Additive in vaccines

A study of 1,047 children who received mercury-containing vaccines as infants has concluded the mercury does not cause learning difficulties or developmental delays.

The research released Wednesday said mercury exposure was associated with very small changes on some measures of attention, speech and motor control. But the changes varied by gender and were mostly beneficial, leading scientists to conclude they were the result of chance.

Dr. Anne Schuchat, an official with the U.S. Centers for Disease Control and Prevention, which paid for the $5.3 million study, said the agency was still trying to assess one finding: Boys with the greatest exposure to vaccines containing mercury had twice the risk of developing tics compared with boys with the lowest mercury exposures.

Schuchat, who heads the CDC's Center for Immunization and Respiratory Diseases, said other studies have detected a correlation between mercury exposure and tics. She noted, however, that the tics were not reported by parents but by evaluators who assessed the children during the study, raising questions about whether the small muscular spasms posed a real problem.

"The finding may or may not have importance," she said.

The report in the New England Journal of Medicine did not examine whether mercury causes autism, as some scientists and advocacy groups have argued. Mercury is a component of thimerosal, which until recently was used as a preservative in virtually all childhood vaccines.

Although several large studies have found no causal link between thimerosal and autism, the issue is contentious, and several thousand parents are seeking legal compensation on behalf of children who developed autism after receiving vaccinations.

A separate study due out in a year will look at that issue, said scientists at the federal Centers for Disease Control and Prevention.

They found no clear link between early exposure to the preservative thimerosal and problems with brain function and behavior in children age 7 to 10. The results are in line with past research that found no connection between vaccines and neurological problems or autism.

Thimerosal has not been used in childhood vaccines since 2001, although it is still in some flu shots. The new findings apply to children immunized before then, or exposed to the preservative through shots their mothers received while pregnant.

NEW LOOK AT DIABETES

In a study being published today, a group of University of Chicago doctors found many diabetics believe that the inconvenience and discomfort of their treatments, especially multiple daily insulin injections, were as bad as the complications that can result from not treating their disease.

On average, patients in the study ranked the burden of comprehensive diabetes care and intensive glucose control as on par with experiencing heart-related chest pain, diabetic nerve damage or kidney damage.

Ten to 18 percent of the total said their treatments were so arduous that they would be willing to die sooner -- some said as much as 10 years earlier -- if they could stop their medications. Lead author Dr. Elbert S. Huang said the true number of people who felt that way might be higher because those interviewed already were receiving regular medical care.

The study, in the journal Diabetes Care, is the first of its kind to examine patient perceptions of quality of life on diabetes treatments and their thoughts about living with diabetes-related complications.

A random sample of 701 adults who had Type II diabetes were interviewed between May 2004 and May 2006. Patients were asked to express their preferences in a series of trade-offs, such as six years of perfect health versus 10 years with an amputation.

An estimated 21 million people currently live with diabetes in the United States.

The Los Angeles Times and Associated Press contributed to this report.