May 11, 2007

Mexican-American twins needed for clinical trial

By Pablo Jaime Sáinz

Ana and Marisela Flores are a pair of 46-year-old twins that have a lot in common: Both are widows, both share many of the same tastes ranging from music to food, and both live together in San Diego.

And as identical twins, they both share the same genes.

That’s why Ana said they were interested in participating in a clinical trial where doctors at the University of California, San Diego, Department of Medicine are studying twin pairs to understand common maladies such as hypertension, obesity, diabetes, and kidney disease.

“My sister and I have so much in common, that we wanted to find out how similar we are genetically,” Ana said. “We saw this as an opportunity to learn more about ourselves as twins at the same time that we contributed to medical research.”


Ana and Marisela Flores are identical twins.

The doctors are especially interested in attracting Mexican-American twins such as the Floreses, since historically, Mexican-American participants have been underrepresented in clinical trials, said Doctor Maple Fung, one of the researchers supervising the clinical trial.

Over the past six years, the twin clinical trial it has enrolled 540 twins, but only about 5 percent of them are Latinos or Mexican-Americans, she said.

”I think you know that obesity, diabetes, kidney disease, and diabetes are over-represented in the Mexican-American population. In this way, we can extend our conclusions about heredity and disease to the Mexican-American population,” said Doctor Daniel O’Connor, the physician in charge of the twin study.

The doctors focus on the heredity of hypertension, and thus studying twins is very important because of their shared genetics.

“We have learned much about heredity and illness,” Fung said.

The test takes about 90 minutes.

They recruit any twins- men, women, both, fraternal, or identical and perform some blood pressure measurements, including under stress with “cold pressor” (hand in ice) and while blowing air to maintain certain pressure.

Some of the measurements help determine the pressures in their heart and the amount of body water they have. Then they obtain blood and urine samples to extract DNA and other data from the subjects.

“We learn so much about ourselves as twins in this clinical trial,” Ana said.

Fung said the researchers are highly interested in studying the Mexican population for a number of reasons.

1. Minorities are underrep-resented in all medical studies.

2. Minorities- including Mexican and black populations- have high rates of hypertension which makes it more imperative to study them.

“We are evaluating what genetic differences may account for these high rates of hypertension,” Fung said. “We definitely would like to keep this study going and need more twins, especially Mexican American ones- all ages and sexes and sizes and shapes.”

White males have the highest participation rates in clinical trials, while African-Americans and Latinos are less likely to participate.

The truth is that clinical trials results most of the time give out information pertaining only to White males, because they are generally the ones who have the most participation in clinical trials.

These studies need more diversity, more minority participation in order to turn out more inclusive results.

If Latinos never participate in clinical trials such as this one, researchers will never know how to treat conditions affecting our Mexican-American community.

The twins need to come in together for about 1.5-2 hours. Unfortunately at this time must be Monday through Friday between 9 a.m. and 3 p.m. on the UCSD campus. It will require a blood draw and urine sample.

All ethnic groups are welcomed, and twins have to be 18 years of age or older.

Twins will be compensated for their time and travel (right now $75 for each twin).

“This project has aided with the advancement of science and medicine by helping us understand the contribution of genes and inheritance in hypertension and its related diseases,” Fung said.

For more information, please contact Brenda Thomas at (858) 552-8585, Ext. 6178.

Return to the Frontpage