Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hot Flashes: Studies Explore The Role Of Genes, Obesity And Alcohol

25.04.2007
Many women in the menopausal transition experience hot flashes: unpredictable, sometimes disruptive, periods of intense heat in the upper torso, neck and face. Although generations of physicians have prescribed hormones to reduce these symptoms, very little research has focused on the underlying causes of hot flashes.

Three new studies explore the role of genes, obesity and alcohol consumption in contributing to - or lessening - the intensity and frequency of hot flashes in midlife women. These studies are part of a five-year research effort led by University of Illinois veterinary biosciences professor Jodi Flaws and colleagues at the University of Maryland, Mercy Medical Center in Baltimore and the School of Medicine at Johns Hopkins University.

Physicians have long noted that some factors, such as smoking, increase the likelihood that a woman will experience more - or more intense - hot flashes than other women. Race also appears to play a role, with African American women at higher risk than others. But the mechanisms that cause some women to suffer from severe (frequent and intense) hot flashes have remained a mystery.

"Even though more than 40 million women experience hot flashes each year," the authors wrote in their paper published in Maturitas, "little is known about the factors that predispose women to hot flashes."

To examine whether genetics might play a role in hot flashes, Flaws and her colleagues conducted a cross-sectional study involving 639 women aged 45 to 54. The researchers looked at individual differences in the genes that code for various hormones. An earlier study by the same team had found that one of these genetic polymorphisms, in an estrogen metabolizing enzyme, cytochrome P450 1B1, was more common in women who reported higher-than-average frequency, intensity and duration of hot flashes.

The new study tied the same genetic polymorphism to lower levels of an androgen known as DHEA-S, and to lower progesterone levels.

These are the first studies to find evidence of a genetic basis for hot flashes, and the first to look at genetic polymorphisms associated with hormone levels in healthy women with and without hot flashes.

The progesterone finding is of particular interest, said Flaws, because the medical community has focused almost exclusively on the role of low estrogen levels in bringing on hot flashes. Hormone replacement therapy, which is sometimes offered to women to alleviate hot flashes or other symptoms of the menopausal transition, may include one or more estrogens alone or in combination with progesterone or an analogue, progestin.

"We think there should be more studies looking at the role of progesterone in causing hot flashes," Flaws said.

The research team identified a second polymorphism, in a gene encoding an enzyme, 3-beta-hydroxysteroid dehydrogenase, which also is associated with an increase in hot flashes.

"People typically didn't think of hot flashes as having a genetic component," Flaws said. "Now we have some evidence that there is at least in part some genetics behind it."

In another paper, published in the journal Climacteric, the researchers used the same data to analyze the link between obesity and hot flashes. They had shown in an earlier study that obesity is associated with more frequent and intense hot flashes in midlife women. They now wanted to see what might be causing this effect: Did the higher incidence of hot flashes in obese women correlate with varying levels of specific hormones or other factors?

When looking at blood levels of specific hormones and related enzymes, the researchers found a significant link between obesity and hormone levels. Higher body mass index (BMI) was significantly correlated with higher testosterone and lower total estradiol, estrone, progesterone and sex hormone binding globulin (SHBG) in midlife women.

The researchers were surprised by the findings related to estrogen, because adipose tissue produces and stores estradiol, the major estrogen in humans. Most people had assumed that obese women would have higher circulating estrogen levels because of this, Flaws said. That assumption turned out to be incorrect, at least for women in midlife.

"It could be that estrogen levels are higher in the fat, but not circulating in the blood," she said. "It's the blood that gets to the brain and to the thermoregulatory centers that govern hot flashes."

A third analysis, published in the journal Fertility and Sterility, examined the influence of alcohol consumption on hot flashes in midlife women.

This study attempted to explain an earlier finding that moderate alcohol consumption (up to three drinks per month) actually reduced the severity of hot flashes by 25 percent. This effect vanished in women who consumed more than three drinks per month.

Because alcohol consumption is known to affect metabolism in some animals, the team thought that light drinking might alter sex steroid hormone levels in midlife women. But their analysis failed to turn up any significant hormonal differences between the alcohol users and the women who never used alcohol.

"We don't know why (moderate alcohol consumption) is reducing the risk of hot flashes, other than it doesn't seem to be doing so by changing hormone levels," Flaws said.

Together, these studies point to some risk factors for hot flashes that women can change and others that cannot be changed, Flaws said.

"Body mass index, alcohol use and smoking are three things that can change," she said. "So probably if women quit smoking, and they lose weight, it will reduce their risk. If they (engage in) light drinking, that might also reduce the risk of hot flashes. And then there's the genetic piece, which we can't change."

Diana Yates | University of Illinois
Further information:
http://www.uiuc.edu

More articles from Health and Medicine:

nachricht 'Icebreaker' protein opens genome for t cell development, Penn researchers find
21.02.2018 | University of Pennsylvania School of Medicine

nachricht Similarities found in cancer initiation in kidney, liver, stomach, pancreas
21.02.2018 | Washington University School of Medicine

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Researchers invent tiny, light-powered wires to modulate brain's electrical signals

21.02.2018 | Life Sciences

The “Holy Grail” of peptide chemistry: Making peptide active agents available orally

21.02.2018 | Life Sciences

Atomic structure of ultrasound material not what anyone expected

21.02.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>