Memorial Sloan Kettering study: detected brown fat linked to fewer depression and anxiety diagnoses

Researchers analyzed the medical records of more than 100,000 patients at Memorial Sloan Kettering Cancer Center in New York, United States. They found an association between detected brown adipose tissue and less frequently recorded diagnoses of anxiety disorders and depressive episodes, ua.news reports, citing ScienceAlert and a study published in the journal Nature. ua.newsua.newsua.newsOpen source ↗

Brown adipose tissue is found, among other places, in the neck area, near the collarbones, and in the armpits. It produces heat when exposed to cold and absorbs a radioactive sugar marker used during certain medical scans. This is why the tissue can be seen in PET/CT images.

Comparison of patient groups

The scientists matched patients with and without detected brown adipose tissue by age, sex, body mass index, and outdoor air temperature. A diagnosis of a depressive episode was recorded in 5.4% of patients in the group with detected tissue and in 8.2% in the group without it. Anxiety disorder diagnoses were also less common among patients with brown fat.

The association remained after accounting for smoking history, cancer type and stage, treatment, and other factors. Patients with detected brown adipose tissue also had lower blood sugar levels, including a marker of long-term glucose levels. ua.newsua.newsua.newsOpen source ↗

Activity, drugs and limitations

Using a software tool, the team assessed brown fat volume and glucose uptake in approximately 8,700 patients in whom the tissue was detected. From these data the researchers calculated its activity in six body regions. Higher activity in the armpit area was associated primarily with better cardiovascular and metabolic health indicators.

Patients taking certain antidepressants from the class of selective serotonin reuptake inhibitors were less likely to have detected brown adipose tissue. Separately, the researchers tested losartan on laboratory-grown brown fat cells and on mice: the drug increased tissue activity, and the animals expended more energy. These experiments did not assess anxiety or depression.

The authors emphasized that the study is retrospective and demonstrates associations rather than a cause-and-effect relationship. The data come from patients at a cancer center, and women made up more than three quarters of participants in the matched groups. According to the authors, differences in tumor types and treatment could have affected the results despite statistical adjustment. ua.newsua.newsua.newsOpen source ↗