Obesity Drivers Differ by Sex

Do underlying obesity drivers differ among men and women? Yes, according to findings published in Brain Communications. Researchers identified sex-specific mechanisms in the brain underlying obesity using multimodal magnetic resonance imaging (MRI).

Although the findings do not establish causality, they may help researchers better understand obesity-related drivers and behaviors that will lead to development of tailored management strategies. For example, women with obesity may be more drawn to highly processed foods with an increased risk of developing cravings and food addiction compared with men, the researchers found.

“We found differences in several of the brain’s networks associated with early life adversity, mental health quality, and the way sensory stimulation is experienced. The resulting brain signatures, based on multimodal MRI imaging, may help us more precisely tailor obesity interventions based on an individual’s sex,” said senior author of the study Arpana Gupta, PhD, a brain, obesity, and microbiome researcher at UCLA.

“In designing treatment plans for females with high BMI, it may be important to focus on emotional regulation techniques and vulnerability factors,” Dr Gupta said.

The findings build on an earlier study in which Gupta and colleagues examined sex-related differences in the prominence and signaling of brain regions in obesity. In addition to finding that emotion-related and compulsive eating appear to play a major role in obesity in women, that study showed that men’s eating behavior tends to be affected by a greater awareness of gut sensations and visceral responses (ie, abdominal discomfort).

Study Design

A total of 183 participants aged 18 to 55 years were enrolled in the study. Of these, 78 had high BMI (>25; 55 female) and 105 had nonobese BMI (19-20; 63 female). All participants filled out a battery of self-report questionnaires assessing childhood trauma, anxiety and depression, visceral sensitivity, food addiction, bowel symptoms, personality traits, and many other factors.

Multimodal MRI (morphometry, functional resting-state MRI, and diffusion-weighted scan) were used to assess structure, function, and connectivity. Data sets from the scans and clinical information were analyzed to identify a limited number of variables from multiple data sets to predict an outcome.

Sex-Specific Obesity Drivers Identified

Sex-specific differences within the cortico-basal-ganglia-thalamic-cortical loop, choroid plexus cerebrospinal fluid system, as well as salience, sensorimotor, and default-mode networks were identified and were associated with early life adversity, mental health quality, and greater somatosensation.

In females, the study identified brain regions and networks with alterations associated with early life trauma. These appear consistent with previous observations that females with obesity, compared with males, may have greater anxiety, lower resilience, and difficulty integrating emotions with action-directed goal planning. Females also may be more susceptible to the sight, smell, and taste of ultra-processed foods.

“We found differences in several of the brain’s networks associated with early life adversity, mental health quality, and the way sensory stimulation is experienced. The resulting brain signatures, based on multimodal MRI imaging, may help us more precisely tailor obesity interventions based on an individual’s sex,” Dr Gupta said.

“Although causality is unknown, the strong associations between clinical markers, such as anxiety, depression, obesity, and neural signatures suggest the importance of the bidirectional mechanistic connection of the gut-brain axis,” the authors concluded.

The research was supported by grants from the National Institutes of Health, National Science Foundation Graduate Research Fellowship, and Ahmanson-Lovelace Brain Mapping Center.

This article originally appeared on Clinical Advisor