An assessment of intervention thresholds for high fracture risk in Chile.

Assessment and treatment pathways using FRAX-based intervention thresholds in Chile can be used to identify patients at high risk of fracture and avoid unnecessary treatment in those at low fracture risk. PURPOSE: The aim of the present study was to explore treatment paths and characteristics of women eligible for treatment in Chile based on major osteoporotic fracture (MOF) probabilities derived from FRAX®. METHODS: Intervention and assessment thresholds were derived using methods adopted by the National Osteoporosis Guideline Group for FRAX-based guidelines in the UK but based on the epidemiology of fracture and death in Chile. Age-dependent and hybrid assessment and intervention thresholds were applied to 1998 women and 1122 men age 50 years or more drawn from participants in the National Health Survey 2016-2017. RESULTS: Approximately 12% of men and women had a prior fragility fracture and would be eligible for treatment for this reason. Using age-dependent thresholds, an additional 2.6% of women (0.3% of men) were eligible for treatment in that MOF probabilities lay above the upper assessment threshold. A BMD test would be recommended in 5% of men and 38% of women. With hybrid thresholds, an additional 13% of women (3.6% of men) were eligible for treatment and BMD recommended in 11% of men and 42% of women. CONCLUSION: The application of hybrid intervention thresholds ameliorates the disparity in fracture probabilities seen with age-dependent thresholds. Probability-based assessment of fracture risk, including the use of the hybrid intervention thresholds for Chile, is expected to help guide decisions about treatment.

Assessing the risk of osteoporotic fractures: the Ecuadorian FRAX model.

The FRAX tool incorporates data on the incidence of fractures and mortality in each country. The epidemiology of fractures changes over time, this makes it necessary to update the specific FRAX model of each population. It is shown that there are differences between old and new FRAX models in older individuals. PURPOSE: A new FRAX® model for Ecuador was released online in April 2019. This paper describes the data used to build the revised model, its characteristics, and how intervention and assessment thresholds were constructed. METHODS: The national rates of hip fracture incidence standardized by age and sex from the age of 40 years for 2016 were used to synthesize a FRAX model for Ecuador. For other major fractures, Ecuadorian incidence rates were calculated using ratios obtained in Malmö, Sweden, for other major osteoporotic fractures. The new FRAX model was compared with the previous model released in 2012. Assessment and intervention thresholds were based on age-specific probabilities of a major osteoporotic fracture equivalent to women with a previous fracture. RESULTS: Fracture incidence rates increase with age. The probability of hip or major fractures at 10 years increased in patients with a clinical risk factor, lower BMI, female sex, a higher age, and a lower BMD T-score. Compared to the previous model, the new FRAX model gave similar 10-year fracture probabilities in men and women age less than70 years but substantially higher above this age. Notwithstanding, there were very close correlations in fracture probabilities between the two models (> 0.99) so that the revision had little impact on the rank order of risk. CONCLUSIONS: The FRAX tool provides a country-specific fracture prediction model for Ecuador. This update of the model is based on the original FRAX methodology, which has been validated externally in several independent cohorts. The FRAX model is an evolving tool that is being continuously refined, as the databases of each country are updated with more epidemiological information.

Quantitative traits and mode of speciation in Martinique anoles.

We investigate extensive quantitative trait variation (dewlap hue, colour pattern, dorsum hue, body proportions and scalation) in the Martinique anole across eight transects representing nascent parapatric ecological speciation, nascent allopatric speciation and allopatric divergence without sufficient genetic structure to suggest speciation. Quantitative trait divergence can be extremely large between adjacent sets of populations, but with one exception that this is associated with difference in habitat rather than past allopatry. Nascent ecological speciation shows the greatest level of quantitative trait divergence across all character sets including those implicated in natural, as well as sexual selection. The sole example of nascent allopatric speciation is associated with fairly strong quantitative trait divergence among most character sets, but not the set most implicated in natural (rather than sexual) selection. The role of sexual selection in ecological speciation is discussed, both in terms of female choice with assortative mating and male-male competition with condition-dependant sexual signals.

The relative importance of ecology and geographic isolation for speciation in anoles.

The biogeographic patterns in sexually reproducing animals in island archipelagos may be interpreted as reflecting the importance of allopatric speciation. However, as the forms are allopatric, their reproductive isolation is largely untestable. A historical perspective integrating geology and molecular phylogeny reveals specific cases where ancient precursor islands coalesce, which allows the application of population genetics to critically test genetic isolation. The Anolis populations on Martinique in the Lesser Antilles are one such case where species-level populations on ancient precursor islands (ca 6-8 Myr BP) have met relatively recently. The distribution of the mtDNA lineages is tightly linked to the precursor island, but the population genetic analysis of microsatellite variation in large samples shows no evidence of restricted genetic exchange between these forms in secondary contact. This tests, and rejects, the hypothesis of simple allopatric speciation in these forms. By contrast, Martinique has pronounced environmental zonation, to which anoles are known to adapt. The population genetic analysis shows restricted genetic exchange across the ecotone between xeric coastal habitat and montane rainforest. This does not indicate full ecological speciation in these forms, but it does suggest the relative importance of the role of ecology in speciation in general.

The roles of allopatric divergence and natural selection in quantitative trait variation across a secondary contact zone in the lizard Anolis roquet.

Populations of the Caribbean lizard, Anolis roquet, are thought to have experienced long periods of allopatry before recent secondary contact. To elucidate the effects of past allopatry on population divergence in A. roquet, we surveyed parallel transects across a secondary contact zone in northeastern Martinique. We used diagnostic molecular mitochondrial DNA markers to test fine-scale association of mitochondrial DNA lineage and geological region, multivariate statistical techniques to explore quantitative trait pattern, and cline fitting techniques to model trait variation across the zone of secondary contact. We found that lineages were strongly associated with geological regions along both transects, but quantitative trait patterns were remarkably different. Patterns of morphological and mitochondrial DNA variation were consistent with a strong barrier to gene flow on the coast, whereas there were no indications of barriers to gene flow in the transitional forest. Hence, the coastal populations behaved as would be predicted by an allopatric model of divergence in this complex, while those in the transitional forest did not, despite the close proximity of the transects and their shared geological history. Patterns of geographical variation in this species complex, together with environmental data, suggest that on balance, selection regimes on either side of the secondary contact zone in the transitional forest may be more convergent, while those either side of the secondary contact zone on the coast are more divergent. Hence, the evolutionary consequences of allopatry may be strongly influenced by local natural selection regimes.