Tuesday, May 28, 2013

Statins and Muscles

     A number of readers have asked me about the recent article in the NY Times which quoted an online article in the Journal of the American College of Cardiology which discussed the adverse effects of statin use on skeletal muscle.

     To begin with, there is a molecule called Co-enzyme Q (or Q-10) which lines the inside of the membrane of mitochondria. A mitochondrion is an organelle inside a cell where ATP, the source of the cell's energy is generated. There are many mitochondria in muscle cells, for obvious reasons. The electron chain to create ATP must pass through Co-Q, so that in the absence of Co-Q the cell can generate no energy. Finally, one side effect of the use of statins is the reduction of the amount of Co-Q in the body. Another side effect of statins is muscle aches and occasionally elevation of CPK, which indicates muscle damage.

     The study involved a study of overweight men and women, who did no exercise, and satisfied the criteria for the metabolic syndrome. They first did a stress test and underwent a muscle biopsy. Then one-half of the subjects were given a daily dose of a statin, and both groups underwent supervised exercise for 45 minutes five times a week. After 12 weeks, repeat stress testing and muscle biopsies were done.

     Now we already have evidence that exercise and statins lower cholesterol, and lower the death rate in patients with dyslipidemia. There also was an article in this year's Lancet (Feb. 2, p. 394) that showed that in veterans with dyslipidemia both exercise and statins  lower cholesterol levels and reduce mortality, and the effect of exercise plus statin was greater than either modality alone.
After the 12 weeks, the non-medicated group had increased their physical fitness, but the medicated group did not. The energy enzyme levels in muscle mitochondria increased in the non-drug group and decreased in the drug group.

     What does this all mean? Since we do not know the precise mechanism(s) by which exercise lowers the death rate, the study cannot be interpreted. One would have to look at the death rate or heart attack rate of both groups, and since this is a group with no history of a heart attack, we would probably have to wait five years to detect a possible difference in outcomes. In other words, we know that exercise is beneficial for cardiac health, and the fact that statin use apparently prevents an increase in aerobic fitness does not mean that exercise plus statin use is no better than either treatment alone.

     Just as lack of exercise and elevated cholesterol are separate risk factors for heart attacks, and together they are synergistic in increasing one's risk, so are statin use and exercise synergistic in preventing such an event.

Friday, May 17, 2013

Does Marijuana Prevent Diabetes?

     An article in this month's (May 2013) American Journal of Medicine shows that current users of marijuana have better glucose control than do former users, who in turn have better glucose control than do abstainers. This study was a retrospective one, and needs to be validated by a forward study. This will probably never happen, for obvious reasons, much as retrospective studies showing that cigarette smokers have a lower incidence of Parkinson's disease were never followed up.

     The use of marijuana was based on interviews with the 4657 members of the study; of this group 579 were current users and 1975 were prior users. Fasting glucose and insulin levels were measured, and the degree of insulin resistance was calculated. Diabetics and pre-diabetics both have insulin resistance.

     This study was triggered by prior studies showing  that marijuana users have a lower incidence of  both obesity and diabetes, but there have been no similar studies of THC users. Current marijuana users in this study were seen to have lower levels of fasting insulin, and were less likely to be insulin resistant. They also had higher levels of HDL cholesterol and smaller waist sizes. Past users (more than 30 days before the study questionnaire) also had a lower incidence of insulin resistance than did non-users, but not as low as did current users.

     The results of this study need to be followed up, but given the current federal law classifying marijuana as a Class I drug, meaning "no significant medical benefit", it is difficult to envision a prospective study being done.  One possibility might be in the state of Washington or Colorado, where marijuana was recently legalized. OTOH, perhaps the federal law could be changed to make it legal to treat diabetes and the metabolic syndrome with THC and to do a study of its effect.



Sunday, May 12, 2013

The New Arabian Coronavirus.

     A new respiratory virus which has killed 18 of the 31 infected cases has arisen in Saudi Arabia, where teams of Arabian physicians, members of the World Health Organization, and infectious disease specialists from the United States are all investigating jointly. This virus is a coronavirus, the same type (but genetically different) of the virus that originated in Chinses poultry and became the SARS virus when it infected man. The disease has developed in clusters of people. In one Arabian cluster of 15 people infected with the virus, 9 died.  The most recent infection detected was in a man in France who inhabited the same hospital room as a person who returned from Dubai to France and was found to have the virus.

     The virus has a predilection for elderly people with underlying chronic medical conditions that might impair their ability to fight disease. There is some evidence for people-to-people transmission, but this connection  is weak and not 100%. For instance, only one doctor taking care of a patient has  developed the disease. But since there are 4 clusters of the disease, this is evidence for weak person-to-person transmission.

     At this point, we do not know the (presumed) animal reservoir of the disease. This disease has the potential to mutate and become much more infective and transmissible, which could create a weak epidemic or a strong pandemic. There is no antiviral currently on the market that treats this
infection, and efforts are just starting to sequence its genome and to develop a vaccine. There is not much more to say, except to recommending avoiding travels to areas in the Middle East where this new coronavirus has been found, as well as avoiding travels to areas of China and Taiwan where the new bird flu, InfluenzaA-N7H9 has been detected.

     I strongly recommend following ProMED,com, the daily e-mailing of the International Society of Infectious Disease (ISID) for up to date information on both viruses.

Monday, May 6, 2013

The New Asian Bird Flu

     I thought I would share some facts with you about the new strain of influenza A H7N9, that has arisen in China and probably comes from birds, although we are not 100% certain of that. There has, as yet, been no evidence of people-to-people transmission (unlike SARS which infected health care workers). Furthermore, although this flu strain is resistant to amantadine, it is susceptible to oral oseltamovir  (Tamiflu).

     As of the end of April, there have been 126 confirmed cases in China, and 24 or 19% died. Older people are more susceptible to both catching the flu and succumbing to it, especially if they have a chronic health problem. Cases have been found in eight contiguous provinces in eastern China as well as in Beijing, Shanghai and Taiwan. China is making prodigious efforts to learn all it can about the flu and the birds' contribution to it. The flu has been found in some chickens and ducks, but the flu virus is harmless to poultry, and birds  who are infected with the virus show no signs of being ill.

     Thankfully, in the over 1500 close contacts of sick patients there has been no evidence of the flu, so unless it mutates there is no risk of an epidemic or pandemic. Except for one pigeon, the virus has only been found in chickens and ducks for sale in marketplaces; farms seem to be exempt. Relatively few poultry are carrying the virus, and 20% of the people with the virus report no exposure to birds. Chinese physicians and technicians are making herculean efforts to track and to find the virus, as well as sequencing its genome, and are examining pigs as well as poultry.

     China has invited members from the World Health Organization as well as from our own Center for Disease Control to come and assist in their work. In addition, the CDC is monitoring patients here in the US for cases of Influenza A/H7N9, but so far have found no cases. There is not even the suggestion of facts or cases being hidden by China, so whatever you read should be accepted.

     In summary, the virus is mild and relatively rare in poultry,  but has a case fatality rate of 20% in humans, and while we think that poultry is the reservoir, we are not yet sure.