The Samoan islands are grappling with public health problems; children may provide some solutions.
For 3,000 years, people have fished and farmed the Samoan islands of the South Pacific Ocean. They thrived on papaya, breadfruit and taro; they caught and prepared fish with lime and coconut.
After World War II, everything changed: the population boomed, food imports began, lifestyles shifted. And in recent decades, the Samoans have suffered some of the highest rates of obesity, diabetes and heart disease in the world. In the early 2000s, the adult overweight and obesity rate in the territory was nearly universal, at 93 percent, while the rate for children was close to 45 percent. Nearly 1 in 3 adults in American Samoa has diabetes.
These diseases of modernity kill many islanders at a grievously early age. Samoa’s devastating public health problems are entangled with food and other cultural practices, as well as with the very genes that have helped Samoans survive for millennia.
Since 2009, Nicola Hawley, Ph.D., an assistant professor in the Department of Chronic Disease Epidemiology, has
worked to pinpoint these factors and figure out how and when to intervene. Early childhood, she believes, is the best time. “The situation in terms of chronic disease in the adult population in Samoa has gotten so bad now that there needs to be some kind of generational shift—public health interventions targeting children—in order to have the most effect,” Hawley said.
Part of the archipelago is a sovereign nation called Samoa, and part is the U.S. territory of American Samoa. Samoans from both polities share a gene pool, but American Samoa was the first to see noncommunicable-disease rates rise, as it took up imported food, technology and sedentary lifestyles earlier. Imported foods like cake, bread and canned meat are cheap and readily available across Samoa.
Mothers who consume these foods may put babies at a disadvantage. Hawley found in a 2015 study that 86 percent of American Samoan mothers were overweight or obese in early pregnancy, which can raise the risk of obesity in babies. Many of these infants are then fed formula. Though most were born at a healthy weight, they gained weight fast. By four months, both boys and girls were above the 90th percentile for weight, and they tended to stay large. At 15 months, nearly 23 percent of boys and close to 17 percent of girls were obese, and obesity was more likely in those fed formula. In 2013, Hawley found that exclusive breastfeeding for the first six months protects a Samoan child from this rapid weight gain. Unfortunately, this practice is not widespread. Only 28 percent of Samoan mothers in the study were still exclusively breastfeeding at four months.
But early infancy could be the perfect time to intervene. Prenatal care is excellent in the Samoas, Hawley said, so including public health messages during routine pregnancy checkups is one potential approach. Her team is now teaching pregnant women about breastfeeding and gestational weight gain, and they’re showing a video they shot about the importance of gestational diabetes screening. A rapid influx of cheap, low-quality calories can displace important micronutrients, like iron. In Hawley’s 2017 Public Health Nutrition study of 305 toddlers in independent Samoa, 1 in 5 had moderate or severe growth stunting, 1 in 3 was anemic and 16 percent were overweight or obese. Some of those heavy children—who tended to come from wealthier families—also had anemia and/or stunting.
That link to wealth is a clue to cultural food practices. Not only are imported foods becoming cheaper in Samoa, they also denote status. “If you show up [at a social gathering] with a can of tinned corned beef, you’re much more well-received than if you show up with papayas from your garden,” Hawley said. In the latter case, “you’re considered to be less well-off or not wanting to make a good-enough contribution.” Such foods can nonetheless exact a high price. In July 2016, Hawley’s team announced in Nature Genetics that it had tracked down a “thrifty” gene, common among Samoans but almost nonexistent elsewhere. This gene likely helps people extract more nutrition from food, which would have conferred a survival advantage on earlier generations. Its effect on body size is the largest ever found.
To understand how the gene interacts with other factors, Hawley and her colleagues returned to Samoa this summer to follow the development of obesity and other diseases in pregnant women and in toddlers and adults.
Research in Samoa
Originally from the United Kingdom, Hawley signed on to her first project in Samoa in 2009 during a postdoctoral fellowship at Brown University. Brown epidemiology professor Stephen T. McGarvey, Ph.D., M.P.H. ’84, with whom she still collaborates, was about to begin a genome study on the islands. “I was looking for something to do that was not behind a desk, and off I went to Samoa,” Hawley recalls. There, she fell in love with its culture and people, whom she finds warm, caring and receptive to new ideas.
Despite a cultural preference for large body size, which denotes strength, beauty and wealth, the islanders are growing concerned about their health. Hawley said Samoans hope to lead the Pacific in understanding their health problems and solutions. Some are training to do so. As of this summer, five Pacific Islander students attending U.S. universities joined Hawley’s team; all of them intend to return to the Pacific to work in their own communities. Add that to her local collaborators—a group of committed physicians and public health experts intent on exacting positive change—and the likelihood for success is real.
Though Hawley cherishes Samoa (and she finds its traditional food delicious!), the capacity-building process means that she might not be needed there indefinitely. That’s fine with her. “I would love to not be working in Samoa in 15 years,” she said. “I would love it if Samoan public health researchers and clinicians were doing what I’m doing now. Even better if these problems are solved.”