Chronic disease and impairment among Alaska native elders : the Alaska Education and Research Towards Health (EARTH) study

Background: Chronic diseases and impairments are prevalent among older Americans. However, prevalence data for Alaska Native (AN) elders are limited, with estimates usually extrapolated from national studies in which AN elders may not be well-represented. The aim of this study was to describe the prevalence of selected chronic diseases, impairments, and measured medical risk factors among a large community sample of AN elders.

Methods: Design, setting, and participants. A community-based cross-sectional study of baseline information from 656 AN elders aged 55 years or over who participated in the Alaska Education and Research Towards Health (EARTH) Study, March 2004 to August 2006. Measurements. Self-reported lifetime prevalence of 17 doctor-diagnosed chronic diseases, and point prevalence of vision, hearing, oral, and general health impairment were estimated from data collected using audio computer-assisted self-administered questionnaires. In addition, height, weight, blood pressure, fasting blood lipids, and fasting blood glucose levels were measured.

Results: The four most prevalent chronic diseases among AN elders were high blood pressure (55%), arthritis (49%), high cholesterol (42%), and adult bone fracture/break (35%). The median number of chronic diseases reported was three (inter-quartile range, 2 to 5). The prevalence of self-reported vision impairment was 15%, hearing impairment 18%, and having had all natural teeth removed 25%. Almost 50% were obese. High blood pressure (systolic ≥ 140 mm Hg and/or diastolic ≥ 90 mm Hg) was measured in 23%, high low density lipoprotein (LDL) cholesterol (≥ 130 mg/dL) in 39%, and high fasting plasma glucose (> 125 mg/dL) in 9%. Obesity was more prevalent among women than men. There were also significant regional differences in rates of obesity and high LDL cholesterol.

Conclusion: These data may be useful in public health programs and health services planning.

Oceanic long-distance navigation : do experienced migrants use the earth's magnetic field?

Albatrosses and sea turtles are known to perform extremely long-distance journeys between disparate feeding areas and breeding sites located on small, isolated, oceanic islands or at specific coastal sites. These oceanic journeys, performed mainly over or through apparently featureless mediums, indicate impressive navigational abilities, and the sensory mechanisms used are still largely unknown. This research used three different approaches to investigate whether bi-coordinate navigation based on magnetic field gradients is likely to explain the navigational performance of wandering albatrosses in the South Atlantic and Indian Oceans and of green turtles breeding on Ascension Island in the South Atlantic Ocean. The possibility that magnetic field parameters can potentially be used in a bi-coordinate magnetic map by wandering albatrosses in their foraging area was investigated by analysing satellite telemetry data published in the literature. The possibilities for using bi-coordinate magnetic navigation varied widely between different areas of the Southern Oceans, indicating that a common mechanism, based on a bi-coordinate geomagnetic map alone, was unlikely for navigation in these areas. In the second approach, satellite telemetry was used to investigate whether Ascension Island green turtles use magnetic information for navigation during migration from their breeding island to foraging areas in Brazilian coastal waters. Disturbing magnets were applied to the heads and carapaces of the turtles, but these appeared to have little effect on their ability to navigate. The only possible effect observed was that some of the turtles with magnets attached were heading for foraging areas slightly south of the control turtles along the Brazilian coast. In the third approach, breeding female green turtles were deliberately displaced in the waters around Ascension Island to investigate which cues these turtles might use to locate and return to the island; the results suggested that cues transported by wind might be involved in the final stages of navigation.