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Update From the Medical Journals: May 2009
May 29, 2009  By Mary Pickett, M.D.
Harvard Medical School What's the latest news in the medical journals this month? Find out what your doctor is reading. New Flu Strain Turns Into a Pandemic The most important health news during the past two months was the appearance of a new strain of flu, influenza A (H1N1), also known as "swine flu." The new flu first appeared in Mexico in March. In April experts identified it as the H1N1 flu strain. They carefully tracked its spread to other countries. By the middle of May (week 19 of our history with this virus) there were 6,552 confirmed cases of H1N1 and 9 deaths in the United States due to the illness. On May 22, the World Health Organization reported that there had been 11,168 cases and 86 deaths in 42 countries due to H1N1. Epidemiologists are concerned about this new strain of flu. It is highly contagious and — since it evolved in pigs, not humans — our immune systems are much less prepared to fight it off. Fortunately, however, the death rate from the H1N1 virus is low — only 4 deaths per 1,000 cases. A team of epidemiologists analyzed the outbreak in Mexico and published their findings online in the May 14 issue of Science. This is a somewhat higher death rate than with seasonal flu viruses, but it is lower than what occurred during the terrible flu pandemic of 1918-1919. Concerns remain that this virus, like all flu viruses, has the potential to change by mutating. We have little immunity to this strain and there is no vaccine yet to protect against it. This virus could become extremely dangerous if it develops into a much more lethal version. Efforts are ongoing to limit the spread of this virus and to develop an effective vaccine. Back to top Global Warming is Biggest Global Health Threat A ground-breaking report named climate change the "biggest global health threat of the 21st Century." The Lancet and the University College London (UCL) announced the findings together on May 11. The report was published online by the Lancet on May 13. The earth's 12 warmest years on record have occured during the last 13 years. Experts predict that the earth's average surface temperatures are likely to increase to more than 2° C above the temperatures that were recorded prior to the Industrial Revolution (mid-19th century). If this occurs, human health will be affected in serious ways: - Heat waves and fatalities from heat exposure will increase.
- Infections that have traditionally been limited to the tropics, such as tick-borne encephalitis, malaria and dengue fever, will become more widespread.
- Water shortages will lead to less abundant food supplies, malnutrition and (due to less available clean water) more epidemics of diarrhea. Experts predict that half of the world's population could face severe food shortages by the year 2100 because of declining crop yields; much of the decline in crop yields could occur during the next 20 years.
- Extreme climate events, such as hurricanes, cyclones and storm surges, will occur more often. They will spread infection due to flooding, injuries and disruption in the usual medical care.
- Some scientists predict that sea level will rise to 13 meters (over 40 feet) by the middle of next century. This could force more than a billion people from their homes and communities, creating urban slums and settlements.
Some of the changes to help limit global warming require action by industries and governments. But we can have a major impact by changing our lifestyles and choices: What we eat, the goods we consume, and the size of our families can all influence global warming. Global warming should get more political attention as awareness of the health problems caused by this growing crisis increases. Back to top More News in Brief - Fenofibrate lowers risk of diabetic amputation by 36%. People with diabetes often have poor circulation in their feet. This can cause skin to breakdown and ulcers to form, which sometimes can't heal. For some people this can lead to amputations. A drug that helps lower triglycerides (a type of blood fat similar to cholesterol) seems to lower the risk of first amputation by 36% in people with type 2 diabetes. The findings were published in The Lancet on May 23. In the study, 9,795 people with type 2 diabetes were treated with either fenofibrate or with a placebo pill. After five years of treatment, 115 people had amputations. But the number of amputations among the people who took fenofibrate was disproportionately lower compared with the placebo group. Fenofibrate is not the only treatment that reduces the complications from diabetes (heart attacks, for example). Currently, most people with diabetes are given statins to lower cholesterol. Statins are in a different family of medicines than fenofibrate. Doctors need to carefully consider how adding fenofibrate to other cholesterol medicines can help prevent complications.
- Genetic factors affect risk of autism. The cause of autism is still a mystery. But three studies this month make it clearer than ever that genetic factors cause some children to have a higher risk for the condition. Autism affects a child's ability to communicate and interact with others. The largest study, published online by Nature on April 28, looked at the genetic make-up of more than 10,000 people. About 4,000 of the people studied were either children with autism or family members of these children. Two genes that are related to the "connectedness" of brain cells were more common in families affected by autism. The genetic connection to autism does not fully explain how the condition occurs, but it is almost certainly one factor that increases the risk.
- Adding steroids reduces chance of relapse in multiple sclerosis. Beta interferon is one of the first-line treatments for multiple sclerosis (MS). It lowers the rate of flare-ups, which cause weakness, eye pain or double vision, and other neurologic symptoms. Taking the steroid methylprednisolone every four weeks lowers the rate of flare-ups even more, according to a study published in The Lancet Neurology on April 30. The two-year study enrolled 130 people with MS who had a recent flare of symptoms. Twenty-two percent of the patients who received interferon plus methylprednisolone had flare-ups compared with 59% of people who got with interferon plus a placebo treatment. The results suggest that methylprednisolone might cut the rate of flare-ups by two thirds when added to beta interferon.
- Women with epilepsy have new pregnancy guidelines. The American Academy of Neurology and the American Epilepsy Society developed new pregnancy guidelines for women with epilepsy. They were published in The May 20 issue of Neurology. The guildelines reassure women with a history of seizures that pregnancy and childbirth are safe. The guidelines recommend that these women avoid certain medications during pregnancy: valproate (valproic acid, Depakote, Depakene), phenytoin (Dilantin) and phenobarbital. They should take other medications as necessary to control seizures.
Back to top Mary Pickett, M.D. is an Associate professor at Oregon Health & Science University where she is a primary care doctor for adults. She supervises and educates residents in the field of Internal Medicine, for outpatient and hospital care. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.
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