Dementia risk following natural disasters
Aftermath of the 2011 Great East Japan Earthquake and Tsunami. Image courtesy of Dylan McCord (US Navy).
Recovery after a major disaster presents particular challenges for elderly people, such as disruption of medical care and social isolation, which may increase the risk of dementia. Studies of changes in the risk of dementia following disaster survival are rare. Hiroyuki Hikichi et al. (pp. E6911–E6918) surveyed more than 3,500 survivors of the 2011 Great East Japan Earthquake and Tsunami who were 65 years or older to determine whether housing damage and loss of relatives or friends due to the tsunami were associated with the development of dementia. The health status of the study participants had been surveyed 7 months prior to the earthquake as part of the Japan Gerontological Evaluation Study, and the prior data allowed the authors to control for changes in other potential risk factors, such as age, stroke, and hypertension. Statistical analysis of the survey data from before and after the earthquake revealed that increased dementia severity was significantly correlated with major housing damage and destruction, but not with loss of relatives or friends. According to the authors, dementia should be considered a health risk for elderly survivors of natural disasters. — B.D.
Origins of settlers in Remote Oceania
Sunset on Mwoakilloa Atoll. Image courtesy of Aaron S. Poteate (North Carolina Museum of Natural Sciences, Raleigh, NC).
Around 3,400 years ago, humans began crossing the Pacific Ocean to settle Remote Oceania, the far-flung collection of islands that includes Tonga, Samoa, and islands in Micronesia. Although archaeological, linguistic, and genetic evidence delimits the time of arrival of many settlers, the origins of these earliest inhabitants have proven difficult to establish. Alvaro Montenegro et al. (pp. 12685–12690) analyzed ocean routes across the Pacific using computer seafaring simulations primed with high-resolution data for winds, ocean currents, precipitation, and land distribution. Additionally, accounting for the influence of the El Niño Southern Oscillation, the authors constructed “shortest-hop” trajectories to identify the most likely port of departure for the inhabitants of five major regions in Remote Oceania. Among other findings, the analysis suggests that the settlers of western Micronesia originated from a location near the Maluku Islands. The authors also compare their results with a number of previously proposed migration scenarios such as “Slow Boat to the Bismarcks,” “Voyaging Corridor Triple I,” and “Mobile Founding Migrant.” The findings demonstrate the need to incorporate Pacific Islander voyaging strategies and the impact of environmental variables on ocean travel into the analysis of colonization in Remote Oceania, according to the authors. — T.J.