The Link between Type 2 diabetes and Alzheimer's disease

Recent statistics indicate that people with type 2 diabetes mellitus have nearly twice the risk of developing Alzheimer's disease as people without diabetes. While the exact reason for this is still being investigated, several interesting findings connecting the two diseases have emerged.

Type 1 vs. Type 2 Diabetes.   The American Diabetes Association reports that in 2012, 29.1 million Americans, or 9.3% of the population had diabetes.  Of these, 90 to 95% have Type 2 diabetes.  While both Type 1 and Type 2 diabetes are characterized by high blood sugar, the mechanism for the development of each type is very different.  Type 1 diabetes is considered to be an autoimmune disease in which the cells within the pancreas that produce insulin are destroyed, resulting in a deficiency of insulin. Without insulin to move sugar from the bloodstream into the body's cells, blood sugar rises. Type 2 diabetes, on the other hand, is considered a disease of "lifestyle".  Poor diet, inactivity, and obesity are major reasons for its development.  In type 2 diabetes elevated blood sugar levels are initially due to the body's inability to use insulin effectively. This is known as "insulin resistance" and is associated with higher than normal insulin levels.
 
Complications of Type 2 diabetes.   In addition to significantly increasing one's risk of heart attack and stroke, Type 2 diabetes mellitus is associated with a number of other medical complications including:

• Blindness from diabetic retinopathy
• Reduced blood flow in the feet and legs requiring amputations
• Kidney failure
• Nerve damage and ulcerations of the feet

If these problems weren't enough, add in the recent findings that Type 2 diabetes may also contribute to the development of Alzheimer's disease.

How could diabetes cause Alzheimer's?   When examining the brain of someone with Alzheimer's disease who has died, two major findings are noted: amyloid plaques and tau protein "tangles".  These are considered to underlie the neurodegenerative process related to development of dementia.  Recent research has shown that the high insulin levels (hyperinsulinemia) from Type 2 diabetes cause changes in the tau protein that result in the tangles.  Another study performed with mice demonstrated that high levels of glucose in the blood can increase amyloid beta, a key component of amyloid plaques, clusters of "sticky" proteins that inhibit the normal function of brain cells. While the relative contribution of high blood sugar or high insulin levels is still under investigation, one or both of these features of
Type 2 diabetes is likely responsible for the increased development of Alzheimer's.

Reducing Alzheimer's risk.  By avoiding the development of Type 2 diabetes, the risk of developing Alzheimer's goes down in parallel. This is best done by staying physically active, eating a healthy diet and keeping one's weight in an ideal range.  In someone who already has Type 2 diabetes, most of the known complications can be prevented or delayed with regular visits to a health care provider, appropriate medication and attention to lifestyle issues.  It stands to reason that these measures would reduce the risk of developing Alzheimer's disease also.  One study performed by scientists at Kaiser Permanente demonstrated a 20% reduction in the development of dementia when treating Type 2 diabetics with the diabetes medication, metformin. While many cases of Alzheimer's disease seem to develop by chance, prevention or management of Type 2 diabetes appears to offer an opportunity to reduce the likelihood of its occurrence.

Violent Video Games and Aggressive Behavior

In 2005, the American Psychological Association (APA) issued a resolution stating that "there appears to be evidence that exposure to violent media increases feelings of hostility, thoughts about aggression, suspicions about the motives of others, and demonstrates violence as a method to deal with potential conflict situations".

In 2013, the APA assembled a Task Force to review research published subsequent to 2005 and update their position relative to violence in video games and interactive media.  Along with consulting leading researchers in the field of video games violence, the Task Force interviewed practitioners in the fields of behavioral science, pediatrics, communications and public health. Most of the studies conducted in this area involved adolescents and young adults.
 
In psychological research, aggression is defined as behavior that is intended to harm another. Violence is considered to be an extreme form of physical aggression or the intentional use of physical force or power that either results in or has a high likelihood of resulting in harm.  Along with validating the 2005 resolution, the more recent report concluded that there is a "...consistent relationship between violent video game use and heightened aggressive behavior, aggressive cognitions, and aggressive affect and reduced prosocial behavior empathy and sensitivity to aggression."

The following are some of the most compelling excerpts from the "American Psychological Association Task Force on Violent Media Technical Report on the Review of the Violent Video Game Literature":

1. “More than 90% of U.S. children play some kind of video game; when considering only adolescents ages 12–17 that figure rises to 97%.  Although high levels of video game use are often popularly associated with adolescence, children younger than age 8 who play video games spend a daily average of 69 minutes on handheld console games, 57 minutes on computer games, and 45 minutes on mobile games, including tablets.“
    
2. "Research has identified a number of risk factors for the development of aggression, including factors at the level of the individual (e.g., aggressive traits), family (e.g., low socio-economic status, harsh discipline practices, peers (e.g., peer rejection), school (e.g., exclusionary disciplinary practices), and neighborhood or community (e.g., poor urban settings). Children who experience multiple risk factors are more likely to engage in aggression.”
    
3. “No single risk factor consistently leads a person to act aggressively or violently. Rather, it is the accumulation of risk factors that tends to lead to aggressive or violent behavior. Each risk factor increases the likelihood of such negative behavior. The research reviewed here demonstrates that violent video game use is one such risk factor."
    
4.  “Although the number of studies directly examining the relation between the amount of violent video game use and the degree of change in adverse outcomes is still limited, existing research suggests that higher amounts of exposure are associated with higher levels of aggression and other adverse outcomes”.
    
5. "Although the media and the public often ask about the association between violent video game use and delinquency or violence … too little research has addressed these outcomes to reach a conclusion."

The link between violent video game use and heightened aggressive behavior is a very complex issue. Today's Health Tip really only skims the surface in regard to the many facets of the analysis that were included in the report from the Task Force.  In addition to examining the effects of playing violent video games on behavior, the authors pointed out numerous potential flaws in existing research and areas that need further study. Some issues not adequately examined in existing research include potential differences between girls and boys or in different ethnic groups in regard to violent video game use and aggressive behavior.
 
As a result of the conclusions drawn by the Task Force, the APA issued a resolution requesting that the video game industry include more parental controls over the amount of violence the games contain.  Additionally, the resolution urges developers to design games that are appropriate to users' age and psychological development.  A summary of the Task Force's finding and a link to the full report can be found here.

Is there really such as thing as…?

Terms used by lay individuals to designate certain medical conditions can vary significantly from those used by medical professionals.  Similarly, certain conditions widely accepted by the general public may or may not have the same degree of acceptance in the medical world. Today's Health Tip looks at some of these terms and conditions to try to separate myth from fact.
 
Brain freeze ---Also known as "ice cream headache", brain freeze occurs after eating cold foods or beverages too quickly.  It develops when a cluster of nerves (sphenopalatine) in the hard palate of the mouth is rapidly chilled.  When this happens, blood vessels within the brain constrict and then dilate, similar to what happens with a migraine headache. The pain itself is "referred", or felt in an area distant from where the palate was chilled, often behind the eyes or in the forehead. The pain usually resolves in a few excruciating minutes. The best way of preventing "brain freeze" is to consume cold food or liquids at a slower rate.

Walking pneumonia---This is a lay term for a relatively mild lung infection in which bed rest or hospitalization is not required.  In walking pneumonia, viruses or the mycoplasma bacteria are the most common causative organisms.  Pneumonia symptoms, such as cough, fever and shortness of breath may be present, but are milder than in more serious cases such as pneumonia caused by the Streptococcus pneumoniae (pneumococcus) bacteria.  In walking pneumonia caused by the mycoplasma bacteria, treatment with antibiotics can shorten the duration of illness.

Glandular cause for obesity----In most cases, obesity is the result of overeating.  In a small percentage of people, however, excess weight gain can be related to an endocrine issue.  The endocrine system includes a collection of glands including the thyroid, ovaries, and adrenals.  Among other functions, the endocrine system regulates metabolism, growth and development.  One of the manifestations of an underactive thyroid gland (hypothyroidism) is weight gain. Cushing's syndrome, a condition in which the adrenal glands produce an excess of the hormone, cortisol, can also lead to excess fat deposition. A third "glandular" cause for weight gain is polycystic ovary syndrome.  This condition, estimated to affect 5 to10 percent of women of childbearing age is caused by high levels of hormones called androgens.

The funny bone---- If you've ever struck your "funny bone", you know that it's inappropriately named---it's not funny at all. In fact, it's downright painful. The structure that is responsible for "funny bone" pain is actually a nerve (ulnar nerve). This nerve lies fairly close to the surface of the skin and when struck, often sends an "electric shock" sensation down the forearm and into the little finger. One theory is that the name "funny bone" comes from the Latin word for the upper arm bone, the humerus.

Spontaneous human combustion---The short answer is no, this doesn't exist. The human body is composed of between 60 and 70 percent non-flammable water and there is no credible explanation for it to simply burst into flames. There have been reported cases of victims who appeared to burn without an obvious source of heat or flame, however, there is no scientific proof that these incidences were related  to spontaneous combustion. When investigated, many of these cases were later attributed to the victim being intoxicated or falling asleep with a lit cigarette. A second theory, the "wick effect", suggests that body fat is capable of burning like a candle. This occurs when the victim's clothing, which is acting as wick, is ignited by a heat source.  Historically, there have been so few suspected cases of spontaneous human combustion that they scarcely deserve to be considered at all.

It is not uncommon for a medical condition to have different designations when being referred to by a lay individual or by a medical professional. In many cases, the lay terminology is actually more colorful or descriptive than the doctor's lingo. This does not mean that one is better than the other, they are just different. On the other hand, there are also lay terms and commonly referred to conditions that fall into the myth category.  In some cases, this can lead to misunderstanding of the significance or appropriate management of the condition.