As some Pacific island cultures have “westernized” over the last several decades, among the changes has been a dramatic increase in obesity. Researchers don’t understand all the reasons why, but even a decade ago in American Samoa 59 percent of men and 71 percent of women were obese. A new Brown University study finds that the Samoan epidemic of obesity may start with rapid weight gain in early infancy.
The implications of the study published online in the journal Pediatric Obesity may not be confined to Polynesian populations, said the authors. American Samoa’s prevalence of obesity in infancy may be the harbinger of a slower-moving trend in the same direction in developed nations. Places like the mainland United States, after all, are the origin of the more sedentary, calorie-rich lifestyle that has largely replaced subsistence fishing and agriculture in American Samoa.
“One of the reasons we think Samoa is interesting is really because we think the level of obesity there could actually foreshadow what we see here in the United States and other high-income nations if we continue the way that we’re going,” said study lead author Nicola Hawley, a postdoctoral research fellow in the Alpert Medical School at Brown University and the Weight Control and Diabetes Research Center.
To conduct the study, Hawley and her co-authors examined the medical records of nearly 800 American Samoan babies born between 2001 and 2008. The babies were all singleton births, carried to term of 37-42 weeks.
In particular, the team tracked the babies’ growth, weight gain, and whether they were breastfed, given formula or a mix of both. They used the data to plot the trajectories of infant weight gain up to 15 months of age.
The researchers made several main findings:
One in five newborns qualified for a diagnosis of macrosomia — excessive birth weight of more than 8.8 pounds or 4 kilograms.
By 15 months of age 23.3 percent of boys and 16.7 percent of girls were obese (based on being heavier than the U.S. CDC’s 95th percentile). A further 16.1 percent of boys and 14.0 percent of girls were overweight.
At 15 months, 38.6 percent of formula-fed boys were obese while only 23.4 percent of breast-fed boys were obese.
Stephen McGarvey, research professor of epidemiology and the study’s senior author, said the babies were perhaps less heavy at birth than one might expect given the prevalence of obesity among their mothers, but the subsequent weight gain in early infancy was the study’s most important finding. Rapid weight gain in infancy is widely understood to be a risk factor for adult obesity.
The median weight gain among the Samoan babies in the first four months of life was 978 grams a month, McGarvey said. That figure is almost 20 percent more than the 820 grams a month documented in a prior study of babies on the U.S. mainland.
The Samoan babies’ average weight gain curve, he said, resembled the trajectory epidemiologists see among undernourished babies who suffer intrauterine growth restriction, meaning they are nutritionally deprived in the womb but then compensate by gaining weight rapidly after birth. Samoan babies are not undernourished, McGarvey said, but they may also be somehow constrained in their growth as fetuses, perhaps because they are at an upper limit of growth before birth.
“We wonder whether this response is not partially a response to the events in utero,” said McGarvey. He and Hawley plan to pursue that question in future research.
Hawley noted that while the seemingly protective effect of breastfeeding has been shown in other studies, the results bolster the case for the idea that it extends to non-European populations. The finding also suggests a specific tactic — encouraging breastfeeding throughout more of infancy — that public health officials can employ in stemming infant obesity, at least in boys.
The researchers acknowledged that further research is required to understand why the benefits of breastfeeding were not seen in girls.
Most importantly, McGarvey and Hawley said, the study indicates that in a population with prevalent obesity such as in American Samoa, excessive weight begins in infancy.
Additional authors on the study are William Johnson of the University of Minnesota and Ofeira Nu’usolia of the Tafuna Clinic of the American Samoa Department of Health.
The National Institutes of Health (grants: R25-TW008102, R18-DK075371, and R01-HL093093)) and Brown University funded the study.
Editors: Brown University has a fiber link television studio available for domestic and international live and taped interviews, and maintains an ISDN line for radio interviews. For more information, call (401) 863-2476.
David Orenstein | EurekAlert!
Millions through license revenues
27.04.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn
New High-Performance Center Translational Medical Engineering
26.04.2017 | Fraunhofer ITEM
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences