Independent of obesity itself, WHR is a key indicator of risk of diabetes, heart disease and mortality, and appears to be regulated differently in women and men.

Reykjavik, ICELAND, 11 October 2010 – In two of the largest metastudies of their kind to date, scientists from the GIANT consortium, including deCODE as well as hundreds of academic institutions on three continents, today report the discovery of eighteen new regions of the human genome contributing to obesity and thirteen new regions influencing waist-hip ratio (WHR). The studies bring together data on body mass index (BMI, a measure of obesity), WHR (a measure of body fat distribution), and detailed genotypic information, from more than a quarter of a million participants from Europe, North America and Australia. The findings demonstrate the effectiveness of collaborations such as GIANT for powering studies large enough to detect lower-impact genetic factors for common traits and diseases.

“To my mind, perhaps the most noteworthy aspect of these findings is that it has indeed been possible to find so many loci for WHR that are independent of BMI. Most of the BMI loci appear to affect central and neuronal processes regulating satiety and appetite. By contrast, the WHR loci appear to be involved in the development and distribution of adipose tissue. Thus, the genetics seems to be pointing us to biological distinctions between two components of the regulation of weight – how much we eat, and how and where calories are stored as fat. Also intriguing, many of the WHR loci show a significantly greater impact in women than in men, a distinction that is stronger here than in any other disease or trait we have looked at. From a health perspective, the distinctions drawn here between BMI and WHR are steps towards better understanding the role of these two traits as risk factors for a range of diseases,” said Kari Stefansson, deCODE CEO and a senior author on the BMI study.

The papers, “Association analyses of 249,796 individuals reveal eighteen new loci associated with body mass index,” and “Meta-analysis identifies 13 novel loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution,” are published online in Nature Genetics at www.nature.com/ng and will appear in an upcoming print edition of the journal.

deCODE scientists have discovered new genetic variants influencing BMI, weight and risk of obesity

As we all know to well, for decades the scales have been tipping in favor of obesity. The epidemic of obesity in many industrialized countries has been driven by many factors, including easy access to fast food, an increasingly sedentary lifestyle, insufficient daily physical activity. All of this while our genomes have evolved on a background of scarcity, often putting a premium on the ability of the body to turn food into fat and store energy for leaner times. A paper published today by deCODE scientists and academic colleagues from the US and Europe provide a significant advance in our knowledge of the underlying genetics and biology of obesity, providing new information for understanding and addressing obesity and perhaps nudging the scales the other way.
In a major study published today, the deCODE-led team reports the discovery of a large number of single-letter variations in the sequence of the human genome (SNPs) influencing body weight, body mass index (BMI) and risk of obesity. (BMI>30kg/m2). The discoveries were made be scanning over 300,000 SNPs in more than  30,000 individuals from Iceland, The Netherlands, and the United States, and then confirming the findings in individuals from Denmark and the multinational GIANT consortium, totaling close to 40,000 individuals. Interestingly, many of the variants discovered are located near genes related to energy sensing or food intake regulation in the brain, suggesting its importance in the development of obesity.   Although these variants only explain a small fraction of the variation in BMI, they provide new insght into the basic mechanisms underlying obesity and a first step towards identifying drug targets that can be used to address the global public health challenge of obesity.

By Edward Weinman

With a simple swab from the inside of your cheek, deCODE genetics can scan your DNA, map your markers and assess your risk of developing 29 common diseases. Edward Weinman, self-described hypochondriac, wonders if he should look too closely at his possible future.

Fifteen hundred Americans will die of cancer today. Tomorrow, another 1,500 will perish. And the day after tomorrow: yet another 1,500.

While I’ve never had cancer (knock on wood) I know how the disease changes lives. My grandmother died from it. My brother has non-Hodgkin’s lymphoma, although thankfully it’s currently in remission after a lengthy round of chemotherapy. Cancer is scary. It accounts for one out of every four deaths. According to the American Cancer Society, cancer is the second leading cause of death in the US, behind heart disease.
Oh, yeah. Heart disease. The great American killer. Heart disease kills 652,486 Americans per year, according to the National Center for Health Statistics. Let’s not forget Alzheimer’s, no pun intended. This cruel disease that strips us of our memories is the sixth leading cause of death, and rising. Every 71 seconds, someone develops Alzheimer’s, including my mother. It’s hard to face the fact there is almost nothing we can do about some diseases, except prepare ourselves and our loved ones for the eventuality.
On the other hand, there are so-called killer diseases on which we can have a positive impact. We cut back on fatty foods and load up on vegetables. We increase our daily intake of fiber by eating cereal that tastes like bark dust. We pop vitamins. We spend time in the gym, going from workout station to workout station like a rat in a cage. Some of us work through crossword puzzles in the hope that mental gymnastics will keep plague from forming in our brains.

But are these healthy habits enough? Is there something more I can do to protect myself from these killer diseases?

For about $1000, deCODE will scan my genome for genetic markers linked to such killers as heart disease, diabetes, certain types of cancer and Alzheimer’s. All that’s required is for me to order a kit, swab the inside of my cheek, drop the swab into the mail, wait a few weeks and then log on to decodeme.com to view my results.

According to deCODE, discovering an inherited propensity toward a particular illness can motivate individuals to get more frequent checkups, take preventive medicines or make lifestyle changes to try to ward off the specter of disease.

But is it really a good idea for a hypochondriac like myself to know my own DNA? What if I discover that I have a high risk of heart disease? Will I soon be hauling myself off to the ER complaining of chest pains? Until recently, my view is that it would have been better to live and hope for the best rather than discover I have a high probability of developing a fatal condition. Ignorance is bliss.

Then my mother fell ill. And my brother got sick. As far as my own health, I exercise like a banshee. However, despite all the hours logged in the gym, I’ve taken more than one trip to the ER because of chest pains. I’ve had EKGs, stress tests, even a CT angiogram which all revealed that my heart was strong. The cause of my chest pains: stomach ulcers and, later, anxiety. But that helpless feeling of lying in the ER as doctors connect EKG leads to my chest sometimes returns. I worry about my health more than most 41-year-olds. So maybe a genetic test is exactly what I need to put my mind at rest.

Yes, I want to arm myself with as much information as possible in order to fight what might be coming, or at least prepare for what might await me on the horizon.

“We need to empower people,” says Dr. Robert Superko, author of the book Before the Heart Attacks, and executive director of the Center for Genomics and Human Health at the St Joseph’s Translational Research Institute. “If a genetic test prompts people to do what’s right for them then we have accomplished our goal.”
I order the kit.

Sitting at my laptop, logged on to deCODEme.com, the genetic secrets to my future health are only a mouse click away. I can click to see my inherent risks of contracting all 29 of the diseases deCODE tests for, or click on the results one disease at a time, leaving the scary diseases for later, or not at all. It’s my choice.

I’m not really concerned about whether or not I’m lactose intolerant. I’m not too worried about Celiac disease, or restless-leg syndrome. No, I’m sweating over the Alpha diseases: Prostate Cancer. Alzheimer’s. Heart Disease. What if my test results portend to a future weighted down by Chemo, or if I’ll one day take Arecept, or have a stent inserted into my arteries?

I demur. You know, no news is good news. The last thing a hypochondriac like myself needs is a fortuneteller mapping out my future in a pack of tarot cards. I understand that information is power, but what about Alzheimer’s? If my risk is relatively high, I can whittle down pencil after pencil working on the NY Times crossword and not really reduce my risk, even if I throw in a few Sudoku puzzles for good measure.
“The test is a way of bringing patient and doctor together,” says Dr. Jeffrey Gulcher, deCODE’s chief scientific advisor. “The test gives you a risk assessment, and then you and your doctor can figure out what to do about it.”

So the test is not definitive. It’s not a diagnostic tool in the usual sense. If I have a higher than normal inherited risk of heart disease that doesn’t mean I have to replace my artery clogging Ben & Jerry’s Chocolate Fudge Brownie with apple slices. If my risk of Alzheimer’s is high I’m not going to have to purchase an identity bracelet with my name, address and phone number engraved on it in case I get lost.

“The genetic test is analogous to a cholesterol test,” says Dr. Gulcher. “Just because you have high cholesterol, doesn’t mean you’ll have a heart attack. Just because you have low cholesterol, doesn’t mean you’re off the hook.”

I breathe a sigh of relief. I can look at my results without breaking out into a cold sweat. My DNA results aren’t going to say: “Tomorrow, Edward Weinman, you’ll contract cancer.”

Then again, Dr. Gulcher’s recent health issues suggest that comparing the deCODEme genetic test to a cholesterol screening is not all together an accurate analogy. Months ago, Dr. Gulcher took the swab, and his genetic profile revealed that he had a 30 percent lifetime risk of contracting prostate cancer. At 48, Gulcher was still two years away from when most medical experts believe prostate screening should begin.
How did Dr. Gulcher take the news? He was empowered. Dr. Gulcher took a standard blood test measuring his prostate-specific antigen, or PSA, which showed he was at the high end of normal. This data, combined with Dr. Gulcher’s DNA test, compelled his doctor to refer Gulcher to a urologist who performed an exploratory biopsy. The biopsy’s result? “A fairly aggressive form of cancer,” Dr. Gulcher recalls. Thankfully, Dr. Gulcher’s cancer had not spread to other parts of his body, and he underwent surgery to remove the cancer. Dr. Gulcher has just had his catheter removed when I ask him if deCODE’s genetic test saved his life.
“I can’t say for sure, but it’s likely it did. I had a tumor at the time of diagnosis. There is a good chance that tumor would’ve already spread” by the time he went in for a normal PSA screening at the age of 50.
Okay, I’m convinced. Time to decode my DNA. I click on the link and my test results are revealed:
My relative genetic risk for Alzheimer’s is 1.74, translating into a lifetime risk of 10.5 percent.

Not so bad, right? Not exactly. The average risk of contracting the disease is 6.4 percent. So I’m higher than average. But what stands out like a scar on a model’s face is when I look at the percentage of the population at a less or equal risk to me: 97.2 percent. In other words, only 2.8 percent of the population has a higher risk of contracting Alzheimer’s than I do.

So what does this mean?

“We emphasize that these are not determinative factors. They reflect risk. Relative risk,” Dr. Gulcher tells me.
He’s got a point. When I look at my risk of becoming obese I realize these results must be taken with a grain or two of salt. My DNA says that my relative genetic risk for obesity is .80, translating into a 31.6 percent chance of becoming fat. I chuckle, because I work out four to five days a week, and I’m what you might call skinny, or as I prefer, lean and toned. Plus, my metabolism works at hyper speed. At 41, I can proudly say that I have a six-pack. So a 31.6 percent risk of becoming fat? I don’t think so. (There’s no need to elaborate more because this grain or two of salt is refuted below, in that the test is necessary, and one that can improve health. One must always present the counter argument to make the argument stronger.)
Again, deCODEme only provides me with information on my “relative” risk of contracting common diseases. It’s not definitive. But can’t I just look at my parents’ and grandparents’ health and the health of my siblings to decode what diseases might afflict me when I grow older? Do I really need to pay $1000 for a genome scan?

“That would work well for certain diseases, like certain types of breast cancer, but common diseases tend to skip generations. Most of us don’t keep track of our genealogy. But that’s what’s going on when we find these common variations.” Dr. Gulcher continues: When we run a test “we are percolating the risk through your family’s history of disease.”

Dr. Gulcher then asks me a question. He curiously wants to know what my top two diseases are in terms of risk. I figure Alzheimer’s is number one, until I scan down my gene profile and learn that I have a 2.3 relative genetic risk of developing Type 2 Diabetes, translating into a 57.5 percent lifetime risk, double the average lifetime risk.

Not a chance. No way is it possible that I’m at risk for diabetes. I’m healthy. I eat right. I exercise. I’m not even close to being overweight. My BMI is perfect. I went so long during my last stress test that the cardiologist asked if I ever ran cross-country competitively. How can I be at risk for Type 2 Diabetes? Surely this proves deCODEme’s genetic test must be taken with many grains of salt. Perhaps this invalidates all my other results.

The doctor draws my blood and ships it off to the lab.

A few days later, I find out that my fasting glucose level is 96 mg/dl. That’s the high end of the normal range but a lot higher than I expected. One indication of pre-diabetes is a fasting glucose level that is between 100 and 125 mg/dl. Talk about a wakeup call. Despite my healthy lifestyle, my glucose levels are too high and that can be nothing other than genetic.

I remember Dr. Gulcher’s words: “The test is a way of bringing patient and doctor together. The test gives you a risk assessment, and then you and your doctor can figure out what to do about it.”
There’s no need to panic, but it is time to make an appointment to see my doctor. It’s time to trade in my Ben & Jerry’s for those apple slices.

Edward Weinman is a freelance writer living in Los Angeles, and a contributor to deCODE’s News Blog. He spent eight years in Iceland, working as a journalist and he co-wrote the film A Little Trip to Heaven.