J Forensic Sci, September 2015, Vol. 60, No. 5 doi: 10.1111/1556-4029.12790 Available online at: onlinelibrary.wiley.com
TECHNICAL NOTE PSYCHIATRY & BEHAVIORAL SCIENCE
Cem Ekmekcioglu1, M.D.; Selin Devletlian1, M.D.; Gerhard Blasche1, Ph.D.; and Michael Kundi1, M.D., Ph.D.
Is There an Association Between the Body Mass Index and Interpersonal Violent Behavior?
ABSTRACT: An inverse relationship between the body mass index (BMI) and the risk of completed suicide was shown in several studies.
Furthermore, it is suggested that obesity might be associated with a lower risk for violent criminality. Therefore, the aim of this study was to analyze whether a higher BMI is associated with a lower risk for being arrested due to violent behavior in a sample of 43,992 male offenders. Multinomial logistic regression analysis was applied to assess the relationship between different BMI categories and categories of committed crime as outcome variable by including various covariates. Our results indicated that compared to a normal BMI a higher BMI was associated with a significantly lower risk for being arrested in different crime categories associated with interpersonal violence, such as crimes against life and limb (for example: odds ratio = 0.60, CI 95%: 0.52–0.69 for 30–34.9 kg/m2).
KEYWORDS: forensic science, body mass index, obesity, violence, offenders, behavior In the foreword of the world report on violence and health from the World Health Organization (1), Nelson Mandela pointed out that “The twentieth century will be remembered as a century marked by violence,” which is especially true for the first half of the century. The nature of violence is very complex and many factors, including biological, social, cultural, economic, and political, may play a role (2–4). Violence can be divided into self-directed violence, interpersonal violence, and collective violence (1). The most extreme form of self-directed violence is completed suicide. In this context, retrospective cohort studies observed a significant inverse relationship between the body mass index (BMI) and the risk of completed suicides, regardless of region of origin and gender of study populations (reviewed in: 5). Relating to interpersonal violence, for a long time, it has been discussed in the field of criminology whether criminals can also be characterized by their body shape (6). One of the most famous theories was put forward by William H. Sheldon, who suggested three somatotypes: the slender and skinny (ectomorph), the soft and round (endomorph), and the solid/strong and muscular (mesomorph) (7–9). In Sheldon’s opinion, which was especially based on observations in boys, offenders tend to be rather mesomorph (7). Recent studies in young adults and prisoners also suggest that a higher BMI/obesity might be associated with lower risk for violent criminality and probability for being arrested (6,9). Therefore, this investigation tries to address the issue of BMI and violence using a large collective of male offenders from Austria. 1 Institute of Environmental Health, Centre for Public Health, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria. Received 25 April 2014; and in revised form 12 Aug. 2014; accepted 18 Aug. 2014.
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Methods Anonymous criminal statistic records were generously provided by the Ministry of Justice, Vienna, Austria, and data from January 1, 2001 until July 31, 2011 were considered for the analyses. These data included, among others, the kind of offense, several covariates (s. below) and also the height and weight of the offenders, which were measured at the beginning of their imprisonment. From the latter data, the body mass index was calculated using the formula kg/m². The leading offense categories in the data set included crimes against life and limb, crimes against personal freedom, crimes according to the narcotic substances act, crimes against (foreign) property, crimes against sexual integrity and self-determination, and the category “other crimes” a heterogeneous group of various offenses such as continuous failure to pay family/child support. Offenses were categorized in this study into the leading offense categories crimes against life and limb (including for example the paragraph homicide), crimes against personal freedom (including for example the paragraph criminal dangerous threat), crimes according to the narcotic substances act (including for example the paragraph illegal handling of narcotic substances), and also into the categories robbery (consisting of the paragraphs “robbery”, “armed robbery”, “theft accompanied by violence”, and “burglary or theft by the use of arms”), theft (consisting of the paragraphs “theft”, “aggravated theft”, and “theft of a commercial nature and theft within the framework of a criminal association”), rape, sexual abuse of minors (consisting of the paragraphs “severe sexual abuse of minors”, and “sexual abuse of minors”), and fraud (consisting of the paragraphs “fraud”, “aggravated fraud”, “fraud of a commercial nature”, and “misappropriation”). These offense categories consisted of various paragraphs from the Austrian penal code and were used © 2015 American Academy of Forensic Sciences
EKMEKCIOGLU ET AL.
due to them differing in inherent violence, with fraud as the category with the least inherent violence. Offenders were classified into these eight categories according to their leading delicts. Other secondary delicts, if applicable, were not considered for the analyses. The original data set included a total of 74,809 offenders. From these female offenders, offenders categorized in the mixed group “other crimes”, those with missing data for the leading offense, those younger than 18 and older than 55, those with missing data for BMI and family situation (including the widowed), and finally those with rather implausible data for height, weight, and BMI were excluded, leaving a total of 43,992 offenders. The covariates included into the statistical analyses were as follows: age, family situation, having children, and geographical region, consisting of central Europe (including Austria), eastern Europe, south-eastern Europe, Africa, and rest of the world (including the stateless ones and those with no indicated nationalities). Due to incomplete data, highest school graduation, income sources, and employment status were not included into the analyses. The study was approved by the ethics committee of the Medical University of Vienna (protocol No.: 1465/2012). Statistics The BMI was categorized into 5 five groups: < 18.5, 18.5– 24.9, 25–29.9, 30–34.9, and ≥ 35 kg/m². To test the effect of BMI on the type of offense, a multinomial logistic regression analysis was performed with the type of offense as dependent variable, BMI as factor and age, family situation (single, divorced/married), children (yes/no) as well as the five
.
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1351
geographical regions of origin of the offender as covariates. For the type of the offense category “fraud” was chosen as reference, as this category is assumed to be associated with a low aggressive potential. The reference category for BMI groups was normal body weight (i.e., a BMI of 18.5–24.9 kg/m²). Odds ratios and 95% confidence intervals were computed for all offense categories and BMI groups. All analyses were carried out using SPSS (version 20). Results Table 1 summarizes the characteristics of the study sample. The largest subsample consisted of offenders who committed theft, whereas rape and sexual abuse of minors included only 627 and 610 offenders, respectively. The youngest delinquents were in the groups robbery and crimes according to the narcotic substances act, whereas the oldest were those sentenced for sexual abuse of minors. Offenders arrested for the categories fraud or sexual abuse of minors showed higher mean BMI scores and a higher percentage of obesity compared to the other categories. Only 16.6% of the offenders were married and 37.6% had children. The odds ratios (OR) from the multinomial regression analysis between five different BMI categories and committed crimes as outcome variables are shown in Table 2. In general, compared to a normal BMI, a higher BMI was associated with significantly lower OR in all offense categories except for sexual abuse of minors. Also a nearly linear decrease in the OR for all offenses (except for sexual abuse of minors) can be seen in the range of normal to the highest BMI category (Fig. 1). Except for offenses against life and limb, no significant OR was found for the underweight (BMI < 18.5 kg/m2) group (Table 2).
TABLE 1––Characteristics of the studied sample*
All crimes N 43,992 Age (years. 30.38 9.19 mean SD) 2 24.67 4.11 BMI (kg/m ; mean SD) BMI categories (n; %)
TECHNICAL NOTE PSYCHIATRY & BEHAVIORAL SCIENCE
Cem Ekmekcioglu1, M.D.; Selin Devletlian1, M.D.; Gerhard Blasche1, Ph.D.; and Michael Kundi1, M.D., Ph.D.
Is There an Association Between the Body Mass Index and Interpersonal Violent Behavior?
ABSTRACT: An inverse relationship between the body mass index (BMI) and the risk of completed suicide was shown in several studies.
Furthermore, it is suggested that obesity might be associated with a lower risk for violent criminality. Therefore, the aim of this study was to analyze whether a higher BMI is associated with a lower risk for being arrested due to violent behavior in a sample of 43,992 male offenders. Multinomial logistic regression analysis was applied to assess the relationship between different BMI categories and categories of committed crime as outcome variable by including various covariates. Our results indicated that compared to a normal BMI a higher BMI was associated with a significantly lower risk for being arrested in different crime categories associated with interpersonal violence, such as crimes against life and limb (for example: odds ratio = 0.60, CI 95%: 0.52–0.69 for 30–34.9 kg/m2).
KEYWORDS: forensic science, body mass index, obesity, violence, offenders, behavior In the foreword of the world report on violence and health from the World Health Organization (1), Nelson Mandela pointed out that “The twentieth century will be remembered as a century marked by violence,” which is especially true for the first half of the century. The nature of violence is very complex and many factors, including biological, social, cultural, economic, and political, may play a role (2–4). Violence can be divided into self-directed violence, interpersonal violence, and collective violence (1). The most extreme form of self-directed violence is completed suicide. In this context, retrospective cohort studies observed a significant inverse relationship between the body mass index (BMI) and the risk of completed suicides, regardless of region of origin and gender of study populations (reviewed in: 5). Relating to interpersonal violence, for a long time, it has been discussed in the field of criminology whether criminals can also be characterized by their body shape (6). One of the most famous theories was put forward by William H. Sheldon, who suggested three somatotypes: the slender and skinny (ectomorph), the soft and round (endomorph), and the solid/strong and muscular (mesomorph) (7–9). In Sheldon’s opinion, which was especially based on observations in boys, offenders tend to be rather mesomorph (7). Recent studies in young adults and prisoners also suggest that a higher BMI/obesity might be associated with lower risk for violent criminality and probability for being arrested (6,9). Therefore, this investigation tries to address the issue of BMI and violence using a large collective of male offenders from Austria. 1 Institute of Environmental Health, Centre for Public Health, Medical University of Vienna, Kinderspitalgasse 15, 1090 Vienna, Austria. Received 25 April 2014; and in revised form 12 Aug. 2014; accepted 18 Aug. 2014.
1350
Methods Anonymous criminal statistic records were generously provided by the Ministry of Justice, Vienna, Austria, and data from January 1, 2001 until July 31, 2011 were considered for the analyses. These data included, among others, the kind of offense, several covariates (s. below) and also the height and weight of the offenders, which were measured at the beginning of their imprisonment. From the latter data, the body mass index was calculated using the formula kg/m². The leading offense categories in the data set included crimes against life and limb, crimes against personal freedom, crimes according to the narcotic substances act, crimes against (foreign) property, crimes against sexual integrity and self-determination, and the category “other crimes” a heterogeneous group of various offenses such as continuous failure to pay family/child support. Offenses were categorized in this study into the leading offense categories crimes against life and limb (including for example the paragraph homicide), crimes against personal freedom (including for example the paragraph criminal dangerous threat), crimes according to the narcotic substances act (including for example the paragraph illegal handling of narcotic substances), and also into the categories robbery (consisting of the paragraphs “robbery”, “armed robbery”, “theft accompanied by violence”, and “burglary or theft by the use of arms”), theft (consisting of the paragraphs “theft”, “aggravated theft”, and “theft of a commercial nature and theft within the framework of a criminal association”), rape, sexual abuse of minors (consisting of the paragraphs “severe sexual abuse of minors”, and “sexual abuse of minors”), and fraud (consisting of the paragraphs “fraud”, “aggravated fraud”, “fraud of a commercial nature”, and “misappropriation”). These offense categories consisted of various paragraphs from the Austrian penal code and were used © 2015 American Academy of Forensic Sciences
EKMEKCIOGLU ET AL.
due to them differing in inherent violence, with fraud as the category with the least inherent violence. Offenders were classified into these eight categories according to their leading delicts. Other secondary delicts, if applicable, were not considered for the analyses. The original data set included a total of 74,809 offenders. From these female offenders, offenders categorized in the mixed group “other crimes”, those with missing data for the leading offense, those younger than 18 and older than 55, those with missing data for BMI and family situation (including the widowed), and finally those with rather implausible data for height, weight, and BMI were excluded, leaving a total of 43,992 offenders. The covariates included into the statistical analyses were as follows: age, family situation, having children, and geographical region, consisting of central Europe (including Austria), eastern Europe, south-eastern Europe, Africa, and rest of the world (including the stateless ones and those with no indicated nationalities). Due to incomplete data, highest school graduation, income sources, and employment status were not included into the analyses. The study was approved by the ethics committee of the Medical University of Vienna (protocol No.: 1465/2012). Statistics The BMI was categorized into 5 five groups: < 18.5, 18.5– 24.9, 25–29.9, 30–34.9, and ≥ 35 kg/m². To test the effect of BMI on the type of offense, a multinomial logistic regression analysis was performed with the type of offense as dependent variable, BMI as factor and age, family situation (single, divorced/married), children (yes/no) as well as the five
.
BODY MASS INDEX AND VIOLENCE
1351
geographical regions of origin of the offender as covariates. For the type of the offense category “fraud” was chosen as reference, as this category is assumed to be associated with a low aggressive potential. The reference category for BMI groups was normal body weight (i.e., a BMI of 18.5–24.9 kg/m²). Odds ratios and 95% confidence intervals were computed for all offense categories and BMI groups. All analyses were carried out using SPSS (version 20). Results Table 1 summarizes the characteristics of the study sample. The largest subsample consisted of offenders who committed theft, whereas rape and sexual abuse of minors included only 627 and 610 offenders, respectively. The youngest delinquents were in the groups robbery and crimes according to the narcotic substances act, whereas the oldest were those sentenced for sexual abuse of minors. Offenders arrested for the categories fraud or sexual abuse of minors showed higher mean BMI scores and a higher percentage of obesity compared to the other categories. Only 16.6% of the offenders were married and 37.6% had children. The odds ratios (OR) from the multinomial regression analysis between five different BMI categories and committed crimes as outcome variables are shown in Table 2. In general, compared to a normal BMI, a higher BMI was associated with significantly lower OR in all offense categories except for sexual abuse of minors. Also a nearly linear decrease in the OR for all offenses (except for sexual abuse of minors) can be seen in the range of normal to the highest BMI category (Fig. 1). Except for offenses against life and limb, no significant OR was found for the underweight (BMI < 18.5 kg/m2) group (Table 2).
TABLE 1––Characteristics of the studied sample*
All crimes N 43,992 Age (years. 30.38 9.19 mean SD) 2 24.67 4.11 BMI (kg/m ; mean SD) BMI categories (n; %)
