The Golden Age of Gray

AVOID A FALL

Kids trip and fall all the time and suffer only skinned knees or bruised elbows. For older adults, however, a single tumble can be devastating.

A fall may be the first step in a cascade of health problems for the elderly, says Albert Wu, MD, MPH, professor in Health Policy and Management.

Each year in the U.S., one in three people over age 65 experiences a fall, and a third are significantly injured. The fallout is expensive: $30 billion in direct medical costs each year, according to the CDC. Clearly, fall prevention is a critical public health issue, says Wu.

The good news: A variety of strategies have been shown to work in preventing falls, and most are quite cost-effective. Wu is leading the Johns Hopkins arm of a 10-institution, $30 million grant-funded project that will assess the effectiveness of individually tailored care plans over five years.

“The study’s approach differs from other research in that it will integrate already proven falls-reduction strategies into cohesive interventions that can be adopted by many health care systems,” notes Wu.

For elderly people at risk of falling, a medication review is often a good start, since some drugs (alone or in combination) can cause weakness and dizziness or impair balance. Other low-cost interventions under study: Vision and hearing screening to identify those who need help navigating their environment; an assessment of strength and balance to determine who could benefit from physical therapy and strength building; and modification of the home to mitigate tripping hazards and add supports.

All these interventions can be done for low cost and are generally covered by Medicare or other insurance, says Wu.

In a separate clinical trial, Johns Hopkins’ Larry Appel, MD, MPH '89, director of the Welch Center for Prevention, Epidemiology, and Clinical Research, will investigate whether something as simple as vitamin D could make a difference, since studies have linked low vitamin D to muscle weakness and loss of bone strength. “Several lines of evidence suggest that vitamin D supplements might substantially reduce the risk of falls, potentially by more than 25 percent, in elderly people who are vitamin D deficient,” notes Appel. Participants will receive one of four daily doses to determine the best dose for preventing falls.

SLEEP WELL

Getting a good night’s sleep can be a problem for people as they advance in age.

Many elderly people awaken a few hours after going to bed, then toss and turn. Others drift in and out of a light sleep, or find their slumber repeatedly interrupted by trips to the bathroom or a restless spouse.

Unfortunately, disturbed sleep may cause more than crankiness—it’s also been linked to cognitive and functional impairment in older adults, notes Adam Spira, PhD, assistant professor in Mental Health.

Most recently in a study of older adults, Spira and his colleagues found that both shorter sleep duration and more restless sleep were associated with higher levels of beta-amyloid in the brain, a well-known biomarker for Alzheimer’s disease (AD). The study, which appeared in the December 2013 issue of JAMA Neurology, was conducted in collaboration with researchers from the National Institute on Aging.

Noting that Alzheimer’s is the most common form of dementia, and that nearly half of older adults report insomnia symptoms, Spira concludes, “Our results may have significant public health implications.”

The good news? Late-life sleep disturbances can be successfully treated in older adults through cognitive-behavioral therapy for insomnia—typically provided by a psychologist and considered much safer than sleep medications, many of which have been linked to falls, confusion and interactions with other medications. Thus, such interventions “may help prevent or slow AD—to the extent that poor sleep promotes AD onset and progression,” Spira reports in his study.

That last point is important. Spira notes that his cross-sectional study used data from the Baltimore Longitudinal Study of Aging, in which subjects self-reported their sleep habits—information that was then compared with the PET images of their brains to make the associative link. This raises a chicken-and- egg conundrum. Does poor sleep cause Alzheimer’s? Or does Alzheimer’s cause disrupted sleep?

Animal studies would appear to lend credence to the first idea. Mice bred to have Alzheimer’s, and that have been sleep-deprived, have been shown to generate an excess of amyloid plaque. Their better-rested counterparts develop fewer amyloid tangles, says Spira, who is planning future studies to better explain the mechanisms linking poor sleep—and sleep apnea—to Alzheimer’s.

STAY HEALTHY IN MIDDLE AGE

Like it or not, as we move into advanced age, we slow down. Even the fittest 60- or 70-year-old will find it impossible to break into a sprint by the time he’s 95 or 100. For most people, an overall slowdown begins much earlier.

One marker of this diminishment is our resting metabolic rate (RMR), the minimal energy required to live, which decreases with age—a necessary development since our bodies expend much less energy once we stop growing and start to lose lean muscle mass in midlife. For the elderly, this drop in RMR occurs at a time when the amount of energy required to perform simple everyday tasks—walking to the mailbox, getting in and out of the bathtub, dressing each morning—goes up. A 90-year-old, for instance, must summon much more energy than his 50-year-old daughter would need to put away the groceries.

“The beauty of resting metabolic rate is that it seems to be a global measure of what’s going on beneath the surface,” says Jennifer Schrack, PhD, assistant professor of Epidemiology and author of a recent study that looked at associations between chronic disease and RMR.  What she found: Elderly people who were coping with diabetes, heart disease and other chronic conditions had higher RMRs than their healthier counterparts.

“We think what this means is that more energy is required to maintain life when you have these other diseases—your body has to work harder to stay alive,” leaving less energy to stay active and mobile.

The bottom line: People who want to enjoy healthy longevity at older ages should take steps now to maintain as much of their energetic capacity as possible by staying physically active and maintaining a healthy weight. “The public health message is prevention. I strongly believe that a lot of the conditions that affect mobility in late life begin in mid-life,” Schrack says. “People who don’t take care of themselves in their 40s and 50s—that’s reflected when they hit their 60s and 70s.”

For healthy people of advanced age, Schrack suggests finding ways to promote activity, reduce sedentary behaviors and preserve energetic capacity to retain mobility and functional independence.  For those facing health challenges, it is important to make their activity “more efficient”—through everything from properly fitted walking aids to design improvements in their living spaces.

TRAIN YOUR BRAIN

Much ado has been made about the value of tackling crossword puzzles and other mental exercises as a strategy for staving off memory loss and dementia.

George Rebok and his research team have taken this idea a compelling step further. Their research shows that elderly people who participate in a series of cognitive training exercises have improved memory and daily function—effects that last for a decade.

“That really gave me pause: the fact that this relatively modest amount of training—10 sessions over six weeks—could still be having results 10 years later,” says Rebok, PhD, MA, a Mental Healthprofessor, of the multisite clinical trial known as ACTIVE (Advanced Cognitive Training for Independent and Vital Elderly). “That carryover effect is very difficult to find and had not been demonstrated before.”

The healthy older adults in Rebok’s study received training in one of three areas. Memory training provided strategies for remembering word lists and main ideas from a story that had been read to them. Reasoning exercises equipped them to find patterns in letters, numbers and words. “Speed-of-processing” exercises helped participants focus on objects in the center of a computer screen despite increasing distractions on the periphery—similar to what they might experience while driving. In fact, “an important part of all the training was to emphasize the everyday usefulness of all the strategies,” Rebok says.

Fast-forward a decade; the participants now are in their 80s. Those who received the cognitive training reported less difficulty with daily functioning (making meals, managing medications and using transportation) than those in a control group. What’s more, nearly 75 percent of the reasoning-trained and over 70 percent of the speed-trained participants were performing at or above their baseline cognitive ability compared with 62 percent and 48 percent, respectively, of control participants.

The results of the ACTIVE study give Rebok great hope for the future. Relatively inexpensive and easy to administer, cognitive training “holds the potential to delay the onset of functional decline and possibly dementia,” in the nation’s rapidly graying population, he says.  “If we could delay the onset of functional impairment by even six years, the number of elderly people affected by 2050 would be reduced by 38 percent—which would be of great public health significance.”

TREAT HEARING LOSS

One of the most common health consequences of aging is hearing loss, estimated to affect nearly half of all people age 75 and over, according to NIH.

The cost to health is far from benign, notes Frank Lin, MD, PhD, an associate professor in Otolaryngology and Geriatric Medicine at Johns Hopkins School of Medicine who holds joint appointments in Epidemiology and Mental Health at the Bloomberg School. Studies by Lin and others point to a growing list of health problems associated with loss of hearing—including increased risk of dementia, falls, hospitalizations and diminished health overall.

Most recently Lin has found evidence that shrinkage of the brain, long known to occur naturally as we age, appears to be “fast-tracked” in older adults with hearing loss.  “Our results suggest that hearing loss could be another ‘hit’ on the brain in many ways,” he says.

Scientists had previously shown that sound-processing brain structures appeared to be smaller in hard-of-hearing people and animals, compared to those with better hearing. But did the structural differences happen before or after the hearing loss?

To find out, Lin and colleagues tapped into data from the Baltimore Longitudinal Study of Aging, conducting a substudy that involved 126 participants who underwent MRI annually to track brain changes for up to 10 years. Each also had a full physical with a hearing test at the time of the first MRI.

The researchers found that people whose hearing was already impaired at the start had accelerated rates of brain atrophy compared to those with normal hearing (losing an additional cubic centimeter of brain tissue each year).

They also experienced significantly more shrinkage in particular regions that process sound and speech, including the superior, middle and inferior temporal gyri. The latter two regions also have roles in memory and sensory integration and have been shown to be involved in the early stages of Alzheimer’s disease.

There’s good reason to deal quickly with loss of hearing rather than ignore it, Lin says. “If hearing loss is potentially contributing to these differences we’re seeing on MRI,” he says, “you want to treat it before these brain structural changes take place.”