Weight Management Trials Have Limited Effect in Early Childhood

Veronica Hackethal

August 08, 2018

Two randomized controlled trials (RCTs) testing obesity prevention in early childhood have differing/conflicting results. In one, a multifaceted intervention did not change body mass index (BMI) trajectory over the course of 3 years in low-income minority children at risk for obesity. In the other, a responsive parenting intervention begun 2 weeks after birth showed modest improvement among infants aged 0 to 3 years.

Both studies were published online on August 7 in JAMA.

Childhood obesity is a growing problem in the United States. According to 2015 to 2016 statistics cited in an editorial published alongside the new studies, 14% of US children aged 2 to 5 years are obese and 2% are severely obese. The problem gets worse with age: 18% of children aged 6 to 11 years are obese and 5% are severely obese; and 21% of those aged 12 to 19 years are obese and 8% are severely obese.

The problem is even more concerning because research suggests early childhood obesity can set children up for later health problems, including heart disease and diabetes. Minority children in underserved areas are especially at risk, with the highest rates of obesity and the highest risk for chronic disease.

Although more than 350 RCTs have tested childhood obesity prevention programs, most have been disappointing and few have lasted long enough to prove sustainability. No guidelines yet exist to guide effective obesity prevention in children.

Largest RCT to Date Shows No Benefit

To test new methods, researchers conducted the Growing Right Onto Wellness (GROW) trial, the largest and longest-running childhood obesity prevention RCT so far. The GROW trial was part of the Childhood Obesity Prevention and Treatment Research consortium, a collaboration between the National Heart, Lung, and Blood Institute and the National Institute of Child Health and Human Development, and the intervention used is consistent with recommendations from the US Preventive Services Task Force.

For the 36-month study, Shari L. Barkin, MD, MSHS, professor of pediatrics and the chief of general pediatrics at the Monroe Carrel Jr Children's Hospital at Vanderbilt University School of Medicine in Nashville, Tennessee, and colleagues enrolled 610 pairs of parents and preschoolers aged 3 to 5 years from an underserved area in Nashville. The families spoke either English or Spanish and included children who were at risk for obesity but were not obese at baseline.

Researchers randomly assigned 304 parent–child pairs to the family-based intervention that took place at a community center. The intervention consisted of a 12-week intensive phase with weekly 90-minute skills-building sessions either in person or over the telephone, followed by a 9-month maintenance phase with monthly coaching with telephone calls and a 24-month sustainability phase to encourage healthy behaviors using texts, personalized letters, and monthly telephone calls. Intervention content included goal setting and skills building focused on diet, physical activity, sleep, media use, and engaged parenting.

The control group consisted of 306 parent–infant pairs who participated in six 30-minute school-readiness group sessions given over the course of 36 months at the Nashville Public Library. Parents in the intervention group also received the school readiness program.

Most (91.4%) of participants were Latino, with a mean age of 4.3 years at the beginning of the study. About half (56.7%) of families had a household income below $25,000, with 42.6% reporting food insecurity and 87.5% using the Special Supplemental Nutrition Program for Women, Infants, and Children and/or the Supplemental Nutrition Assistance Program.

Results showed no difference in childhood mean BMI at 36 months (17.8 kg/m2 in the intervention group vs 17.8 kg/m2 in control patients). The two groups also showed no significant difference in the primary outcome of BMI trajectory over the course of 36 months (P = .39).

At the end of the study, when children were 6 to 8 years old, 35.5% of the intervention group and 34.2% of the control group were obese.

The authors mentioned that preventing childhood obesity in underserved, low-income communities may require more intensive or longer-term interventions. In addition, noting that many children with food scarcity had a different BMI trajectory, such changes may not be feasible for some extremely low-income minority families.

"This finding emphasizes the importance of addressing systemic factors that affect health behaviors to achieve child obesity prevention," they emphasized.

Earlier Interaction May Be Better

In the second study, called the Intervention Nurses Start Infants Growing on Health Trajectories (INSIGHT) study, Ian M. Paul, MD, professor of pediatrics & public health sciences at Penn State College of Medicine in Hershey, Pennsylvania, and colleagues enrolled 279 first-time mother–infant pairs in a 3-year single-center RCT conducted at the Penn State College of Medicine.

They randomly assigned 140 mother–infant pairs to a responsive parenting intervention that began 2 weeks after birth and consisted of four home visits by nurses during infancy, followed by annual research center visits. The responsive parenting curriculum focused on how to respond to a child's needs, including feeding guidance and lactation support, sleep, interactive play, and emotion regulation.

The control group consisted of 139 mother–infant pairs who received a home safety intervention that covered issues such as sudden infant death syndrome and breast milk storage/infant formula preparation.

The mothers in the study had a mean age of 28.7 years, 86% were white, 86% were privately insured, and 62% were college-educated.

By age 3 years, infants in the responsive parenting group had a significantly lower mean BMI z score than control patients (−0.13 vs 0.15, respectively; absolute difference, −0.28; P = .04), which was the primary endpoint. However, the difference was not statistically significant (47th vs 54th percentile, respectively; reduction in mean BMI percentiles of 6.9 percentile points; 95% confidence interval [CI], −14.5 to 0.6; P = .07).

At the end of the study, 11.2% of the children in the responsive parenting group were overweight compared with 19.8% in the control group (absolute difference, −8.6%; odds ratio [OR], 0.51; P = .07). Just 2.6% of those in the responsive parenting group were obese compared with 7.8% of those in the control group (absolute difference, −5.2%; OR, 0.32; P = .09).

The authors noted that the z score difference was less than a prespecified clinically important difference. However, it was similar to the range suggested by the US Preventive Services Task Force, and the results (although not always statistically significant) consistently favored the responsive parenting group over time.

"This suggests that it may be possible for early effects to be maintained longitudinally," they write.

In the linked editorial, Jody W. Zylke, MD, JAMA deputy editor, and Howard Bauchner, MD, JAMA editor-in-chief, write that the study by Paul and colleagues may offer a "glimmer of hope." However, although the results are "encouraging," they are not "definitive," they caution.

In comparing the two studies, Zylke and Bauchner say a likely explanation for the different findings lies in the different population differences: low-income minority families vs mostly white, well-educated, privately insured families.

"The types or intensity of interventions needed to achieve weight loss or prevent weight gain in children living in poverty may differ from children in more advantaged environments due to biological or physiological processes," they write.

Also, the age of children may contribute to the different results. "Perhaps interventions to prevent obesity must begin as early as possible. By preschool age, habits of the child or family may be too ingrained to alter," they add.

The editorialists stress the public health importance of fighting childhood obesity. "Overall population health in the United States is unlikely to improve and the cost of health care is likely to continue to increase unless the prevalence of obesity and severe obesity in children, adolescents, and adults is reduced," they conclude.

Paul reports advisory board membership for Johnson & Johnson, Pfizer, and Boehringer Ingelheim. The other authors and the editorialists have disclosed no relevant financial conflicts.

JAMA. 2018;320(5):443-444, 450-468. Barkin article full text, Paul article abstract, Editorial extract

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