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A study by researchers at the University of Southern California (USC) found that overweight Hispanic children are at significant risk for pre-diabetes, a condition marked by higher than normal blood glucose levels that are not yet high enough for a diagnosis of diabetes. The persistence of pre-diabetes during growth is associated with progression in risk towards future diabetes, according to the study, which will be published in an upcoming issue of the journal Diabetes, and is now available online.

With a population of more than 35 million, Hispanics are the largest and fastest growing minority group in the United States. Despite the fact that Hispanics are at high risk for developing type 2 diabetes, few previous studies have looked at physiological causes of the disease within this population.

Researchers led by Michael I. Goran, Ph.D., professor of preventive medicine, physiology and biophysics and pediatrics, and director of the USC Childhood Obesity Research Center at the Keck School of Medicine of USC, followed a cohort of 128 overweight Hispanic children in East Los Angeles. The children were tested over four consecutive years for glucose tolerance, body mass index, total body fat and lean mass and other risk factors for type 2 diabetes. The study found that an alarming 13% of the children had what the investigators termed “persistent pre-diabetes.”

Most prior studies examining pre-diabetes in overweight and obese children looked at a one-time assessment of metabolic risk factors for type 2 diabetes, but fluctuations over time led to poor reliability for these tests. In the new study, Goran and colleagues examined longitudinal data to look at a progression of risk factors over four years. Children were identified as having persistent pre-diabetes if they had three to four positive tests over four annual visits. The children who had persistent pre-diabetes had signs of compromised beta-cell function, meaning that their bodies were unable to fully compensate to maintain blood glucose at an appropriate level, and they had increasing accumulation of visceral fat or deposition of fat around the organs. Both of these outcomes point towards progression in risk towards type 2 diabetes.

“What this study shows is that doctors should be doing regular monitoring of these children over time, because a one-time checkup might not be enough to tell if they are at risk for developing diabetes,” Goran says.

Visceral fat, which pads the spaces between abdominal organs, has been linked to metabolic disturbances and increased risk for cardiovascular disease and type 2 diabetes.

Increased obesity has been identified as a major determinant of insulin resistance. Lower beta-cell function is a key component in the development of type 2 diabetes, as the cells are unable to produce enough insulin to adequately compensate for the insulin resistance.

“To better treat at-risk children we need better ways to monitor beta-cell function and visceral fat buildup,” Goran says. “Those are tough to measure but are probably the main factors determining who will get type 2 diabetes.”

Future studies will examine different interventions, including improving beta-cell function and reducing visceral fat.

“The study provides great insight into the risk factors that lead to the progression towards type 2 diabetes in this population,” says Francine Kaufman, professor of pediatrics at the Keck School of Medicine at USC and head of the division of endocrinology and metabolism at Childrens Hospital Los Angeles, who was not directly involved in the study. “Only by understanding how this devastating disease develops will be able to begin taking steps to prevent it.”

Source: University of Southern California

Children and teens who get less sleep, especially those who spend less time in rapid eye movement (REM) sleep, may be more likely to be overweight, according to a report in the August issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

The obesity rate has more than tripled among children aged 6 to 11 years in the past 30 years, and approximately 17 percent of U.S. adolescents are now overweight or obese, according to background information in the article. Obesity results from an imbalance between calorie intake and energy expenditure from physical activity, but little is known about other factors that can alter this balance. A number of studies have documented an association between fewer hours of sleep and higher body mass index (BMI) in both adults and children.

Xianchen Liu, M.D., Ph.D., of the University of Pittsburgh School of Medicine Department of Psychiatry and Western Psychiatric Institute and Clinic of the University of Pittsburgh Medical Center, and colleagues studied 335 children and adolescents age 7 to 17 years (average age 10.8). For three consecutive nights, participants’ sleep was monitored through polysomnography, which assesses total sleep time, time spent in REM, the time it takes to fall asleep and other variables. Weight and height were measured to calculate BMI.

A total of 49 participants (14.6 percent) were at risk for becoming overweight and 45 (13.4 percent) were overweight. Compared with children at a normal weight, those who were overweight slept about 22 minutes less per night and had lower sleep efficiency (percentage of time in bed that an individual is asleep), shorter REM sleep, less eye activity during REM sleep and a longer wait before the first REM period.

After adjusting for other related factors, one hour less of total sleep was associated with two-fold increased odds of being overweight and one hour less of REM sleep was associated with three-fold increased odds.

“Although the precise mechanisms are currently under investigation, the association between short sleep duration and overweight may be attributed to the interaction of behavioral and biological changes as a result of sleep deprivation,” the authors write. Sleep loss causes changes in hormone levels that may affect hunger, and also provides an individual with more waking hours in which to eat. In addition, sleep loss contributes to fatigue the following day, which may decrease physical activity and calorie expenditure.

“Given the fact that the prevalence of overweight among children and adolescents continues to increase and chronic sleep insufficiency becomes more prevalent in modern society, family- and school-based sleep interventions that aim to enhance sleep hygiene and increase sleep duration may have important public health implications for the prevention and intervention of obesity and type 2 diabetes in children,” the authors conclude. “Furthermore, our results demonstrate an important relationship between REM sleep and high BMI and obesity, suggesting that the short sleep–obesity association may be attributed to reduced REM sleep time and decreased activity during REM sleep.”

Source: JAMA and Archives Journals

Research suggests that childhood obesity begins in infancy

Over the last decade, childhood obesity has grown into an epidemic, reflected in soaring rates of type 2 diabetes and recommendations that pediatricians check toddlers for elevated cholesterol.

What hasn’t been as clear is how early to intervene.

A study presented at a pediatric research program on Friday suggested obesity prevention efforts should begin as early as age two, when children reach a “tipping point” in a progression that leads to obesity later in life.

“This study suggests that doctors may want to start reviewing the diet of children during early well-child visits,” said John W. Harrington, M.D., a pediatrician at Virginia’s Children’s Hospital of The King’s Daughters (CHKD). “By the time they reach eight years old, they’re already far into the overweight category, making treatment more difficult.”

The study examined records of 111 overweight children from a suburban pediatric practice. All of the children had their height and weight measured at least five times during pediatric visits. The average age was 12.

Children whose body mass index exceeded that of 85 percent of the general population were classified as overweight. Researchers charted the recorded body mass index of the children from infancy. through They found that the obese children had started gaining weight in infancy at an average rate of .08 excess BMI units per month. On average, they began this progression at three months of age.

Over half the children could be classified as overweight at two years old, 90 percent before reaching their fifth birthday.

Vu Nguyen, a second year student at Eastern Virginia Medical School, CHKD’s academic partner, said the results surprised him.

“I didn’t think that that obesity would start that early,” said Nguyen, who presented the results Friday at a pediatric research scholars program.

Nguyen conducted the study with Harrington and Lawrence Pasquinelli, M.D., a pediatrician with Tidewater Children’s Associates in Virginia Beach, Va.

More research is needed to determine the causes of early obesity including “information on family history and the dietary and exercise habits in infancy,” said Harrington, an EVMS associate professor. “We may then have to look prospectively to see what interventions work in reversing this trend.”

Source: Children’s Hospital of The King’s Daughters