Posts Tagged ‘male’

Medicine looking deeper into vital differences between women, men

That’s hardly an earth-shattering observation, but the fact is that, aside from the most obvious physical differences between the sexes, medicine has traditionally treated women as if they were merely smaller men.

“When we look closely, we tend to find differences” between men and women, said Sarah L. Berga, M.D., professor and chair of obstetrics and gynecology and vice president for women’s health services at Wake Forest Baptist Medical Center. “But for most of the past, we never looked.”

That started to change in the late 1980s, when physicians and researchers recognized that women’s health encompassed more than those conditions unique to females; that women’s experiences with gender-common conditions and the treatments for them often differed significantly from those of men.

“If women didn’t respond to a drug the same way as men, the thought was that it was because their body size was different,” Berga said. “Then the idea arose that maybe it was also because their bodies were different.”

When investigators began to explore how women’s and men’s bodies differed, some of the answers were startling.

“One of the biggest things we’ve learned is that cellular biology is sex-specific,” said Berga, whose interest in sex differences dates to her undergraduate days at the University of Virginia in the 1970s. “Every single cell has a chromosomal sex, and the ‘cellular machinery’ is independent of hormones.

“But we’ve also learned that most sex differences are the result of the interaction between this chromosomal distinction and hormones.”

As a result, it is now commonly accepted that there is a biological basis for sex differences in a number of common conditions, among them heart disease, stroke, arthritis, dementia, colon cancer and depression. And there’s active research into why other conditions — including obesity, bronchitis, asthma, multiple sclerosis and thyroid disease — occur more frequently in women than men.

“We’re beginning to truly understand how men and women differ in very fundamental ways and how these differences affect disease risk, symptoms, diagnostic sensitivity and specificity and responses to therapy,” said Berga, who joined the Wake Forest Baptist faculty in November 2011. “We now need to adjust our approaches and develop sex-specific interventions and therapies so both men and women benefit.”

The best way to do that, Berga said, is through research that directly compares men and women.

“If you do a study in men and then do another study in women you will not have learned anything about sex differences,” she said. “You may have learned about X in men and Y in women but you probably won’t have gotten the full story. Direct comparison is the only way to get that. It’s important that we discipline ourselves to do it this way.”

In addition to gender, age and ethnicity are also being studied as factors more frequently than in the past.

“Age is a definitely big modifier,” Berga said, “and we’re beginning to understand different genetic elements in different populations that can affect responses to drugs or make a disease more common in one group than another.”

Wake Forest Baptist researchers are among those active in this field, with recently published studies indicating that:

● High blood pressure is potentially more dangerous for women than men.

● Women who survive a stroke have a worse quality of life than their male counterparts.

● Calcium supplements regularly prescribed to prevent osteoporosis in women undergoing treatment for breast cancer may not be effective and could even be harmful.

● Therapies that reduce hot flashes in women are ineffective in men who experience hot flashes as a side effect of hormone therapy for prostate cancer.

● Women and African-Americans are at higher risk of heart attack from atrial fibrillation than men and whites.

Have findings such as these had a widespread impact on diagnosis and treatment? “Not as much as you might think,” Berga said, adding that the vast majority of diagnoses, therapies and drug dosages for common conditions are still based on symptoms, responses and outcomes in adult white males.

“That doesn’t mean they’re all bad or wrong,” she said. “You might suspect that something should be done differently according to gender, but you can’t say there is unless you prove it.”

And that’s not necessarily a simple, direct path.

“There are two things going on at once,” Berga said. “One is the urge to simplify, to make things efficient, to arrive at something that’s one-size-fits all. The other is that if something doesn’t work in a one-size-fits all model, then you have to find the reason and determine what should be changed, and you run into questions about how much it will cost to do this, how long it will take and so on.”

But Berga is generally in favor of going down that road.

“Now that we have the tools to find out certain things, we should use them,” she said. “The more we know about individual people, the better we can help them.”

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Genetic flaw in males triggers onset of liver cancer, diabetes

The research, published in the online issue of Cancer Cell, found that when the NCOA5 gene, present in both men and women, was altered in male mice to a deficient level, a spontaneous reaction occurred producing cells that can lead to hepatocellular carcinoma, a type of liver cancer found to be two-to-four times more prevalent in men than women.

Findings also showed that prior to cancer development there were occurrences of glucose intolerance, a prediabetic condition that is believed to increase the risk of type 2 diabetes in humans. Conversely, the study showed female mice did not develop these diseases.

"Essentially, what this provides is evidence for a genetic susceptibility in males to this particular type of liver cancer and diabetes," said Hua Xiao, lead researcher of the project and associate professor of physiology in MSU’s College of Human Medicine. "Ninety-four percent of the male mice we looked at developed the liver cancer, while 100 percent of these mice developed glucose intolerance."

Xiao notes the reason for the distinct outcomes between males and females also may have to do with the different levels of hormones between genders.

"Because estrogen may function through the NCOA5 gene and previously has been found to play somewhat of a protective role against both diseases, the result is a decreased risk in females," he said. "Since males produce lower amounts of estrogen, this can contribute to their susceptibility."

Type 2 diabetes has been widely associated with liver cancer as a common risk factor. Yet due to the increasing prevalence of diabetes worldwide and the limited treatments for hepatocellular carcinoma, this research could open the door to new therapeutic options.

"At this point, it’s not known if the genetic deficiency can be reversed and needs to be investigated further," Xiao said. "But if it can somehow be changed through treatments such as drug therapies, this could substantially increase the chances of men in particular warding off these diseases."

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