Dhejne 2011 — Swedish long-term study

In 2011, Dhejne and colleagues published a long-term cohort study in PLOS ONE of 324 transgender people in Sweden who underwent gender-affirming surgery between 1973 and 2003.

Background

In 2011, Dhejne and colleagues published a long-term cohort study in PLOS ONE of 324 transgender people in Sweden who underwent gender-affirming surgery between 1973 and 2003. The study compared them with the general Swedish population.

Key findings

The study found higher mortality, an increased risk of suicide and suicide attempts, and higher psychiatric morbidity compared with the general population. The authors concluded that although gender-affirming surgery may alleviate dysphoria, additional mental health care remains essential.

Interpretation and debate

The study is cited both as evidence of continued vulnerability after transition and in support of extensive psychosocial counseling. The authors themselves have emphasized that the study does not demonstrate a causal relationship between surgery and negative outcomes, because it lacked a control group of transgender people who had not undergone surgery.

Study design and figures

The 324 participants included 191 people who had transitioned from male to female and 133 from female to male. Each of them was compared with ten randomly selected Swedes of the same birth year and sex. Mortality in the surgical group was nearly three times as high as in the comparison group, and the risk of death by suicide was approximately nineteen times as high. The difference in mortality did not become apparent until more than ten years later. This is one of the reasons the study is so often cited: it shows that short follow-up can produce a distorted picture. The figures for each outcome are summarized at genderrisico.nl.

Strengths

The study's strength lies in the Swedish registers. Every resident has a personal identification number that allows data on hospital admissions, causes of death, and convictions to be linked. As a result, almost no one was lost to follow-up, a problem that significantly weakens other research in this field. The thirty-year follow-up period is exceptional in this area.

What the study cannot tell us

The study compares people who underwent surgery with the general population, not with people with gender dysphoria who did not undergo surgery. It therefore cannot determine whether surgery improved, worsened, or left the outcomes unchanged. What it does show is that surgery does not eliminate this group's psychological vulnerability and that ongoing aftercare remains necessary. The later Swedish registry study by Bränström in 2019 made that comparison only after criticism, following which the authors had to revise their conclusion. More about this type of research can be found in cohort studies in transgender health care.

Frequently asked questions