Research Notes

Well-heeled retirees often relocate to warmer climes in search of sunny skies and year-round golfing, but they also move to avoid paying higher taxes, says a U-M economist.

A study by Joel Slemrod of the Stephen M. Ross School of Business and colleague Jon Bakija of Williams College indicates wealthy elderly people change their real or reported state of residence to avoid paying high state taxes, particularly those that target estates and inheritance, as well as purchases.

High personal income and property taxes also give upper-bracket taxpayers additional incentives to pack their bags and head for places with lower, less progressive tax rates.

The wealthy elderly almost exclusively are the ones impacted by state estate and inheritance taxes, and their behavior may have implications for the optimal progressivity of a state tax system, says Slemrod, professor of business economics and director of the Ross School Office of Tax Policy Research.

The researchers found that the number of federal estate tax return filers reported as residing in each state is negatively influenced by the level of taxes imposed on high-income and high-wealth people in that state—suggesting that taxes act as a deterrent to location.

Generally speaking, a one-percentage-point increase in the effective state estate and inheritance average tax rate targeted specifically at the wealthy classes is associated with a 1.4 percent to 2.7 percent decline in the number of federal estate tax returns filed in the state.

In addition, Slemrod and Bakija report that sales, income and property tax rates have similar and sometimes larger negative effects on the number of federal estate tax returns filed in a state, because, other things being equal, the rich prefer not to live in a state that taxes them heavily.—Bernie DeGroat, News Service

Racial differences seen among disabled elderly in home care

Older disabled Blacks receive more family and other informal care than their white counterparts primarily because Blacks have a greater need for care, according to a U-M study.

The findings do not support the notion that Blacks have stronger informal care networks and, therefore, receive more informal care than whites, says Lydia Li, an assistant professor in the School of Social Work and research lead author. Instead, the informal care networks of low-income Blacks may be vulnerable in that they are more likely to be composed of a sole caregiver or are caring for elders with higher levels of disability compared with whites.

Brant Fries, a professor of health management and policy and a researcher at the Institute of Gerontology, co-wrote the paper, which appeared in The Gerontologist.

In studying the structural and functional dimensions of the applicants' informal care networks, the researchers learned that there were significant racial differences. Blacks were more likely than whites to be cared for by relatives, live with their caregivers, have a sole care provider and receive help with in-home chores.

Racial differences in the functional components—such as the amount of care and scope of assistance received and the receipt of personal care—were accounted for by different levels of disability between older Blacks and whites.—Jared Wadley, News Service

Women's health suffers under welfare reform

Women who are current and former welfare recipients suffer a host of health problems—and getting a job doesn't always help matters.

Many people say welfare reform is working because welfare rolls are dropping, reversing a decades-long trend, says George Kaplan, professor of epidemiology at the School of Public Health (SPH). "But there has been virtually no attempt to ask what effect these changes have on the health of the affected people," he says.

Kaplan is lead author of an article in the July issue of the American Journal of Public Health. The study looked at data from 1996-2000 when welfare reform cut caseloads in half.

Comparing data from the Women's Employment study—a random sample of single mothers receiving cash benefits in an urban county in Michigan—to women of the same age and race who participated in the National Health and Nutrition Examination Survey (NHANES), U-M researchers found the welfare recipients 2.4 times more likely to have hypertension, 1.8 times more likely to be obese, and nearly five times as likely to have elevated levels of HbA1c—a marker related to diabetes.

In addition the women are almost three times as likely to describe their health as poor or fair than the NHANES women.

Kaplan says the findings are not surprising given the many challenges poor women face: low-skill jobs with constantly changing work schedules, struggles with child care and transportation, and few or no benefits.

Kaplan emphasized that all of the findings are from data that ends in 2000, while the economy was still relatively strong.

Kaplan collaborated on the paper with Kristine Siefert, associate director, Research Center on Poverty, Risk, and Mental Health; Nalini Ranjit, research investigator, Epidemiology Department; Trivellore E. Raghunathan, professor of biostatistics, SPH; Elizabeth A. Young, professor of psychiatry and research professor, Reproductive Sciences Program; former U-M doctorate student Diem Tran; Sandra Danziger, director of the Michigan Program on Poverty and Social Welfare Policy; Susan Hudson, epidemiologist and emergency preparedness coordinator; John W. Lynch, associate professor, epidemiology department; and Richard Tolman, associate dean, School of Social Work.

The paper was funded through a $10 million grant from the National Institute for Child Health and Human Development, with additional support from the Michigan Initiative on Inequalities in Health.—Colleen Newvine, News Service

Scientists use gene technology, common virus to block pain in animals

Neuropathic pain is a common complication of many diseases and medical conditions, especially diabetes. Drugs have little effect on this type of pain, which is caused by damage to neurons that transmit sensory signals to and from the brain.

Scientists at the Medical School and VA Ann Arbor Healthcare System have developed a way to block the signals responsible for neuropathic pain. The secret to their success is based on a virus called herpes simplex or HSV—the same virus that causes cold sores and genital herpes. The scientists use a disabled form of the virus, called a vector, to deliver genes to the nucleus of neural cells.

A study published in the June 2005 issue of the Annals of Neurology describes how laboratory rats with nerve damage showed much less pain-related behavior after receiving injections of the HSV-based vector, which contained a gene called GAD, or glutamic acid decarboxylase.

The study is the first to demonstrate the successful use of gene transfer technology, using a herpes viral vector, to treat peripheral neuropathic pain in animals. The vector is used to provide targeted gene delivery to the nervous system, says Dr. David J. Fink, the Robert W. Brear Professor of Neurology in the Medical School and staff neurologist at the VA Ann Arbor Healthcare System, who co-directed the research study.

When the HSV gene carrier is injected under the skin of a laboratory rat, the vector is taken up by sensory nerve terminals in the animal's skin and carried through the axon back to the sensory ganglia cell bodies next to the spinal cord, says Dr. Shuanglin Hao, a U-M research investigator and first author of the study.

There was a sustained, continuous pain-suppressing effect that began one week after inoculation with the vector and lasted for six weeks, according to Dr. Marina Mata, staff neurologist at the VA Ann Arbor Healthcare System, professor of neurology in the Medical School and co-director of the research team.—Sally Pobojewski, Medical School Communications

Drug use differs considerably among Hispanic subgroups

A greater percentage of Hispanic adolescents in 8th grade use drugs than adolescents in the general population, but there are some important differences among various Hispanic groups in their level of involvement, an article from the Monitoring the Future study shows.

Jorge Delva, associate professor in the School of Social Work (SSW), is the lead author of the article, which appeared in the American Journal of Public Health.

Since 1991 the percentage of Mexican American, Puerto Rican and Cuban American adolescents who have used marijuana or cocaine in the prior year has been higher than the percentage of adolescents of other Latin American heritage, primarily Central and South Americans, and also higher than the percentage of youth who use these substances in the general population.

The Monitoring the Future study showed an increase in the annual prevalence of marijuana and cocaine use during the 1990s, followed by a decrease in 2000-02. Meanwhile, the prevalence of heavy drinking was highest in 1994-96, followed by a small decline during 1997-99 for all groups. These drug usage trends also were observed among all of the Hispanic groups of 8th-grade students, says Delva, but Cuban Americans experienced a slight increase in alcohol use in the late 1990s.

In addition to Delva, other authors were John Wallace, now at the University of Pittsburgh; Patrick O'Malley, research professor, Survey Research Center (SRC); Jerald Bachman and Lloyd Johnston, distinguished senior research scientists, Institute for Social Research (ISR); and John Schulenberg, research professor and associate director, SRC. Delva is appointed at both the SSW and ISR.—Jared Wadley, News Service

Discovery shows where stem cells reside in tissue

Scientists at the Medical School have discovered the biological equivalent of a grocery store bar code on the surface of primitive, blood-forming stem cells in mice. Called hematopoietic stem cells, they give rise to all the different types of specialized cells found in blood.

The arrow points to a CD150+ hematopoietic stem cell in contact with a sinusoidal cell, surrounded by more mature blood cells. Scientists have discovered the equivalent of a grocery store bar code on the stem cells that helps differentiate them from other cells. (Photo by Toshihide Iwashita)

By reading the bar code, scientists can separate stem cells from their more advanced descendants—progenitor cells that already are committed to becoming one type of blood cell. The secret, according to U-M scientists, is to look for the presence or absence of cell surface receptor proteins expressed by a family of genes called SLAM.

Scientists knew that the 10 or 11 genes in the SLAM family helped regulate the development and activation of white blood cells called lymphocytes, but no one knew they also were associated with hematopoietic stem cells.

SLAM is the first family of receptors whose patterns of gene expression can be used to precisely distinguish hematopoietic stem cells from progenitor cells, and to identify stem cells in tissue sections, says Sean Morrison, associate professor of internal medicine and of cell and development biology in the Medical School, and Howard Hughes Medical Institute investigator.

Currently, scientists must search for many different markers and use complex procedures to separate rare hematopoietic stem cells, or HSCs, from other cells in a blood sample. Using SLAM markers will streamline the process considerably, says Mark J. Kiel, a doctoral student who is co-first author of the study.

Many of the current markers used to purify HSCs are expressed as a gradient from high to low across the hematopoietic cell hierarchy, says Omer H. Yilmaz, co-first author and a student in the M.D./Ph.D. program. What's exciting about this finding is that now there are markers that turn on and off abruptly as stem cells differentiate, he says.

Knowing where primitive hematopoietic stem cells hang out in blood-forming organs will give scientists important clues to how they work, according to Morrison.

Dr. Toshide Iwashita, a former research fellow in Morrison's laboratory and co-first author on the study, was responsible for the tissue section analysis. Results of the research study were published in the July 1 issue of Cell.—Sally Pobojewski, Medical School Communications

Snoring now, hyperactive later?

Several years ago U-M researchers published some of the strongest evidence yet that children who snore when they sleep are far more likely to have attention and hyperactivity problems than their non-snoring peers. That link takes on a new dimension today with the publication in the journal Sleep of follow-up data from some of the same children who took part in the earlier study.
Children in the original study who snored regularly, in comparison to those who did not, were about four times more likely to have developed new hyperactivity by the time the team contacted their families four years later. In other words, snoring early in life predicted new or worsened behavior problems four years later.

Similar behavior was seen among children who experienced other symptoms of obstructive sleep apnea, in which repeated pauses in breathing disrupt sleep and can reduce blood oxygen levels. For example, children with daytime sleepiness in the original study also were more likely to have developed hyperactivity four years later.

Dr. Ronald Chervin, lead author and sleep researcher, says inattention and hyperactivity usually were predicted better by snoring and other sleep apnea symptoms that were
diagnosed four years earlier.

The paper is the first to show that sleep problems come before hyperactive behavior, and that one predicts the other—which may help bolster the sleep-behavior theory.

Co-authors of the paper with Chervin are Deborah Ruzicka, Department of Neurology research associate; and Dr. James Dillon, adjunct clinical child psychiatrist.—Kara Gavin, UMHS Public Relations

The rich die differently from you and me

The inequalities that mark American life maintain their hold through age and even death, a new study shows.

Wealthier elders are significantly less likely than poorer ones to suffer pain at the end of their lives, according to a study to be published in the August issue of the Journal of Palliative Care.

Specifically, men and women age 70 or older whose net worth was $70,000 or higher were 30 percent less likely than poorer people to have felt pain often during the year before they died. This difference persisted after the researchers controlled for age, gender, ethnicity, education and diagnosis.

Wealthier elders also experienced a lower number of symptoms overall, the study found. Those in the wealthiest half of the elderly population not only had less pain, but were less likely to suffer from shortness of breath and depression.

Regardless of wealth, older Americans carry an unacceptable burden of suffering in their last year of life, says Dr. Maria Silveira, a physician at the VA Ann Arbor Healthcare System, a research scientist at U-M and lead author of the study. Fatigue was the most common symptom, experienced by 57 percent of those who died. More than 50 percent experienced pain, and 59 percent of those who experienced pain were reported to have suffered pain at severe levels.

The study was based on an analysis of data from the Health and Retirement Study conducted by the Institute for Social Research and funded by the National Institute on Aging.

For the study, Silveira and colleagues Mohammed Kabeto, research associate in general medicine at the Medical School, and Dr. Kenneth Langa, Medical School assistant professor of general medicine, were especially interested in symptoms of pain, depression and shortness of breath at the end of life.—Diane Swanbrow, News Service

Women overestimate breast cancer risk

While breast cancer is a significant health threat—striking 211,000 American women each year—a study finds most women have a distorted view of their risk.

When asked to estimate the lifetime risk of breast cancer, 89 percent of women overestimated their risk at 46 percent—more than three times the actual risk of 13 percent, according to a study by U-M Health System researchers.

Lead study author Angela Fagerlin, research investigator in internal medicine at the Medical School and with the VA Ann Arbor Healthcare System, said most women feel a sense of relief upon learning the actual number.

The senior study author is Dr. Peter Ubel, professor of internal medicine at the Medical School and director of the Center for Behavioral and Decision Sciences in Medicine. Results of the study appear in the June issue of the journal Patient Education and Counseling.

The researchers suggest doctors can use these findings to help patients who seem particularly concerned about their risk of breast cancer.

At the same time, the researchers stress, overestimating the risk does not diminish the importance of prevention strategies, such as yearly mammograms and monthly breast self-exams.

Brian Zikmund-Fisher, a research investigator in the Department of Internal Medicine also was a study author. Funding for the study was from the National Institutes of Health, the Department of Veterans Affairs and a Presidential Early Career Award for Scientists and Engineers.—Nicole Fawcett, Comprehensive Cancer Center