May 04, 2012
NIH Podcast Episode #0158
Balintfy: Welcome to episode 158 of NIH Research Radio. NIH Research Radio bringing you news and information about the ongoing medical research at the National Institutes of Health – NIH . . . Turning Discovery Into Health®. I'm your host Joe Balintfy, and coming up in this episode, May is an important month for some health reminders. It is Healthy Vision Month so we talk to a vision expert about eye health. Since May also has Mother’s Day, we’ll talk about a type of diabetes that only affects pregnant women. But first, this news update. Here’s Craig Fritz.
Fritz: researchers supported by NIH have found that Avastin and Lucentis two widely used drugs to treat age-related macular degeneration, or AMD, improve vision when administered monthly or on an as needed basis, although greater improvements in vision were seen with monthly administration for this common, debilitating eye disease. Of the two drugs, Avastin is most frequently used to treat AMD. However, prior to a two-year clinical trial, the two drugs had never been compared head-to-head. AMD is the leading cause of vision loss and blindness in older Americans. In its advanced stages, the wet form of AMD spurs the growth of abnormal blood vessels, which leak fluid and blood into the macula and obscure vision. The macula is the central portion of the retina that allows us to look straight ahead and to perceive fine visual detail. Accumulation of fluid and blood damages the macula, causing loss of central vision, which can severely impede mobility and independence. Without treatment, most patients become unable to drive, read, recognize faces or perform tasks that require hand-eye coordination.
NIH research on obesity is highlighted in the new HBO documentary series and public awareness campaign called the Weight of the Nation. Launching this week, the documentary shows how obesity affects the country's health and how interventions can turn the tide against obesity and its complications. HBO, in consultation with NIH and other major health organizations, developed four documentaries focused on obesity. The project also includes a three-part HBO family series for kids, 12 short features, a social media campaign, and a nationwide community-based campaign to mobilize action to move the country to a healthier weight. The films feature several NIH-funded clinical studies that have formed the basis of scientific evidence on the causes and consequences of being overweight or obese. More than one-third of adults in the United States and nearly 17 percent of the nation's children are obese, which increases their chances of developing many health problems, including type 2 diabetes, heart disease, high blood pressure, stroke, fatty liver disease, and some cancers. In 2008, the nation's obesity-related medical costs were an estimated $147 billion. Last year, NIH funding for obesity research totaled $830 million.
For this NIH News Update – I’m Craig Fritz.
Balintfy: News updates are compiled from information at www.nih.gov/news. Coming up, having a healthy pregnancy, and healthy vision tips. That’s next on NIH Research Radio.
(BREAK FOR PUBLIC SERVICE ANNOUNCEMENT)
May is Healthy Vision Month
Balintfy: Healthy Vision Month an opportunity for health experts to emphasize the importance of eye health and promote the message that comprehensive dilated eye exams are an important part of preserving eye health and identifying diseases of the eye. We’re talking to Dr. Rachel Bishop at the NIH’s National Eye Institute. Dr. Bishop, first what are the most common eye diseases and conditions?
Bishop: The most common eye diseases and conditions in this country are macular degeneration in the older population, glaucoma most commonly in those aged 40 and above, diabetic eye disease associated with those people who have diabetes. So that could be at any age group but typically we see these patients in middle to later life. And Cataract causes a lot of loss of visual function. Cataract is not really considered a disease because it’s treated surgically. It often results from a natural aging change of the eye, but to leave that would be incorrect because that is an important medical problem that we deal with in the eye.
Balintfy: What is a comprehensive dilated eye exam and why is it important?
Bishop: most of the tissues of the eye that are affected with the common eye diseases, macular degeneration, glaucoma, diabetes eye disease, cataract, the tissues are hidden behind the iris, the colored part of the eye that you can see when you look in the mirror. So to be able to see the nerve and the retina and even the lens of the eye, the pupil has to be opened. We use eye drops to dilate the eye, that’s called dilation. The pupil has to be open so that we can look in with special lenses to actually see the details of the retina and the nerve.
Now it’s true that certain cameras with new technology can get pretty good glimpses inside the eye without dilation and that’s an exciting development. But to get a true complete eye exam, dilating drops must be used because otherwise there are tissues that are not visible.
Balintfy: Dr. Bishop, what exactly do you see when giving a dilated eye exam, for example with glaucoma?
Bishop: Speaking as an eye doctor, what the doctor sees is quite exciting. It’s really the only part in the body where you can see live nerve tissue. The blood vessels, you can look at them directly, they’re not seen through complicated imaging modalities. So when we look in a dilated eye, we literally look at the nerve, look at the blood vessels, look at the retinal tissue, which is also nerve tissue. In glaucoma, the nerve appears different than a healthy nerve in that the nerve is thought to carry about 1.2 million nerve fibers, we call them axons, from the retina to the brain. That’s kind of like the information highway from the eye to the brain. In glaucoma, a lot of those cells die. So if you reduce the number of cells say by half, you’ll see a nerve that occupies the same space but the nerve tissue itself is thinned and so there are characteristic changes that we see on examination that are necessary to conclude a person has glaucoma or has suffered, excuse me, has suffered glaucoma damage to the nerve.
Balintfy: Are there treatment options for someone with glaucoma?
Bishop: Well absolutely. Happily, the treatment options have advanced over the many years that glaucoma has been treated. Most people are well controlled with eye drops, which reduce the pressure in the eye and if eye drops are not adequate to treat the disease, they are laser therapies, which help increase the outflow of fluid and thereby lower the pressure in the eye and then surgical interventions where proper surgery is performed to improve the drainage of fluid from the eye, again to reduce the pressure.
Those treatments don’t get at what caused the glaucoma in the first place, of course, it would be very exciting to figure that out so that we could treat the underlying cause but they do reduce the pressure, save the nerve and preserve vision.
One thing that’s just an important message for people to understand, a medicine is only useful if it’s used. So I know we have patients who use their drops diligently right before their eye exam because they want to show their doctor their pressure is good. But actually unless those drops are used every day as prescribed, the patient can be suffering damage during the periods where they’re not using them and they come in, they use the right drops right before an exam, the pressure is good and we think they’re under good control, yet we’re seeing damage to the eye. We can’t quite put the picture together. So really, it’s very important that people who are prescribed eye drops for example for managing glaucoma that they use them as prescribed.
Balintfy: With glaucoma, how important is starting treatment early?
Bishop: Well unfortunately, the damage to the optic nerve as with most central nervous system nervous tissue is irreversible, and that’s also somewhat unfortunate that a person can lose many nerve cells within that optic nerve and not be aware of this. In fact, in glaucoma, the peripheral vision is the area that’s first affected. So a person can have significant loss, not notice it and be pretty advanced in the disease stage before it’s even picked up. For this reason, it’s very important that we screen for disease and identify people with disease because like some of the other diseases as well, damage can occur prior to anyone knowing they have a problem with their vision and then it’s a little bit too late to – we certainly can’t bring back nerve cells. So early screening is important for glaucoma and other diseases.
Balintfy: We’ll be talking more about those other diseases in our next episode, but is there something you’d like to emphasize right now, Dr. Bishop?
Bishop: Joe, I can’t resist. It’s springtime and people are out doing all the activities they love here in Washington anyway and I really can’t resist putting a plug in for some prevention for eye health. One is wearing sunglasses. We see a lot of sun damage to eye structures, which can either be a nuisance later in life or truly we believe contribute toward some of the eye diseases we’ve been talking about. The second is for those who like healthy lifestyles and who maintain their yards with lawn mowing and weed whacking and all stuff, we emphasize eye protection during sports and during activities where tools are being used and foreign objects are flying around. What can I say, eyeglasses, eye protection, goggles, things like this. So if I have just one more moment it’s my plug to try to encourage use of sunglasses and protective eyewear where it’s appropriate.
Balintfy: Thank you Dr. Rachel Bishop. For more information about eye health and Healthy Vision Month this May, visit www.nei.nih.gov. Again, we’ll have more about eye health, in our next episode. Up next on NIH Research Radio: gestational diabetes.
(BREAK FOR PUBLIC SERVICE ANNOUNCEMENT)
Healthy pregnancy and diabetes risk
Balintfy: May is not only Healthy Vision Month, it is the month of Mother’s Day, and National Women’s Health Week: May 13 through 19. So in this portion of NIH Research Radio, we’re talking about women who are pregnant – or want to get pregnant – and what they need to know about the risks of having or developing diabetes during pregnancy. Dr. Judith Fradkin is the Director of Division of Diabetes, Endocrinology & Metabolic Diseases at the NIH’s National Institute of Diabetes and Digestive and Kidney Disease. She’s also a leader of the National Diabetes Education Program, a joint program of the NIH and CDC. So first Dr. Fradkin, for a woman who may already have diabetes, what should she consider before getting pregnant?
Fradkin: It's really important to get your diabetes well controlled before you become pregnant because the developmental problems that can occur in children born to mothers with diabetes often develop before you even know that you are pregnant. And we know that women who control their blood sugar prior to conception have a much, much lower risk of having babies who have birth defects. So women with diabetes who are thinking of becoming pregnant should see their physician, get their diabetes in really good control before they try to get pregnant.
It's also very important for women who are overweight and so who are at risk of developing diabetes during pregnancy to try to get themselves down to a healthier weight before getting pregnant. And also getting your weight down can actually make it easier to get pregnant because sometimes women who are very overweight have trouble getting pregnant, and losing weight can help get your periods more regular and help you get pregnant.
Balintfy: For a woman who is pregnant, what should she be doing to stay healthy?
Fradkin: So it's basically the same things that everybody needs to do to stay healthy, and that's to eat healthy foods, eat lots of fruits and vegetables, avoid a lot of calorie-dense foods, a lot of sugared snacks, and also to be physically active. And even walking a half an hour a day can make a huge difference in a person's health.
Balintfy: We started talking about women that have diabetes, but what is gestational diabetes? How is it different than type 2 diabetes?
Fradkin: So gestational diabetes is diabetes that is first diagnosed during pregnancy. And most of the time, that happens because people become more insulin-resistant when they're pregnant and they need more insulin, and so if the capacity to make insulin is impaired, pregnancy may unmask diabetes, which is called gestational diabetes, which then will resolve after pregnancy.
Sometimes, preexisting diabetes is first diagnosed during pregnancy, and then in that case, of course, it won't go away after the pregnancy. So it's important for women to be tested for diabetes when they're pregnant, and the time at which women get tested for diabetes during pregnancy depends on how much at risk for diabetes they are. Somebody who is at very high risk might get tested early in pregnancy. Women who are at lower risk for gestational diabetes would be tested later in pregnancy when the rates of gestational diabetes start to rise. It's also really important for women who have gestational diabetes to get retested 6 to 12 weeks after pregnancy to make sure that the diabetes has gone away.
Balintfy: How are women tested for gestational diabetes?
Fradkin: So the test for the gestational diabetes involves drinking a glucose-containing solution and then measuring your blood sugar an hour after you drink that. And right now there's a little bit of controversy about the best criteria for the diagnosis of gestational diabetes. The NIH is actually going to be having a consensus conference this fall because some new data has come out to suggest that the complications of high blood sugar during pregnancy can occur at lower blood sugar levels than were previously appreciated.
So we've found that the risk for example of having a large baby who then -- because if a baby is large, a woman is more likely to need a Caesarian section. The baby is more likely to have a birth injury during a vaginal delivery such as damage to the shoulders going through the birth canal. And so we found out that those risks actually occur at lower blood sugar levels than had previously been recognized.
So some groups now have changed the threshold for the diagnosis of gestational diabetes to a lower cutoff for blood sugar after the glucose tolerance test based on those results. And so we're going to be considering all of that information this fall and trying to come up with some recommendations with regard to the diagnosis. But regardless of the criteria that are chosen, women should be tested usually around 28 weeks of pregnancy for gestational diabetes.
Balintfy: Dr. Fradkin, what are the long-term risks associated with gestational diabetes?
Fradkin: So there are long-term risks both to the mother and to the baby. The major long-term risk for the mother is the prospect of going on to develop type 2 diabetes, and that's something that can be delayed or prevented and so it's very important for women who have gestational diabetes to be tested after the pregnancy at about 6 to 12 weeks to see whether their blood sugar is normal or whether it's in a level that's called prediabetes which is higher than normal but not as high as diabetes.
And NIH research has shown that women who have gestational diabetes are at up to 60% chance of developing type 2 diabetes over the next 10 years. In particular, women who after pregnancy have what we call prediabetes are at high risk of progressing, and those women then should continue to be tested every year.
But the really important message also for them is that there are things that they can to do to reduce the risk of going on to develop type 2 diabetes by more than half. So losing a modest amount of weight, about 15 pounds, can dramatically reduce the risk of going on to develop type 2 diabetes. And also there's a medication called metformin which works particularly well in women with prediabetes who had a history of gestational diabetes and can help protect them against the development of type 2 diabetes.
For the baby, if a baby is exposed to high blood sugar or even is just the offspring of an obese mother who was obese during pregnancy, that does set the baby up for a long-term risk of obesity and diabetes in the baby. We know that the environment in the womb changes the metabolism of the offspring in a way that predisposes them to develop obesity and diabetes. And so it's really important then for families that have gestational diabetes to develop healthy patterns of both eating and physical activity both to protect the mother from developing type 2 diabetes but also to protect the child.
Balintfy: For a woman who has had gestational diabetes, what should she do after her baby is born?
Fradkin: She should be tested at 6 to 12 weeks to make sure that the diabetes has resolved. If that test at 6 to 12 weeks shows that she has pre-diabetes, she should take the steps that we talked about to try to prevent herself from developing type 2 diabetes, and because she is at such high risk for type 2 diabetes, she should be tested every year subsequently for type 2 diabetes if she has pre-diabetes after the pregnancy.
Balintfy: What else can a new mother do to help prevent diabetes in herself and her child?
Fradkin: So breastfeeding is helpful both to the mother and to the offspring. It helps women get back to a healthy weight after pregnancy, and it gives the baby the healthiest start in life and may decrease the risk of later obesity in the offspring.
The food that the mother and the child eat is tremendously important. Health habits start early and fruits, vegetables, whole grain foods, and avoiding high-sugar, high-fat foods makes a huge difference. Being physically active, working that into the pattern of daily life, even a half an hour a day of walking can make a very big difference.
Balintfy: Anything else you’d like to add Dr. Fradkin?
Fradkin: I think one very hopeful finding from the NIH's Diabetes Prevention Program is that even women who have the highest risk gene for type 2 diabetes can prevent or delay type 2 diabetes by making healthy lifestyle changes. So you can overcome your genetic predisposition to diabetes by making healthy choices.
Balintfy: Thank you Dr. Judith Fradkin. For more information on pregnant women, healthy eating and physical activity, visit the Weight-control Information Network at www.win.niddk.nih.gov. And for materials that can help women with a history of gestational diabetes make lifestyle changes to prevent or delay type 2 diabetes, visit www.YourDiabetesInfo.org, or call 1-888-693-NDEP.
Balintfy: That’s it for this episode of NIH Research Radio. Please join us again on Friday, May 18 when our next edition will be available. Again, we’ll have more on Healthy Vision Month, as well as May being Asthma Awareness Month in that episode. In the mean time, if you have any questions or comments about this program, or have story suggestions for a future episode, please let me know. Send an email to NIHRadio@mail.nih.gov. Also, please consider following NIH Radio via Twitter @NIHRadio, or on Facebook. Until next time, I'm your host, Joe Balintfy. Thanks for listening.
Announcer: NIH Research Radio is a presentation of the NIH Radio News Service, part of the News Media Branch, Office of Communications and Public Liaison in the Office of the Director at the National Institutes of Health in Bethesda, Maryland, an agency of the US Department of Health and Human Services.