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Chew on this. Calcium and vitamin D supplements can prevent tooth loss in older adults, according to Elizabeth Krall, associate professor of health policy and health services research at the Goldman School of Dental Medicine.

The adults she studied had a lowered risk of tooth loss of as much as 60 percent with a daily intake of 1,200 milligrams of calcium and 800 international units of vitamin D – amounts within the range recommended to prevent bone loss for older adults.

Krall and her colleagues at SDM and at the USDA Human Nutrition Research Center on Aging at Tufts University examined the pattern of tooth loss in 62 men and 83 women over age 65 for five years. They were randomly assigned to one of two groups – one receiving daily calcium and vitamin D supplements for three years, the other receiving a placebo. Teeth were counted after six months and after three years. Subjects were given an oral examination five years after the study began, two years after the supplements were discontinued. The researchers controlled for other factors that contribute to tooth loss, such as smoking, oral hygiene, tooth decay, and periodontal disease.

"These findings are clearly in line with research showing the importance of calcium in maintaining strong bones as we age," says Krall. "Maintaining bone mass is important not only in supporting the skeleton, but in supporting the teeth as well."

Krall’s work was presented at the meeting of the American Society for Bone and Mineral Research, held in September in Toronto. For information about Krall’s earlier research on the relationship between osteoporosis, estrogen replacement therapy, and tooth loss, visit http://dentalschool.bu.edu/departments/HealthPol/research/estrogen.htm.

Did you hear that? Young children spend most of their time in complex environments – playgrounds, classrooms, and the like – where an important sound source often has to compete for attention with other, distracting sounds. Ruth Litovsky, a senior research associate in the Hearing Research Center of ENG’s department of biomedical engineering, is conducting a series of studies to better comprehend how young children understand speech in complex environments. She stimulates situations where competing sounds come from a number of different directions.

Recent research on adults has shown that binaural hearing, hearing with two ears, makes it easier to understand what is being said when the target speech and any distracting sounds are spatially separated. Litovsky worked with Aarti Dalal (CAS’01), an undergraduate in the UROP program, and Gerald Ng (ENG’02), a graduate student in biomedical engineering, to develop an innovative hearing test for young children to determine if this is also the case with children.

The test was administered to 45 children, ages four to seven, with normal hearing. The children played a game where they were asked to identify a picture, out of a group of age-appropriate pictures, that matched a word they heard. They were tested with no competing sound, with competing speech sounds coming from the same direction as the target speech, and with spatially separated sound sources. Twelve adults were tested as well. The children were less able than the adults to ignore irrelevant, distracting information, especially when competing sounds came from the same direction.

"Children who have no binaural hearing, who have diminished hearing in one or both ears, are at a tremendous disadvantage in a classroom setting," says Litovsky. She hopes to further develop her hearing assessment tool so that audiologists can more effectively fit hearing aids or cochlear implants to account for complex auditory environments. Additionally, she believes, the tool can be used to better determine where a child with hearing impairment should sit in a classroom, and which assistive devices will help to improve the child’s hearing abilities.

The work is funded by a National Institutes of Health First Award and a seed grant from the Hearing Research Center. For more information, visit http://bme.bu.edu/faculty/litovsky/projects.htm.

"Research Briefs" is written by Joan Schwartz in the Office of the Provost. To read more about BU research, visit http://www.bu.edu/research.

4 December 2000
Boston University
Office of University Relations