Age-Varying Associations Between Attempts to Change Weight and Suicidal Ideation Among Adolescents in the United States

Abstract

Purpose:

The goal of this study was to inform theory and suicide prevention efforts by examining how the link between attempts to change weight and suicidal ideation varies across adolescence, when it is strongest, and whether there are sex differences.

Methods:

Data were from 13,518 youth ages 14 – 18 years who participated in the 2019 Youth Risk Behavior Survey, a nationally representative study of U.S. high school students. Time-varying effect modeling was used to estimate associations between attempts to change weight and suicidal ideation as continuous functions of age and to test sex differences in these links.

Results:

The link between attempts to lose weight and suicidal ideation was positive and significant between ages 14.0 – 17.3 years, with the strongest association at age 15.0 (OR = 2.07). There were no sex differences in this age-varying association. The association between attempts to gain weight and suicidal ideation was positive and age-varying for girls, with the strongest association at age 17.2 years (OR = 2.79). This association was not significant for boys at any age.

Conclusions:

Girls and boys who are trying to lose weight and girls who are trying to gain weight may be at elevated risk for suicidal ideation between ages 14 and 18 years. Findings illuminate patterns of association during adolescence and have implications for suicide prevention.

Introduction

Suicide is the third leading cause of death among adolescents ages 14 to 18 years in the U.S., and nearly one in five high school students seriously considered attempting suicide in 2019.^1,2 Attempts to change weight are also prevalent during adolescence and differ by sex: Results from a nationally representative sample of U.S. adolescents indicated that approximately 45% of girls and 22% of boys were attempting to lose weight and 30% of boys and 8% of girls were attempting to gain weight.³ Adolescents’ intentions and attempts to change their weight have been linked to adverse mental health outcomes^4,5 and may involve health risk behaviors such as maladaptive eating behavior and substance use.^6–8 There is evidence for co-occurrence of attempts to change weight and suicidal ideation in subclinical^9–13 and clinical populations of adolescents.¹⁴ Some research suggests that attempts to change weight and suicidal ideation are bidirectionally linked.^15,16 Yet, little is known regarding developmental patterns of association between attempts to change weight and suicidal ideation during adolescence and findings are mixed regarding sex differences.^9,10,13 The purpose of this study was to advance understanding of associations between attempts to change weight and suicidal ideation by identifying sensitive periods when adolescents may be at elevated risk for both, characterizing how co-occurrence changes with age, and examining sex differences. This information may inform whether integrated programming is needed to address suicidal ideation among adolescents who are trying to change their weight, guide the timing of suicide prevention programs, and suggest whether these prevention efforts should be tailored by sex.

Attempts to change weight are a behavioral correlate of body image concerns, which are theorized to arise in response to societal pressure to conform to beauty ideals.^17,18 Beauty ideals for women in the U.S. include figures that are thin and toned or “slim thick” (i.e., curvy yet small waisted), whereas ideals for men emphasize muscularity.^19–21 Thus, girls’ body image concerns often reflect a desire to lose weight and boys’ reflect a desire to gain weight.^19–21 Adolescents may attempt to change their weight to minimize perceived discrepancies between their bodies and societal ideals.^17,22 Concerns with overweight and corresponding behavior generally increase between ages 12 and 17 years, with a greater proportion of girls exhibiting this trajectory compared to boys.²³ The prevalence of attempts to gain weight increases among boys and remains relatively stable among girls across adolescence.⁷ Physical changes associated with pubertal development may contribute to adolescents’ attempts to change weight, particularly for girls.²⁴

Theories of suicidal ideation include sociological, biological, and psychological explanations. However, a common theme is the experience of intense emotional distress.²⁵ For example, Escape Theory suggests that self-attributions for disappointments and perceived failures can lead to low self-esteem and depressive symptoms.^25,26 Individuals may consider suicide a means to escape this unbearable state of negative affect.²⁶ Hopelessness Theory suggests that individuals develop suicidal ideation due to intense thoughts and feelings of hopelessness.^25,27 Longitudinal studies indicate that suicidal ideation follows an inverted U-shaped trajectory across adolescence, peaking around age 15 – 16 years.^28,29 Peaks in prevalence during mid-adolescence may reflect that youth have greater exposure to distressing situations in adolescence than in previous developmental stages, and a limited number of perceived options for coping with this distress.²⁹ However, as youth transition from middle to late adolescence, their options for responding to distressing situations typically increase in number, thereby reducing the likelihood that they will seriously consider suicide.²⁹ Some research suggests sex differences in developmental patterns of suicidal ideation. Rates of suicidal ideation are higher among adolescent girls than boys.^28,30 Further, one study detected a U-shaped developmental trajectory for girls, but a linear trajectory for boys, such that past-year prevalence steadily increased across adolescence among boys.²⁸

Evidence suggests that attempts to change weight and suicidal ideation co-occur during adolescence. For example, results from a nationally representative study of comorbidity in the U.S. revealed that adolescents who reported ever experiencing suicidal ideation were significantly more likely to report ever having an eating disorder.³⁰ Findings from cross-sectional studies with community samples of U.S. adolescents also suggest positive associations between attempts to change weight and suicidal ideation for girls and boys.^9,13 For example, a cross-sectional study of U.S. adolescents revealed a positive association between attempts to lose weight and suicidal ideation for girls and boys.³¹ Prospective research examining the link between attempts to change weight and suicidal ideation during adolescence is limited. However, results from a large prospective study of older adolescents (~ age 17 years) in the U.S. indicated that extreme weight control behavior (e.g., use of diet pills), was associated with suicidal ideation five years later among girls but not boys.¹⁰ Results from a study of adolescents and young adults in Canada suggested that muscle dysmorphia symptoms (i.e., pathological pursuit of muscularity) predicted suicidal ideation one year later.³¹

Hypotheses

The aims of this study were to test whether and how the strength of the association between attempts to change weight and suicidal ideation changes across adolescence and explore sex differences in these links. Based on the developmental patterns of attempts to change weight and suicidal ideation and prior research indicating their comorbidity during adolescence, we hypothesized that the associations between attempts to lose and gain weight and suicidal ideation would be positive and increase in strength until approximately age 15 years, after which the associations would remain positive but decrease in strength through age 18 years. Given the mixed findings for sex differences in comorbidity during adolescence^9,10,13, the test of sex differences was exploratory.

Method

Participants

Participants were 13,518 adolescents ages 14 – 18 years who participated in the 2019 Youth Risk Behavior Survey (YRBS), a nationally representative study of high school students in the U.S. designed to track health risk behaviors. The full 2019 YRBS sample included 13,677 youth ranging in age from 12 – 18 years, however, there were too few adolescents younger than age 14 to reliably estimate associations at these ages; therefore, these 159 participants were excluded from analyses. Due to missing observations, the analytic sample was 9,213. Demographic characteristics for the full 2019 YRBS sample are available online.³² Demographic characteristics for participants ages 14 – 18 years are presented in Table 1.

Table 1.

Demographic Characteristics of U.S. Adolescents in 2019 (n = 13,518)

Demographic Characteristic	Weighted Frequency	Percent
Race/Ethnicity
American Indian/Alaskan Native	86	<1
Asian	667	5.1
Black or African American	1610	12.2
Native Hawaiian or Pacific Islander	44	<1
White	6778	51.4
Hispanic/Latino	1214	9.2
Multiracial – Hispanic/Latino	2208	16.7
Multiracial – Non-Hispanic/Latino	589	4.5
Sex
Female	6663	49.4
Male	6825	50.6
Age
14	1617	11.9
15	3369	24.9
16	3480	25.7
17	3218	23.8
18	1864	13.8

Procedures

The Centers for Disease Control and Prevention administers the National YRBS using a three-stage cluster sampling procedure to obtain a representative sample of U.S. public, Catholic, and private high school students (grades 9 – 12).³³ In 2019, 136 of the 181 sampled schools (75.1%) participated. Of the 17,025 students sampled, 13,677 provided usable data. Parents provided informed permission for youth to participate.³⁴ Surveys were administered during class time. Weights were created to adjust for oversampling of Black and Hispanic/Latino students and for nonresponse.³³ Additional details on the procedures are described elsewhere.³⁴ This study was carried out in accordance with the Declaration of Helsinki. The Institutional Review Board declared the secondary data analyses performed for this study not human subjects research.

Measures

Attempts to change weight were measured with the item, “Which of the following are you trying to do about your weight?”³³ Dummy coded variables were created to represent attempts to lose weight (0 = otherwise, 1 = trying to lose weight) and attempts to gain weight (0 = otherwise, 1 = trying to gain weight). Participants who reported that they were not trying to change their weight or that they were trying to maintain their weight were treated as not trying to change weight. Suicidal ideation was measured with the question, “During the past 12 months, did you ever seriously consider attempting suicide?” Response options were coded as 0 = No, 1 = Yes. Biological sex was coded as 0 = female, 1 = male (no other response options were provided). Given established links between body mass index (BMI) and weight concerns³⁵ as well as weight stigma and suicidal ideation³⁶, BMI percentile was included as a covariate. The CDC generated BMI percentiles for each participant from self-reports of height, weight, age, and sex, as well as CDC growth charts.³³ The CDC determined that the included measures were reliable but that BMI percentiles are likely conservative estimates.³⁴

Analyses

As a descriptive step, weighted frequencies for suicidal ideation and attempts to change weight were calculated by age and sex. Research questions were then addressed using time-varying effect modeling (TVEM), a novel extension of linear regression that enables estimation of regression coefficients as nonparametric, continuous functions of age.³⁷ TVEM produces coefficient curves (or odds ratio (OR) curves in the case of binary outcome variables) that visually represent how the strength of association between two variables varies as a continuous function of age in years. Variables can be specified to have time-varying effects or time-invariant effects, and complex sampling procedures or data structures can be accommodated via weight and cluster statements. In the current study, weighted logistic TVEM was used to estimate the associations between attempts to lose and gain weight and suicidal ideation as continuous functions of age in years, and to test for sex differences in age-varying associations. TVEM uses all available data. A survey weight was specified to adjust for oversampling and nonresponse, and primary sampling unit, the highest level of clustering in this sample, was specified to account for interdependence in the data. The outcome variable, suicidal ideation, was specified to have a binary distribution, and the coefficients for the intercept, attempts to lose weight, attempts to gain weight, and sex were specified as age-varying. The coefficient for BMI percentile was estimated as a time-varying effect with the intention to re-specify it as a time-invariant effect should the initial results indicate that it did not vary across age and/or was not statistically significant at any age. Sex differences across age were tested by adding two-way interactions between attempts to lose weight and sex and attempts to gain weight and sex. Significant interactions were probed by examining the OR curves for girls and boys. The optimal number of knots for each time-varying effect, which corresponds to the complexity in each coefficient function, was selected to minimize Akaike’s Information Criterion and Bayesian Information Criterion.³⁸ Analyses were conducted with SAS 9.4.³⁹

Results

Descriptive statistics are presented in Table 2. Weighted frequencies revealed a high prevalence of attempts to change weight, with 59.6% of girls and 36.0% of boys reporting attempts to lose weight, and 8.3% of girls and 22.6% of boys reporting attempts to gain weight at age 14 years. Suicidal ideation was also prevalent, with 23.5% of girls and 12.3% of boys reporting suicidal ideation at age 14 years.

Table 2.

Weighted Percentages of U.S. Adolescents Who Reported Attempts to Change Weight and Suicidal Ideation in 2019, by Age and Sex (n = 13,518)

Age	Females			Males
	Attempts to Lose Weight	Attempts to Gain Weight	Suicidal Ideation	Attempts to Lose Weight	Attempts to Gain Weight	Suicidal Ideation
14	59.6	8.3	23.5	36.0	22.6	12.3
15	61.1	8.8	24.7	36.8	27.3	11.3
16	59.8	12.4	23.7	39.7	28.1	14.7
17	59.9	11.9	25.4	38.0	30.6	13.3
18	58.0	8.9	21.4	32.7	32.9	15.0

Note. Weighted percentages were calculated based on the analytic sample of n = 13,518.

OR curves for the TVEM estimating associations between attempts to change weight and suicidal ideation across adolescent age, adjusting for sex and BMI percentile, are presented in Figure 1. OR curves are statistically significant at ages when the confidence interval does not include one. BMI percentile was neither age-varying nor statistically significant, therefore its effect was specified as time-invariant in the final model. There was an age-varying association between attempts to lose weight and suicidal ideation. The OR curve for attempts to lose weight and suicidal ideation was significant between ages 14.0 (OR = 1.55, 95% CI [1.04, 2.30]) and 17.3 years (OR = 1.48, 95% CI [1.01, 2.17]). ORs increased through age 15.0 then gradually decreased through age 17.3 years. At age 15.0, when the association was strongest, odds of suicidal ideation were 107% higher among youth who were trying to lose weight compared to youth who were not, adjusting for sex and BMI percentile (OR = 2.07, 95% CI [1.46, 2.95]). The OR curve for the association between attempts to gain weight and suicidal ideation was statistically significant only between ages 16.6 and 16.8 years.

Figure 1.

Odds Ratio Curves for the Associations Between Attempts to Change Weight and Suicidal Ideation Among U.S. Adolescents in 2019 (n = 9,213)

Note. The odds ratio curves for association between attempts to lose weight and suicidal ideation (left) and attempts to gain weight and suicidal ideation (right) are shown as solid black lines. Both models are adjusted for sex and BMI percentile. Odds ratios are statistically significant at ages when the 95% confidence interval (shown with dashed lines) does not include one. The association between attempts to lose weight and suicidal ideation is strongest at age 15.0 years, as denoted by the black diamond. The age-varying association between attempts to lose weight and suicidal ideation was not moderated by sex, thus this odds ratio curve depicts the age-varying association for girls and boys. The association between attempts to gain weight and suicidal ideation was moderated by sex.

The OR curves for the interactions testing sex differences in associations between attempts to change weight and suicidal ideation are provided in Supplementary Material. The OR curve for the interaction between attempts to lose weight and sex was not statistically significant at any age, indicating that the association between attempts to lose weight and suicidal ideation was not moderated by sex. Thus, the OR curve shown in Figure 1 (left side) represents the age-varying association between attempts to lose weight and suicidal ideation for both girls and boys. The interaction between attempts to gain weight and suicidal ideation was statistically significant between ages 15.0 and 15.4 and between ages 1.5 and 17.4 years, indicating that the OR curves for girls and boys were significantly different from each other at those ages. The OR curves for attempts to gain weight and suicidal ideation are shown separately for girls and boys in Figure 2. For girls, the association between attempts to gain weight and suicidal ideation was positive and statistically significant between ages 14.3 and 15.7 years and between 16.2 and 17.7 years, with the strongest association at age 17.2 (OR = 2.79, 95% CI [1.22, 6.37]). The association between attempts to gain weight and suicidal ideation was not significant for boys at any age.

Figure 2.

Sex Differences in Odds Ratio Curves for Attempts to Gain Weight and Suicidal Ideation Among U.S. Adolescents in 2019 (n = 9,213)

Note. Odds ratio curves for the association between attempts to gain weight and suicidal ideation are depicted as solid black lines for girls (left) and boys (right). These odds ratio curves were generated from the time-varying effect model including two-way interactions between attempts to gain and lose weight and sex and are analogous to simple slopes. Odds ratio curves are statistically significant at ages when the 95% confidence interval (shown with dashed lines) does not include one. In this case, the association between attempts to gain weight and suicidal ideation is statistically significant for girls between ages 14.3 and 15.7 years and between 16.2 and 17.7 years. The association is not significant for boys at any age.

Discussion

The purpose of this study was to illuminate age trends in the association between attempts to change weight and suicidal ideation across adolescence and to explore sex differences in these trends. The broader goal of this research was to advance knowledge and inform intervention efforts for suicidal ideation and attempts to change weight. We applied TVEM, an innovative statistical method, to examine whether there are sensitive periods during adolescence when attempts to change weight and suicidal ideation are most closely linked. Findings from this study indicated that attempts to lose weight and suicidal ideation were positively associated for both girls and boys between the ages of 14 and 17 years, with the strongest association among youth in mid-adolescence, at age 15. Age-varying associations between attempts to gain weight and suicidal ideation differed by sex. Attempts to gain weight were positively associated with suicidal ideation throughout most of adolescence for girls, with the strongest associations in middle and late adolescence. Among boys, attempts to gain weight were not associated with suicidal ideation at any age. These findings provide insight into two prevalent and co-occurring health concerns during adolescence and suggest opportunities to intervene to support adolescents’ well-being.

The hypothesis that there would be a positive, age-varying association between attempts to change weight and suicidal ideation between ages 14 and 18 years was largely supported. As noted above and consistent with our expectations, the association between attempts to lose weight and suicidal ideation was positive, suggesting comorbidity, and increased in magnitude between ages 14 and 15, then decreased until age 17, when it became statistically nonsignificant. This pattern of comorbidity appears similar to changes in suicidal ideation across adolescence observed in prior studies, which have documented that suicidal ideation follows an inverted U-shape during adolescence, at least for girls, peaking in mid-adolescence.^28,29 The association between attempts to lose weight and suicidal ideation was strong across the ages included in this study, however, at age 15 years, youth attempting to lose weight had 107% higher odds of experiencing suicidal ideation relative to their same-age peers who were not trying to lose weight, adjusting for youth BMI and sex. The age of this peak in vulnerability may reflect negative affect or distress due to or exacerbated by emotional, social, and academic challenges related to the transition to high school⁴⁰, pubertal development, or navigating adolescence more generally, coupled with a limited number of perceived options for mitigating distress.²⁹

The association between attempts to gain weight and suicidal ideation was also positive for girls across adolescence, suggesting comorbidity. Findings from this study indicate that girls who are trying to gain weight are at elevated risk for suicidal ideation relative to girls who are not trying to change their weight throughout most of adolescence, with the highest risk around age 17 years. This unexpected finding may reflect societal pressures that many girls experience to conform to curvy or toned beauty ideals.¹⁹ Specifically, curvy ideals are difficult to attain because body fat is considered desirable only in certain areas.⁴¹ Perceived discrepancies between girls’ bodies and ideals—regardless of the ideal—may be emotionally distressing and promote risk for suicidal ideation. In contrast, the association between attempts to gain weight and suicidal ideation was not significant for boys across adolescence, suggesting that boys trying to gain weight are not at elevated risk for suicidal ideation. This is somewhat inconsistent with a previous study that linked muscle dysmorphia and suicidal ideation among adolescents and young adults and may reflect that attempts to gain weight are not necessarily maladaptive.³¹ The observed sex differences may stem from differences in socialization; girls (more so than boys) in the U.S. are socialized to believe that conforming to beauty ideals is key to success in personal and professional domains and that their value depends on their weight and appearance.^42,43

Despite sex differences in the developmental course and prevalences of attempts to lose weight and suicidal ideation during adolescence^3,23,28,30, there were no sex differences in age-varying associations between attempts to lose weight and suicidal ideation among youth between ages 14 and 18 years. That is, both girls and boys in middle and late adolescence who reported trying to lose weight were similarly vulnerable to suicidal ideation. This finding may reflect pervasive weight stigma, which may motivate both girls and boys to try to lose weight and has been linked to suicidal ideation.³⁶ This is an important contribution to the literature as it highlights that despite attempts to lose weight and suicidal ideation being less prevalent among boys, both boys and girls who are trying to lose weight may be at risk for suicidal ideation during middle to late adolescence.

Findings from this study have implications for preventive interventions for suicidal ideation during adolescence. First, integrated intervention programming for suicidal ideation among adolescents who are trying to change their weight may be helpful, as this study suggests strong links between attempts to change weight and suicidal ideation during adolescence. Second, screening adolescents for intentions to change weight and suicidal ideation between ages 14 to 18 years may facilitate early identification of youth who would benefit from interventions for weight concerns and suicidal ideation. This may prevent or minimize escalation of current mental and behavioral health concerns as well as development of comorbid conditions. Third, this study provides insight into developmentally informed preventive interventions for suicidal ideation among adolescents who are attempting to change their weight. Based on our findings, integrated prevention programming may have the strongest effect on adolescents’ attempts to lose weight and suicidal ideation if deployed around age 15 years, when the association is strongest. Intervention effects may be strongest at age 17 for girls who are trying to gain weight. However, integrated prevention programs may yield benefits as early as age 14 years.

Strengths and Limitations

This study has several notable strengths, including the focus on novel and important research questions regarding comorbidity between attempts to change weight and suicidal ideation, application of an innovative statistical method, and use of data from a large, nationally representative sample of adolescents. Although prior research has documented links between attempts to change weight and suicidal ideation among adolescents, a potentially problematic assumption of traditional regression approaches is that the strength of this association is static across age. Thus, in this study we harnessed TVEM to illuminate how comorbidity between attempts to change weight and suicidal ideation varies across adolescence, with attention to how the strength of association varies as a function of age, and ages when the association is strongest. Our use of a large, nationally representative sample of high school students enhances the likelihood that findings from this study are generalizable to 14- to 18-year-olds residing in the U.S. Limitations of this study include the single item measures of attempts to change weight and suicidal ideation. The measure of attempts to change weight also did not enable us to differentiate between maladaptive and healthy weight change behavior. The measure of suicidal ideation was also limited in that it only captures severe suicidal ideation. The lack of information on gender identity precluded analysis of gender differences. An important next step is to investigate the role of gender identity in links between attempts to change weight and suicidal ideation. Another limitation was the correlational and cross-sectional study design. Although TVEM reveals how associations vary as a function of age, associations are concurrent and do not reflect within-person change over time. Finally, it is possible that a third variable accounts for associations between attempts to change weight and suicidal ideation.

Conclusion

This study sheds light on how comorbidity between attempts to change weight and suicidal ideation changes across adolescent ages, revealing that although youth who are trying to change their weight are vulnerable to suicidal ideation throughout adolescence, the association is strongest for girls and boys who are trying to lose weight at age 15, and girls who are trying to gain weight at age 17. Future directions include utilizing prospective study designs to test mechanisms (e.g., negative affect) linking attempts to change weight and suicidal ideation as well as possible temporal sequencing in the development of these concerns. Future research should aim to inform streamlined prevention programming by identifying shared protective factors for suicidal ideation and attempts to change weight.

Conflicts of Interest and Funding

The authors have no conflicts of interest to disclose. This work was supported by a grant from the National Heart, Lung, and Blood Institute (PI: D. Neumark-Sztainer; grant number T32HL150452) of the National Institutes of Health. The Youth Risk Behavior Surveillance System was conducted by the Centers for Disease Control and Prevention. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Heart, Lung, and Blood Institute, National Institutes of Health, or the Centers for Disease Control and Prevention. The National Heart, Lung, and Blood Institute was not involved in the study design, collection, analysis and interpretation of data, the writing of the manuscript, or the decision to submit the manuscript for publication.

Highlights.

• Adolescents attempting to lose weight are at risk for suicidal ideation

• Adolescent girls attempting to gain weight are at risk for suicidal ideation

• Comorbidity between attempts to change weight and suicidal ideation is age-varying

Abbreviations:

YRBS

Youth Risk Behavior Survey

CDC

Centers for Disease Control and Prevention

BMI

body mass index

TVEM

time-varying effect modeling