The effect of modifiable risk factors on geographic mortality differentials : a modelling study

Background Australian mortality rates are higher in regional and remote areas than in major cities. The degree to which this is driven by variation in modifiable risk factors is unknown.

Methods We applied a risk prediction equation incorporating smoking, cholesterol and blood pressure to a national, population based survey to project all-causes mortality risk by geographic region. We then modelled life expectancies at different levels of mortality risk by geographic region using a risk percentiles model. Finally we set high values of each risk factor to a target level and modelled the subsequent shift in the population to lower levels of mortality risk and longer life expectancy.

Results Survival is poorer in both Inner Regional and Outer Regional/Remote areas compared to Major Cities for men and women at both high and low levels of predicted mortality risk. For men smoking, high cholesterol and high systolic blood pressure were each associated with the mortality difference between Major Cities and Outer Regional/Remote areas--accounting for 21.4%, 20.3% and 7.7% of the difference respectively. For women smoking and high cholesterol accounted for 29.4% and 24.0% of the difference respectively but high blood pressure did not contribute to the observed mortality differences. The three risk factors taken together accounted for 45.4% (men) and 35.6% (women) of the mortality difference. The contribution of risk factors to the corresponding differences for inner regional areas was smaller, with only high cholesterol and smoking contributing to the difference in men-- accounting for 8.8% and 6.3% respectively-- and only smoking contributing to the difference in women--accounting for 12.3%.

Conclusions These results suggest that health intervention programs aimed at smoking, blood pressure and total cholesterol could have a substantial impact on mortality inequities for Outer Regional/Remote areas. Background: Australian mortality rates are higher in regional and remote areas than in major cities. The degree to which this is driven by variation in modifiable risk factors is unknown. Methods. We applied a risk prediction equation incorporating smoking, cholesterol and blood pressure to a national, population based survey to project all-causes mortality risk by geographic region. We then modelled life expectancies at different levels of mortality risk by geographic region using a risk percentiles model. Finally we set high values of each risk factor to a target level and modelled the subsequent shift in the population to lower levels of mortality risk and longer life expectancy. Results: Survival is poorer in both Inner Regional and Outer Regional/Remote areas compared to Major Cities for men and women at both high and low levels of predicted mortality risk. For men smoking, high cholesterol and high systolic blood pressure were each associated with the mortality difference between Major Cities and Outer Regional/Remote areas - accounting for 21.4%, 20.3% and 7.7% of the difference respectively. For women smoking and high cholesterol accounted for 29.4% and 24.0% of the difference respectively but high blood pressure did not contribute to the observed mortality differences. The three risk factors taken together accounted for 45.4% (men) and 35.6% (women) of the mortality difference. The contribution of risk factors to the corresponding differences for inner regional areas was smaller, with only high cholesterol and smoking contributing to the difference in men - accounting for 8.8% and 6.3% respectively - and only smoking contributing to the difference in women - accounting for 12.3%. Conclusions: These results suggest that health intervention programs aimed at smoking, blood pressure and total cholesterol could have a substantial impact on mortality inequities for Outer Regional/Remote areas.

Isolation and characterisation of polymorphic microsatellite loci for Noisy Miners Manorina melanocephala, with successful cross-amplification in Bell Miners M. melanophrys

We characterized 15 polymorphic microsatellite loci identified from a Noisy Miner (Manorina melanocephala) blood sample using 454 whole genome shotgun sequencing. Levels of polymorphism were assessed using 15 Noisy Miners. The average number of alleles per locus was 5.1. These loci were then cross-amplified to assess their suitability in a single population of Bell Miners (M. melanophrys). Given the landscape level impact that these species are having on the health of vegetation and biodiversity of a range of vertebrates throughout much of south-eastern Australia, these primers will help identify colony dispersal patterns and thus aid in modeling predictions of miner presence and tenure length in threatened ecosystems.

Isolation and characterization of 12 polymorphic tetranucleotide microsatellite loci in the apostlebird (Struthidea cinerea)

The apostlebird (Struthidea cinerea) is an Australian endemic passerine belonging to the Corcoracidae family. The species is highly gregarious throughout the year and the name of the species refers to the apparent prevalence of social groups of around 12 birds. The species is becoming a model system for the study of sociality in vertebrates, which will require the analysis of relatedness, paternity and maternity. We characterize 12 microsatellite loci tested for polymorphism on 25 individuals from a population in western New South Wales, Australia. The number of alleles ranged from 4 to 9 per locus. Expected heterozygosities ranged from 0.69 to 0.88. This microsatellite panel will facilitate future studies that will advance our understanding of dispersal processes, inbreeding avoidance and reproductive skew in social animals.

Isolation and characterisation via 454 sequencing of microsatellites from the tawny frogmouth, Podargus strigoides (Class Aves, Family Podargidae)

We isolated 24 novel polymorphic microsatellite markers from the tawny frogmouth, a nocturnal bird endemic to Australia, which has successfully adapted to urban environments. Initially, 454 shotgun sequencing was used to identify 733 loci with primers designed. Of these, we trialled 30 in the target species of which all amplified a product of expected size. Subsequently, all 30 of these loci were screened for variation in 25 individuals, from a single population in Melbourne, Victoria, Australia. Twenty-eight loci were polymorphic with observed heterozygosity ranging from 0.03 to 0.96 (mean 0.58) and the number of alleles per locus ranged from 2 to 18 (average of 6.5); we confirmed that 24 loci conformed to Hardy–Weinberg expectations. The 24 loci identified here will be sufficient to unequivocally identify individuals and will be useful in understanding the reproductive ecology, population genetics and the gene flow amongst localities in urban environments where this bird thrives.

How did this snail get here? Several dispersal vectors inferred for an aquatic invasive species

1. How species reach and persist in isolated habitats remains an open question in many cases, especially for rapidly spreading invasive species. This is particularly true for temporary freshwater ponds, which can be remote and may dry out annually, but may still harbour high biodiversity. Persistence in such habitats depends on recurrent colonisation or species survival capacity, and ponds therefore provide an ideal system to investigate dispersal and connectivity. 2. Here, we test the hypothesis that the wide distributions and invasive potential of aquatic snails is due to their ability to exploit several dispersal vectors in different landscapes. We explored the population structure of Physa acuta (recent synonyms: Haitia acuta, Physella acuta, Pulmonata: Gastropoda), an invasive aquatic snail originating from North America, but established in temporary ponds in Doñana National Park, southern Spain. In this area, snails face land barriers when attempting to colonise other suitable habitat. 3. Genetic analyses using six microsatellite loci from 271 snails in 21 sites indicated that (i) geographically and hydrologically isolated snail populations in the park were genetically similar to a large snail population in rice fields more than 15 km away; (ii) these isolated ponds showed an isolation-by-distance pattern. This pattern broke down, however, for those ponds visited frequently by large mammals such as cattle, deer and wild boar; (iii) snail populations were panmictic in flooded and hydrologically connected rice fields. 4. These results support the notion that aquatic snails disperse readily by direct water connections in the flooded rice fields, can be carried by waterbirds flying between the rice fields and the park and may disperse between ponds within the park by attaching to large mammals. 5. The potential for aquatic snails such as Physa acuta to exploit several dispersal vectors may contribute to their wide distribution on various continents and their success as invasive species. We suggest that the interaction between different dispersal vectors, their relation to specific habitats and consequences at different geographic scales should be considered both when attempting to control invasive freshwater species and when protecting endangered species.