Can leptin help individuals with Alzheimer’s? Part 2

The scientists observed that higher leptin levels were associated with a lower incidence of Alzheimer's and all other forms of dementia. At least ¼ of the study who had the lowest leptin levels had a 25% risk of developing AD over a 12-year period. On the other hand those with high levels of leptin had a much lower incidence of developing AD. Moreover, lower leptin levels were also linked to a decrease in brain size.

Dr Seshadri went on to say that at present the role of leptin in the brain is a mystery and, “we're not recommending that anyone get leptin or increase leptin levels."  

As a final note, all consumers should know that there is no correlation between levels of leptin and AD. Even though low levels of leptin have been found in patients with AD, this is by no means a universal or reproducible finding.

Over the past decade, Leptin supplements have been widely sold in many health food stores and experts believe that these are just fake pills. Even though leptin is heavily marketed as a weight loss agent, there is no proof in humans that it does what the vendors of the products claim. At least for now, the only thing leptin can reduce is the weight of your hard earned money.

Study is reported in the Dec. 16 issue of Journal of the American Medical Association,

Can leptin help individuals with Alzheimer’s? Part 1

Almost every week there is news about leptin. This small peptide hormone discovered about 12 years ago is still looking for a disease it can cure or prevent. In the past leptin has been promoted as a cure for aging, help with weight loss, improving depression, increasing libido and cognition. Now there is news that fat hormone may help prevent Alzheimer’s dementia (AD).

Said Dr Sudha Seshadri, an associate professor of neurology at the Boston University School of medicine, "Hopefully, in 10 or 15 years this may be one of many agents that we use to reduce the risk of Alzheimer's disease. Or it may be one of many markers that we measure in combination to predict risk.”

Dr Seshadri added, “But many more studies of different population groups are needed to determine whether leptin can play such a pivotal role in predicting the risk of Alzheimer's. There has been some data relating body weight to the risk of Alzheimer's disease. When we looked at animal studies, we found some data to indicate that leptin not only produces a feeling of satiety but also has a beneficial effect on the hippocampus. It was important to see if that was true in humans."

In the present study, 198 patients had MRI scans that calculated brain volume an average of 7.7 years after leptin was measured. The researchers also kept a lookout for all new patients diagnosed with AD among the study participants.

Big head- less dementia!

While a big head may not always look attractive, there are some long-term benefits. The latest research from Germany indicates that people who have big heads may be protected against the depredation of dementia. In this study done in Munich, researchers followed people with big heads for many years. The patients had their head size measured, were given memory and cognitive skill tests followed by a brain scan to estimate the level of their disease. Over time, researchers discovered that individuals with Alzheimer dementia with the biggest heads had overall better cognition, memory and thinking skills compared to individuals with smaller skulls. A larger head was associated with better performance in the tests, even when individuals had similar amounts of Alzheimer's-related brain cell loss. 

The Munich researchers speculate that having a large brain means that there is more brain reserves, which buffers against dementia related brain cell death. The study looked at over 270 patients recruited from registries across Europe and North America.  The researchers observed that for every 1% brain cell death, an extra centimeter of skull size was associated with a greater than 6% score on the cognitive and memory tests.

So what does all this mean? 

It is not as if someone can increase brain size overnight because brain size is genetically determined. However, these researchers say that the first few years of life are critical for brain growth and by age 6, the brain will have reached almost 94% of its absolute size.

"Improving prenatal and early life conditions could significantly increase brain reserve, which could have an impact on the risk of developing Alzheimer's disease or the severity of symptoms of the disease," lead researcher Dr Robert Perneczky said.

Dr Simon Ridley, head of research for the Alzheimer's Research Trust, said, "Alzheimer's is a very complex disease, so we should be careful not to focus too much on a single risk factor, particularly as there is little we can do about the size of our heads.”

Added Dr Simon, "The researchers have also posed the idea that nutrition, injury or infection in early life can have an impact on brain reserve, suggesting that we should look after our brain from day one. Research is the only answer to dementia. We must invest in research now to deliver the treatments needed to avert the coming dementia crisis."

The two major criticisms about the study is that 1) no one has ever shown that having a small brain or body stature leads to an increased risk of dementia and 2) it is the function of particular areas of the brain which are far more important than size.

Early diagnosis of dementia: Part 2

Even though the MMSE is the current gold standard test for dementia testing, it is not ideal for all dementia and the test is not universally applicable to all patients with dementia.

The current 16-point test is heavily focused on ability to recall skills, verbal memory performance, and orientation issues such as the ability to identify a person, place, time and/or situation. The test is fast and does not involve any writing. When compared with the MMSE, it has been shown to have higher sensitivity in detecting cognitive impairment. However, experts also indicate that the test does give a high rate of false positives.

While no one disagrees for the need of better cognitive test, it is not known if this test will fit the bill. The MMSE is cumbersome, requires writing and it is also difficult to score.

Says Dr Gary J. Kennedy, director of geriatric psychiatry at Montefiore Medical Center in New York City, “I would say that reading this description of the 'Sweet 16,' it sounds like it's much more easily administrated. But still, I'm not convinced this is the answer to the problem. Because diagnosing cognitive impairment is not the same as diagnosing diabetes. It is much more complicated than that. People's cognition varies with life experience. It is not like simply testing for blood sugar levels. There isn't a single diagnostic marker."

Final point:  With early diagnosis of dementia, will that mean doctors will start to prescribe more medications? The point to understand is that the majority of people who have early dementia do not require any treatment and the rates of progression of dementia are very variable.

Early diagnosis of dementia: Part 1

In the last decade, there has been a major emphasis on early detection of dementia. Currently there are an estimated 3.4 million elderly Americans diagnosed with dementia, while another 5.4 million suffer from mild forms of cognitive impairment.

Recently, researchers from Boston developed a screening test to help identify individuals with early cognitive impairment. The test is designed to quickly identify people who have problem with learning, thinking and memory. Classified as “The Sweet 16" for its 16-point scale, the test rapidly exposes telltale signs of dementia through a cognition grading system that ranks mental skills from a low score of zero up to a high of 16.

However, the researchers who have formulated this test caution that it still needs further analysis to ascertain its reliability, particularly if it is to be compared to the already well -established measure of cognitive dysfunction-- the Mini-Mental State Examination (MMSE). The investigators indicate that unlike the MMSE the Sweet 16 is faster and can identify early cognitive impairment.

"For many older adults, cognitive impairment contributes to loss of independence, decreased quality of life and increased health-care costs. While the public health impact of cognitive impairment is clear, this condition is often under-recognized," said Dr. Tamara G. Fong, of Hebrew Senior Life, Beth Israel Deaconess Medical Center and Harvard Medical School .

Dr Fong also added, ""A simple, rapid cognitive assessment instrument is therefore a valuable tool for use in both clinical and research settings."