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AUGUSTA, Ga. – Even while their blood pressures are still normal, overweight male teens may have elevated levels of a hormone known to increase pressures as well as early signs of heart damage, researchers say.

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

Westchester, Ill. — A study in the June 1 issue of the journal SLEEP found that waist circumference and body mass index (BMI) are consistent, independent risk factors for all severity levels of sleep disordered breathing (SDB) in children, suggesting that as with adult SDB, metabolic factors are important risk factors for childhood SDB.

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