1Anthropology, University of Michigan, 2Epidemiology, University of Michigan
April 16, 2020 , Platinum Ballroom
In industrialized humans, skeletal robusticity has declined and obesity has risen globally, but urban communities are disproportionately affected. Similarly, age at menarche has declined globally, while happening earlier for Black girls. Although higher body fat, earlier menarche, and lower bone density are seen in children of all socioeconomic statuses, children of color in urban environments bear a higher cumulative allostatic load, for which the biological effects have largely been ignored. We hypothesize that high allostatic load in subadults causes interrelated physiological and metabolic changes that lead to obesity, earlier age at menarche, and reduced skeletal acquisition. We examined the effects of chronic stress on body mass, body fat, bone mineral density (BMD), and bone mineral content (BMC) in a mouse model. We predicted that chronic stress would increase body mass and body fat and decrease skeletal acquisition. Female C57BL/6J mice were subjected to varying stressors (S) or were not stressed (N) (n=8/group) from 3-6 wks of age. Stressors included exposure to music or mouse distress sounds, dim light during sleep, social isolation, and frequent group changes. Results indicated no significant differences in body mass, BMD, or BMC. S mice gained less body fat (48%) than N mice (64%) (p<0.05 for all). Food intake increased by 46% for S mice and 123% for N mice (p<0.001). These findings don’t support the hypothesis that chronic stress increases body fat. This short-term study shows that stress can affect food intake, but longer studies are needed to understand how chronic stress impacts skeletal acquisition.