Alzheimer disease is a chronic condition that afflicts more than 14% of the geriatric population. It is the most common cause of dementia, characterized by a progressive decline in cognitive function. Although there are pharmaceutical drugs (i.e., donepezil) that attempt to stave this decline, there is yet no cure.

A recent study published in the American Journal of Clinical Nutrition has correlated green tea consumption with a lower prevalence of cognitive impairment. Although previous animal studies have suggested a protective effect of green tea against neurodegenerative diseases, this is the first study that addresses the topic in humans.

Researchers at the Tohoku University School of Medicine (Sendai, Japan) surveyed 1003 geriatric citizens at ages 70 years or older from the Tsurugaya district of Sendai City. The study examined several variables, including the consumption of certain beverages, the health status, and the social habits of the participants. Their cognitive function was assessed using the Mini-Mental Status Examination (MMSE), a tool commonly used by neurologists and geriatricians.

The study found that participants who routinely consumed greater quantities of green tea generally scored higher on the MMSE. Consumption of black or oolong tea, or coffee did not produce similar trends. The researchers also adjusted the data for several possible confounders, such as presence of different diseases, level of physical activity, educational background, dietary habits, and substance use. The results still demonstrated a positive effect of green tea in cognitive function.

Does green tea hold promise for dementia patients? Can it reverse the cognitive decline in Alzheimer disease? What about using it as prophylaxis by healthy individuals? The findings are exciting, but there is yet much research needed to validate and extend the results of the Tsurugaya Project.

• Source
• Kuriyama S, Hozawa A, Ohmori K, Shimazu T, Matsui T, Ebihara S, Awata S, Nagatomi R, Arai H, Tsuji I. Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project. Am J Clin Nutr 2006;83:355-61.

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The Valentine’s Day Edition of Grand Rounds (Vol. 2, No. 21) can be found at intueri. In keeping with the Valentine’s Day ambience, Maria creatively presents each article in the form of a “personal ad”. The On The Wards article on melatonin is listed as follows:

What can I do to make you sleep with me? Perhaps you can help cure me of my insomnia because melatonin won’t.

On a related note, I have decided to no longer feature each Grand Rounds as a separate blog entry. I feel this may be a redundant effort, as the majority of other medical blogs–some which you probably read–already announce the weekly [Tuesday] arrival of the Grand Rounds. I have nevertheless placed the Grand Rounds schedule as a link on the right-hand column of On The Wards for easy access.

Melatonin is a hormone produced by the pineal gland and associated with regulation of the sleep cycle. There have consequently been melatonin products, and biosynthetic variants (i.e., ramelteon), marketed as sleep aid products. A popular use for melatonin has been to combat jet lag or for adaptation to different time zones. Two recurring questions I have encountered regarding melatonin are whether it actually works and whether there are any adverse side-effects.

The February 10 issue of the British Medical Journal includes a study by a Canadian group that reviewed the efficacy and safety of melatonin use with secondary sleep disorders and sleep restriction. Secondary sleep disorders are sleep problems with a physiologic cause, such as hyperthyroidism or substance abuse (toxicity). Sleep restriction, on the other hand, results from voluntary sleep disruption. On-call physicians or third-shift police officers are examples of people who endure sleep restriction.

According to the meta-analysis (a review of several research efforts examining the same topic) of 15 separate studies (524 participants), melatonin is not effective for both secondary sleep disorders and sleep restriction. Commonly reported side-effects were drowsiness, headache, nausea, and dizziness. Otherwise, the report does not indicate significant adverse effects of short-term melatonin use (3 months or less).

In another meta-analysis performed by the same group, and published two months earlier in the Journal of General Internal Medicine, there is some evidence of efficacy in delayed sleep phase syndrome (DSPS), a shift in the circadian rhythm that makes it difficult for the person to fall asleep and wake up. Study participants who suffered from this disorder were able to fall asleep around 38.8 minutes earlier with melatonin. The study does not however report significant improvement in sleep onset with melatonin use for other sleep disorders. The findings on safety are similar here as in the BMJ article.

In short, melatonin is not effective for most sleep disorders, but it is safe with short-term use.

• Sources
• Buscemi N, Vandermeer B, Hooton N, Pandya R, Tjosvold L, Hartling L, Baker G, Klassen TP, Vohra S. The efficacy and safety of exogenous melatonin for primary sleep disorders. A meta-analysis. J Gen Intern Med 2005;20:1151-8.
• Buscemi N, Vandermeer B, Hooton N, Pandya R, Tjosvold L, Hartling L, Vohra S, Klassen TP, Baker G. Efficacy and safety of exogenous melatonin for secondary sleep disorders and sleep disorders accompanying sleep restriction: meta-analysis. BMJ 2006.

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This week, Grand Rounds (Vol 2. No. 20) is hosted at Science and Politics. There is a diversity of articles to read. Some categories include research, education, patient care, and of course, politics.

In just the past decade, cell phones have evolved from a luxury item reserved for an elite few to a standard personal accessory for the masses. The ubiquity of these devices has dramatically changed the landscape of interpersonal communication, benefitting virtually every industry. Unfortunately, the medical industry, particularly among hospital-based practices, still lags in the adaptation of mobile technology. All too frequent, we may be gently reminded by signs or hospital personnel to not use our cell phones in certain areas. The primary concern with these devices is possible electromagnetic interference (EMI) that would affect sensitive medical equipment. With the advancement of mobile technology and better shielding for medical equipment, this perception may change.

According to several Internet news sites, the Tan Tock Seng Hospital in Singapore recently concluded from an internal study that cell phones pose no significant risk to medical equipment. The hospital is purportedly converting its medical staff from the antiquated pagers to mobile phones. I could not find a reliable source (i.e., journal publication or hospital press release) to verify the reports, so I will not identify any sources.

There have nonetheless been other studies examining the impact of mobile phones on medical equipment. A study published last year in Anesthesia & Analgesia, for example, found that routine use of cell phones was acceptable even in critical care units. There are published specifications on how far the phone may be from a medical device, but a general guideline for a safe distance is 1 meter. I have observed wireless devices used at much closer distances to anesthesia machines without notable effect. But, I did not perform any formal or informal study, so I will not comment further on this.

• Source
• Wallin MK, Marve T, Hakansson PK. Modern wireless telecommunication technologies and their electromagnetic compatibility with life-supporting equipment. Anesth Analg 2005; 101:1393-400.

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