WEDNESDAY, July 9 (HealthDay News) -- Diabetes and being over- or underweight can have a negative effect on male fertility.

That's the conclusion of two reports to be presented July 9 at the annual conference of the European Society of Human Reproduction & Embryology, in Barcelona, Spain.

While semen samples from diabetics look normal under the microscope, a closer examination revealed DNA damage, Dr. Con Mallidis, of Queen's University in Belfast, Northern Ireland, said in a news release issued by the conference sponsors.

"Sperm RNA was significantly altered, and many of the changes we observed are in RNA transcripts involved in DNA repair," he said. "And comparison with a database of men of proven fertility confirmed our findings. Diabetics have a significant decrease in their ability to repair sperm DNA, and once this is damaged, it cannot be restored."

Sperm DNA quality is known to be tied to decreased embryo quality, low embryo implantation rates, higher miscarriage rates and some serious childhood diseases, including cancers.

"We found a class of compounds known as advanced glycation end products (AGEs) in the male reproductive tract. These are formed as the result of glycation (the addition of sugar)," Mallidis said, "and accumulate during normal aging. They are dependent on lifestyle, diet, smoking, etc., and in many diabetic complications are centrally implicated in DNA damage. We believe that they play a similar role in the male reproductive system."

The researchers plan to now determine how AGEs cause and contribute to DNA damage.

Obesity, which often plays a factor in diabetes, and being too thin, was also found to cause problems with sperm. In a separate study, scientists found that men with a higher body mass index (BMI, a ratio of weight to height) had less seminal fluid and more abnormal sperm.

The findings showed that men with an optimal BMI of 20 to 25 had higher levels of normal sperm than those who were either overweight or underweight. They also had higher semen volume.

The researchers did not look at DNA damage in the sperm, though.

"Our findings were quite independent of any other factors," scheduled presenter A. Ghiyath Shayeb, from the University of Aberdeen, in Scotland, said in the news release from the conference, "and seem to suggest that men who are trying for a baby with their partners should first try to achieve an ideal body weight."

"Adopting a healthy lifestyle, a balanced diet, and regular exercise will, in the vast majority of cases, lead to a normal BMI," he said. "We are pleased to be able to add improved semen quality to the long list of benefits that we know are the result of an optimal body weight."

More information

The American Urological Association has more about male infertility  .

TUESDAY, July 8 (HealthDay News) -- Rising levels of a blood protein called fetuin-A may indicate an elevated risk of developing type 2 diabetes, new research suggests.

Reporting in the current issue of the Journal of the American Medical Association, researchers from the University of California, San Diego, found that older people with the highest levels of fetuin-A were more likely to develop diabetes than those with lower levels.

"If fetuin-A can really differentiate diabetes risk, it gives us an opportunity for public health interventions," said the study's lead author, Dr. Joachim Ix, an assistant professor of medicine at the University of California, San Diego, and the San Diego Veterans Affairs Healthcare System.

Ix said that interventions to fight diabetes, such as healthy diet and exercise, can be difficult to accomplish on a wide scale. However, efforts could be made easier "if we could use something like fetuin to identify people with the highest risk," he said.

According to the American Diabetes Association (ADA), almost 21 million Americans now have diabetes. Most of them have the type 2 form of the disease, which is often linked to obesity. People with type 2 diabetes either don't produce enough insulin, or their bodies become desensitized to insulin and can't effectively use it. Untreated, diabetes can lead to a number of complications, including heart disease, stroke, kidney failure, blindness and more, according to the ADA.

The exact cause of type 2 diabetes still remains elusive. For example, being overweight is a significant risk factor for developing the disease, but not everyone who's overweight or obese will become diabetic. Fetuin-A is a protein secreted by liver cells that may play a role in insulin resistance -- the precursor to type 2 diabetes.

The current study included 406 people between 70 and 79 years old, all of who had their fetuin-A levels measured at the beginning of the study. At the time, none of them had diabetes.

Six years later, 135 of the study participants had developed diabetes.

Those with the highest fetuin-A levels had twice the risk of diabetes than those with the lowest levels -- 13.3 per 1,000 person-years compared to 6.5 cases per 1,000 person-years, the researchers found.

The team adjusted the data to account for other known diabetes risk factors, such as age, physical activity levels, body mass, and more. The association between diabetes and fetuin-A remained, except for when the researchers controlled for abdominal fat.

"When we adjusted for visceral fat, the link between fetuin and diabetes was still there, but was weaker," said Ix.

One expert said the findings are likely only a beginning.

"This is a very preliminary result which suggests that there might be a relationship between fetuin-A and diabetes, and this study suggests a potential target for drug development, but it's something that will take years to tease out," said Dr. John Buse, president of medicine and science at the American Diabetes Association, and director of the diabetes care center at the University of North Carolina School of Medicine, Chapel Hill.

Ix agreed that the findings need to be confirmed by other researchers. But he also believes that this work is a jumping off point for other research.

"This study suggests that there are factors coming from the liver that might control glucose, and there's a chance that this might ultimately lead to new treatments and screening strategies," said Ix.

More information

To learn more about preventing type 2 diabetes, visit the American Diabetes Association  .

TUESDAY, June 24 (HealthDay News) -- Almost 24 million Americans had diabetes in 2007, an increase of more than 3 million over two years, the U.S. Centers for Disease Control and Prevention reported Tuesday.

In addition, another 57 million Americans had pre-diabetes, which puts people at increased risk for diabetes.

There was some good news. Over two years, the proportion of people with diabetes who don't know they have the disease decreased from 30 percent to 25 percent.

"It is concerning to know that we have more people developing diabetes, and these data are a reminder of the importance of increasing awareness of this condition, especially among people who are at high risk," Dr. Ann Albright, director of the CDC Division of Diabetes Translation, said in a prepared statement.

"On the other hand, it is good to see that more people are aware that they have diabetes. That is an indication that our efforts to increase awareness are working, and more importantly, that more people are better prepared to manage this disease and its complications," Albright said.

Among adults, diabetes increased in both men and women in all age groups, but the disease still disproportionately affects the elderly. Almost 25 percent of people aged 60 and older had diabetes in 2007, the CDC said.

Ethnic and minority disparities persist in rates of diagnosed diabetes: Native Americans and Alaska Natives, 16.5 percent; blacks, 11.8 percent; Hispanics, 10.4 percent; Asian Americans, 7.5 percent; and whites, 6.6 percent.

The data is in the 2007 Diabetes Fact Sheet developed by the CDC and other federal agencies.

The CDC also released estimates of diagnosed diabetes for all counties in the United States, which show higher rates of diabetes in areas of the Southeast and Appalachia where people traditionally been recognized as being at higher risk for heart disease, stroke and other chronic diseases.

"These data are an important step in identifying the places in a state that have the greatest number of people affected by diabetes. If states know which communities or areas have more people with diabetes, they can use that information to target their efforts or tailor them to meet the needs of specific communities," Albright said.

Diabetes, the seventh leading cause of death in the United States, can cause serious health complications such as heart disease, blindness, kidney failure and lower extremity amputations.

More information

The CDC has more about diabetes.