Obesity and metabolic syndrome associated with impaired brain function in adolescents

Contact: Jessica Guenzel Jessica.Guenzel@nyumc.org 212-404-3591 NYU Langone Medical Center / New York University School of Medicine

NEW YORK, September 3, 2012 – A new study by researchers at NYU School of Medicine reveals for the first time that metabolic syndrome (MetS) is associated with cognitive and brain impairments in adolescents and calls for pediatricians to take this into account when considering the early treatment of childhood obesity.

The study, funded by the National Institutes of Health under award number DK083537, and in part by award number 1ULIRR029892, from the National Center for Research Resources, appears online September 3 in Pediatrics.

As childhood obesity has increased in the U.S., so has the prevalence of metabolic syndrome – a constellation of three or more of five defined health problems, including abdominal obesity, low HDL (good cholesterol), high triglycerides, high blood pressure and pre-diabetic insulin resistance. Lead investigator Antonio Convit, MD, professor of psychiatry and medicine at NYU School of Medicine and a member of the Nathan Kline Research Institute, and colleagues have shown previously that metabolic syndrome has been linked to neurocognitive impairments in adults, but this association was generally thought to be a long-term effect of poor metabolism. Now, the research team has revealed even worse brain impairments in adolescents with metabolic syndrome, a group absent of clinically-manifest vascular disease and likely shorter duration of poor metabolism.

“The prevalence of MetS parallels the rise in childhood obesity,” Dr. Convit said. “There are huge numbers of people out there who have problems with their weight. If those problems persist long enough, they will lead to the development of MetS and diabetes. As yet, there has been very little information available about what happens to the brain in the setting of obesity and MetS and before diabetes onset in children.”

For the study, the researchers compared 49 adolescents with metabolic syndrome to 62 teens without the disorder. Of those who were not in the MetS group, 40 percent were considered overweight or obese, so while they were not in ideal health, they did not have three out of the five health issues needed to fall into the MetS group. The findings reported, therefore, are conservative and reflective of the real world.

Dr. Convit and colleagues balanced each group according to age, socioeconomic status, school grade, gender and ethnicity to ensure things like cultural differences in diet and access to quality healthcare did not cloud the data. They then conducted endocrine, MRI and neuropsychological evaluations on the adolescents and found that those classified as having MetS showed significantly lower math and spelling scores, as well as decreased attention span and mental flexibility. They also showed differences in brain structure and volume, presenting with smaller hippocampal volumes – involved in the learning and recall of new information, increased brain cerebrospinal fluid and reductions of microstructural integrity in major white matter tracts in the brain. The more MetS-characterizing health problems the participants had, the more profound the effect across the board.

“The kids with MetS took longer to do tasks, could not read as well and had poorer math scores,” Dr. Convit said. “These findings indicate that kids with MetS do not perform well on things that are very relevant to school performance.”

The researchers concluded that even a few years of problems with metabolism may cause brain complications. They suggest the adverse impact of MetS on brain function in children could be used by pediatricians as a powerful motivator to get families more involved in meaningful lifestyle change.

“Only now are pediatricians becoming aware of some of these issues,” Dr. Convit explained. “Many pediatricians don’t even take a blood pressure, and they certainly are not taking cholesterol levels and testing insulin resistance.” He added that about one third of children who are obese have abnormal cholesterol levels and more than 40 percent of those who are really obese have insulin resistance. “Obesity in kids is sky-high. Nearly 40 percent of the U.S. population is considered obese. Parents need to understand that obesity has medical consequences, even in children, and some of those consequences may be impacting more than just the long term health of the cardiovascular system. We need to do what our grandmothers have told us all along: ‘Eat well, don’t overeat and try to move as much as possible.'”

Dr. Convit added that simple changes in daily routine would go a long way in preventing MetS – changes like walking more and taking the stairs. Future research is needed to determine whether the reductions in cognitive performance and structural brain abnormalities are reversible with significant weight loss, he explained.

“The take home message is that just being overweight and obese is already impacting your brain,” Dr. Convit said. “Kids who are struggling with their weight and moving toward having MetS may have lower grades, which could ultimately lead to lower professional achievement in the long run. These are run-of-the-mill, garden-variety kids, not kids that came into the hospital because they were sick. It is imperative that we take obesity and physical activity seriously in children. In this country, we’re taking away gym class in order to give children more class time in an effort to improve school performance, but that effort may be having the exact opposite effect.”

Dr. Convit’s focus on combating and raising awareness about the impact of childhood obesity led him to create the The BODY Project, a program that works with New York City schools and parents to evaluate students’ height, weight, blood pressure, test for insulin resistance and record other measures of health, giving parents an overview of their child’s health status. Simply receiving this report motivates visits to the pediatrician, meal-planning changes at home and other interventions to prevent MetS and obesity. The program has impacted more than 3,400 children since its creation four years ago.

“If we can help one kid not become diabetic, that’s one kid’s life we’ve saved,” Dr. Convit said.

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About NYU School of Medicine:

NYU School of Medicine is one of the nation’s preeminent academic institutions dedicated to achieving world class medical educational excellence. For 170 years, NYU School of Medicine has trained thousands of physicians and scientists who have helped to shape the course of medical history and enrich the lives of countless people. An integral part of NYU Langone Medical Center, the School of Medicine at its core is committed to improving the human condition through medical education, scientific research and direct patient care.  The School also maintains academic affiliations with area hospitals, including Bellevue Hospital, one of the nation’s finest municipal hospitals where its students, residents and faculty provide the clinical and emergency care to New York City’s diverse population, which enhances the scope and quality of their medical education and training. Additional information about the NYU School of Medicine is available at http://school.med.nyu.edu/.

Antibiotic use in infants before 6 months associated with being overweight in childhood

Contact: lorinda klein lorindaann.klein@nyumc.org 212-404-3533 NYU Langone Medical Center / New York University School of Medicine

New York City (August 21, 2012)  – Treating very young  infants with antibiotics may predispose them to being overweight in childhood, according to a study of more than 10,000 children by researchers at the NYU School of Medicine  and the NYU Wagner School of Public Service and published in the online August  21, 2012, issue of the International Journal of Obesity.

The study found that on average, children exposed to antibiotics from birth to 5 months of age weighed more for their height than children who weren’t exposed.  Between the ages of 10 to 20 months, this translated into small increases in body mass percentile, based on models that incorporated the potential impacts of diet, physical activity, and parental obesity. By 38 months of age, exposed children had a 22% greater likelihood of being overweight. However, the timing of exposure mattered: children exposed from 6 months to 14 months did not have significantly higher body mass than children who did not receive antibiotics in that same time period.

The NYU School of Medicine researchers, led by Leonardo Trasande, MD, MPP, associate professor of pediatrics and environmental medicine, and Jan Blustein, MD, PhD, professor of population health and medicine, caution that the study does not prove that antibiotics in early life causes young children to be overweight.  It only shows that a correlation exists. Further studies will need to be conducted to explore the issue of a direct causal link.

“We typically consider obesity an epidemic grounded in unhealthy  diet and exercise, yet increasingly studies suggest it’s more complicated,” said Dr. Trasande. “Microbes in our intestines may play critical roles in how we absorb calories, and exposure to antibiotics, especially early in life, may kill off healthy bacteria that influence how we absorb nutrients into our bodies, and would otherwise keep us lean.”

In recent years there has been a growing concern about the overuse of antibiotics, especially in children. Preliminary studies of the microbiome, the trillions of microbial cells inhabiting our bodies and outnumber our own cells 10 to 1, implicate obesity, inflammatory bowel disease, asthma, and other conditions with changes in the microbiome. It is still a field in its infancy, however, and no one has yet proved that altering the composition of bacteria in the body leads to disease.

This is the first time that a study has analyzed the association between the use of antibiotics and body mass starting in infancy.  One previous study had identified a link between antibiotic use in early infancy and obesity at seven years of age, but was unable to examine potential impacts of antibiotic use later in infancy on body weight in childhood.

The NYU School of Medicine researchers evaluated the use of antibiotics among 11,532 children born in Avon, United Kingdom, during 1991 and 1992. The children are part of the Avon Longitudinal Study of Parents and Children (ALSPAC), a long-term study that provides detailed data on the health and development of these children.

The NYU School of Medicine researchers analyzed health information on these children during three periods: from birth to 5 months of age; 6 months to 14 months; and, finally from 15 to 23 months. They also examined body mass or weight at five different points of time—6 weeks, 10 months, 20 months, 38 months, and 7 years of age.

Antibiotic use only appeared to have an effect in very young infants (those given antibiotics from birth to 5 months of age.) Although children exposed to antibiotics at 15 to 23 months had somewhat greater BMI (Body Mass Indices) for their age and gender by the age of 7, there was no significant increase in their being overweight or obese.

“For many years now, farmers have known that antibiotics are great at producing heavier cows for market,” said Dr. Blustein. “While we need more research to confirm our findings, this carefully conducted study suggests that antibiotics influence weight gain in humans, and especially children too.”

In addition to Dr. Trasande, who is also associate professor of health policy, NYU Wagner School of  Public Service, and Dr. Blustein, who is also a professor of health policy at the NYU Wagner School of  Public Service, the authors of the study are: Mengling Liu, PhD, associate professor  of environmental medicine, NYU School of Medicine; Elise Corwin, BA, NYU Wagner School of  Public Service; Laura M. Cox, BA, Department of Microbiology, NYU School of Medicine;  Martin J. Blaser, MD, the Frederick H. King Professor of Internal Medicine and chair Department of Medicine, and professor of microbiology, NYU School of Medicine.

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Support for this preliminary work with the ALPSAC database was provided through a pilot grant from the NYU Global Public Health Research Challenge Fund, and by NIH grants 1GM090989 and 1UL1RR029893.

Disclosures:

All authors have no financial relationships or conflicts of interests to declare.

About NYU School of Medicine:

NYU School of Medicine is one of the nation’s preeminent academic institutions dedicated to achieving world class medical educational excellence.  For 170 years, NYU School of Medicine has trained thousands of physicians and scientists who have helped to shape the course of medical history and enrich the lives of countless people. An integral part of NYU Langone Medical Center, the School of Medicine at its core is committed to improving the human condition through medical education, scientific research and direct patient care.  The School also maintains academic affiliations with area hospitals, including Bellevue Hospital Center, one of the nation’s finest municipal hospitals where its students, residents and faculty provide the clinical and emergency care to New York City’s diverse population, which enhances the scope and quality of their medical education and training.  Additional information about the NYU School of Medicine is available at http://school.med.nyu.edu/