Obesity is a growing health issue across the globe. According to the World Health Organization, obesity is at epidemic proportions, with over 4 million people dying each year as a result of being overweight or obese.
High rates of overweight and obesity are not just found among adults. From 1975 to 2016, the prevalence of children and adolescents aged 5 to 19 years with overweight or obesity increased more than four-fold, from 4% to 18% globally, according to the WHO.
Nicola Hawley, an associate professor (chronic disease epidemiology) at the Yale School of Public Health (YSPH), specializes in maternal and child health and how it is affected by obesity and diabetes. Hawley’s research has found evidence that both genetic and environmental factors play a role in the development of obesity.
Hawley and her former student Courtney Choy, MPH ’16, who is now a postdoctoral associate at YSPH, have been studying obesity for nearly a decade in Samoa, an island country where they are conducting the first longitudinal study of child health in the Pacific. Their most recent research was published in the journal, Pediatric Obesity.
Based on data from studies they performed in 2015 and 2020, the prevalence of Samoan children with overweight or obesity has more than doubled – from 16% to 36%. In their most recent paper, published in Pediatric Obesity, Choy and Hawley present new data showing extremely high risks of diabetes and elevated blood pressure among Samoan children as young as 6 to 9 years old. One in 10 children in the study were showing high glycated hemoglobin levels for their age, which may signal prediabetes, the researchers said.
Importantly though, there were characteristics of the early childhood growth trajectory that could be used to predict which children may experience these poor outcomes. These indicators may help local clinicians decide which children are in need of intervention.
“Those worrisome levels in and of themselves are motivation for us to continue our work and try to better understand the state of obesity, diabetes, and hypertension in Samoa,” said Choy, the study’s lead author.
Obesity is one side of malnutrition; being underweight or experiencing micronutrient deficiencies is the other, according to the WHO. Environmental and economic factors also play a role in obesity in Samoa, including consumption of micronutrient-poor imported foods, as well as increasing costs for local produce.
The last few decades have been a period of rapid modernization in Samoa, resulting in a shift from active lifestyles in villages where food is grown and prepared in the household, to a culture where people are working in more sedentary jobs and consuming less nutritious foods.
Less than 10% of adult women in Samoa can maintain a normal weight. Hawley’s and Choy’s latest study is the first attempt to describe childhood cardiometabolic risk in a setting known for high adult obesity, said Hawley, the paper’s senior author.
“No other study in the Pacific Island nations outside of New Zealand has attempted to follow children over time,” said Hawley. “Also, there is huge potential in a longitudinal study design like this to be able to drill down on the optimal timing and targets for intervention for some of these adult diseases.”
Improving Pacific health
The longitudinal study began nine years ago in partnership with the Samoa Ministry of Health, Bureau of Statistics, and Ministry of Women, Community, and Social Development. Choy, then a YSPH student, used her summer MPH internship with the Samoa Ministry of Health to recruit the study participants.
After graduation, she continued the project through a Fulbright fellowship and then as a PhD student at Brown University with funding from the National Institutes of Health. Her work continued with the support of a Fogarty Global Health Equity Postdoctoral Fellowship of Epidemiology and Yale Center for Clinical Investigation Multidisciplinary Postdoctoral Fellowship in Translational Research. Today her research is supported by an NIH National Heart, Lung, and Blood Institute K99 grant.
Choy’s first year at Yale was also Hawley’s first as a member of the YSPH faculty, and they had the chance to meet early on.
“My center of being has always been around how can I continue to engage with communities in Samoa, to try and improve Pacific health,” said Choy, who is from Hawai’i.
Hawley remembers Choy’s “dogged determination” that was very evident to her the second Choy walked into her office.
“I saw the same kind of fire in her as I feel like I have for this community,” Hawley said. “Courtney has forged a unique path in child-focused studies. It has been fun to watch her go from MPH student to an epidemiologist, to an independent investigator in her own right, where I get to call her a colleague instead of a student,” Hawley said.
Working with communities
Hawley and Choy’s study also looks at childhood in Samoa – how social and cultural structures intersect with a child’s physical, emotional, and mental well-being. Their findings will inform interventions. The questions they ask include, “What interventions are most appropriate at any given age? How do we best prevent these adult diseases?” Choy said.
After data is collected, Choy works with community partners to give feedback to the village participants about exactly what was found, and how their village-level data compares to the rest of the country.
“It involves the kids in a wonderful way,” Hawley said. “They all got these fantastic stickers that said, ‘I'm a scientist.’ We try and engage them and make it clear how important what they contribute is to what we learn.”
Choy said their next step is to ask the study’s participants and others in the country what they think would work best to address the identified risk factors related to obesity and diabetes, hypertension, and other cardiometabolic diseases, “so that children don't follow a high-risk trajectory growing up and can achieve the dreams that they tell us about.”