Non-hip and non-vertebral fractures : the neglected fracture sites

Summary: Non-hip, non-vertebral fractures (NHNVF) were compared with hip, vertebral and controls. NHNVF were younger and heavier than controls and hip/vertebral fractures in both men and women, respectively. Falls and prior fractures were less common in NHNVF than hip fractures. Glucocorticoid use was lower in NHNVF compared to vertebral fracture (VF) in men. Introduction: Although hip fracture (HF) and vertebral fractures (VF) receive the most attention in the literature and are the targeted sites for fracture prevention, non-hip, non-vertebral fracture (NHNVF) sites account for a greater proportion of fractures than the hip or vertebrae. This study aimed to assess risk factors for NHNVF and compare them with those for HF, VF and controls. Methods: Incident fractures during 2005–2007 for men and 1994–1996 for women were identified using computerised keyword searches of radiological reports, and controls were selected at random from electoral rolls for participation in the Geelong Osteoporosis Study. Participants aged 60+ years were included in this study. Results: Compared to controls, men and women with NHNVF were younger (ORs, 0.90, 95 % CI 0.86–0.94; and 0.96, 0.93–0.98, respectively) and had a lower femoral neck bone mineral density (BMD) T-score (age-adjusted; difference [men] 0.383, P = 0.002; [women] 0.287, P = 0.001). Compared to HF, men and women with NHNVF were heavier (difference [men] 9.0 kg, P = 0.01; [women] 7.6 kg, P < 0.001). Heavier weight was also a risk factor for women with NHNVF compared to VF (1.03, 1.01–1.06). In men with NHNVF, falls (0.37, 0.14–0.97) and prior fractures (0.38, 0.15–0.98) were less common compared to HF; and glucocorticoid use was less common for NHNVF (0.30, 0.11–0.85) compared to VF. Conclusions: Given the high numbers of NHNVF sustained by men and women in this study, fracture prevention strategies should focus on individuals with high risk of sustaining these types of fractures, as well as on individuals who are more likely to sustain a HF or VF.

Behavioural and neurochemical consequences of chronic gut microbiota depletion during adulthood in the rat

Gut microbiota colonization is a key event for host physiology that occurs early in life. Disruption of this process leads to altered brain development which ultimately manifests as changes in brain function and behaviour in adulthood. Studies using germ-free mice highlight the extreme impact on brain health that results from life without commensal microbes, however the impact of microbiota disturbances occurring in adulthood is less studied. To this end, we depleted the gut microbiota of 10-week-old male Sprague Dawley rats via chronic antibiotic treatment. Following this marked, sustained depletion of the gut bacteria, we investigated behavioural and molecular hallmarks of gut-brain communication. Our results reveal that depletion of the gut microbiota during adulthood results in deficits in spatial memory as tested by Morris water maze, increased visceral sensitivity and a greater display of depressive-like behaviours in the forced swim test. In tandem with these clear behavioural alterations we found change in altered CNS serotonin concentration along with changes in the mRNA levels of corticotrophin releasing hormone receptor 1 and glucocorticoid receptor. Additionally, we found changes in the expression of BDNF, a hallmark of altered microbiota-gut-brain axis signaling. In summary, this model of antibiotic-induced depletion of the gut microbiota can be used for future studies interested in the impact of the gut microbiota on host health without the confounding developmental influence of early-life microbial alterations.

Effects of isolation on stress responses to novel stimuli in Subadult chickens (Gallus gallus)

Extensive research has examined the effects of social isolation in neonatal and adult animal populations, but few studies have examined the effect of social isolation in early adulthood. Animals reaching reproductive age often experience extensive social changes as they leave their natal site, and a social stressor like isolation may uniquely affect this age group. Furthermore, adolescence is a time when sex differences in behavior become more pronounced. As such, the effects of social stressors are likely to vary by sex. In this study, we used noninvasive methods to evaluate stress responses to social change in male and female subadult chickens (Gallus gallus). Half of the birds experienced regular sessions of social isolation over the course of 2 wk, while the other half were never isolated. Subsequently, all of the animals were exposed to a suite of three novel probes, including an open-field test. We monitored the birds’ behavioral (head movements) and physiological (fecal glucocorticoid metabolites, FGM) response to the tests. Our results indicate that, for subadult chickens, the effect of social isolation is sex dependent: Male FGM and behavioral responses did not change with subsequent experiences, in contrast to females. Females also exhibited more social reinstatement behavior compared to males. Our results are consistent with the expectations of differences between the sexes based on changes in the social environment due to sex-biased dispersal patterns. For both sexes, the FGM and behavioral responses varied independently, which highlights the necessity for multiple measures of stress in animal populations.