Data Link Alzheimer’s to Head Injuries

Head injuries suffered earlier in life may increase the risk of developing Alzheimer’s disease, according to a new study.

“As a practical matter, [this] may be one more reason to wear that bike helmet instead of keeping it in a closet,” said Dr. Richard J. Havlik of the National Institute on Aging.

Several prior studies of a possible link between head injuries and Alzheimer’s have yielded conflicting results. Scientists have attributed this to “recall bias”--errors on the part of friends and relatives, and of the patient himself, in recalling head injuries that may have occurred decades earlier. The new study by Havlik and epidemiologist Brenda L. Plassman of Duke University avoided that problem by examining the military records of male Navy and Marine veterans of World War II. They identified 548 veterans who had suffered a well-documented head injury during the war and compared them to 1,228 veterans with no history of head injury. The veterans were tracked down in 1996-97.

The team reported in the Oct. 24 Neurology that veterans who had suffered a moderate head injury were twice as likely to suffer from Alzheimer’s and other forms of dementia as those with no injury. Veterans with severe injuries--who had been hospitalized and who remained unconscious or amnesiac for at least 24 hours--had four times the normal risk. The researchers do not know, however, how the injury increases risk.

Study OKs Radiation for High-Risk Breast Cancer

Radiation therapy does not pose a heightened risk to women with breast cancer who carry certain genetic mutations, according to researchers at the University of Michigan.

Physicians had suspected that women carrying the BRCA-1 and BRCA-2 genes--which place them at higher risk of developing breast cancer--were more vulnerable to DNA damage produced by irradiation, which would cause side effects that include skin fibrosis, pain and shortness of breath. The question of side effects is important because radiation therapy after lumpectomy can reduce the risk of cancer recurrence by 35% to 40%.

Dr. Lori Pierce and her Michigan colleagues monitored 71 breast cancer patients who had one of the two mutations and 213 who did not have either. All received conventional treatment, including radiotherapy. The team reported Oct. 24 at a Boston meeting of the American Society for Therapeutic Radiation Oncology that the two groups had similar high rates of survival and low rates of cancer recurrence. Furthermore, the women with the mutations had no increase in side effects from the therapy.

Gum Disease May Increase Stroke Risk

Another reason not to ignore your dentist’s advice to brush and floss your teeth regularly: Researchers in New York have found that gum disease can double the risk of having a stroke. Previous studies have shown that gum disease--technically called periodontitis--increases the risk of heart attacks, and researchers believe both results operate through the same mechanism. The bacteria and bacterial toxins promote an inflammatory response by the immune system that increases the likelihood of clots forming in blood vessels.

Dr. Teijian Wu and his colleagues at the State University of New York at Buffalo examined the records of 9,962 adults between the ages of 25 and 75 who took part in the first National Health and Nutrition Examination Survey in 1972-74 and the followup study in 1992. They reported in the October Archives of Internal Medicine (https://archinte.ama-assn.org) that those people suffering from periodontal disease during the first exam were twice as likely to suffer a stroke as those with no gum disease.

Protein May Help Boost AIDS Drugs

Supplementing AIDS drug cocktails with a naturally occurring protein called interleukin-2 (IL-2) restores the immune system faster than the drugs alone, according to UCLA researchers. The treatment also reduces opportunistic infections, Dr. Ronald Mitsuyasu reported Oct. 25 at an international AIDS meeting in Glasgow, Scotland.

Mitsuyasu and his colleagues studied 55 HIV-positive individuals who received the conventional drug cocktails--a regimen called HAART--and another 109 who received HAART plus a five-day course of IL-2 every eight weeks. All the patients had CD4 cell counts of about 50 at the beginning of the study, an indication that their immune systems had been severely damaged. After 60 weeks, those taking only HAART had a 32% increase in their CD4 count, while those also receiving the IL-2 had a median increase of 132%.

Research Implicates TB in 1918 Flu Pandemic

Infectious disease experts fear a recurrence of the 1918 flu pandemic in which half a million Americans died from the disease in only a year’s time. But studies of the flu virus isolated from bodies recovered from the Alaskan tundra in 1998 show no evidence of increased virulence. A new study from UC Berkeley suggests that the large number of deaths was actually due to a concurrent outbreak of tuberculosis, which was widespread in factories where men worked in densely packed, poorly ventilated conditions.

Andrew Noymer, a doctoral student in demography, reported in the current issue of Population and Development Review (https://demog.berkeley.edu/~andrew/1918/) that victims in the pandemic were mostly between the ages of 20 and 40, the age group most afflicted with tuberculosis. Men were about 35% more likely to die from influenza than women during the epidemic, and men are about 30% more likely to die from TB than are women. Finally, the death rate from TB dropped dramatically in the years immediately after the pandemic, suggesting that those with the disease were killed by the flu virus. Calculations showed that 500,000 more TB deaths would have occurred between 1918 and 1932 had there been no flu pandemic.

Noymer’s conclusion is that a new flu epidemic does not represent a severe threat because TB is now largely under control in the United States.

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Medical writer Thomas H. Maugh II can be reached at thomas.maugh@latimes.com.