Update From the Medical Journals: March 2011 - What Your Doctor Is Reading - Harvard Commentaries

What's the latest news in the medical journals this month? Find out what your doctor is reading.

Japan Crisis Prompts Review of Risks From Radiation
New Drug Cuts Rate of Seasonal Asthma Flares
One Out of Two Men Carries the Human Papilloma Virus
More News in Brief: New Insulin Gets Results With Only Three Shots Per Week, and Car Seat Advice Updated for Child Passengers

Public health experts are using the nuclear plant crisis in Japan as an opportunity to remind us of the health risks from large and small radiation exposures. Most of what we know about radiation injury comes from the 1986 nuclear accident in Chernobyl, Ukraine. The World Health Organization (WHO) and a research group called the Chernobyl Forum studied the health effects of the Chernobyl accident and published an extensive report in 2006. You can read a fact sheet that summarizes the WHO report.

After a nuclear accident, people can be exposed to radioactive iodine and cesium. The expected health risks from such exposure include:

Acute radiation sickness – Heavy radiation exposure can cause vomiting, bloody diarrhea, fatigue, weakness and a rash. It can also lead to poor wound healing, crippling of the immune system, and (in some cases) death from infection. After Chernobyl, 134 workers assigned to decontaminate the leak site developed acute radiation sickness. In the first year after exposure, 28 died.
Thyroid cancer – Thyroid cancer was the major health threat after the Chernobyl accident. Experts estimate that 5,000 cases occurred. It was especially common among children who had been exposed to the radiation. People were affected up to 500 kilometers (310 miles) from Chernobyl. Taking iodine tablets at the time of a radiation exposure can help to prevent thyroid cancer. These tablets saturate the thyroid gland with iodine, which prevents the thyroid from absorbing the radioactive iodine.
Leukemia and other cancers – Radiation also doubles the risk of leukemia for people with high exposure, such as clean-up crews. This was seen after Chernobyl and also after the atomic bombings in Japan. The risk for other cancers also is increased. But radiation exposure would add only a very small fraction to a person's total cancer risk, experts say.
Cataracts – Fairly small exposures to radiation can cause cataracts.
Social displacement and anxiety – The most widespread health impact of a nuclear accident comes from people being removed from their homes. Food, housing and sanitation become scarce. People also are vulnerable to epidemics of infections.

Japanese officials are monitoring radiation levels closely. Small amounts of radiation have been detected in locally produced foods (tap water, milk, vegetables, and fish). More than 170,000 people have been removed from an area that extends 20 kilometers from the affected nuclear plant. Outside of this immediate plant area, radiation is not expected to be a significant health threat.

A study published in the March 17 issue of the New England Journal of Medicine showed that a new asthma drug can eliminate the spring and fall increase in asthma symptoms that are usually seen in allergic patients. The drug is an injectable medicine called omalizumab (Xolair). The study was sponsored by the National Institutes of Health.

In the study, 419 young asthma patients ranging in age from 6 years to 20 years were randomly assigned to receive either omalizumab or a placebo injection every two to four weeks. Most of the children in the study lived in urban areas and were black or Hispanic. Both groups still got standard asthma treatments such as inhaled steroids and inhaled bronchodilators.

The new drug is a laboratory-made antibody protein that binds to the allergic antibody in the bloodstream called "IgE." IgE doesn't trigger symptoms when the drug antibody interferes with its function.

Overall, children and adolescents who were treated with omalizumab had 25% fewer days with symptoms. They also had 75% fewer hospitalizations. This treatment is a huge advance for asthma care. Long-term safety is unknown for this new drug; the cost of the drug may be significant.

Human papilloma virus (HPV) causes genital warts and cervical cancer. It also causes a variety of other genital, anal and throat cancers. But did you know that about half of adult men may be infected with human papilloma virus (HPV)? This is according to results from a new study. The journal Lancet published the study online March 1. A previous unrelated study in women showed fairly similar infection rates.

The 1,159 men in the study came from the United States, Brazil and Mexico. The men were paid volunteers, but they appeared to have an average risk for sexually transmitted infections. They were recruited from universities, medical clinics and the general public. Their average age was 32.

The fact that HPV infection is so common makes it important for women to get regular Pap tests. A Pap test can detect changes that HPV causes on the cervix. The risk of getting cancer is low if abnormal areas found on the cervix are treated. Vaccination against HPV can prevent cervical cancer and genital warts. The vaccine is given in a series of three shots. The U.S. Centers for Disease Control and Prevention recommends the series for girls and young women, ages 9 through 26. It can also be given to boys ages 9 through 18. It helps them to avoid genital warts and to keep from spreading HPV.

New Insulin Gets Results With Only Three Shots Per Week. A new long-acting form of insulin can be injected just three times per week, instead of daily. This is good news for people who need insulin to treat diabetes. The new insulin, called degludec, showed excellent benefit and safety in a small human study. The study was published online March 9 by The Lancet. In this study, adults were randomly assigned to receive either three shots of degludec a week or a once daily shot of a standard long-acting insulin called glargine. Both groups had good control of blood sugar. There were fewer episodes of low blood sugar (hypoglycemia) in the group receiving the new drug, compared with the daily injection group. Most people who are treated with insulin require both long-acting and short-acting insulin injections. This new insulin will not spare patients who need both from having daily injections. Still, it will be a welcome addition to insulin treatment options if larger studies confirm its safety and the new drug is approved.

Car Seat Advice Updated for Child Passengers. Children should ride in rear-facing car seats until they are 2 years old instead of 1. The American Academy of Pediatrics and the National Highway Traffic Safety Administration issued new recommendations March 21 in the journal Pediatrics. Both organizations say older children should ride in booster seats until the lap-shoulder belt fits appropriately. Children usually can graduate from a booster seat when they reach 4 feet 9 inches. Children younger than 13 should be in the back seat for safest travel.

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.