Medical College of Georgia researchers looking at 126 healthy 15- to17-year-olds in high school in Augusta, Ga., found the hormone aldosterone highest among the overweight males. Early intervention could help these young people avoid growing up to be adults with cardiovascular disease, the number one killer in the United States.

“These associations give us reason to question whether we should be screening for and treating high aldosterone in obese males with normal pressures, particularly those with a family history of cardiovascular disease,” MCG Endocrinology Fellow Dayal D. Raja says of the collaborative study with the Department of Pediatrics.

“Our failure to halt the progression of heart damage is attributed to late detection, because early heart damage is usually asymptomatic,” Dr. Raja says. “We have evidence that we could identify individuals early and stop or even reverse that damage. We need more study to confirm our findings and a plan for whom and how to screen.”

This first evidence of elevated aldosterone levels and early heart damage in a pediatric population with normal blood pressure earned Dr. Raja first place in the poster session at the recent American Association of Clinical Endocrinologists 18th Annual Meeting and Clinical Congress in Houston.

Aldosterone, a hormone produced by the adrenal gland, is known to increase blood pressure by increasing sodium and water retention. Despite normal blood pressures, the overweight males had thickened heart walls and an increase in the size of the pumping chamber of the heart, Dr. Raja says. Structural changes in the young hearts can be linked to a lesser-known aldosterone fact: it also promotes inflammation and formation of fibrous tissue in the heart muscle.

Overweight females in the group did not have elevated aldosterone levels or the associated heart damage, Dr. Raja says, noting that estrogen’s cardioprotective effect may have made the difference.

Blood and urine test are available to measure aldosterone levels, but they typically aren’t measured unless a patient on multiple medications still has uncontrolled blood pressure. By then, Dr. Raja says, significant cardiovascular damage may have been done.

It’s more likely, young, overweight people would be told to lose weight, but that isn’t working for most, Dr. Raja says. “We are trying weight loss but we are failing miserably,” he says, noting the worldwide obesity epidemic. In fact, since that’s today’s standard, losing weight is just what these researchers told their study participants to do. Losing weight – if it happens – will decrease aldosterone levels.

Although the exact relationship between increased fat and increased aldosterone is still being sorted out, the latest research suggests that fat cells stimulate the adrenal glands to make more aldosterone, says Dr. Gregory Harshfield, director of MCG’s Georgia Prevention Institute and a hypertension researcher.

As a follow up to Dr. Raja’s study, Dr. Harshfield wants to block aldosterone levels in overweight teens with a family history of cardiovascular disease to determine if it can prevent or reverse dangerous heart changes and forestall hypertension. The GPI already is doing similar studies blocking the kidney’s production of the powerful blood vessel constrictor angiotensin in young people with an impaired ability to secrete sodium.

The landmark 1999 RALE trial illustrated the potential benefit of reducing aldosterone levels even in people already suffering from heart failure. The study of 1,663 patients was halted early because of significantly reduced death rates in those taking the aldosterone-lowering, anti-hypertensive spironolactone. Patients on other anti-hypertensives failed to show as impressive results.

Source: Medical College of Georgia

Results indicate that BMI and waist circumference, but not neck circumference, were significant and strong predictors of SDB at all severity levels – primary snoring, mild SDB and moderate SDB. Nasal anatomic factors such as chronic sinusitis, rhinitis and nasal drain were significant predictors of mild SDB; minority status was associated with primary snoring and mild SDB. Tonsil size, assessed by visual inspection, was not a significant risk factor for any level of SDB. Overall, 1.2 percent of children had moderate SDB (an apnea/hypopnea index of five or more breathing pauses per hour of sleep), 25 percent had mild SDB (AHI of at least one but less than five) and 15.5 percent had primary snoring.

According to principal investigator Edward O. Bixler, PhD, of Penn State University College of Medicine in Hershey, Penn., it is often assumed that the primary mechanism of SDB in children is the presence of large tonsils or adenoids. The study suggests, however, that the causes of SDB in children are more complex, that there may be a systemic influence of obesity, and that adenotonsillectomy may not always be the most effective, first-line treatment.

“Risk factors for SDB in children are complex and include metabolic, inflammatory and anatomic factors,” said Bixler. “Because SDB in children is not just the outcome of anatomical abnormalities, treatment strategies should consider alternative options, such as weight loss and correction of nasal problems.”

The American Academy of Sleep Medicine reports that snoring is one warning sign for obstructive sleep apnea, a common form of SDB that occurs when soft tissue in the back of the throat collapses and blocks the airway during sleep. Snoring that is related to sleep apnea tends to be loud and may include obvious pauses in breathing and gasps for breath. Parents often notice that the child seems to be working hard to breathe during sleep.

The study gathered data from 700 children between the ages of 5 and 12 years who were randomly selected from 18 public elementary schools in Dauphin County, Penn. Fifty-two percent were female, and 23.8 percent of the children were either Black or Hispanic.

Each child was evaluated by a physical exam and monitored for nine hours during one night of polysomnography in a sleep laboratory.

The overall average AHI was 0.8 breathing pauses per hour of sleep, with a maximum value of 24.6. The prevalence of moderate SDB was higher in older children; two percent of children between the ages of 9 and 12 years had moderate SDB, compared with only 0.2 percent of children between 5 and 8 years of age.

Source: American Academy of Sleep Medicine

In their study, Halliday and Kwak document strong correlations in weight gain between adolescents and their friends, even after controlling for confounding factors such as race, sex and age. While these correlations may be indicative of pupils causing their peers to gain weight, the authors provide evidence that a substantial part of the correlations is a consequence of sorting on BMI.

In addition, they discuss many of the econometric issues in estimating such effects while accounting for growth spurts and difficulties in defining adolescent obesity. Halliday and Kwak discuss policy implications of such findings for school-based interventions to combat obesity. Their work contributes to a growing body of literature studying the impact of peers on student outcomes.

Source: University of Hawaii at Manoa

Investigators from the Department of Family Medicine, Medical University of South Carolina, Charleston compared the results of two large-scale studies of the US population in 1988-1994 and in 2001-2006. In the intervening 18 years, the percentage of adults aged 40-74 years with a body mass index greater than 30 has increased from 28% to 36%; physical activity 12 times a month or more has decreased from 53% to 43%; smoking rates have not changed (26.9% to 26.1%); eating 5 or more fruits and vegetables a day has decreased from 42% to 26%; and moderate alcohol use has increased from 40% to 51%. The number of people adhering to all 5 healthy habits has decreased from 15% to 8%.

The National Health and Nutrition Examination Survey (NHANES) is a national survey of non-institutionalized persons in the US conducted regularly by the National Center for Health Statistics. The researchers used data from a sub sample of the NHANES surveys of 1988-1994 and 2001-2006, adults aged 40-74 years, because this age span is the primary time for initial diagnosis of cardiovascular risk factors and disease. In the NHANES 1988-1994, the number of respondents 40-74 years old was 7340, representing a weighted sample size of 78,794,217. For NHANES 2001-2006, the number of respondents was 7811, for a weighted sample size of 65,476,573.

Since people with diagnosed health conditions such as cardiovascular disease, diabetes, hypertension, or high cholesterol were part of the samples, the researchers sought to determine whether such individuals were adhering to the healthy habits to a greater or lesser degree than people without those conditions, and whether adherence had changed over time. The study also concluded that people with cardiovascular disease, diabetes, high blood pressure or high cholesterol, or risk factors for those conditions, were no more likely to adhere to a healthy lifestyle pattern than people without such risk factors.

Writing in the article, Dana E. King, MD, MS, states, “The potential public health benefits from promoting a healthier lifestyle at all ages, and especially ages 40-74 years, are substantial. Regular physical activity and a prudent diet can reduce the risk of premature death and disability from a variety of conditions including coronary heart disease, and are strongly related to the incidence of obesity. In the US, medical costs due to physical inactivity and its consequences are estimated at $76 billion in 2000 dollars. Research indicates that individuals are capable of adopting healthy habits in middle age, and making an impact on cardiovascular risk.”

Source: Elsevier Health Sciences

Those who take statins after a stroke may also be less likely to die within the next 10 years than those who do not take statins.

“Considering the large burden that stroke carries around the world, these potential benefits of statins are significant,” said study author Sotirios Giannopoulos, MD, DSc, of the University of Ioannina School of Medicine in Greece. “Also, second strokes tend to result in more disability and longer time spent in hospitals than first strokes, so anything that can prevent these recurrent strokes is beneficial.”

The study involved 794 people who had strokes and had health information available for 10 years after the stroke. Researchers looked back at the records to see what factors affected the risk for having a second stroke or dying within 10 years after the stroke.

During that time, 112 people had a second stroke and 224 people died. Those who took statins were 35 percent less likely to have a second stroke and 57 percent less likely to die within 10 years than those who did not take statins.

About eight percent of those on statins had a second stroke, compared to 16 percent of those not taking statins.

Researchers analyzed other risk factors for stroke, such as high blood pressure, diabetes, smoking, and heart problems, but found that statin use was the only factor tied to a reduced risk of recurrent stroke and death.

“It’s possible that effects from the drugs that are separate from their cholesterol-lowering effects are responsible for this result,” Giannopoulos said. “Statins have anti-inflammatory and antioxidative effects and also prevent blood clotting and stabilize plaque in the arteries, so one of these mechanisms may help to prevent recurrent stroke.”

Source: American Academy of Neurology

Professor Boyd Swinburn believes that research funding would be better directed at testing possible solutions rather than continuing to unpick what is causing the rise in obesity.

“It seems counter intuitive, but knowing the causes or mechanisms for weight gain does not always help with identifying the solutions,” he said.

“For an individual person, we know the causes of weight gain over time include the obesogenic environment, genetic predisposition, and increasing age – none of which can be influenced by the health professional trying to help the person lose weight. At a population level, the commercial drivers which promote our overconsumption of food are unlikely to be reversed by the private sector because there is no commercial gain for the food industry to promote eating fewer calories.

“The twin bottom line is that we need to re-orient our research towards testing potential solutions rather than just better identifying the problem. The most promising approaches for individuals and populations will involve identifying the right set of ‘rules’ or policies which lead to sustainable environmental and behavioural changes.”

Professor Swinburn says that identifying solutions needs specific solutions-oriented research and unfortunately most of the current research into obesity is problem-oriented.

“Interestingly, the solutions that are the most likely to work seem to be ‘rule-based’ solutions,” Professor Swinburn explained.

“For overweight individuals, so long as they can stick to a set of dietary rules which results in a reduced calorie intake, it doesn’t seem to matter what foods are included or excluded. This is why lots of different types of diets which are unrelated to the dietary causes of weight gain can produce weight loss.

“Similarly, at a population level, it is likely that rules or policies are likely to be the most promising for prevention. Education, guidelines, industry self-regulation, and government ads on TV are unlikely to have much influence and stronger policies will be needed.”

Professor Swinburn will be speaking about the causes of the current obesity epidemic and potential solutions today (Thursday 21 May) at the Public Health Association of Australia ACT Branch’s Sax Oration in Canberra.

Sleep apnea has long been known to be associated with obesity. But a new study published in the June issue of Diabetes Care finds that the disorder is widely undiagnosed among obese individuals with type 2 diabetes – nearly 87 percent of participants reported symptoms, but were never diagnosed.

For those with untreated sleep apnea, it doesn’t just mean their sleep is disrupted; existing research shows that it can also mean an increased risk of heart disease and stroke.

“The high prevalence of undiagnosed, and therefore, untreated sleep apnea among obese patients with diabetes constitutes a serious public health problem,” said Gary Foster, PhD, lead author and director of the Center for Obesity Research and Education at Temple University.

The new study, called Sleep AHEAD, looked at 306 obese patients with type 2 diabetes already enrolled in the Look AHEAD trial, a 16-site study investigating the long-term health impact of an intensive lifestyle intervention in 5, 145 overweight or obese adults with type 2 diabetes.

Each participant had a sleep study (polysomnogram) that measures various breathing and brain activity during sleep. Participants also filled out a series of questions about symptoms related to sleep (snoring, sleepiness during the day), and had their weight, height, waist and neck circumferences measured.

Researchers found that 86.6 percent of participants had sleep apnea, yet reported never being diagnosed. More than 30 percent of these had between 16 and 20 episodes per hour where they would stop breathing, and 22 percent had more than 30 episodes per hour, considered severe sleep apnea. Most of these also had a larger waist circumference, which researchers found, along with higher BMI, to be significantly associated with sleep apnea.

Obesity has long been known to be associated with sleep apnea, but researchers say that these findings are alarming.

“Doctors who have obese patients with type 2 diabetes need to be aware of the possibility of sleep apnea, even if no symptoms are present, especially in cases where the patient has a high BMI or waist circumference,” said Foster.

Currently, more than half of obese or overweight individuals have diabetes, the seventh leading cause of death in the United States.

Source: Temple University

Although vitamin D is naturally produced in the body through exposure to direct sunlight, vitamin D deficiency has become widely common in the United States. Vitamin D deficiency has been shown to have a significant negative impact on muscle and bone health, and can lead to conditions including osteoporosis and rickets.

“We know vitamin D deficiency can weaken the muscular and skeletal systems, but until now, little was known about the relationship of vitamin D with muscle power and force,” said Dr. Kate Ward, Ph.D., of the University of Manchester in the U.K., and lead author of the study. “Our study found that vitamin D is positively related to muscle power, force, velocity and jump height in adolescent girls.”

For this study, researchers followed 99 adolescent girls between the ages of 12 and 14 years. Dr. Ward and her colleagues took blood samples to measure the girls’ serum levels of vitamin D. Many of these girls were found to have low levels of vitamin D despite not presenting any symptoms.

Researchers used a novel outcome measure called jumping mechanography to measure muscle power and force. Jumping mechanography derives power and force measurements from a subject’s performance in a series of jumping activities. Dr. Ward says this method of testing is ideal as the muscles required to jump are those most often affected in subjects with vitamin D deficiency. Girls without vitamin D deficiency performed significantly better in these tests.

“Vitamin D affects the various ways muscles work and we’ve seen from this study that there may be no visible symptoms of vitamin D deficiency,” said Dr. Ward. “Further studies are needed to address this problem and determine the necessary levels of vitamin D for a healthy muscle system.”

September 4, 2008 (Portland, Ore.) – Obese people who have asthma are nearly five times more likely to be hospitalized for the condition than non-obese people with asthma, according to a Kaiser Permanente study published in the September issue of the Journal of Allergy and Clinical Immunology.

This is the first study to control for the risk factors – smoking, use of oral or inhaled corticosteroid medications, gastroesophageal reflux disorder, and demographics – that might explain the obesity-asthma association. Previous studies have shown that obese people are more likely to suffer asthma than non-obese people, and that obese patients often have more severe asthma than their non-obese counterparts.

More than 20 million Americans have been diagnosed with asthma. Nearly a third of adults with asthma are also obese, according to researchers. The Centers for Disease Control and Prevention defines obesity as having a Body Mass Index of 30 or higher (http://www.cdc.gov/nccdphp/dnpa/obesity/defining.htm)

Researchers at Kaiser Permanente Center for Health Research in Portland, Ore., and the Kaiser Permanente Institute for Health Research in Denver surveyed 1,113 patients in Oregon, Washington, and Colorado, age 35 and older, who have persistent asthma. The researchers asked the patients about their weight, height, smoking habits, other illnesses, treatment and their asthma-specific quality of life, asthma control and asthma-related hospitalizations.

“The big finding here is that even after adjusting for risk factors, obese adults were nearly five times more likely to be hospitalized for their asthma,” said study lead author David M. Mosen, Ph.D., MPH, of the Kaiser Permanente Center for Health Research. “Given that nearly 30 percent of our country is obese, this study is yet another example of the long-term dangers of obesity, along with heart disease, diabetes, stroke and dementia.”

The study uncovered these findings:

• Obese people with asthma had significantly worse asthma control, lower asthma-related quality of life, and had 4.6 times higher risk for asthma-related hospitalizations than non-obese asthmatics
• Obese people with asthma were younger and less educated than non-obese people with asthma
• Obese people with asthma used more oral corticosteroids
• Obese people with asthma had a higher incidence of gastroesophageal reflux disorder.

“The take-home message of this study for clinicians is that obese people with asthma need to be followed more carefully because it’s harder to control their asthma, so they are more likely to end up in the hospital,” said study co-author Dr. Michael Schatz, Chief of Allergy at Kaiser Permanente San Diego Medical Center. “My advice for obese asthmatics is: be vigilant to keep your asthma symptoms in check, make sure you know what to do when your symptoms worsen, and do whatever you can to lose weight.”

Source: Kaiser Permanente

In addition to removing about two-thirds of the stomach, gastric bypass in effect produces a “double intestine,” said Gilles Mithieux of Institut National de la Sante et de la Recherche Medicale in France. The portion closest to the stomach is taken out of the loop so that it receives no nutrients. The segment normally farther down is then attached directly to the stomach, where it receives all the nutrients coming in.

In both cases, those positional changes ramp up production of blood sugar by the small intestine, Mithieux said. He noted that fasting normally induces blood sugar production by the upper small intestine. By placing the lower small intestine, which doesn’t normally produce much glucose, in close proximity to the stomach, it starts to act more like the upper portion.

That blood sugar synthesized in the intestine pours into the portal vein (a large vein that carries blood from the digestive tract to the liver) where it sends a signal to the brain, he and his colleagues earlier found. “The walls of the portal vein system detect the glucose and inform the brain,” he said. “It’s an important signal for decreasing hunger.”

They now find an important new element of glucose production by the intestine. It also increases insulin sensitivity and lowers blood sugar, improving the symptoms of diabetes. Mithieux said that’s in part because glucose production by the intestine lowers glucose production by the liver, which accounts for a much greater overall proportion of blood sugar synthesis. These metabolic changes take place within days of surgery, well before any weight loss takes place.

While gastric banding, in which a prosthetic band is placed around the upper stomach, works for weight loss, it doesn’t affect the intestine at all and lacks the immediate metabolic benefits of bypass, they report.

Further evidence for the mechanism involved came from studies of mice lacking GLUT-2, a glucose transporter required for glucose sensing in the portal vein. Gastric bypass lost its insulin-sensitizing benefits in those GLUT-2-deficient mice. Similarly, mice whose portal veins had lost their nerve supply also stopped responding to the surgical procedure.

The bottomline, according to Mithieux: the intestine deserves more respect. “Up to now, the intestine had been considered like a machine to assimilate nutrients. We’ve now begun to realize that it is a complex endocrine organ” with particular importance when it comes to glucose metabolism.

As for what patients weighing gastric bypass versus lap-band surgery should do, Mithieux recommends they talk to their doctors about the possible benefits and risks of both procedures. The new findings do support the notion that gastric bypass may be an effective treatment for diabetes in obese patients. It might even have potential for people who are diabetic, whether they are obese or not, he said.

Source: Cell Press