Shorter Arms and Legs Associated with Increased Alzheimer's Risk
Here's something I must admit I've never considered: Are shorter arms and legs linked to an increased risk for Alzheimer's or other dementias?Apparently, there's some research to back this up. A study just published in the journal Neurology found that women with shorter arm spans were 1.5 times more likely to develop Alzheimer's than women with longer arm spans. Long legs were also a plus for women, indicated by a 16% reduction in Alzheimer's risk for each additional inch of leg length beyond the average. While arm length affected Alzheimer's risk in men, leg length was not a significant factor.
This study supports three previous studies in Korea that linked shorter limbs with an increased risk for cognitive impairment. Why are researchers finding this link? They theorize that shorter limbs are often due to poor nutrition in early life, which can also affect brain development. If the brain doesn't develop properly in childhood, it might be more susceptible to brain disorders in adulthood.
I know what you're thinking: "My mom and dad are/were both short, so that's why I'm short! It wasn't because of poor nutrition." That's right, genetic factors play a significant role in our development, too. Luckily, the researchers acknowledge that. Still, I guess I have another reason to be happy about being six feet tall.
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Should Drugs for Alzheimer's and Incontinence Be Combined?
Researchers from Wake Forest University School of Medicine have been busy conducting great research on Alzheimer's and related issues (see my previous blog). This time, they teamed up with researchers from Purdue University to study the combined effect of Alzheimer's medications and drugs for incontinence on 395 nursing home residents in Indiana. Changes in the residents' functioning were compared to changes in functioning among over 3,000 nursing home residents who were taking an Alzheimer's medication but not an incontinence drug.The results were startling. Those taking both Alzheimer's and incontinence drugs showed a 50% faster decline in functioning compared to those who were taking only an Alzheimer's medication.
There's a good reason why those taking both medications declined more rapidly. Alzheimer's medications such as Aricept, Exelon, and Razadyne increase levels of acetylcholine in the brain; on the other hand, incontinence drugs such as Ditropan actually block acetylcholine. In essence, the drugs work against each other.
If you're scratching your head at this point, you're not alone. I'm trying to figure out why approximately one third of people taking an Alzheimer's medication are also prescribed drugs for urinary incontinence.
Dr. Kaycee M. Sink, the lead author of the study, recommends that when treating people with Alzheimer's, "clinicians should continue to try non-drug management strategies for incontinence before beginning therapy with one of these common drugs." I couldn't agree more.
The good news: This study was conducted from 2003-2004, before newer incontinence medications became available. These newer drugs may have less of an effect on acetylcholine levels than older medications -- but this still needs to be researched.
What are your thoughts on this study? Post a comment to this blog, or start a new discussion in the forum.
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Photo of Ditropan © Gold Standard
Researchers Discover More About Memory
Researchers at Wake Forest University School of Medicine have learned by studying mice that protein-destroying "machines" hovering in the connections between brain cells might impede the formation of memories.What's interesting is that these cylinder-shaped machines -- called proteasomes -- are helpful to memory when they occur in a cell's nucleus. It's only when they linger in the dendrites -- the branches at the end of a nerve cell that transmit electrical signals to other cells -- that they interfere with memory.
The study, which was funded by the National Institutes of Health, is important because it could pave the way to future treatments for Alzheimer's and other dementias that focus on blocking the activity of proteasomes in the dendrites with the goal of improving memory.
Illustration of Neurons in the Aging Brain © A.D.A.M.
Does Anesthesia Increase Alzheimer's Risk?
Considering that over 200 million people undergo surgery each year, it's important to know whether common anesthetics could increase one's risk for Alzheimer's or other cognitive disorders.Researchers at Massachusetts General Hospital/Harvard Medical School recently studied human brain cells subjected to the common anesthetic desflurane for six hours in order to simulate a surgery situation. They found that when oxygen levels were normal, desflurane did not adversely affect the brain cells. However, when the cells were subjected to low oxygen levels, the desflurane was associated with increased production of beta amyloid, a protein found in elevated quantities in the brains of those with Alzheimer's. Low oxygen alone did not increase beta amyloid production.
What does this mean? The researchers say that because the study used cell cultures, their next step is to test the findings in animal models. It's not certain that anesthesia and low oxygen actually increase beta amyloid production in humans during surgery, but this is an important area of study given the prevalence of anesthetic use in medical care.
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Illustration © Alzheimer's Disease Education and Referral Center
Florida Congressman Wants Silver Alert Program
We've all heard of Amber Alert, the highly successful program designed to find missing children before it's too late. But have you heard of Silver Alert? Modeled after Amber Alert, Silver Alert notification systems help locate missing individuals who have Alzheimer's disease or related dementias.Five states currently operate Silver Alert programs: Colorado, Illinois, Michigan, North Carolina, and Texas. Florida Congressman Gus Bilirakus wants every state to have the resources to start Silver Alert programs.
Bilirakis recently introduced the Silver Alert Grant Program Act of 2008 (H.R. 5898). If passed, the program would provide state legislatures with seed money to implement their own Silver Alert systems. The congressman recently told the St. Petersburg Times that "states should make this a priority, and we don't want them to have any excuses."
I applaud Congressmen Bilirakus for introducing this bill, which was referred to the House Committee on the Judiciary. I'll be sure to keep you posted on its status.
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Rehabilitation Technique Increases Gray Matter
In an exciting study at the University of Alabama at Birmingham, researchers found that a rehabilitation technique actually increased gray matter in the brains of stroke patients.The technique, called constraint induced therapy, involves forcing the use of affected arms or legs by restraining the unaffected limbs for an extended period. When the researchers -- including Dr. Edward Taub, who pioneered the approach -- applied constraint induced therapy to 16 stroke patients, MRIs showed an increase in gray matter in areas of the brain responsible for motor skills; a control group showed no increase in gray matter.
What does this have to do with Alzheimer's disease? After Alzheimer's, vascular disease (such as stroke) is one of the second most common causes of dementia. Alzheimer's and vascular dementia can even occur together, resulting in mixed dementia.
Even though constraint induced therapy focuses on improvements in motor skills as opposed to memory, it's encouraging to see evidence that gray matter in the brain can actually increase in response to therapies aimed at helping people recover from traumatic injury or disease. Could an increase in gray matter slow Alzheimer's or improve symptoms? Sounds like a ripe area for research to me.
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Illustration © A.D.A.M.
Different Dementias, Different Treatments?
Alzheimer's disease involves the buildup of plaques and tangles in the brain; interestingly, tangles made of tau protein aren't unique to Alzheimer's. Yet a new study found that an enzyme called Pin1 has opposite effects for different dementias. While the enzyme "detangled" tau proteins in Alzheimer's, it actually sped up the progression of another kind of tau-related disorder called frontotemporal dementia with parkinsonism-17.While dementia is an "umbrella" term for all disorders that create progressive brain dysfunction, that doesn't mean that all dementias are the same. Each dementia should be carefully evaluated and treated according to its specific cause or causes instead of assuming that an effective treatment for one dementia will work for similar disorders. Such an assumption might be ineffective, and it could actually make things worse.
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Alzheimer's Vaccine Study Halted Because of Safety Concern
A clinical trial evaluating the efficacy and safety of Alzheimer's vaccine ACC-001 was suspended in early April because one of the study's participants developed inflammatory brain lesions. The participant was hospitalized but later released.The vaccine targets beta amyloid, a protein that accumulates in the brains of those with Alzheimer's disease. Interestingly, a previous study evaluating a similar vaccine was discontinued because some participants developed encephalitis -- another type of brain inflammation.
Dr. Jeffrey Cummings of UCLA was not involved in the trial, but he suggested that we shouldn't jump to conclusions about the most recent study because little information is available about the nature of the participant's lesions or whether the person was receiving the vaccine or a placebo. Still, the fact that two different studies of Alzheimer's vaccines have encountered problems with brain inflammation highlights the difficult road ahead for scientists trying to find a safe, effective vaccine against Alzheimer's.
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Flurizan Slows Alzheimer's Progression, But Only In Earliest Stages
A recent study of the experimental drug Flurizan indicated that it slows the progression of Alzheimer's disease during its early stages, but it made no difference when taken during more advanced stages.Flurizan works by blocking the production of beta amyloid in the brain. Beta amyloid buildup is a hallmark of Alzheimer's, although scientists hesitate to say whether it actually causes the disease.
Flurizan is not FDA-approved and is only available in clinical research settings. Still, the study's results emphasize the importance of early diagnosis and treatment. To learn more about the first signs of Alzheimer's disease, see my article on Early Indicators of Alzheimer's. For a discussion of FDA-approved medications, see Treatments for Alzheimer's Disease.
Illustration © Alzheimer's Disease Education & Referral Center
Statins Improve Cholesterol Levels, Not Memory
There's been a lot of interesting talk about cholesterol at the American Academy of Neurology's 60th Annual Meeting. In my previous blog, I reviewed a report from the meeting that suggested we should keep our cholesterol levels down in mid-life to reduce our risk for developing Alzheimer's down the road.Another study presented at the annual conference focused on statins -- drugs such as Lipitor that help lower cholesterol -- and how they work when administered to those who already have Alzheimer's disease. Although previous research indicated that statins might improve cognitive functioning, this more scientifically rigorous study was not as encouraging. While individuals with Alzheimer's taking statins experienced lower cholesterol levels, they didn't show any significant improvement in thinking or memory.
It appears that instead of relying on statins later in life, managing cholesterol levels earlier in life is a better strategy for maintaining a healthy brain.
Photo of Lipitor © Gold Standard