such a big difference between the diseases that affect men and women and between their patient care courses in a society where otherwise, we have equal and uniform access to the healthcare system. Now we are trying to map out what really lies behind the differences we see. Can they e.g. be attributed to genetics or environment and culture?' asks first author and Postdoc David Westergaard, Novo Nordisk Foundation Center for Protein Research.

'But we need to think about the fact that there may be a sex difference right from the beginning at the hospitals and in the research. Traditionally, e.g. 50 men and women will be recruited for clinical trials. Afterwards you look at the overall effect for the test participants. But you forget to make a subanalysis, where you look at the groups separately to see if there are differences. This has only been done during recent years,' says David Westergaard.

• In connection with 770 types of diseases, women were diagnosed later than men. There was an average difference of about four years.
• In case of cancer, women were on average diagnosed 2.5 years later than men.
• For metabolic diseases such as diabetes, women were on average diagnosed about 4.5 years later.