Low Vitamin K May Reduce Mobility in Older Adults

Catharine Paddock wrote . . . . . . . . .

Dietary sources of vitamin K include kale, spinach, broccoli, and other leafy greens. Some dairy foods also contain vitamin K.

The investigators who carried out the study say that their findings “suggest vitamin K may be involved in the disablement process in older age.”

They describe their work in a paper that features in a recent issue of The Journals of Gerontology: Series A.

Previous studies have established links between vitamin K and long-term conditions that can raise the risk of mobility disability. These conditions include cardiovascular disease and osteoarthritis.

However, none of those earlier investigations had examined the relationship between vitamin K and mobility disability directly.

M. Kyla Shea is the new study’s first and corresponding author. She researches Vitamin K at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, MA.

Shea explains that: “Low vitamin K status has been associated with the onset of chronic diseases that lead to disability, but the work to understand this connection is in its infancy.”

She and her colleagues believe that they are the first to evaluate the relationship between “vitamin K status and incident mobility disability” in older adults.

The new evidence builds on earlier studies that have associated low levels of circulating vitamin K with “slower gait speed and a higher risk of osteoarthritis,” Shea explains.

Mobility is fundamental to healthy aging

Researchers typically define mobility as the “ability to move independently” from one place to another.

Physical independence is integral to healthy aging and older adults’ quality of life. From being able to get out of bed to walking and climbing stairs, much of daily activity involves mobility.

A 2018 study that reviewed the available evidence suggested that around 30% of older adults have limited mobility.

The most common causes of mobility disability in older people are the onset of lung problems, arthritis, and other long-term conditions.

A common measure of mobility is the ability to walk and climb stairs.

Mobility and vitamin K status

Vitamin K is a group of fat-soluble compounds that have a similar chemical structure and are present in some foods. Phylloquinone is the main dietary form of vitamin K and is present mainly in leafy greens.

To assess vitamin K status, Shea and her colleagues measured two blood biomarkers: phylloquinone and uncarboxylated matrix Gla protein (ucMGP), a protein that requires vitamin K. They note that ucMGP in the blood “increases when vitamin K status is low.”

The data that they analyzed came from 688 women and 635 men in the Health, Aging, and Body Composition (Health ABC) Study. Around 40% of the participants were black, and their ages ranged from 70 to 79 years.

The Health ABC study assessed mobility every 6 months for a period of between 6 and 10 years. The participants attended clinics and also completed interviews on the phone.

The researchers defined mobility limitation as two consecutive 6-monthly reports of experiencing “any amount of difficulty either with walking a quarter of a mile or climbing 10 steps without resting.”

They defined mobility disability as two consecutive 6-monthly reports of experiencing “a lot of difficulty or inability” to complete the same walking and climbing challenge.

The analysis showed that the older people who were most likely to develop mobility limitation and disability were the ones with low blood levels of phylloquinone.

In particular, the researchers found that developing mobility limitation was almost 1.5 times more likely in those with low blood levels of phylloquinone compared with those who had sufficient levels.

In addition, the chance of developing mobility disability for those low in phylloquinone was almost double that of those with sufficient levels.

There was no clear relationship between either mobility limitation or disability with blood levels of ucMGP.

The results for men and women were largely similar.

The researchers call for further studies to confirm their findings and clarify the mechanisms that might link vitamin K to mobility.

Source: Medical News Today

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Home Exercise Program Reduces Rate of Falling in At-risk Seniors

An in-home exercise program reduced subsequent falls in high-risk seniors by 36 per cent, according the results of a 12-month clinical trial published today in the Journal of the American Medical Association.

The study, conducted by UBC faculty of medicine researchers in partnership with the clinical team at the Falls Prevention Clinic at Vancouver General Hospital, found a reduction in fall rate and a small improvement in cognitive function in seniors who received strength and balance training through the clinical trial.

“When we think about falls we often think about loss of muscle strength and poor balance,” said Dr. Teresa Liu-Ambrose, principal investigator at the Vancouver Coastal Health Research Institute and professor in the department of physical therapy at the University of British Columbia. “However, the ability to remain upright and not fall is also dependent on cognitive abilities—calculating how far to lift your foot to get over a curb, making a decision as to when to cross the road, and paying attention to your physical environment while you are having a conversation.”

Falls increase risk of injury and loss of independence for older adults. Exercise is a widely recommended fall prevention strategy, but whether it can reduce subsequent falls in those who have previously fallen is not well established.

The study involved 344 adults aged 70 and older who had been referred to the Falls Prevention Clinic following a fall that had resulted in a visit to a medical facility, such as an emergency room. Participants had a history of falls, with an average of three prior falls per person, and generally had symptoms of frailty and limited mobility.

The study had participants perform a set of balance and resistance training exercises in the comfort of their homes, using simple equipment such as free weights, a minimum of three times per week. Over the course of six months, a physical therapist made five home visits to prescribe exercises and ensure that exercises were done properly. For those who completed the program, the results were notable. Participants were less likely to experience repeat falls, and as a secondary benefit, they improved in some markers of cognitive function.

Falls in older adults are the third-leading cause of chronic disability. According to the Public Health Agency of Canada, 20 to 30 per cent of Canadian seniors suffer falls each year, and falls are the leading cause of hospitalization for adults over age 65.

“It is well known that exercise benefits older people in general, but what was special about this study group was that they are at very high risk for losing their independence—they had both mobility and cognitive impairments and another fall may mean the inability to live in their own homes. Many already had difficulty navigating public spaces independently,” said Liu-Ambrose, who holds a Canada Research Chair in Physical Activity, Mobility, and Cognitive Neuroscience.

“Older adults who experience falls that require medical attention falls are medically complex and at high risk for both morbidity and mortality, and we demonstrated that exercise is a practical and cost-effective intervention that can improve older peoples’ outcomes after a significant fall,” she added.

Liu-Ambrose and her team at the Centre for Hip Health and Mobility are now looking at whether the exercise program resulted in reduced health care utilization and medical cost savings in this high-risk population.

Source: The University of British Columbia


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Virtual Reality Can Spot Navigation Problems in Early Alzheimer’s Disease

Virtual reality (VR) can identify early Alzheimer’s disease more accurately than ‘gold standard’ cognitive tests currently in use, suggests new research from the University of Cambridge.

The study highlights the potential of new technologies to help diagnose and monitor conditions such as Alzheimer’s disease, which affects more than 525,000 people in the UK.

In 2014, Professor John O’Keefe of UCL was jointly awarded the Nobel Prize in Physiology or Medicine for ‘discoveries of cells that constitute a positioning system in the brain’. Essentially, this means that the brain contains a mental ‘satnav’ of where we are, where we have been, and how to find our way around.

A key component of this internal satnav is a region of the brain known as the entorhinal cortex. This is one of the first regions to be damaged in Alzheimer’s disease, which may explain why ‘getting lost’ is one of the first symptoms of the disease. However, the pen-and-paper cognitive tests used in clinic to diagnose the condition are unable to test for navigation difficulties.

In collaboration with Professor Neil Burgess at UCL, a team of scientists at the Department of Clinical Neurosciences at the University of Cambridge led by Dr Dennis Chan, previously Professor O’Keefe’s PhD student, developed and trialled a VR navigation test in patients at risk of developing dementia. The results of their study are published today in the journal Brain.

In the test, a patient dons a VR headset and undertakes a test of navigation while walking within a simulated environment. Successful completion of the task requires intact functioning of the entorhinal cortex, so Dr Chan’s team hypothesised that patients with early Alzheimer’s disease would be disproportionately affected on the test.

The team recruited 45 patients with mild cognitive impairment (MCI) from the Cambridge University Hospitals NHS Trust Mild Cognitive Impairment and Memory Clinics, supported by the Windsor Research Unit at Cambridgeshire and Peterborough NHS Foundation Trust. Patients with MCI typically exhibit memory impairment, but while MCI can indicate early Alzheimer’s, it can also be caused by other conditions such as anxiety and even normal aging. As such, establishing the cause of MCI is crucial for determining whether affected individuals are at risk of developing dementia in the future.

The researchers took samples of cerebrospinal fluid (CSF) to look for biomarkers of underlying Alzheimer’s disease in their MCI patients, with 12 testing positive. The researchers also recruited 41 age-matched healthy controls for comparison.

All of the patients with MCI performed worse on the navigation task than the healthy controls. However, the study yielded two crucial additional observations. First, MCI patients with positive CSF markers – indicating the presence of Alzheimer’s disease, thus placing them at risk of developing dementia – performed worse than those with negative CSF markers at low risk of future dementia.

Secondly, the VR navigation task was better at differentiating between these low and high risk MCI patients than a battery of currently-used tests considered to be gold standard for the diagnosis of early Alzheimer’s.

“These results suggest a VR test of navigation may be better at identifying early Alzheimer’s disease than tests we use at present in clinic and in research studies,” says Dr Chan.

VR could also help clinical trials of future drugs aimed at slowing down, or even halting, progression of Alzheimer’s disease. Currently, the first stage of drug trials involves testing in animals, typically mouse models of the disease. To determine whether treatments are effective, scientists study their effect on navigation using tests such as a water maze, where mice have to learn the location of hidden platforms beneath the surface of opaque pools of water. If new drugs are found to improve memory on this task, they proceed to trials in human subjects, but using word and picture memory tests. This lack of comparability of memory tests between animal models and human participants represents a major problem for current clinical trials.

“The brain cells underpinning navigation are similar in rodents and humans, so testing navigation may allow us to overcome this roadblock in Alzheimer’s drug trials and help translate basic science discoveries into clinical use,” says Dr Chan. “We’ve wanted to do this for years, but it’s only now that VR technology has evolved to the point that we can readily undertake this research in patients.”

In fact, Dr Chan believes technology could play a crucial role in diagnosing and monitoring Alzheimer’s disease. He is working with Professor Cecilia Mascolo at Cambridge’s Centre for Mobile, Wearable Systems and Augmented Intelligence to develop apps for detecting the disease and monitoring its progression. These apps would run on smartphones and smartwatches. As well as looking for changes in how we navigate, the apps will track changes in other everyday activities such as sleep and communication.

“We know that Alzheimer’s affects the brain long before symptoms become apparent,” says Dr Chan. “We’re getting to the point where everyday tech can be used to spot the warning signs of the disease well before we become aware of them.

“We live in a world where mobile devices are almost ubiquitous, and so app-based approaches have the potential to diagnose Alzheimer’s disease at minimal extra cost and at a scale way beyond that of brain scanning and other current diagnostic approaches.”

Source: University of Cambridge


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Among Older Women, 10,000 Steps Per Day Not Needed for Lower Mortality

In the world of step goals and activity trackers, the number 10,000 can sound like a magic one. Many wearable devices that track the number of steps a person takes each day come pre-programmed with a daily goal of 10,000 steps. But while a large body of evidence shows that physical activity is good for a person’s health and longevity, few studies have examined how many steps a day are associated with good health, particularly long-term health outcomes. A new study led by investigators from Brigham and Women’s Hospital sought to address this knowledge gap by examining outcomes over an average of more than four years for older women in the Women’s Health Study who had measured their steps for a full week. The team reports that, among older women, taking as few as 4,400 steps per day was significantly associated with lower risk of death compared to taking 2,700 steps per day. Risk of death continued to decrease with more steps taken but leveled off at around 7,500 steps per day — less than the 10,000 steps default goal in many wearables. The team’s results are presented today at the American College of Sports Medicine Annual Meeting and published simultaneously in JAMA Internal Medicine.

“Taking 10,000 steps a day can sound daunting. But we find that even a modest increase in steps taken is tied to significantly lower mortality in older women,” said I-Min Lee, MBBS, ScD, an epidemiologist in the Division of Preventive Medicine at the Brigham. “Our study adds to a growing understanding of the importance of physical activity for health, clarifies the number of steps related to lower mortality and amplifies the message: Step more — even a little more is helpful.”

According to previous studies, the average number of steps taken by people in the U.S. is between 4,000 and 5,000 per day. The origin of the 10,000-step goal is unclear but may trace back to 1965, when a Japanese company began marketing a pedometer called Manpo-kei, which translates to “10,000 steps meter” in Japanese.

To conduct their study, Lee and colleagues included participants from the Women’s Health Study, a randomized trial originally conducted to evaluate risk of cardiovascular disease and cancer among women taking low-dose aspirin and vitamin E. When the original trial ended, participants were invited to participate in a long-term observational study. For the present study of steps and health, almost 18,000 women were asked to wear an ActiGraph GT3X+ accelerometer device — a research grade wearable — on their hips for seven consecutive days during all waking hours. The team analyzed 16,741 of the women who were compliant with wearing the device; their average age was 72.

Participants were followed for an average of more than four years, during which time 504 women died. Participants in the bottom 25 percent of steps walked (average of 2,700 steps per day) were at greatest risk of death, with 275 women dying. Those who walked modestly more (average of 4,400 per day) were at 41 percent lower risk of death. Risk of death continued to decrease with more steps walked, up to 7,500 steps per day, after which risk leveled off. The team also found that for women who walked the same number of steps per day, the intensity — how fast or slow they walked — was not associated with risk of death.

Due to the observational nature of the study, the authors cannot definitively separate cause from correlation (that is, to differentiate between “do more steps lower mortality?” or “do women in better health step more?”). However, the team did take several measures to try to ensure that the association observed was more likely causal than not, such as excluding women with heart disease, cancer, diabetes and less than excellent or good self-rated health and excluding the first year of follow-up data. The findings also are supported by previous experiments showing physical activity causes beneficial changes in short-term markers of health e.g., blood pressure, insulin/glucose levels, lipid profile, inflammation, and more.

The Women’s Health Study included primarily older, white women, and further studies will be needed in younger and diverse populations to determine if the findings are applicable to other groups, especially those who may, on average, take more steps. Other outcomes — such as quality of life and risk of specific diseases — were not assessed, but will be addressed in future studies.

“Of course, no single study stands alone. But our work continues to make the case for the importance of physical activity,” said Lee. “Clearly, even a modest number of steps was related to lower mortality rate among these older women. We hope these findings provide encouragement for individuals for whom 10,000 steps a day may seem unattainable.”

Source: Science Daily


Read also at Reuters:

Daily strides may mean longer life for older women . . . . .


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Video: How Aging Really Affects Your Sleep

With age comes wisdom. But it can also come with a change in your sleep patterns.

See four ways aging affects your sleep, and what you can do about it.

Watch video at You Tube (1:31 minutes) . . . . .