'Silent' strokes may occur in early middle age

NEW YORK (Reuters Health) — Silent cerebral infarctions (strokes) — brain damage detected on magnetic resonance imaging (MRI) in the absence of stroke symptoms — may be present in early middle age and are associated with many of the same risk factors as strokes that do cause symptoms, according to findings from a study released last week.

The findings reinforce the importance of prevention, early detection and treatment of cardiovascular risk factors in mid-life, the study group maintains. "This is especially true because silent cerebral infarction has been associated with an increased risk of incident stroke and cognitive impairment."

Dr. Sudha Seshadri, at Boston University School of Medicine, and associates determined the prevalence of silent brain infarctions in 2040 people whose average age was 62 years and who were free of stroke and cognitive impairment when they had an MRI of the brain between 1998 and 2001.

The overall prevalence of silent brain infarction was roughly 11 percent, increasing from about seven percent in subjects aged 30 to 49 years to more than 15 percent in subjects aged 70 to 89 years.

These silent strokes were significantly associated with the presence of cardiovascular risk factors such as high blood pressure, as well as the presence of a heart arrhythmia called atrial fibrillation and with thick neck arteries, and partially blocked neck arteries.

Low birth weight, preemies are autism risk

NEW YORK (Reuters Health) — Low birth weight and preterm delivery increase the likelihood that a child will be autistic, with girls being at particular risk, researchers from the US Centers for Disease Control and Prevention report.

"Paediatricians are probably sensitive to the fact that low birth weight children or children born too soon have special developmental needs," researcher Dr. Diana Schendel of the CDC's National Center on Birth Defects and Developmental Disabilities, told Reuters Health. "This study simply supports that they should not overlook the behavioural aspects of development."

She noted that while boys far outnumber girls in the general population of children with autism, physicians "may need to be aware that they will see more equal numbers of boys and girls" with autism among low birth weight and preterm children, based on the current findings.

Schendel and colleague Tanya Karapurkar Bhasin based their results on a comparison of 565 autistic children with 578 children the same age without the disorder. All of the children were born in the Atlanta area between 1981 and 1993.

The researchers found that among low-birth-weight and preterm children, autism was less common than other developmental disabilities, such as cerebral palsy and hearing or vision loss. However, children born weighing less than 2,500 grams — or roughly 5.5 pounds — had about twice the risk of autism as those with a normal birth weight.

Similarly, children born before the 33rd week of pregnancy were twice as likely to develop the disorder as those born at full-term.

Girls seemed to be particularly at risk. Low-birth-weight girls were, for example, four times more likely to have autism accompanied by mental retardation or other developmental disabilities, compared with girls born at heavier weights.

The findings support the hypothesis that males and females have different causal "pathways to autism," the researchers write. Girls, they speculate, may be more likely than boys to need a "prenatal insult" — such as poor growth — to set them on the path toward developing autism.

The researchers are investigating this and other hypotheses in the CDC's Study to Explore Early Development, a five-year study including roughly 2,700 children ages two to five. The study will be the largest collaborative investigation to date on the causes of autism.

Circulatory rate woes in blacks still a puzzle

NEW YORK (Reuters Health) — The rate of occurrence of peripheral artery disease is greater in blacks than whites in the United States, and various risk factors for heart disease do not completely account for the difference, researchers report.

Peripheral artery disease affects the circulation in the legs, and can lead to pain and difficulty walking. Dr. Joachim H. Ix of the University of California, San Diego and colleagues note that traditional risk markers such as diabetes and hypertension have failed to account for the high rate of peripheral artery disease in African Americans.

To investigate whether other risk factors might shed light on the matter, the researchers studied 104 patients with peripheral artery disease and 164 matched "controls."

Compared to others in the study, African Americans had a threefold higher risk for peripheral artery disease, the team reports in the Journal of the American College of Cardiology. Factoring in traditional risk factors and certain non-traditional risk markers reduced the likelihood to two-fold, according to the article.

The main non-traditional risk factors that made a difference were levels fibrinogen, associated with clotting, and lipoprotein (a), which is involved in plaque build-up in arteries.

Summing up, Ix told Reuters Health, "We observed that the combination of traditional risk factors like higher blood pressure and diabetes, in conjunction with the new risk factors accounted for approximately 60 percent of the higher prevalence of African-Americans compared to Caucasians. Thus, approximately 40 percent of the higher prevalence remains unexplained in our study."

The investigators say life-style and genes may be the missing link.

NSAIDS don't protect against melanoma

NEW YORK (Reuters Health) — Lab evidence suggests that the class of painkillers known as nonsteroidal anti-inflammatory drugs (NSAIDs) could play a role in preventing melanoma, but a large study has failed to find any evidence to support this possibility.

Dr. Maryam M. Asgari at Kaiser Permanente Northern California in Oakland and colleagues analysed data on approximately 64,000 white individuals aged 50-76 years with no history of melanoma when they enrolled between 2000 and 2002.

The subjects reported their use of NSAIDs — including aspirin, ibuprofen, naproxen, celecoxib, rofecoxib, piroxicam and indomethacin — during the previous ten years.

Information was also collected on lifestyle, diet, cancer risk factors, and family history of skin cancer.

Almost two-thirds of the subjects had regularly taken an NSAID at least once a week for 1 year in the decade prior to study enrolment, the researchers report in the Journal of the National Cancer Institute.

Overall, 349 new cases of malignant melanoma occurred by the end of 2005. "After adjusting for melanoma risk factors and indications for NSAID use, no association between NSAID use and melanoma risk was found," Asgari's group reports.

They also discerned no link between the dose of any NSAID and the aggressiveness of melanomas. "The search must continue for a good chemopreventive agent for melanoma," the researchers conclude.

Net-based care aids blood pressure control

NEW YORK (Reuters Health) — Advice and medications delivered via the internet, along with home blood pressure (BP) monitoring, lets people with high blood pressure get their condition under control, researchers have report in this week's Journal of the American Medical Association.

Dr. Beverly B. Green, at the University of Washington in Seattle, and colleagues tested whether high blood pressure could be managed over the Internet without the need for visits to a doctor.

"Our demographic was middle-aged, working people for whom Web-based care is particularly convenient, particularly for reporting BP numbers and simple or structured communications," Green told Reuters.