On average, women get diagnoses later in their lives than men when they contract a disease, a new study in Denmark suggests.

“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,” says coauthor Søren Brunak, a professor in the Novo Nordisk Foundation Center for Protein Research at the University of Copenhagen.

“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 personalized medicine,” Brunak says.

Image: Nature Communications

The researchers analyzed data from 6.9 million Danish people. They divided the population into two groups according to their sex. Over a 21-year period, from 1994 to 2015, the researchers have analyzed 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 receive diagnoses compared to men. The entire sequence of the women’s and men’s patient care course was different and time-staggered.

Women received diagnoses later than men in connection with 770 types of diseases. 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.

In connection with ADHD, there was a difference of almost six years between the time when the two groups received diagnoses. 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 externalizing behavior often seen in boys with ADHD.

Osteoporosis was one of the exceptions where women received diagnoses first. Here, women were typically diagnosed before they had a fracture as a result of the disease, while the course for men was the opposite. They typically didn’t receive a diagnosis 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 of these factors. They’re 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 [for example] be attributed to genetics or environment and culture?” asks coauthor David Westergaard, a postdoc at the 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, [for example,] 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 Westergaard.