University of Pennsylvania researchers develop formula to gauge risk of disease clusters

Aug 16, 2007

Researchers at the University of Pennsylvania have developed a mathematical formula to assess whether concentrated disease outbreaks can be ascribed to random-chance events or, instead, suggest a contagious or environmental effect that requires epidemiological investigation.

A feature of the formula is that, given the relevant data, the required probability calculations can be done in less than five seconds on a personal computer.

In statistical terms, the formula gives an exact expression for the probability distribution of the maximum of a number of multinomially distributed random variables. Mathematically, the formula depends on generating function technology developed by Herbert Wilf, professor of mathematics in the School of Arts and Science at Penn. Warren Ewens of Penn’s Department of Biology joined Wilf in developing the formula. Until now, only potentially unreliable, approximate formulae have been available.

The formula was used to investigate two disease cluster cases.

The first was the classic case of a clustering of eight cases of leukemia in Niles, Ill., in 1956-1960, which was reasonably assessed as a chance, random event. On the other hand, 12 cases of acute lymphocytic leukemia in Churchill County, Nev., in 1999-2001 was assessed not to be a chance event but due to a common, possibly environmental cause.

Multiple cases of non-communicable disease, like leukemia, have clustered in small geographic areas quickly, resulting in costly epidemiological study. The authors note that a purely mathematical calculation cannot answer serious public-health questions, but that they can nevertheless point to cases that appear to require further public health study.

Source: University of Pennsylvania

Explore further: US scientists make embryonic stem cells from adult skin

add to favorites email to friend print save as pdf

Related Stories

First look at breast microbiota raises tantalizing questions

Mar 24, 2014

The female breast contains a unique population of microbes relative to the rest of the body, according to the first-ever study of the breast microbiome. That study sought to lay the groundwork for understanding how this bacterial ...

Undergrad researcher has the formula for success

Sep 30, 2013

Manasi Malik has just begun her junior year at the University of Kentucky, but the 19-year-old biology major has already been published as a lead author on a paper in a prestigious scientific journal.

Recommended for you

Leeches help save woman's ear after pit bull mauling

22 hours ago

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Impact glass stores biodata for millions of years

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...