In a pair of recently published studies, scholars and alumni of the Robert Wood Johnson Foundation (RWJF) Health & Society Scholars program explore the causes and consequences of weight gain in U.S. adolescents. One study concluded that for young women, weight gain and obesity are risk factors for depression. The other described how social disadvantages compound to create racial/ethnic disparities in obesity among young women. Research for both studies was supported by RWJF.
Weight Change and Depression
Sociologists Michelle Frisco, PhD, MA (2003-2005) and Jason Houle, PhD (2011-2013), who both were RWJF Health & Society Scholars at the University of Wisconsin-Madison, have partnered on studies of adolescent and young adult health since 2005. They became interested in what they saw as “a schism” in existing research: In clinical research samples, there often was an association between obesity and depression among adolescents, while in nationally representative research samples there often was not.
“We decided to dig more and look at where those relationships do and don’t exist,” says Frisco, now an associate professor at Pennsylvania State University. Previous research showed that weight was not a risk factor for depression among all adolescents—but it was a risk factor for depression during the transition from childhood to adolescence. Reasoning that the same principle might apply to a later life passage, the scholars conducted what they believe is the first study to assess whether weight and weight change influence depression as young women grow from teens into adults.
Their study was published in the June 9, 2013, issue of the American Journal of Epidemiology. Co-author Houle is now an assistant professor at Dartmouth College. A third co-author, Adam Lippert, will be an RWJF Health & Society Scholar (2013-2015) at Harvard University this fall.
Frisco, Houle, and Lippert used data from the National Longitudinal Study of Adolescent Health, known as Add Health, which gathered information on a nationally representative sample of 7th- to 12th-grade students first interviewed in 1994-1995 and followed up in 1996, 2001-2002, and 2008-2009.
The Add Health sample analyzed by the researchers consisted of 5,243 young women who participated in the 1996 and the 2001-2002 surveys. For both surveys, respondents answered questions that are part of a scale designed to measure depression symptoms. Using the depression assessments from both time points, the researchers divided survey participants into four categories: never depressed, consistently depressed, recovered from depression, or experiencing depression onset. They used the Add Health height and weight assessments to classify women as never overweight, consistently overweight, consistently obese, weight gainers, or weight losers.
In the study sample, about three-fourths of the young women never were depressed during the transition to adulthood, and just over half never were overweight. When the researchers estimated the relationship between weight change and depression change, they found that “normal weight and overweight adolescent girls who were obese by young adulthood, as well as young women who were consistently obese during adolescence and young adulthood, had roughly twice the odds of depression onset as did young women who were never overweight.” Young women who were consistently obese during adolescence and early adulthood were also more likely to be consistently depressed than young women who were never overweight—a relationship that was explained by poor health. The researchers reasoned that weight gain and continued obesity “may be particularly stigmatizing and distressing” in the new social settings and relationships young women encounter as they transition to adulthood.
The authors say their study offers evidence that “weight gain is a significant public health concern in the transition to adulthood,” because it not only affects physical health but “also jeopardizes mental well-being.” They conclude: “Policies prioritizing healthy weight maintenance may help improve young women’s mental health as they begin their adult lives.”
Weight Change and Social Risk Factors
RWJF Health & Society Scholars program alumnae Hedwig Lee, PhD (2009-2011) and Margaret Hicken, PhD, MPH (2010-2012) set out to explain “the stark racial/ethnic disparities in adolescent obesity in the United States.” Their study was published in the May 2013 issue of the Journal of Health Care for the Poor and Underserved.
Lee, an assistant professor at the University of Washington, and Hicken, a research fellow at the University of Michigan, started from an established research finding: that, compared with White Americans, “non-White Americans experience higher levels of social disadvantage” including a lack of wealth, power, and resources. Social disadvantage has been shown to affect health; the scholars sought to learn more about how it affects obesity. They devised what they believe is the first study to test “the notion that social risks accumulate to explain racial/ethnic disparities in obesity.”
Using Add Health survey data, they categorized participants’ obesity status. The scholars also created a cumulative risk index (CRI) of eight family and neighborhood social risk factors that have been associated with obesity—among them, not being breastfed as an infant, living in an unsafe or high-poverty neighborhood, and suffering physical abuse. They then examined whether the CRI factors might explain racial/ethnic disparities in obesity.
Hicken says she and Lee wanted to know: “Are racial disparities in obesity during this period simply due to socioeconomic status? That’s a very common argument.” But when the scholars controlled for factors such as welfare status and parents’ educational level, the racial disparity persisted.
The scholars found pronounced disparities in the number of risk factors faced by females in different racial groups. Sixteen percent of White females had no risk factors present, but that was true for only 4 percent of Black females and 9 percent of Hispanic females. Five or more risk factors were present for 13 percent of Black females, 6 percent of Hispanic females, but only 2 percent of White females. The scholars also found that the CRI helped to explain Black-White disparities in obesity onset and persistence.
The study did not find racial/ethnic disparities in obesity for males. Hicken suggests the reason could be “gender differences in coping strategies.”
The scholars say their findings suggest “social disadvantage as a fundamental cause of disease,” and show how multiple factors accumulate to heighten racial/ethnic minorities’ risk of obesity and related conditions. Lee says the findings confirm “there’s no silver bullet explaining the causes for obesity or racial disparities in obesity.”
Mindful of that, the scholars suggest that intervention and prevention programs be designed to “take into account how risk factors may accumulate to increase obesity risk among vulnerable populations.”