Relationship between Distorted Body Weight Perception. the gap between Subjective Body Image and Body Mass Index. and Suicidal Ideation.

Transcription

1 Relationship between Distorted Body Weight Perception 6 the gap between Subjective Body Image and Body Mass Index 7 and Suicidal Ideation Jaeyong Shin 1,2,3, Young Choi 1,2, Kyu-Tae Han 1,2, Sung-Youn Cheon 1,2, Jae-Hyun Kim 1,2, Sang Gyu Lee 4, Eun-Cheol Park 1,2,3* Department of Public Health, Graduate School, Yonsei University 14 2 Institute of Health Services Research, College of Medicine, Yonsei University 15 3 Department of Preventive Medicine, College of Medicine, Yonsei University 16 4 Department of Hospital Management, Graduate School of Public Health, Yonsei University Total words: 3,164

2 19 20 Keywords: body mass index, body weight perception, body image, obesity, suicide, suicidal ideation 21 * Corresponding author Eun-Cheol Park, MD, PhD Department of Preventive Medicine, College of Medicine, Yonsei University 50, Yonsei-ro, Seodaemun-gu, Seoul , Korea Tel: Fax: ecpark@yuhs.ac

3 39 Authors contributions All authors contributed to this study in its entirety and approved this manuscript, agreeing to submit this final version to Body Image. 42 Conflict of interest statement 43 There are no conflicts of interest to declare. 44 Funding sources We did not receive any funding for this study. Further, none of the researchers were associated with privately funded research institutes. 47 Ethics committee approval Since we used publically available national secondary data, we did not require verification from an Institutional Review Board (IRB). 50

4 51 Abstract 52 Objectives Mental health disorders and suicide have been an important and growing public health concern in South Korea. In addition, evidence has shown that both globally and in Korea, obesity is increasingly widespread and is associated with an increased risk of developing psychiatric disorders. Therefore, in this study, we examined the association between distorted body weight perception (BWP) and depression. 58 Methods Data was obtained from the Korean National Health and Nutritional Evaluation Survey (KNHANES: Korea Centers for Disease Control and Prevention), a cross-sectional nationwide survey, conducted from 2007 to 2012 with 14,276 men and 19,428 women. KNHANES is conducted periodically by the Korean Ministry of Health and Welfare. Multiple logistic regression analysis was conducted to investigate the associations between nine BWP categories combining body image (BI) and body mass index (BMI) categories and suicidal ideation. Moreover, to verify the adequacy of models, we used -2logL method for the combination BWP, only BMI, and only BI. 67 Results Consistent with previous studies, suicidal ideation was associated with marital status, household income, education level, and perceived health status in both genders. Moreover, only women were significantly more likely to have distorted BWP. In category B1 (low BMI; normal BI), women (Odds Ratio [OR], 2.25; 95% Confidence Interval [CI], ) were more likely to express suicidal ideation compared to the control category B2 (normal BMI; normal, BI). Another overweight perception category, C2 (normal BMI; fat BI), also had

5 increased odds ratio for suicidal ideation among women (OR, 2.25; 95% CI, ). With regard to normal BWP categories, odds ratios for dependent variables in both genders did not show any statistical difference. Among underweight perception categories, only the odds ratio of the category A2 among women (normal BMI; skinny BI) was significant (OR, 1.34; 95% CI, ). 79 Conclusion In conclusion, we suggest that distorted BWP should be considered an important factor in preventing suicide and improving individuals mental health, especially for women who appear to be more vulnerable to the effects of distorted BWP. 83

6 84 Introduction Mental health disorders have been an important and growing public health concern in South Korea. According to Korean Statistical Informational Service (KOSIS, 2011), about 27.6% of the population had a lifetime history of mental disorders that met the criteria for one or more DSM-IV disorders (Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition, American Psychiatric Association) [1]. Among women, 23.5% (12.0% for anxiety disorder and 9.1% for major depressive disorder [MDD]) experienced at least one mental disorder in their lifetime. Additionally, the annual suicide rates have steeply increased in Korea. According to Organisation for Economic Co-operation and Development (OECD) health statistics data, the age-standardized suicide mortality rate in 2011 was 33.3 per 100,000 individuals, the highest among all OECD countries, although the rate of increase in suicidal mortality remained constant [2] Evidence has shown that the increasing prevalence of obesity worldwide and in South Korea [3-5] is associated with an increased risk of developing psychiatric disorders [6-9]. However, most prior research has failed to simultaneously evaluate the effects of obesityrelated comorbidities (ORCs), lifestyle factors (smoking, alcohol consumption, and physical activity) or other psychosocial factors (general health status, emotional support, and life satisfaction) on mental health, even though they are known to affect mental health status [10, 11] and contribute to mental disorders [12-14]. However, some studies have not found a relationship [15] or have found an inverse relationship between overweight/obesity and mental disorders among men [16]. Thus, the relationship between mental disorders and body mass index (BMI) remains controversial Therefore, in this study, we used the term distorted body weight perception (BWP) to examine the association of BMI and body image (BI) with depression. Since it is a challenge

7 to clarify the association between BMI and mental disorders, we examined the difference between objective BMI, reflecting true obesity, and subjective BI to yield BWP. Several studies have previously investigated the association between the perception of being overweight and suicidal ideation among adolescents [17]. However, considering we were unable to find sufficient reports targeting adults, we attempted to examine the impact of distorted BWP on suicidal ideation among adults. 114

8 115 Materials and Methods 116 Subjects Data was obtained from the Korean National Health and Nutritional Evaluation Survey (KNHANES: Korea Centers for Disease Control and Prevention, Korean Ministry of Health and Welfare), a cross-sectional nationwide survey conducted from 2007 to A stratified, multistage, clustered probability sampling method was used for the survey (KCDC, 2012) The survey comprised a health interview, nutrition survey, and health examination. For data collection, household interviews and physical examinations were conducted. An informed consent form was obtained from all participants. Since the KNHANES website provides public access to survey data, additional ethical approval was not required to analyze KNHANES data The total sample size for data collected from 2007 to 2012 was 50,405, of which, 12,801 participants were 19 years of age or younger and were not included in the analysis. Further, missing data were excluded, resulting in a final study sample comprising 14,276 men and 19,428 women, at least 19 years old Dependent variable The presence of suicidal ideation was assessed by responses (yes/no) to the question, In the last one year, have you had suicidal ideation? Primary independent variables

9 The intersections between subjective BI and the degree of obesity were classified into nine BWP categories (Table 1). Subjective BI was assessed by the question, In your opinion, how do you perceive your body? Response options were: (A) skinny, (B) normal, or (C) fat. BMI was classified into: (1) low, BMI < 18.5 kg/m 2 ; (2) normal, 18.5 kg/m 2 BMI <25 kg/m 2 ; and (3) high, BMI > 25 kg/m 2. The combination of normal weight perception and normal BMI categories was selected as the baseline Covariates Socioeconomic and demographic factors included age, residential area, marital status, employment status, educational level, and household income. Data regarding age were classified into six categories: 20 29, 30 39, 40 49, 50 59, 60 69, and at least 70 years. Residential area categories were urban and rural. Marital status comprised two categories: married or unmarried. Educational level was categorized according to questionnaire responses including, elementary, middle, and high school, and college or higher. Economic status was based on monthly household income quartiles. Employment status categories were unemployed and employed Health-related factors included sleep duration, perceived health status, BMI, and the presence of chronic diseases such as hypertension and diabetes, which were diagnosed by doctors. Perceived health status was divided into 5 categories: extremely good, good, moderate, bad, and extremely bad. Stress level consisted of two categories: mild and severe. In addition, stress levels relating to routine life and the presence of depressive symptom judged by doctors during the last one year were included as mental health-related factors.

10 158 The data collection period ( ) was also considered. 159 Statistical analysis Multiple logistic regression analyses were conducted to investigate the associations between the nine BWP categories and suicidal ideation. Our models were adjusted for age, data collection period, residential area, marital status, employment status, household income, educational level, perceived health status, sleep duration, stress level, BMI, and the presence of diseases such as hypertension, diabetes, and MDD Moreover, we used - Akaike information criterion (AIC) to verify the adequacy of models for BMI only, BI only, and the combined BWP. Odds ratios (OR) with a 95% confidence interval (CI) were calculated. Statistical significance was set at p < Statistical analyses were performed using SAS, version 9.3 (SAS Institute Inc., Cary, NC, US). 169

11 170 Results 171 Demographic characteristics of men and women Table 2 shows the demographic characteristics of the sample. A total of 1,573 men (11.0%) and women (20.3%) had suicidal ideation during the twelve months prior to the survey, while 12,703 men and 15,481 women did not. Five men and four women matched the BWP category C1, representing overweight perception and low BMI, none of whom expressed suicidal ideation Multiple logistic regression analysis The results of the multiple logistic regression analysis of the relationship between difference in BI and BMI, and suicidal ideation are presented in Tables 3 and 4. Table 3 depicts the odds ratio of adjusted factors such as age, data collection period, residential area, marital status, employment status, household income, educational level, perceived health status, sleep duration, presence of diseases including hypertension, diabetes, and MDD, high stress levels, and high BMI. In Table 4, the nine categories are rearranged as underweight perception categories (A2, A3, B3), normal perception categories (A1, B2, C3), and overweight perception categories (B1, C1, C2). As none of the participants in C1 expressed suicidal ideation, it was not possible to calculate the OR of C Married participants were more likely to express suicidal ideation than were unmarried participants, for both men (OR = 1.84, 95% CI: ) and women (OR = 1.42, 95% CI: ). With regard to employment status, employed men were less likely to express suicidal ideation (OR = 0.71, 95% CI: ) than were unemployed men.

12 In terms of household income, the odds ratios for suicidal ideation for both men and women were very similar. Relative to the lowest quartile group, the odds ratios for suicidal ideation were 0.88 (95% CI: ) for men and 0.83 (95% CI: ) for women in the second lowest quartile, 0.72 (95% CI, ) for men and 0.85 (95% CI: ) for women in the third lowest quartile, and 0.68 (95% CI: ) for men and 0.63 (95% CI: ) for women in the highest quartile Suicidal ideation was also influenced by education level in both genders. The likelihood of suicidal ideation decreased as the level of education rose; thus, men (OR, 0.73; 95% CI, ) and women with middle school education (OR = 0.76, 95% CI: ) were less likely to express suicidal ideation than those in elementary school. Men (OR = 0.63, 95% CI: ), and women with high school education showed an even lower likelihood (OR = 0.60, 95% CI: ), followed by the lowest among men (OR = 0.51, 95% CI: ) and women with a college education or higher (OR = 0.43, 95% CI: ) Participants perceiving themselves to be healthy with an excellent (for men: OR = 0.18, 95% CI: ; and women: OR = 0.26, 95% CI: ) or very good self-rating (for men: OR = 0.21, 95% CI: ; and women: OR = 0.28, 95% CI: ) were less likely to express suicidal ideation. Furthermore, men (OR = 4.56, 95% CI: ) and women (OR = 4.47, 95% CI: ) with severe stress were more likely to express suicidal ideation compared to those with mild stress Among diseases, only the odd ratios for MDD showed a strong positive association with suicidal ideation (men; OR = 5.11, 95% CI: , women; OR = 2.75, 95% CI: ). 214 When we adjusted for all the other covariates, all overweight perception categories showed

13 statistically significant odds ratios for suicidal ideation among women (Table 4 and supplementary table 1). In category B1 (low BMI; normal BI), the increased odds ratio for suicidal ideation was found among women (OR = 2.25, 95% CI: ) compared to the control category B2 (normal BMI; normal BI), while men (OR= 1.20, 95% CI: , p <0.001) were not likely to show any difference. In addition, women in category C2 (normal BMI; fat BI), were more likely to express suicidal ideation (OR = 1.28, 95% CI: , p <0.001) In terms of normal BWP categories, odds ratios for dependent variables for both genders did not show any statistical differences. Among underweight perception categories, the odds ratio of the category A2 (normal BMI; skinny BI) showed an increased likelihood only for women (OR = 1.34, 95% CI: ) In summary, a few categories for women had statistically higher odds ratios for suicidal ideation, while none were higher for men Adequacy of the models using Akaike information criterion (AIC) The analyses suggested that the model using BMI and BI both was superior to the one using only BMI, and only BI (Table 5). Although the differences in AIC were not significant, the difference between BMI and BI both and only BMI was larger than that between BMI and BI both and only BWP.

14 234 Discussion Based on the results of this study, it was observed that suicidal ideation was associated with not only typical socioeconomic variables such as marital status, household income level, and educational level, but also health-related variables such as the presence of MDD, routine stress, and perceived health status. Several other studies have also supported these associations between socioeconomic and mental health-related factors and suicidal ideation [18-21]. Inder et al. identified determinants of suicidal ideation and suicide attempts using data from the 2007 National Survey of Mental Health and Wellbeing (2007-NSMHWB, n = 8,463) in Australia [18]. According to their study, psychiatric disorders were the main determinant of 12-month and lifetime suicidal ideation and lifetime suicide attempts. Moreover, marital status, employment status, perceived financial adversity, and mental health service use were also important determinants; these findings were consistent with our results. Lee et al. also studied differential associations of socio-economic status with gender- and age-defined suicidal ideation among adults and elderly individuals in South Korea using the KNHANES [19]. They found that household income was the main protective factor for women and those aged years, just as educational attainment was for individuals aged >65 years. In another report in South Korea, the graphical representation of the relationship between sleep duration and suicidal ideation formed a U-shaped curve [22]. However, in the present study we did not find a statistically meaningful association between sleep duration and suicidal ideation, despite finding a similar U-shaped pattern of odds ratios When investigating BWP, it was necessary to examine suicidal ideation and related factors by gender. Chin et al. suggested that the development of a suicide prevention program for Korean adults requires different approaches for each gender [23]. For example, for working men aged years, the focus should be on the management of work-related stress and

15 depression, while community support programs could substantially help women who are less educated, are not formally employed, and/or experience a great deal of stress and depression. Although their study had a robust methodology, they did not consider the possibility that distorted BI may have induced stress and even fostered suicidal ideation Therefore, we examined BWP to understand the impact of BI on suicidal ideation. Several studies have examined the association between BWP and suicidal ideation [17, 21, 24-27]. Lee and Seo studied the trajectory of suicidal ideation in relation to perceived overweight from adolescence to young adulthood in a representative American sample, using data from four waves ( ) of the National Longitudinal Study of Adolescent Health. They found that in general, suicidal ideation tended to decrease with age. However, participants who perceived themselves as overweight were more likely to think about committing suicide, especially women, even after controlling for rigorously measured depressive symptoms [28]. According to a study of adolescents in South Korea, a significantly higher proportion of girls reported suicidal ideation and suicide attempts than did boys. Factors associated with suicidal ideation were overestimation of weight (vs. accurate estimation) and behaviors to lose or gain weight (vs. no weight control) among boys, and overestimation of weight and attempting to lose weight among girls [24]. Another questionnaire study in Korea suggested that body image distortion in fifth and sixth grade students may lead to stress, depression, and undesirable dieting behavior [21]. Compared to participants without distorted BIs, the group that overestimated their weight demonstrated greater interest in weight control, expressed dissatisfaction with body weight, presented unhealthy reasons to lose weight, and had higher scores for feeling sad when comparing own body with others and for easily getting annoyed and tired, even though they had similar obesity indices. 281 However, the majority of these studies targeted adolescents rather than adults. Thus, a

16 study of the general population was needed. Kim et al. studied the effect of weight perception on suicidal ideation among young Korean women using data from the 2001 and 2005 KNHANES, the same source as our study [26]. Overweight women were more likely to think about suicide than their normal-weight counterparts in both periods. However, in both periods, the association between overweight and suicidal ideation was not significant when perceived weight was taken into account. In our opinion, the difference between the results of this study and the present study may reflect different data collection periods and targeted age groups. In addition, Kim et al. did not analyze the combination group of BI and BMI, reflecting BWP, in detail. On the other hand, we divided the same BWP category into three groups, based on actual BMI, anticipating that these differences may yield meaningful statistical outcomes in our study Another similar study examining the role of BWP in the general population was conducted in 2011 in Seoul, Korea [26]. Kim et al. examined the effects of actual and perceived body weight on unhealthy weight control behaviors (UWCB) and depressed mood. They found that women who perceived themselves to be heavier than their actual BMIs appeared more likely to engage in UWCB (OR = 1.44, 95% CI: ). Furthermore, women with a distorted BWP, whether an underestimation (OR, 1.49; 95% CI, ) or overestimation of their BMI (OR = 1.26, 95% CI: ), tended to be at a greater risk for depressed mood than those who had a realistic BWP. Interestingly, contrary to previous studies on adolescents, women with underweight perceptions also suffered from depressive mood Gaskin et al. performed a study to determine if BWP mediates the associations between measured weight and depression [29]. They analyzed the data of 13,548 adults age 18 or older, collected in the National Health and Nutrition Examination Survey of the United States

17 from 2005 to Among women, adjusting for perception weakened the relationship between measured weight and depression. The ORs of depression for being obese and overweight were 2.26 (95% CI; ) and 1.92 (95% CI; ) before being adjusted for perception and 1.72 (95% CI; ) and 1.62 (95% CI; ) when perception was adjusted for. Independent from measured weight, women who perceived themselves as underweight (OR=2.95, 95% CI; ) or overweight (OR=1.73, 95% CI; ) had an increased odds of depression compared with women who perceived themselves as about the right weight. Among men, measured weight, neither overweight nor underweight, was associated with depression, perceiving oneself as underweight (OR=2.80, 95% CI; ) was associated with depression. In this study, the authors did not measure the suicidal ideation as a dependent variable, the increasing depressive symptoms is able to the increase the probability of suicidal ideation. To put all these previous studies and our results together, we have reason to believe that there has been possible relationship between the distorted BWP from the difference of objective BMI and subjective perception and suicidal ideation. Thus, when we examine some women who were suffered from distorted body image, we have to consider measuring not just the obesity but the difference of real BMI and self-perception for body weight to identify the presence of suicidal ideation. Moreover, we believe that this simple measurement might help the early detection for the patients with suicidal ideation and reduce the number of suicidal attempts and suicides thorough early intervention for prevention This study has some strength as follow. First, we measured the presence of suicidal ideation, rather than one of depressive mood. Although there is an established association between the depressive mood and suicidal ideation, the outcome can be more clearly defined by investigating the dependent variable firsthand. Second, we used nationwide data,

18 considered to be representative of the population, thus strengthening the study s reliability. In addition, it was more suitable to use recent data ranging from 2007 to 2012 (a six-year period), permitting us to make relevant interpretations. 333 Regardless of these strengths, this study has several limitations First, due to its cross-sectional design, causal relationships could not be determined. However, since we divided BMI categories and examined BMI as independent variable, it was extremely unlikely that the reverse relation may have been valid. Second, the measured outcome was suicidal ideation and not attempted suicide, even though the association between suicidal ideation and attempts exists [30-32]. Since suicidal ideation does not directly result in a suicidal attempt or suicide, making a connection between suicidal ideation and suicide without considering the role of mental illness may be a risky assumption In conclusion, t his study supported the association between distorted BWP and suicidal ideation. Women with overweight perception in all BMI categories and underweight perception within the normal BMI range were more likely to express suicidal ideation than those with normal weight perception and normal BMI range. In conclusion, it is encouraged that BWP is considered an important factor in preventing suicidal ideation and improving individuals mental health, especially for women. 347

19 Table 1. Nine categories of body weight perception (BWP) by three body image categories (BI) and three body mass index (BMI) categories. 350 Body Mass Index (BMI) Subjective body image (1) BMI < 18.5 (2) 18.5 BMI < 25 (3) BMI 25 (A) Skinny Normal (A1) Under (A2) Under (A3) (B) Normal Over (B1) Normal (B2) Under (B3) (C) Fat Over (C1) Over (C2) Normal (C3) To measure the impact of distorted BWP on suicidal ideation, we atomized BWP and selected the category B2 as the control, because this category refers to normal BI and normal BMI range

20 361 Table 2. Demographic characteristics and the presence of suicidal ideation by gender Women Men Absence Presence Total p-value Absence Presence Total p -value Age <0.001 < , ,250 1, , , ,902 2, , , ,626 2, , , ,563 2, , , ,144 2, , , ,943 1, ,088 Town <0.001 <0.001 Urban area 12, , ,879 9, , ,813 Rural area 6, , ,549 3, ,463 Marital status Married 13, , ,341 10, , ,099 Single 1, ,087 1, ,177 Job status <0.001 <0.001 Unemployed 7, , ,208 2, ,551 Employed 7, , ,220 9, ,725 Sleep hours <0.001 <0.001 Less than 6 hours 2, ,374 1, ,891 6 to 8 hours 11, , ,424 10, , ,341 More than 8 hours 1, , ,044 House income <0.001 < Q (lowest) 2, , ,239 2, ,650 2Q (second lowest) 3, , ,925 3, ,629 3Q (third lowest) 4, ,127 3, ,964 4Q (highest) 4, ,137 3, ,033 Educational level <0.001 <0.001 Elementary school 4, , ,510 2, ,735 Middle school 1, ,012 1, ,736 High school 5, , ,127 4, ,082 College or over 4, ,779 4, ,723 Perceived health status <0.001 <0.001 Excellent Very good 4, ,727 4, ,021 Good 6, , ,066 5, ,952 Poor 2, , ,038 1, , Very poor

21 The presence of HTN <0.001 <0.001 No 12, , ,157 9, , ,116 Yes 3, , ,271 2, ,160 The presence of DM <0.001 No 14, , ,994 11, , ,930 <0.001 Yes 1, ,434 1, ,346 The presence of MDD <0.001 No 14, , ,334 12, , ,039 <0.001 Yes , Level of stress <0.001 High 3, , ,768 2, ,466 <0.001 Low 12, , ,660 10, ,810 The Difference in body image <0.001 A1; low BMI and skinny BI (N) <0.001 A2; middle BMI and skinny BI (U) 1, ,879 2, ,638 A3; high BMI and skinny BI (U) B1; low BMI and normal BI (O) B2; normal BMI and normal BI (N) 5, , ,679 4, ,861 B3; high BMI and normal BI (U) ,008 C1; low BMI and fat BI (O) C2; normal BMI and fat BI (O) 3, ,039 1, ,300 C3; high BMI and fat BI (N) 3, , ,741 3, , TO TAL 15, , ,428 12, , ,276 $ Year and body mass index (BMI) are adjusted; 1Q: lowest household income quartile; 2Q: second lo west household income quartile; 3Q: third lowest household income quartile; 4Q: highest household inc ome quartile; HTN: hypertension; DM: diabetes mellitus; MDD: major depressive disorder. * N means normal BWP, U for distorted under-weighted BWP, and O for over-weighted BWP. HTN: hyperten sion; DM: diabetes mellitus; MDD: major depressive disorder

22 Table 3. Multiple logistic regression analysis of suicidal ideation by gender according to socioeconomic and health-related factors Women Men OR 95% C.I. OR 95% C.I. Age ** ** ** ** ** Town Urban area Rural area Marital status Married Single 1.42* ** Job status Unemployed Employed ** Sleep hours Less than 6 hours to 8 hours More than 8 hours House income 1Q (lowest) Q (second lowest) 0.83* Q (third lowest) 0.85* * Q (highest) 0.63** * Educational level Elementary school Middle school 0.76** * High school 0.60** ** College or over 0.43** ** Perceived health status Excellent 0.26** ** Very good 0.28** ** Good 0.32** ** Poor 0.51** ** Very poor The presence of HTN No

23 Yes The presence of DM No Yes The presence of MDD Absence Presence 2.75** ** 7.62 Level of stress High 4.47** ** 5.32 Low $ Year, body mass index (BMI), and the difference between body image and objective obesity are adjusted; 1Q: lowest household income quartile; 2Q: second lowest household income quartile; 3Q: third lowest household income quartile; 4Q: highest household income quartile; HTN: hypertension; DM: diabetes mellitus; MDD: major depressive disorder. *p-value < 0.05, **p-value <

24 Table 4. Multiple logistic regression analysis of suicidal ideation by gender according to body weight perception (BWP), the gap between subjective body image (BI) and b ody mass index (BMI) 383 Perception Under Normal Over Women Men Body image (BI) BMI category Category OR 95% C.I. OR 95% C.I. Skinny Middle A2 1.34** Skinny High A Normal High B Skinny Low A Normal Middle B Fat High C Normal Low B1 2.25** Fat Middle C2 1.28** Fat Low C $ All other variables except for BWP were adjusted. ** p <

25 Table 5. The fittness of the models of both BMI and BWP, only BWP, and only B MI, according to AIC (Akaike information criterion) Models AIC All Men Women BWP 24,755,172 9,704,093 14,882,892 BMI + BI, both 24,787,467 9,713,517 14,908,230 BI only 24,801,575 9,715,349 14,912,369 BMI only 24,799,963 9,713,597 14,926,893 This BWP model appeared to be more acceptable than the others, because the AIC was minimal in all subjects including men and women regardless of the increase in degrees of freedom; BWP: body weight perception; BMI: body mass index; BI: subjective body image

26 Supplementary table 1. The Odds Ratios for nine categories of body weight perception by three types of body image (BI) and three body mass index (BMI) categories (1) BMI < 18.5 (2) 18.5 BMI < 25 (3) BMI 25 (A) Skinny F; 1.20/M; 1.30 F; 1.34**/M; 1.05 F; 1.39/M; 1.64 (B) Normal F; 2.25**/M; 1.20 F; 1.00/M; 1.00 F; 0.94/M; (C) Fat - F; 1.28**/M; 1.14 F; 1.09/M; 0.84 **p-value < Under the normal BMI category (2), both skinny (A2) and fat (C2) BI were associated with suicidal ideation among female participants. In addition, women with low BMI and normal BI (B1) with an overweight self-perception showed were more likely to express suicidal ideation. 428

27 429 References Korea Statistics. National Health Statistics. List.jsp?vwcd=MT_ZTITLE&parentId=D#SubCont Development(OECD). TOfEC-oa. Health at a Glance 2013, OECD INDICATORS. h ttp://stats.oecd.org/index.aspx?datasetcode=health_stat# Ng M, Fleming T, Robinson M, Thomson B, Graetz N, Margono C, et al. Global, regional, and national prevalence of overweight and obesity in children and adults du ring : a systematic analysis for the Global Burden of Disease Study Lancet 2014;384(9945): Kang HT, Shim JY, Lee HR, Park BJ, Linton JA, Lee YJ. Trends in prevalence of overweight and obesity in Korean adults, : the Korean National Health and Nutrition Examination Survey. J Epidemiol 2014;24(2): Khang YH, Yun SC. Trends in general and abdominal obesity among Korean adult s: findings from 1998, 2001, 2005, and 2007 Korea National Health and Nutrition Ex amination Surveys. J Korean Med Sci 2010;25(11): Barry D, Pietrzak RH, Petry NM. Gender differences in associations between body mass index and DSM-IV mood and anxiety disorders: results from the National Epide miologic Survey on Alcohol and Related Conditions. Ann Epidemiol 2008;18(6): Bjerkeset O, Romundstad P, Evans J, Gunnell D. Association of adult body mass i ndex and height with anxiety, depression, and suicide in the general population: the H UNT study. Am J Epidemiol 2008;167(2): Kasen S, Cohen P, Chen H, Must A. Obesity and psychopathology in women: a th ree decade prospective study. Int J Obes (Lond) 2008;32(3):

28 Petry NM, Barry D, Pietrzak RH, Wagner JA. Overweight and obesity are associate d with psychiatric disorders: results from the National Epidemiologic Survey on Alcoh ol and Related Conditions. Psychosom Med 2008;70(3): Simon GE, Ludman EJ, Linde JA, Operskalski BH, Ichikawa L, Rohde P, et al. A ssociation between obesity and depression in middle-aged women. Gen Hosp Psychiatr y 2008;30(1): Heo M, Pietrobelli A, Fontaine KR, Sirey JA, Faith MS. Depressive mood and ob esity in US adults: comparison and moderation by sex, age, and race. Int J Obes (Lo nd) 2006;30(3): Bjerkeset O, Nordahl HM, Mykletun A, Holmen J, Dahl AA. Anxiety and depress ion following myocardial infarction: gender differences in a 5-year prospective study. J Psychosom Res 2005;58(2): Fan AZ, Strine TW, Jiles R, Mokdad AH. Depression and anxiety associated with cardiovascular disease among persons aged 45 years and older in 38 states of the U nited States, Prev Med 2008;46(5): Herbst S, Pietrzak RH, Wagner J, White WB, Petry NM. Lifetime major depressio n is associated with coronary heart disease in older adults: results from the National Epidemiologic Survey on Alcohol and Related Conditions. Psychosom Med 2007;69(8): John U, Meyer C, Rumpf HJ, Hapke U. Relationships of psychiatric disorders wit h overweight and obesity in an adult general population. Obes Res 2005;13(1): Carpenter KM, Hasin DS, Allison DB, Faith MS. Relationships between obesity a nd DSM-IV major depressive disorder, suicide ideation, and suicide attempts: results f rom a general population study. Am J Public Health 2000;90(2):

29 Kim DS. Body image dissatisfaction as an important contributor to suicidal ideatio n in Korean adolescents: gender difference and mediation of parent and peer relations hips. J Psychosom Res 2009;66(4): Inder KJ, Handley TE, Johnston A, Weaver N, Coleman C, Lewin TJ, et al. Dete rminants of suicidal ideation and suicide attempts: parallel cross-sectional analyses exa mining geographical location. BMC Psychiatry 2014;14: Lee HY, Hahm MI, Park EC. Differential association of socio-economic status wit h gender- and age-defined suicidal ideation among adult and elderly individuals in So uth Korea. Psychiatry Res 2013;210(1): Moon SS, Park SM. Risk factors for suicidal ideation in Korean middle-aged adult s: the role of socio-demographic status. Int J Soc Psychiatry 2012;58(6): Cho JH, Han SN, Kim JH, Lee HM. Body image distortion in fifth and sixth gra de students may lead to stress, depression, and undesirable dieting behavior. Nutr Res Pract 2012;6(2): Kim JH, Park EC, Cho WH, Park CY, Choi WJ, Chang HS. Association between total sleep duration and suicidal ideation among the Korean general adult population. Sleep 2013;36(10): Chin YR, Lee HY, So ES. Suicidal ideation and associated factors by sex in Kor ean adults: a population-based cross-sectional survey. Int J Public Health 2011;56(4): Kim JS, Lee K. The relationship of weight-related attitudes with suicidal behaviors in Korean adolescents. Obesity (Silver Spring) 2010;18(11): Kim DS, Cho Y, Cho SI, Lim IS. Body weight perception, unhealthy weight cont rol behaviors, and suicidal ideation among Korean adolescents. J Sch Health 2009;79 (12):

30 Kim DS, Kim HS, Cho Y, Cho SI. The effects of actual and perceived body wei ght on unhealthy weight control behaviors and depressed mood among adult women i n Seoul, Korea. J Prev Med Public Health 2008;41(5): McCabe MP, Ricciardelli LA. Body image dissatisfaction among males across the lifespan: a review of past literature. J Psychosom Res 2004;56(6): Lee CG, Seo DC. Trajectory of suicidal ideation in relation to perceived overweig ht from adolescence to young adulthood in a representative United States sample. J A dolesc Health 2013;53(6): Gaskin JL, Pulver AJ, Branch K, Kabore A, James T, Zhang J. Perception or real ity of body weight: which matters to the depressive symptoms. J Affect Disord 2013; 150(2): Miranda R, Ortin A, Scott M, Shaffer D. Characteristics of suicidal ideation that p redict the transition to future suicide attempts in adolescents. J Child Psychol Psychiat ry Miranda R, De Jaegere E, Restifo K, Shaffer D. Longitudinal follow-up study of adolescents who report a suicide attempt: aspects of suicidal behavior that increase ris k of a future attempt. Depress Anxiety 2014;31(1): Miranda R, Scott M, Hicks R, Wilcox HC, Harris Munfakh JL, Shaffer D. Suicid e attempt characteristics, diagnoses, and future attempts: comparing multiple attempters to single attempters and ideators. J Am Acad Child Adolesc Psychiatry 2008;47(1):

31 1 2 Table 1. Nine categories of body weight perception (BWP) by three body image categories (BI) and three body mass index (BMI) categories. 3 Body Mass Index (BMI) Subjective body image (1) BMI < 18.5 (2) 18.5 BMI < 25 (3) BMI 25 (A) Skinny Normal (A1) Under (A2) Under (A3) (B) Normal Over (B1) Normal (B2) Under (B3) (C) Fat Over (C1) Over (C2) Normal (C3) To measure the impact of distorted BWP on suicidal ideation, we atomized BWP and selected the category B2 as the control, because this category refers to average BI and normal BMI range

32 14 Table 2. Demographic characteristics and the presence of suicidal ideation by gender Women Men Absence Presence Total p-value Absence Presence Total p -value Age <0.001 < , ,250 1, , , ,902 2, , , ,626 2, , , ,563 2, , , ,144 2, , , ,943 1, ,088 Town <0.001 <0.001 Urban area 12, , ,879 9, , ,813 Rural area 6, , ,549 3, ,463 Marital status Married 13, , ,341 10, , ,099 Single 1, ,087 1, ,177 Job status <0.001 <0.001 Unemployed 7, , ,208 2, ,551 Employed 7, , ,220 9, ,725 Sleep hours <0.001 <0.001 Less than 6 hours 2, ,374 1, ,891 6 to 8 hours 11, , ,424 10, , ,341 More than 8 hours 1, , ,044 House income <0.001 < Q (lowest) 2, , ,239 2, ,650 2Q (second lowest) 3, , ,925 3, ,629 3Q (third lowest) 4, ,127 3, ,964 4Q (highest) 4, ,137 3, ,033 Educational level <0.001 <0.001 Elementary school 4, , ,510 2, ,735 Middle school 1, ,012 1, ,736 High school 5, , ,127 4, ,082 College or over 4, ,779 4, ,723 Perceived health status <0.001 <0.001 Excellent Very good 4, ,727 4, ,021 Good 6, , ,066 5, ,952 Poor 2, , ,038 1, , Very poor

33 The presence of HTN <0.001 <0.001 No 12, , ,157 9, , ,116 Yes 3, , ,271 2, ,160 The presence of DM <0.001 No 14, , ,994 11, , ,930 <0.001 Yes 1, ,434 1, ,346 The presence of MDD <0.001 No 14, , ,334 12, , ,039 <0.001 Yes , Level of stress <0.001 High 3, , ,768 2, ,466 <0.001 Low 12, , ,660 10, ,810 The Difference in body image <0.001 A1; low BMI and skinny BI (N) <0.001 A2; normal BMI and skinny BI (U) 1, ,879 2, ,638 A3; high BMI and skinny BI (U) B1; low BMI and normal BI (O) B2; normal BMI and normal BI (N) 5, , ,679 4, ,861 B3; high BMI and normal BI (U) ,008 C1; low BMI and fat BI (O) C2; normal BMI and fat BI (O) 3, ,039 1, ,300 C3; high BMI and fat BI (N) 3, , ,741 3, , TO TAL 15, , ,428 12, , , $ Year and body mass index (BMI) are adjusted; 1Q: lowest household income quartile; 2Q: second lo west household income quartile; 3Q: third lowest household income quartile; 4Q: highest household inc ome quartile; HTN: hypertension; DM: diabetes mellitus; MDD: major depressive disorder. * N means normal BWP, U for distorted under-weighted BWP, and O for over-weighted BWP. HTN: hypertens ion; DM: diabetes mellitus; MDD: major depressive disorder

34 29 30 Table 3. Multiple logistic regression analysis of suicidal ideation by gender according to socioeconomic and health-related factors Women Men OR 95% C.I. OR 95% C.I. Age ** ** ** ** ** Town Urban area Rural area Marital status Married Single 1.42* ** Job status Unemployed Employed ** Sleep hours Less than 6 hours to 8 hours More than 8 hours House income 1Q (lowest) Q (second lowest) 0.83* Q (third lowest) 0.85* * Q (highest) 0.63** * Educational level Elementary school Middle school 0.76** * High school 0.60** ** College or over 0.43** ** Perceived health status Excellent 0.26** ** Very good 0.28** ** Good 0.32** ** Poor 0.51** ** Very poor The presence of HTN No

35 Yes The presence of DM No Yes The presence of MDD Absence Presence 2.75** ** 7.62 Level of stress High 4.47** ** 5.32 Low $ Year, body mass index (BMI), and the difference between body image and objective obesity are adjusted; 1Q: lowest household income quartile; 2Q: second lowest household income quartile; 3Q: third lowest household income quartile; 4Q: highest household income quartile; HTN: hypertension; DM: diabetes mellitus; MDD: major depressive disorder. *p-value < 0.05, **p-value <

36 Table 4. Multiple logistic regression analysis of suicidal ideation by gender according to body weight perception (BWP), the gap between subjective body image (BI) and body mass index (BMI) 36 Perception Under Normal Over Women Men Body image (BI) BMI category Category OR 95% C.I. OR 95% C.I. Skinny Normal A2 1.34** Skinny High A Normal High B Skinny Low A Normal Normal B Fat High C Normal Low B1 2.25** Fat Normal C2 1.28** Fat Low C $ All other variables except for BWP were adjusted. ** p <

37 Table 5. The fittness of the models of bodyweight perception (BWP), body mass index (BMI) and body image (BI) both, BI only, and BMI only, according to AIC (Akaike information cr iterion) Models AIC All Men Women BWP 24,755,172 9,704,093 14,882,892 BMI + BI, both 24,787,467 9,713,517 14,908,230 BI only 24,801,575 9,715,349 14,912,369 BMI only 24,799,963 9,713,597 14,926,893 This BWP model appeared to be more acceptable than the others, because the AIC was minimal in all subjects including men and women regardless of the increase in degrees of freedom; BWP: body weight perception; BMI: body mass index; BI: subjective body image

38 Supplementary table 1. The Odds Ratios for nine categories of body weight perception by three types of body image (BI) and three body mass index (BMI) categories (1) BMI < 18.5 (2) 18.5 BMI < 25 (3) BMI 25 (A) Skinny F; 1.20/M; 1.30 F; 1.34**/M; 1.05 F; 1.39/M; 1.64 (B) Normal F; 2.25**/M; 1.20 F; 1.00/M; 1.00 F; 0.94/M; (C) Fat - F; 1.28**/M; 1.14 F; 1.09/M; 0.84 **p-value < Under the normal BMI category (2), both skinny (A2) and fat (C2) BI were associated with suicidal ideation among female participants. In addition, women with low BMI and average BI (B1) with an overweight self-perception showed were more likely to express suicidal ideation