A Cross-Section of Recent Results in the Study of Aging
It is important to remember that much of the study of aging is just that - study of aging, no more. Most of the researchers involved in the field are not working on ways to enhance healthy longevity, or ways to treat aging as a medical condition. They are merely studying aging: collecting data and establishing theories about how aging proceeds. Aging science remains a strange field in that respect. If you look at cancer research, to pick one example, a much higher proportion of research is aimed at producing treatments or carried out in direct support of producing treatments, and you certainly won't find the same phenomenon of researchers quick to deny that any of their work would be used to actually treat the medical condition they focus on. While things have changed for the better in the aging research community, as illustrated by the fact that many noted researchers now advocate working towards greater human longevity, there remains a sizable contingent of researchers who do not talk about treating aging and who would avow that goal if asked in public.
Bear in mind that for every interesting item I point out here at Fight Aging! there are a dozen more papers that report on gathering data on aging and nothing more. The majority of funding goes towards a mix of epidemiological work that arguably has absolutely no impact whatsoever on the prospects for defeating age-related disease, and an endless cataloging of the changing biology of aging in ever-greater detail, which has only a minor impact. The small segment of research that might actually produce meaningful results, involving repair of the causes of aging, presently makes up a tiny fraction of a tiny fraction of the overall resources devoted to aging science. That whole field in and of itself is a small fraction of overall medical research, very much underfunded for its importance. Stepping up another level, medical research in general is a forgotten child in our culture, largely ignored and also poorly funded for its importance. People would rather have war, celebrity, and circuses. Much must change in the years ahead, and the past decade of growth and change in the culture of aging research has been but start. A good start, yes, but there is much to be done yet.
Here is a selection of papers that represent the sort of work that makes up much of aging research at the moment.
Declining intelligence in old age linked to visual processing
Age-related declines in intelligence are strongly related to declines on a very simple task of visual perception speed. The evidence comes from experiments in which researchers showed 600 healthy older people very brief flashes of one of two shapes on a screen and measured the time it took each of them to reliably tell one from the other. Participants repeated the test at ages 70, 73, and 76. The longitudinal study is among the first to test the hypothesis that the changes they observed in the measure known as "inspection time" might be related to changes in intelligence in old age. "The results suggest that the brain's ability to make correct decisions based on brief visual impressions limits the efficiency of more complex mental functions. As this basic ability declines with age, so too does intelligence. The typical person who has better-preserved complex thinking skills in older age tends to be someone who can accumulate information quickly from a fleeting glance."
Study examines midlife hypertension, cognitive change over 20-year period
Authors used the Atherosclerosis Risk in Communities (ARIC) study to examine the effects of hypertension by analyzing the results of three cognitive tests over time. Data from 13,476 participants were used and the maximum follow up was 23.5 years. The decline in global cognitive scores for participants with hypertension was 6.5 percent greater than for individuals with normal blood pressure. An average ARIC participant with normal blood pressure at baseline had a decline of 0.840 global cognitive z score points during the 20-year period compared with 0.880 points for participants with prehypertension and 0.896 points for patients with hypertension. Individuals with high blood pressure who used medication had less cognitive decline during the 20 period than participants with high blood pressure who were untreated.
Exercise, Sedentary Pastimes, and Cognitive Performance in Healthy Older Adults
Moderately vigorous physical activity (MVPA) provides a protective affect against cognitive decline and cardiovascular risk factors. Less is known about sedentary pastimes or non exercise physical activity (NEPA) and cognitive performance. 125 healthy adults 65 or older with no clinical evidence of cognitive impairment were enrolled. Sedentary pastimes were associated with executive dysfunction; MVPA with high memory scores and NEPA with improved working memory. Only sedentary pastimes and executive dysfunction retained significance after correction for multiple comparisons. Smoking and alcohol confounded the association of memory with sedentary pastimes and MVPA.
Incidence and Predictors of Multimorbidity in the Elderly: A Population-Based Longitudinal Study
We aimed to calculate 3-year incidence of multimorbidity, defined as the development of two or more chronic diseases in a population of older people free from multimorbidity at baseline. Data were gathered from 418 participants in the first follow up of the Kungsholmen Project (Stockholm, Sweden, 1991-1993, 78+ years old) who were not affected by multimorbidity (149 had none disease and 269 one disease). After 3 years, 33.6% of participants who were without disease and 66.4% of those with one disease at baseline, developed multimorbidity. After adjustments, worse cognitive function was associated with increased risk of multimorbidity among subjects with no disease at baseline. Higher age was the only predictor of multimorbidity in persons with one disease at baseline.
The contribution of personality to longevity: Findings from the Australian Centenarian Study
Centenarians were currently low in Openness and Extraversion and high in Neuroticism, but were low in Openness and high in Neuroticism, Conscientiousness and Extraversion when reflecting on past traits. Currently, centenarians in high care facilities reported higher levels of Neuroticism, as did centenarians who did not socialize. Cognitively intact centenarians reported higher levels of Agreeableness; and males reported lower Neuroticism compared to females when reflecting on past experiences. Centenarians were characterized by several personality traits, which facilitated positive health behaviors and thus contributed to their longevity. It is possible that personality may not be static across the lifespan, but instead, reflect advancing age, psychosocial factors and changes in life circumstances.
FWIW I would hypothesize that the association in the first study is primarily the result of demyelination.