Dietary assimilation and the digestive strategy of the omnivorous anomuran land crab Birgus latro (Coenobitidae).

On Christmas Island, Indian Ocean, the diet of robber crabs, Birgus latro (Linnaeus) was generally high in fat, storage polysaccharides or protein and largely comprised fruits, seeds, nuts and animal material. The plant items also contained significant amounts of hemicellulose and cellulose. In laboratory feeding trials, crabs had similar intakes of dry matter when fed artificial diets high in either fat or storage polysaccharide, but intake was lower on a high protein diet. Assimilation coefficients of dry matter (69–74%), carbon (72–81%), nitrogen (76–100%), lipid (71–96%) and storage polysaccharide (89–99%) were high on all three diets. B. latro also assimilated significant amounts of the chitin ingested in the high protein diet ( 93%) and hemicellulose (49.6–65%) and cellulose (16–53%) from the high carbohydrate and high fat diets. This is consistent with the presence of chitinase, hemicellulase and cellulase enzymes in the digestive tract of B. latro. The mean retention time (27.2 h) for a dietary particle marker (⁵⁷Co-labelled microspheres) was longer than measured in leaf-eating land crabs. The feeding strategy of B. latro involves the selection of highly digestible and nutrient-rich plant and animal material and retention of the digesta for a period long enough to allow extensive exploitation of storage carbohydrates, lipids, protein and significant amounts of structural carbohydrates (hemicellulose, cellulose and chitin).

Urban area disadvantage and physical activity: a multilevel study in Melbourne, Australia

Objective: To estimate variation between small areas in the levels of walking, cycling, jogging, and swimming and overall physical activity and the importance of area level socioeconomic disadvantage in predicting physical activity participation.

Methods: All census collector districts (CCDs) in the 20 innermost local government areas in metropolitan Melbourne, Australia, were identified and ranked by the percentage of low income households (<$400/week) living in the CCD. Fifty CCDs were randomly selected from the least, middle, and most disadvantaged septiles of the ranked CCDs and 2349 residents (58.7% participation rate) participated in a cross sectional postal survey about physical activity. Multilevel logistic regression (adjusted for extrabinomial variation) was used to estimate area level variation in walking, cycling, jogging, and swimming and in overall physical activity participation, and the importance of area level socioeconomic disadvantage in predicting physical activity participation.

Results: There were significant variations between CCDs in all activities and in overall physical participation in age and sex adjusted models; however, after adjustment for individual SES (income, occupation, education) and area level socioeconomic disadvantage, significant differences remained only for walking (p = 0.004), cycling (p = 0.003), and swimming (p = 0.024). Living in the most socioeconomically disadvantaged areas was associated with a decreased likelihood of jogging and of having overall physical activity levels that were sufficiently active for health; these effects remained after adjustment for individual socioeconomic status (sufficiently active: OR 0.70, 95% CI 0.55 to 0.90 and jogging: OR = 0.69, 95% CI 0.51 to 0.94).

Conclusion: These research findings support the need to focus on improving local environments to increase physical activity participation.

Abbreviations: SES, socioeconomic status; CCD, census collector district

Half the burden of fragility fractures in the community occur in women without osteoporosis. When is fracture prevention cost-effective?

To determine the age- and BMD-specific burden of fractures in the community and the cost-effectiveness of targeted drug therapy, we studied a demographically well-categorized population with a single main health provider. Of 1224 women over 50 years of age sustaining fractures during 2 years, the distribution of all fractures was 11%, 20%, 33%, and 36% in those aged 50–59, 60–69, 70–79, and 80+ years, respectively. Osteoporosis (T score < −2.5) was present in 20%, 46%, 59%, and 69% in the respective age groups. Based on this sample and census data for the whole country, treating all women over 50 years of age in Australia with a drug that halves fracture risk in osteoporotic women and reduces fractures in those without osteoporosis by 20%, was estimated to prevent 18,000 or 36% of the 50,000 fractures per year at a total cost of $573 million (AUD). Screening using a bone mineral density of T score of −2.5 as a cutoff, misses 80%, 54%, 41%, and 31% of fractures in women in the respective age groups. An analysis of cost per averted fracture by age group suggests that treating women in the 50- to 59-year age group with osteoporosis alone costs $156,400 per averted fracture. However, in women aged over 80 years, the cost per averted fracture is $28,500. We infer that treating all women over 50 years of age is not feasible. Using osteoporosis and age (>60 years) as criteria for intervention reduces the population burden of fractures by 28% and is cost-effective but solutions to the prevention of the remaining 72% of fragility fractures remain unavailable.

Activity patterns of insectivorous bats and birds in northern Scandinavia (69° N), during continuous midsummer daylight

Previous studies suggest that many species of insectivorous bats are nocturnal, despite the relatively low availability of their insect prey at night, because of the risk of predation by diurnal predatory birds. We hypothesised that if this was the case bats living above the arctic circle would alter their feeding behaviour during midsummer because there would no longer be any benefit to restricting their activity to the period when their prey are least abundant. Alternatively, if bats were more influenced by competition from aerial insectivorous birds they would continue to feed at ‘night’ to avoid such competition. In northern Norway (69° N), during continuous midsummer daylight, insectivorous sand martins (Riparia riparia) concentrated their aerial feeding activity when aerial insects were most abundant. The birds stopped feeding between 23:00 and 07:00 when aerial insects were least abundant. In contrast, northern bats (Eptesicus nilssonii), fed mostly between 22:00 and 02:00, coinciding with the lowest aerial insect availability, and with the period when light levels were lowest (ca 1000 lux). Bat activity patterns were closest to those predicted by the avian competition hypothesis. The low densities of both sand martins and Northern bats in the study area, however, were less consistent with this hypothesis. Possibly populations of both species were higher historically and the observed patterns reflected historical competition. Bat activity was most closely correlated to ambient light levels. This raised two alternative explanations that we could not eliminate. Perhaps there was differential predation risk, between the brightest and darkest parts of the day, because the visual capacities of falcons are strongly dependent on luminance. Alternatively the bats may have been entrained to emerge at given light levels by their behaviour at other times of year.

Higher dietary calcium intakes are associated with reduced risks of fractures, cardiovascular events, and mortality: a prospective cohort study of older men and women

The aim of this population-based, prospective cohort study was to investigate long-term associations between dietary calcium intake and fractures, non-fatal cardiovascular disease (CVD), and death from all causes. Participants were from the Melbourne Collaborative Cohort Study, which was established in 1990 to 1994. A total of 41,514 men and women (∼99% aged 40 to 69 years at baseline) were followed up for a mean (SD) of 12 (1.5) years. Primary outcome measures were time to death from all causes (n = 2855), CVD-related deaths (n = 557), cerebrovascular disease-related deaths (n = 139), incident non-fatal CVD (n = 1827), incident stroke events (n = 537), and incident fractures (n = 788). A total of 12,097 participants (aged ≥50 years) were eligible for fracture analysis and 34,468 for non-fatal CVD and mortality analyses. Mortality was ascertained by record linkage to registries. Fractures and CVD were ascertained from interview ∼13 years after baseline. Quartiles of baseline energy-adjusted calcium intake from food were estimated using a food-frequency questionnaire. Hazard ratios (HR) and odds ratios (OR) were calculated for quartiles of dietary calcium intake. Highest and lowest quartiles of energy-adjusted dietary calcium intakes represented unadjusted means (SD) of 1348 (316) mg/d and 473 (91) mg/d, respectively. Overall, there were 788 (10.3%) incident fractures, 1827 (9.0%) incident CVD, and 2855 people (8.6%) died. Comparing the highest with the lowest quartile of calcium intake, for all-cause mortality, the HR was 0.86 (95% confidence interval [CI] 0.76-0.98, ptrend  = 0.01); for non-fatal CVD and stroke, the OR was 0.84 (95% CI 0.70-0.99, ptrend  = 0.04) and 0.69 (95% CI 0.51-0.93, ptrend  = 0.02), respectively; and the OR for fracture was 0.70 (95% CI 0.54-0.92, ptrend  = 0.004). In summary, for older men and women, calcium intakes of up to 1348 (316) mg/d from food were associated with decreased risks for fracture, non-fatal CVD, stroke, and all-cause mortality.

A prospective observational study of prevalence and outcomes of patients with Gold Standard Framework criteria in a tertiary regional Australian Hospital

OBJECTIVES: Report the use of an objective tool, UK Gold Standards Framework (GSF) criteria, to describe the prevalence, recognition and outcomes of patients with palliative care needs in an Australian acute health setting. The rationale for this is to enable hospital doctors to identify patients who should have a patient-centred discussion about goals of care in hospital.

DESIGN: Prospective, observational, cohort study.

PARTICIPANTS: Adult in-patients during two separate 24 h periods.

MAIN OUTCOME MEASURES: Prevalence of in-patients with GSF criteria, documentation of treatment limitations, hospital and 1 year survival, admission and discharge destination and multivariate regression analysis of factors associated with the presence of hospital treatment limitations and 1 year survival.

RESULTS: Of 626 in-patients reviewed, 171 (27.3%) had at least one GSF criterion, with documentation of a treatment limitation discussion in 60 (30.5%) of those patients who had GSF criteria. Hospital mortality was 9.9%, 1 year mortality 50.3% and 3-year mortality 70.2% in patients with GSF criteria. One-year mortality was highest in patients with GSF cancer (73%), renal failure (67%) and heart failure (60%) criteria. Multivariate analysis revealed age, hospital length of stay and presence of the GSF chronic obstructive pulmonary disease criteria were independently associated with the likelihood of an in-hospital treatment limitation. Non-survivors at 3 years were more likely to have a GSF cancer (25% vs 6%, p=0.004), neurological (10% vs 3%, p=0.04), or frailty (45% vs 3%, p=0.04) criteria. After multivariate logistic regression GSF cancer criteria, renal failure criteria and the presence of two or more GSF clinical criteria were independently associated with increased risk of death at 3 years. Patients returning home to live reduced from 69% (preadmission) to 27% after discharge.

CONCLUSIONS: The use of an objective clinical tool identifies a high prevalence of patients with palliative care needs in the acute tertiary Australian hospital setting, with a high 1 year mortality and poor return to independence in this population. The low rate of documentation of discussions about treatment limitations in this population suggests palliative care needs are not recognised and discussed in the majority of patients.

TRIAL REGISTRATION NUMBER: 11/121.