Study Finds No Sex Differences in Anorexia Susceptibility in Animal Model
A new study using an animal model of anorexia nervosa found that male and female mice exhibit identical patterns of vulnerability and resilience to activity-based anorexia, with no significant sex differences in susceptibility or behavior. The findings challenge assumptions that biological mechanisms alone explain why anorexia nervosa is far more prevalent in women than men. The results suggest that sociocultural pressures on women to lose weight, rather than innate biological differences, may be the primary driver of the sex disparity in human anorexia rates.
Researchers tested young adult male C57BL/6N mice using the same activity-based anorexia (ABA) protocol previously applied to age-matched females, analyzing daily bodyweight, food intake, water intake, and wheel running. Both male and female mice displayed the same two distinct phenotypes: vulnerable mice experienced catastrophic weight loss driven by excessive light-cycle running, while resilient mice stabilized their weight through adaptive changes in eating and drinking behavior. Critically, the proportion of mice falling into each phenotype did not differ between sexes, nor did the behavioral characteristics defining each group. The study also found that vulnerability was not caused by animals choosing to run instead of eat during feeding windows in either sex, ruling out a simple behavioral trade-off as the mechanism. Because the biological underpinnings of ABA susceptibility appear sex-neutral in this model, the authors conclude that the well-documented higher prevalence of anorexia nervosa in human women is more likely attributable to sociocultural factors, such as greater social pressure on women to achieve thinness, than to sex-based biological differences.
What's missing
The study uses inbred C57BL/6N mice, which may limit generalizability to other genetic backgrounds or species. The authors acknowledge prior animal studies have yielded conflicting findings on sex differences in ABA, but do not fully reconcile why those discrepancies exist. The sociocultural explanation offered in the conclusion, while plausible, is speculative and not directly tested in this study.
What different sources said
- bioRxivCenter
Vulnerability and Resilience to Activity-Based Anorexia is Not Sex-Dependent
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