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01.12.2011 | Research article | Ausgabe 1/2011 Open Access

BMC Public Health 1/2011

Violence witnessing, perpetrating and victimization in medellin, Colombia: a random population survey

Zeitschrift:
BMC Public Health > Ausgabe 1/2011
Autoren:
Luis F Duque, Nilton E Montoya, Alexandra Restrepo
Wichtige Hinweise

Electronic supplementary material

The online version of this article (doi:10.​1186/​1471-2458-11-628) contains supplementary material, which is available to authorized users.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

LFD conceived the study, and leaded its design and coordinated its implementation and helped to draft the manuscript; AR participated in its design and coordination and was responsible to draft the manuscript, and NM participated in the design of the study and performed the statistical analysis.
All authors read and approved the final manuscript

Background

Out of 1.6 million deaths that are caused by violence annually in the world, around 90% occur in developing countries [1]. Compared to developed countries, there is still scant empirical information on the magnitude and composition of interpersonal violence, which represents the most widespread type of violence in the world and has become a serious public health problem [24]. For instance, Medellin that is the second largest city in Colombia, with a population of nearly 2.5 million has suffered a severe epidemic of violence during past three decades, reaching a peak of 348 homicides per 100,000 inhabitants in 1991. The rate declined as low as 34 homicides per 100,000 inhabitants in 2005 [5] to increase again to 94.4 in the last two years [6]. Even having such an important and long lasting problem, most of the information on violence in Colombia continues to be based on mortality statistics, police reports, statistics on victims attended by the health care system, or reports to the justice system, all of which may severely underestimate the magnitude of the violence due to inaccurate reporting [7, 8].
The economic cost of violence is especially high in Colombia, estimated at 4.3% of the country's gross national product (GNP). Among WHO Member States that reported data on violence, Colombia ranks second in terms of cost of violence after Burundi. It was the country with the highest cost of violence as a percentage of GNP in the Americas, followed by El Salvador (2.0% of GNP) and Venezuela (1.9% of GNP) in the year 2002 [9].
The purpose of this article is to estimate the prevalence and distribution of witnesses, victims, and perpetrators of different forms of interpersonal violence in a representative sample of the general population in Medellin in 2007.

Methods

This cross-sectional survey was carried out in a random sample of non-institutionalized population (12 to 60 years of age) in the urban area of Medellin. The target sample size was 2,300. The actual sample size was 2,095, equivalent to a response rate of 91%. Of the remaining 9%, most did not respond because they were not in the household at the time of the visit. The sample was selected in four stages. First, sampling was conducted proportionate to the population of each of the 16 urban districts (known as comunas). Next, street intersections within each district (comuna) were selected randomly. Then, a map of properties was used to undertake a census of inhabitants in the first ten to twelve housing units in a clockwise direction in each of the sampling sites selected. In this way, at least 45 persons between 12 and 60 years of age for each site were identified. Finally, twelve (12) persons for each sampling segment were chosen at random among them.
All interviews were conducted by professionals or advanced university students who had undergone previous training. Each face to face interview lasted forty-five minutes to an hour, and was done through personal interviews in the interviewee's home in a place where confidentiality was provided. Interviewees were explained the purpose of the study, its benefits for the community, the aims of the sponsoring and executing institutions of the survey, and interviewees' rights with respect to answering questions and the confidentiality of information. Questions concerning violence were left to the end of the interview, after having established a positive relationship with the participant.
The survey questionnaire was based on a questionnaire that was previously used in Bogota, Colombia [3], Itagui,[10] and in the Medellin metropolitan area, [2, 4] and was based on a set of existing measurement forms [1113]. The original questionnaire was reviewed by four experts who evaluated its content validity and comprehension. It was tested in extreme known groups (e.g., male and female populations in prisons, meditation and religious groups) and only those questions with discriminatory validity were included. A pilot was carried out with 48 families in two neighborhoods of Medellin and with two focal groups to validate the comprehensibility of the instrument.
The research protocol was reviewed and approved by the Ethics Committee of the School of Public Health at the University of Antioquia. Prior, informed consent was obtained using consent forms approved by the School of Public Health Ethics Committee, which were presented and explained to both the interviewer and interviewee before each interview. Prior consent for minors was obtained from the father, mother, or other responsible adult present in the household.
The items that explored violence during the past year were verbal violence, fraud/deception, yelling and heavy pranks, and unarmed aggression. Respondents were asked to report the incidence of these items during the last year, while the more severe items were reported over respondent's lifetime. Severe aggressions included armed threats, severe threats, unarmed robbery, armed physical aggression and sexual aggression. See table 1 for description of each one of these violence forms.
Table 1
Types of violence studied.
TYPE OF VIOLENCE
COMPONENTS
Verbal aggression
Insults, angry shouting
Defraud or deceive
Taking advantage of others, fraud, deceit
Yelling and heavy pranks
Yelling and practical jokes
Unarmed aggression
Strike with the hand or fist with an object, such as a stick or belt
Less severe threat
Threats of beating, threats of injuring, threats of hitting with an object,
Armed threat
Threats with a sharp instrument, knife or firearm
Severe threat
Threats of extortion (being coerced to provide money, property, or services), threats of forced displacement
Unarmed robbery
Robbery with no use of a sharp instrument, knife or firearm
Armed physical aggression
To attack with a sharp instrument, knife or firearm
Sexual aggression
Rape, attempted rape, or not consented caresses
Medellin and metropolitan area. 2007.
For each type of violence, interviewees' were questioned about their experience as witnesses, as victims, and as perpetrators. Besides this information, the questionnaire also included information on sociodemographic characteristics. Socioeconomic status was defined using the household classification scheme employed by the municipality, which is based on the physical characteristics of the household and the block where it is located. The questionnaire also addresses other themes, such as psychoactive substance abuse and protective and risk factors related to personal characteristics, family, peers, neighborhood, and society variables. Each research supervisor carried out a daily revision of missing and inconsistent data, and verified the completion of a sample of 10% of the interviews through follow-up with the respondents by telephone.
Rates of prevalence and their respective confidence intervals were calculated and analyzed by age, sex, level of education, and socioeconomic status. Prevalence rates were compared using the Z-test for difference in proportions and the Chi-square test for association or trend, as appropriate. The Chi-square test for trend was used to compare a nominal variable with an ordinal variable. When the value of the test was significant, the value was used. Otherwise, the value of the Chi-square test of association was used.

Results

A response rate of 91% was obtained. In total, there were 2,095 interviews, implying a rate of sampling error of 2% and a confidence level of 0.95. The sample consisted of 43.4% males, 20.7% minors (less than 18), 13.7% within the age range 19 to 24, and 42.5% from the lower socioeconomic strata. These sample characteristics do not differ from projections based on the latest population census (2005) carried out by National Department of Statistics [14].
In order to allow for cross-country comparison, adjusted prevalence rates were estimated based on the universal population truncated for ages between 15 and 60 [15] (Table 2).
Table 2
Adjusted prevalence rates per 100 (95% CI) of violence in Medellin.
AGRESSION TYPES
VICTIM
PERPETRATOR
WITNESS
DURING PAST YEAR
Yelling and heavy pranks
25.0
18.2
49.6
 
(23.2 - 26.9)
(16.6 - 20.0)
(47.4 - 51.7)
Insults or angry shouting
31.4
27.4
60.9
 
(29.4 - 33.5)
(25.5 - 29.3)
(58.8 - 63.0)
Total verbal aggression
31.4
27.4
60.9
 
(29.4 - 33.5)
(25.5 - 29.3)
(58.8 - 63.0)
Slapping, hitting with arm or fist
4.1
4.0
19.0
 
(3.3 - 5.1)
(3.2 - 4.9)
(17.4 - 20.8)
Hit with an object
3.8
5.8
21.2
 
(3.0 - 4.7)
(4.8 - 6.9)
(19.4 - 23.0)
Total unarmed physical aggression
6.8
8.7
30.4
 
(5.8 - 8.0)
(7.5 - 10.0)
(28.4 - 32.4)
DURING LIFETIME
Beating or injuring threats
9.3
6.6
32.6
 
(8.1 - 10.6)
(5.6 - 7.8)
(30.6 - 34.7)
Hitting with an object threats
4.5
6.0
22.8
 
(3.6 - 5.4)
(5.0 - 7.1)
(21.0 - 24.7)
Total threats of unarmed physical aggression
11.3
10.3
39.6
 
(10.0 - 12.8)
(9.0 - 11.6)
(37.5 - 41.7)
To injure with sharp instrument or knife
5.5
1.1
23.1
 
(4.6 - 6.6)
(0.7 - 1.7)
(21.3 - 25.0)
To shoot at a person
3.8
1.4
25.6
 
(3.0 - 4.7)
(0.9 - 2.0)
(23.7 - 27.5)
Total armed aggression
8.0
2.1
34.5
 
(6.9 - 9.3)
(1.5 - 2.8)
(32.5 - 36.6)
Rape intent
2.4
0.1
3.5
 
(1.8 - 3.2)
(0.0 - 0.4)
(2.8 - 4.4)
Rape
1.3
0.1
1.6
 
(0.9 - 1.9)
(0.0 - 0.3)
(1.1 - 2.3)
Non consented caresses
4.8
0.9
10.2
 
(4.0 - 5.9)
(0.6 - 1.5)
(9.0 - 11.6)
Total sexual aggression
6.3
0.1
3.5
 
(5.3 - 7.5)
(0.0 - 0.4)
(2.8 - 4.4)
Extortion threat
5.5
0.6
14.8
 
(4.5 - 6.5)
(0.3 - 1.1)
(13.3 - 16.4)
Forced displacement threat
5.2
0.4
15.1
 
(4.3 - 6.2)
(0.1 - 0.7)
(13.5 - 16.7)
Total severe threat
9.6
0.8
24.3
 
(8.4 - 11.0)
(0.5 - 1.3)
(22.5 - 26.2)
Threat with knife or sharp instrument
13.3
1.7
34.9
 
(11.9 - 14.9)
(1.2 - 2.3)
(32.9 - 37.0)
Threat with firearm
12.2
1.4
27.0
 
(10.8 - 13.6)
(1.0 - 2.0)
(25.1 - 28.9)
Total armed threat
20.0
2.6
41.4
 
(18.3 - 21.8)
(1.9 - 3.3)
(39.2 - 43.5)
Robbery with no weapon
21.4
2.5
25.0
 
(19.7 - 23.2)
(1.9 - 3.2)
(23.1 - 26.9)
Armed assault
18.7
0.5
25.4
 
(17.0 - 20.4)
(0.3 - 1.0)
(23.6 - 27.4)
To take advantage of others, defraud or deception
14.6
2.9
26.7
 
(13.1 - 16.2)
(2.2 - 3.7)
(24.8 - 28.7)
 
n = 2095
n = 2095
n = 2095
Colombia. 2007.
Over the previous year, the most frequent expression of violence was verbal, followed by yelling and heavy pranks, unarmed physical aggression and, representing the lowest proportion, fraud or deception. The highest proportions of violence over the lifespan were unarmed robbery and unarmed threats, followed by armed threats and sexual violence. Participants reported that they were more likely to be a witness to violence than a victim, and more likely to be a victim than a perpetrator. More severe aggression was associated with a higher victim-perpetrator ratio (i.e., the number victims/number perpetrators for each type of violence in the sample). Lesser forms of aggression show 1.0 to 1.2 victims per perpetrator, compared with 10 to 12 in the case of the more severe forms of aggression.
Table 3 contains the total prevalence proportions, and prevalence proportions by age. Although not included in the table, 15.9% of the interviewees stated having witnessed a homicide in their lifetime. Close to 20% had been victims of armed threat or unarmed robbery. Around 8% were victims of severe threats (threat of displacement or murder), and 5% were victims of sexual aggression over their lifetimes.
Table 3
Prevalence per 100 (95% CI) of being a victim, perpetrator and witness of different forms of violence by age (12 to 60, both sexes).
Types of aggression
Total
Age groups
P value
  
12 to 17
18 to 35
36 to 55
56 or more
 
During past year
      
Verbal aggression
      
Victim
28.3
42.3
31.9
21.5
9.8
***
 
(26.3 - 30.2)
(37.3 - 47.4)
(28.6 - 35.2)
(18.6 - 24.4)
(5.7 - 15.4)
 
Perpetrator
24.3
39.2
29.3
15.8
6.1
***
 
(22.5 - 26.2)
(34.3 - 44.3)
(26.1 - 32.5)
(13.2 - 18.4)
(3.0 - 10.9)
 
Witness
59.7
71.9
65.6
52.5
37.2
***
 
(57.6 - 61.8)
(67.2 - 76.4)
(62.2 - 69.0)
(48.9 - 56.0)
(29.8 - 45.1)
 
Defraud or deceive
      
Victim
13.5
12.2
15.2
14.1
4.9
**
 
(12.0 - 14.9)
(9.1 - 15.9)
(12.7 - 17.8)
(11.7 - 16.6)
(2.1 - 9.4)
 
Perpetrator
3.0
6.0
4.1
0.8
0.6
***
 
(2.2 - 3.7)
(3.8 - 8.8)
(2.7 - 5.5)
(0.2 - 1.4)
(0.0 - 3.4)
 
Witness
26.9
37.4
29.5
21.5
15.9
***
 
(25.0 - 28.8)
(32.6 - 42.4)
(26.2 - 32.7)
(18.6 - 24.4)
(10.6 - 22.4)
 
Yelling and heavy pranks
      
Victim
23.8
36.1
25.8
17.5
14.6
***
 
(21.9 - 25.6)
(31.3 - 41.1)
(22.8 - 28.9)
(14.8 - 20.2)
(9.6 - 21.0)
 
Perpetrator
17.1
37.4
20.2
6.9
3.7
***
 
(15.5 - 18.7)
(32.6 - 42.4)
(17.3 - 23.0)
(5.1 - 8.6)
(1.4 - 7.8)
 
Witness
47.7
68.8
53.7
36.8
21.3
***
 
(45.6 - 49.9)
(63.9 - 73.4)
(50.2 - 57.3)
(33.4 - 40.3)
(15.3 - 28.4)
 
Unarmed aggression
      
Victim
22.2
32.7
23.1
17.9
13.4
***
 
(20.4 - 24.0)
(28.1 - 37.7)
(20.2 - 26.1)
(15.2 - 20.6)
(8.6 - 19.6)
 
Perpetrator
22.2
33.2
23.5
17.5
12.8
***
 
(20.5 - 24.0)
(28.6 - 38.2)
(20.5 - 26.5)
(14.8 - 20.2)
(8.1 - 18.9)
 
Witness
29.5
43.4
29.8
24.5
19.5
***
 
(27.6 - 31.5)
(38.4 - 48.5)
(26.6 - 33.1)
(21.4 - 27.5)
(13.7 - 26.4)
 
During life time
      
Armed threat
      
Victim
20.2
8.8
23.8
23.2
15.9
***
 
(18.5 - 21.9)
(6.2 - 12.1)
(20.8 - 26.8)
(20.2 - 26.2)
(10.6 - 22.4)
 
Perpetrator
2.1
1.3
3.2
1.7
1.2
 
 
(1.5 - 2.8)
(0.4 - 3.0)
(2.0 - 4.5)
(0.8 - 2.6)
(0.1 - 4.3)
 
Witness
39.3
35.6
45.9
36.8
29.3
*
 
(37.2 - 41.4)
(30.8 - 40.6)
(42.3 - 49.5)
(33.4 - 40.3)
(22.4 - 36.9)
 
Severe threat
      
Victim
8.8
5.7
9.3
10.1
7.3
 
 
(7.6 - 10.0)
(3.6 - 8.5)
(7.3 - 11.3)
(8.0 - 12.2)
(3.8 - 12.4)
 
Perpetrator
0.7
0.8
0.8
0.6
  
 
(0.3 - 1.0)
(0.2 - 2.3)
(0.2 - 1.4)
(0.1 - 1.2)
ND
 
Witness
24.9
24.2
26.6
23.9
22.6
 
 
(23.0 - 26.7)
(20.0 - 28.8)
(23.5 - 29.8)
(20.9 - 26.9)
(16.4 - 29.7)
 
Unarmed robbery
      
Victim
21.5
19.0
21.3
24.1
15.9
 
 
(19.7 - 23.2)
(15.2 - 23.2)
(18.4 - 24.2)
(21.1 - 27.1)
(10.6 - 22.4)
 
Perpetrator
2.1
4.7
2.5
1.0
 
***
 
(1.5 - 2.8)
(2.8 - 7.3)
(1.4 - 3.5)
(0.3 - 1.8)
ND
 
Witness
25.5
33.3
26.6
22.3
16.5
***
 
(23.6 - 27.3)
(28.6 - 38.3)
(23.5 - 29.7)
(19.3 - 25.2)
(11.1 - 23.0)
 
Armed physical aggression
      
Victim
7.6
3.1
8.4
9.2
6.7
*
 
(6.5 - 8.7)
(1.6 - 5.4)
(6.4 - 10.4)
(7.2 - 11.2)
(3.4 - 11.7)
 
Perpetrator
1.9
0.8
2.5
1.9
1.2
 
 
(1.3 - 2.4)
(0.2 - 2.3)
(1.4 - 3.5)
(1.0 - 2.9)
(0.1 - 4.3)
 
Witness
33.3
27.8
37.1
34.1
24.4
***
 
(31.3 - 35.3)
(23.4 - 32.6)
(33.7 - 40.6)
(30.7 - 37.4)
(18.0 - 31.7)
 
Sexual aggression
      
Victim
5.9
3.9
7.0
6.2
4.3
 
 
(4.9 - 6.9)
(2.2 - 6.3)
(5.2 - 8.8)
(4.5 - 7.9)
(1.7 - 8.6)
 
Perpetrator
1.1
1.6
1.8
0.5
ND
*
 
(0.7 - 1.6)
(0.6 - 3.4)
(0.9 - 2.7)
(0.0 - 1.0)
  
Witness
11.6
14.5
13.4
10.1
3.7
***
 
(10.3 - 13.0)
(11.2 - 18.5)
(11.0 - 15.8)
(8.0 - 12.2)
(1.4 - 7.8)
 
 
n = 2095
n = 385
n = 774
n = 772
n = 164
 
Medellin, Colombia. 2007.
*P < 0.05 ** p < 0.01 *** p < 0.001
NA: Does not apply ND: No data
Younger age groups were more likely to report being victims, perpetrators, and witnesses to verbal aggression, fraud or deception, yelling and heavy pranks, unarmed aggression and unarmed robbery. Younger age groups were also more likely to be witnesses and victims of armed aggression. Minors (18 years of age or less) generally showed the highest incidence of being perpetrators and were more likely to be the victims of the different forms of violence compared to other age groups. Nearly half had already witnessed a robbery, and one-sixth indicated having witnessed at least one sexual aggression. The prevalence of being an armed physical perpetrator and severe threats were similar in all age groups.
Marital status was determined as being without a partner (single, divorced, widowed or widower) or with a partner (married or common law). Participants without a partner were significantly more aggressive in so much as verbal violence, deception/fraud, yelling and heavy pranks, physical aggression without a weapon, robbery, and sexual aggression were concerned, while those who had a partner were more so in terms of unarmed threats. There is a positive association between level of education and being a victim of deception/fraud, armed threats, robbery, and sexual violence. Respondents with a secondary education showed a greater likelihood of being victims of verbal aggression and yelling and heavy pranks, as well as a higher chance of being a victim of armed threats, unarmed robbery and sexual aggression as higher levels of education imply older age. Respondents with secondary educations were more likely to have committed verbal aggression and yelling and heavy pranks, and higher levels of education were also associated with a higher risk of committing aggression by armed threats (Table 4).
Table 4
Prevalence proportion per 100 (95% CI) of being the victim, perpetrator or witness of different forms of violence over the previous year and lifespan by marital status and educational level.
Types of violence
Marital status
P value
Educational level
P value
 
Without partner
With partner
 
Elementary
High school
Technical school
University or graduate studies
 
During past year
        
Verbal aggression
        
Victim
33.0
21.0
***
22.1
31.9
26.0
25.6
***
 
(30.4 - 35.6)
(18.3 - 23.8)
 
(18.1 - 26.6)
(29.2 - 34.7)
(20.1 - 32.6)
(21.3 - 30.3)
 
Perpetrator
29.2
16.9
***
18.8
28.4
21.6
20.3
***
 
(26.7 - 31.7)
(14.4 - 19.5)
 
(15.0 - 23.0)
(25.8 - 31.1)
(16.1 - 27.9)
(16.4 - 24.7)
 
Witness
64.8
51.9
***
47.4
62.1
59.3
66.0
***
 
(62.1 - 67.5)
(48.5 - 55.4)
 
(42.3 - 52.5)
(59.2 - 65.0)
(52.2 - 66.1)
(61.0 - 70.7)
 
Defraud or deceive
        
Victim
15.5
10.5
***
11.5
12.4
15.7
17.7
**
 
(13.5 - 17.4)
(8.4 - 12.5)
 
(8.5 - 15.1)
(10.4 - 14.3)
(11.0 - 21.4)
(14.0 - 21.9)
 
Perpetrator
4.3
1.0
***
1.0
4.0
1.5
2.9
*
 
(3.2 - 5.4)
(0.3 - 1.6)
 
(0.3 - 2.6)
(2.8 - 5.1)
(0.3 - 4.2)
(1.5 - 5.1)
 
Witness
30.7
21.0
***
17.2
29.2
22.5
33.0
***
 
(28.2 - 33.3)
(18.3 - 23.8)
 
(13.5 - 21.3)
(26.5 - 31.8)
(17.0 - 28.9)
(28.3 - 38.0)
 
Yelling and heavy pranks
        
Victim
27.9
17.4
***
18.5
26.9
18.1
23.0
**
 
(25.4 - 30.4)
(14.9 - 20.0)
 
(14.7 - 22.7)
(24.3 - 29.5)
(13.1 - 24.1)
(18.8 - 27.5)
 
Perpetrator
22.6
8.8
***
9.9
22.4
12.3
12.4
***
 
(20.3 - 24.9)
(6.9 - 10.7)
 
(7.1 - 13.3)
(19.9 - 24.8)
(8.1 - 17.6)
(9.3 - 16.1)
 
Witness
55.2
36.5
***
33.6
52.2
45.1
52.0
***
 
(52.4 - 57.9)
(33.3 - 39.8)
 
(28.9 - 38.6)
(49.2 - 55.1)
(38.1 - 52.2)
(46.8 - 57.1)
 
Unarmed aggression
        
Victim
24.8
18.3
***
21.1
23.6
21.6
20.3
 
 
(22.4 - 27.2)
(15.6 - 20.9)
 
(17.1 - 25.5)
(21.1 - 26.1)
(16.1 - 27.9)
(16.4 - 24.7)
 
Perpetrator
24.5
18.9
***
21.1
23.5
23.0
20.3
 
 
(22.1 - 26.9)
(16.2 - 21.5)
 
(17.1 - 25.5)
(21.0 - 26.0)
(17.4 - 29.4)
(16.4 - 24.7)
 
Witness
32.8
24.6
***
29.2
31.2
26.0
27.7
 
 
(30.2 - 35.4)
(21.7 - 27.6)
 
(24.7 - 34.0)
(28.5 - 34.0)
(20.1 - 32.6)
(23.3 - 32.5)
 
During life time
        
Armed threat
        
Victim
20.1
20.3
***
16.7
17.1
26.0
30.1
***
 
(17.9 - 22.3)
(17.6 - 23.0)
 
(13.1 - 20.8)
(14.8 - 19.3)
(20.1 - 32.6)
(25.5 - 35.0)
 
Perpetrator
2.0
2.4
**
2.3
2.9
0.5
0.8
*
 
(1.2 - 2.7)
(1.4 - 3.4)
 
(1.1 - 4.4)
(1.9 - 3.9)
(0.0 - 2.7)
(0.2 - 2.3)
 
Witness
40.5
37.6
***
31.8
38.7
45.6
45.9
***
 
(37.8 - 43.2)
(34.3 - 40.9)
 
(27.1 - 36.7)
(35.9 - 41.6)
(38.6 - 52.7)
(40.8 - 51.1)
 
Severe threat
        
Victim
8.1
9.7
***
0.8
0.8
0.5
0.3
 
 
(6.6 - 9.6)
(7.7 - 11.7)
 
(0.2 - 2.3)
(0.3 - 1.3)
(0.0 - 2.7)
(0.0 - 1.5)
 
Perpetrator
0.8
0.5
 
23.0
24.2
26.0
28.0
 
 
(0.3 - 1.3)
(0.0 - 1.0)
 
(18.9 - 27.5)
(21.6 - 26.7)
(20.1 - 32.6)
(23.5 - 32.8)
 
Witness
25.4
24.1
***
10.2
7.7
9.8
9.0
 
 
(23.0 - 27.8)
(21.2 - 27.0)
 
(7.3 - 13.6)
(6.1 - 9.2)
(6.1 - 14.7)
(6.3 - 12.3)
 
Unarmed robbery
        
Victim
21.6
21.4
***
16.9
20.2
27.5
26.9
***
 
(19.3 - 23.8)
(18.6 - 24.2)
 
(13.3 - 21.1)
(17.9 - 22.6)
(21.5 - 34.1)
(22.5 - 31.7)
 
Perpetrator
2.8
1.2
***
2.3
3.0
1.0
0.3
**
 
(1.9 - 3.7)
(0.5 - 1.9)
 
(1.1 - 4.4)
(2.0 - 4.0)
(0.1 - 3.5)
(0.0 - 1.5)
 
Witness
27.9
21.8
***
18.2
27.1
25.0
29.0
**
 
(25.4 - 30.4)
(19.0 - 24.6)
 
(14.5 - 22.5)
(24.5 - 29.7)
(19.2 - 31.5)
(24.5 - 33.9)
 
Armed physical aggression
        
Victim
7.2
8.2
***
9.9
6.5
8.3
7.7
 
 
(5.8 - 8.6)
(6.3 - 10.0)
 
(7.1 - 13.3)
(5.0 - 7.9)
(4.9 - 13.0)
(5.2 - 10.8)
 
Perpetrator
1.9
1.8
*
2.6
2.0
1.5
1.1
 
 
(1.1 - 2.7)
(0.9 - 2.7)
 
(1.3 - 4.7)
(1.2 - 2.8)
(0.3 - 4.2)
(0.3 - 2.7)
 
Witness
33.0
33.5
***
28.4
32.8
36.3
38.3
**
 
(30.4 - 35.6)
(30.3 - 36.7)
 
(23.9 - 33.2)
(30.0 - 35.5)
(29.7 - 43.3)
(33.3 - 43.4)
 
Sexual aggression
        
Victim
7.0
4.3
***
4.9
4.5
8.3
9.5
***
 
(5.6 - 8.4)
(2.9 - 5.7)
 
(3.0 - 7.6)
(3.3 - 5.7)
(4.9 - 13.0)
(6.7 - 12.9)
 
Perpetrator
1.7
0.4
***
0.5
1.4
0.5
1.6
 
 
(1.0 - 2.4)
(0.0 - 0.8)
 
(0.1 - 1.9)
(0.7 - 2.0)
(0.0 - 2.7)
(0.6 - 3.4)
 
Witness
13.4
9.0
***
8.6
11.4
12.7
15.3
**
 
(11.5 - 15.3)
(7.1 - 11.0)
 
(6.0 - 11.9)
(9.5 - 13.2)
(8.5 - 18.1)
(11.8 - 19.3)
 
 
n = 1262
n = 832
 
n = 384
n = 1108
n = 204
n = 379
 
Population 12 - 60 years of age. Medellin, Colombia. 2007.
*P < 0.05 ** p < 0.01 *** p < 0.001
NA: Do not apply
ND: No data
Table 5 details the level of violence according to employment status over the previous year and socioeconomic stratum (SES). Those who were employed during each of the twelve months were less likely to have been perpetrators or victims of verbal violence, fraud/deception, yelling and heavy pranks, and unarmed aggression. Participants that had been unemployed for 4 to 8 months were in general more likely to be perpetrators and victims of violence than those who had experienced the same situation for less than 4 months or more than 8; however, these differences were not significant.
Table 5
Proportion of prevalence per 100 (95% CI) of being a victim, perpetrator and witness of different forms of violence over the previous year and lifespan, by employment status over the previous year and SES.
Types of violence
Unemployment, past year
P value
Socioeconomic status
P value
 
0 months
1 - 3 months
4 - 8 months
9 - 12 months
 
Low
Middle
High
 
During past year
        
Verbal aggression
        
Victim
14.1
36.2
45.7
32.7
***
29.4
27.9
25.5
 
 
(10.4 - 18.5)
(25.0 - 48.7)
(34.6 - 57.1)
(26.6 - 39.4)
 
(26.4 - 32.4)
(25.0 - 30.7)
(20.2 - 31.4)
 
Perpetrator
11.1
30.4
44.4
24.5
***
26.6
23.6
19.1
*
 
(7.8 - 15.2)
(19.9 - 42.7)
(33.4 - 55.9)
(19.0 - 30.8)
 
(23.7 - 29.5)
(20.9 - 26.3)
(14.4 - 24.5)
 
Witness
44.1
68.1
74.1
66.8
***
59.4
58.6
64.9
 
 
(38.5 - 49.9)
(55.8 - 78.8)
(63.1 - 83.2)
(60.2 - 73.0)
 
(56.1 - 62.7)
(55.4 - 61.7)
(58.7 - 70.8)
 
Defraud or deceive
         
Victim
9.5
17.4
22.2
14.5
*
12.9
13.8
13.9
 
 
(6.4 - 13.3)
(9.3 - 28.4)
(13.7 - 32.8)
(10.2 - 19.9)
 
(10.7 - 15.1)
(11.6 - 16.0)
(9.9 - 18.9)
 
Perpetrator
1.6
4.3
3.7
5.0
 
3.4
3.1
0.8
 
 
(0.5 - 3.8)
(0.9 - 12.2)
(0.8 - 10.4)
(2.5 - 8.8)
 
(2.2 - 4.6)
(2.0 - 4.3)
(0.1 - 2.8)
 
Witness
18.6
39.1
25.9
27.3
**
28.5
24.5
30.3
 
 
(14.4 - 23.4)
(27.6 - 51.6)
(16.8 - 36.9)
(21.5 - 33.7)
 
(25.6 - 31.5)
(21.8 - 27.3)
(24.7 - 36.4)
 
Yelling and heavy pranks
       
Victim
15.7
27.5
24.7
25.9
*
25.1
23.4
20.7
 
 
(11.8 - 20.3)
(17.5 - 39.6)
(15.8 - 35.5)
(20.3 - 32.2)
 
(22.2 - 27.9)
(20.7 - 26.1)
(15.9 - 26.3)
 
Perpetrator
9.5
13.0
19.8
18.2
*
19.6
16.2
12.0
 
 
(6.4 - 13.3)
(6.1 - 23.3)
(11.7 - 30.1)
(13.3 - 23.9)
 
(16.9 - 22.2)
(13.9 - 18.6)
(8.2 - 16.6)
 
Witness
39.9
50.7
53.1
44.5
 
47.9
47.9
46.6
 
 
(34.3 - 45.6)
(38.4 - 63.0)
(41.7 - 64.3)
(37.9 - 51.4)
 
(44.5 - 51.2)
(44.7 - 51.1)
(40.3 - 53.0)
 
Unarmed aggression
         
Victim
16.0
29.0
35.8
23.6
***
25.6
20.2
17.5
***
 
(12.1 - 20.6)
(18.7 - 41.2)
(25.4 - 47.2)
(18.2 - 29.8)
 
(22.8 - 28.5)
(17.7 - 22.8)
(13.0 - 22.8)
 
Perpetrator
15.4
30.4
33.3
23.2
***
25.1
21.3
15.9
**
 
(11.5 - 19.9)
(19.9 - 42.7)
(23.2 - 44.7)
(17.8 - 29.3)
 
(22.2 - 27.9)
(18.7 - 23.9)
(11.6 - 21.1)
 
Witness
20.9
42.0
43.2
28.6
***
33.4
26.3
28.3
**
 
(16.5 - 25.9)
(30.2 - 54.5)
(32.2 - 54.7)
(22.8 - 35.1)
 
(30.3 - 36.5)
(23.5 - 29.1)
(22.8 - 34.3)
 
During life time
       
Armed threat
         
Victim
19.9
31.9
23.5
20.9
 
17.5
22.1
22.3
*
 
(15.6 - 24.9)
(21.2 - 44.2)
(14.8 - 34.2)
(15.7 - 26.9)
 
(15.0 - 20.0)
(19.5 - 24.8)
(17.3 - 28.0)
 
Perpetrator
1.3
7.2
4.9
0.9
**
2.8
2.0
0.4
*
 
(0.4 - 3.3)
(2.4 - 16.1)
(1.4 - 12.2)
(0.1 - 3.2)
 
(1.7 - 3.9)
(1.1 - 2.9)
(0.0 - 2.2)
 
Witness
31.7
49.3
49.4
44.1
**
38.3
40.0
40.2
 
 
(26.5 - 37.2)
(37.0 - 61.6)
(38.1 - 60.7)
(37.4 - 50.9)
 
(35.1 - 41.5)
(36.9 - 43.2)
(34.1 - 46.6)
 
Severe threat
         
Victim
9.5
8.7
6.2
12.3
 
0.8
0.6
0.4
 
 
(6.4 - 13.3)
(3.3 - 18.0)
(2.0 - 13.8)
(8.2 - 17.4)
 
(0.2 - 1.4)
(0.1 - 1.1)
(0.0 - 2.2)
 
Perpetrator
1.0
SD
SD
0.9
 
27.6
22.9
22.7
*
 
(0.2 - 2.8)
  
(0.1 - 3.2)
 
(24.7 - 30.5)
(20.2 - 25.6)
(17.7 - 28.4)
 
Witness
20.0
30.4
35.8
30.5
**
9.8
7.9
8.8
 
 
(15.7 - 24.9)
(19.9 - 42.7)
(25.4 - 47.2)
(24.4 - 37.0)
 
(7.8 - 11.7)
(6.2 - 9.6)
(5.6 - 13.0)
 
Unarmed robbery
       
Victim
12.7
30.4
19.8
23.6
***
19.7
21.6
27.5
*
 
(9.2 - 17.0)
(19.9 - 42.7)
(11.7 - 30.1)
(18.2 - 29.8)
 
(17.1 - 22.3)
(19.0 - 24.2)
(22.1 - 33.5)
 
Perpetrator
2.0
2.9
4.9
1.8
 
3.1
1.7
0.4
**
 
(0.7 - 4.2)
(0.4 - 10.1)
(1.4 - 12.2)
(0.5 - 4.6)
 
(2.0 - 4.3)
(0.9 - 2.5)
(0.0 - 2.2)
 
Witness
19.6
36.2
25.9
28.2
**
24.1
26.8
25.1
 
 
(15.3 - 24.5)
(25.0 - 48.7)
(16.8 - 36.9)
(22.3 - 34.6)
 
(21.3 - 26.9)
(24.0 - 29.6)
(19.9 - 30.9)
 
Armed physical aggression
       
Victim
7.2
13
13.6
9.1
 
8.3
7.4
5.6
 
 
(4.6 - 10.7)
(6.1 - 23.3)
(7.0 - 23.0)
(5.6 - 13.7)
 
(6.5 - 10.1)
(5.8 - 9.1)
(3.1 - 9.2)
 
Perpetrator
1.3
4.3
2.5
3.6
 
2.5
1.7
0.4
*
 
(0.4 - 3.3)
(0.9 - 12.2)
(0.3 - 8.6)
(1.6 - 7.0)
 
(1.5 - 3.5)
(0.9 - 2.5)
(0.0 - 2.2)
 
Witness
27.1
39.1
42.0
41.8
**
34.7
33.0
29.1
 
 
(22.2 - 32.5)
(27.6 - 51.6)
(31.1 - 53.5)
(35.2 - 48.6)
 
(31.6 - 37.8)
(30.0 - 36.0)
(23.5 - 35.1)
 
Sexual aggression
         
Victim
2.6
11.6
9.9
5.0
**
4.7
6.6
7.6
*
 
(1.1 - 5.1)
(5.1 - 21.6)
(4.4 - 18.5)
(2.5 - 8.8)
 
(3.3 - 6.1)
(5.0 - 8.2)
(4.6 - 11.6)
 
Perpetrator
0.7
4.3
2.5
1.4
 
1.2
1.3
0.4
 
 
(0.1 - 2.3)
(0.9 - 12.2)
(0.3 - 8.6)
(0.3 - 3.9)
 
(0.5 - 2.0)
(0.6 - 2.0)
(0.0 - 2.2)
 
Witness
5.9
14.5
14.8
11.4
*
11.0
11.5
14.3
 
 
(3.5 - 9.1)
(7.2 - 25.0)
(7.9 - 24.4)
(7.5 - 16.3)
 
(9.0 - 13.1)
(9.5 - 13.6)
(10.3 - 19.3)
 
 
n = 306
n = 69
n = 81
n = 220
 
n = 890
n = 954
N = 251
 
Population 12 - 60 years of age. Medellin, Colombia. 2007.
*P < 0.05 ** p < 0.01 *** p < 0.001
NA: Do not apply
ND: No data
Lower socioeconomic status was associated with a higher likelihood of being a verbal perpetrator, yelling and heavy pranks, unarmed aggression, severe threats, unarmed robbery and armed physical aggression. It was found that, the higher a respondent's socioeconomic status, the greater was their likelihood of being a victim of verbal aggression and armed threat.
Bivariate analysis by sex revealed that men were the main victims of violence, except in cases of unarmed robbery and sexual violence. There was difference between sexes of having witnessed violence or having been perpetrators; they were higher in men for all forms of violence studied (Table 6).
Table 6
Prevalence per 100 (95% CI) of being a victim, perpetrator and witness of different forms of violence, by sex and marital status.
Types of violence
Sex
P value
Men
P value
Women
P value
 
Man
Woman
 
Without partner
With partner
 
Without partner
With partner
 
During past year
         
Verbal aggression
         
Victim
31.8
25.6
**
37.4
23.0
***
29.6
19.6
***
 
(28.7 - 34.8)
(23.1 - 28.1)
 
(33.4 - 41.6)
(18.7 - 27.7)
 
(26.3 - 33.1)
(16.1 - 23.4)
 
Perpetrator
28.1
21.4
***
34.7
17.9
***
25.0
16.2
***
 
(25.2 - 31.1)
(19.1 - 23.8)
 
(30.8 - 38.9)
(14.1 - 22.3)
 
(21.8 - 28.2)
(13.0 - 19.8)
 
Witness
63.8
56.5
***
70.0
54.3
***
60.8
50.1
***
 
(60.6 - 67.0)
(53.7 - 59.4)
 
(66.0 - 73.8)
(49.0 - 59.6)
 
(57.1 - 64.4)
(45.5 - 54.7)
 
Defraud or deceive
         
Victim
17.5
10.4
***
19.7
14.0
*
12.1
7.8
*
 
(15.0 - 19.9)
(8.6 - 12.1)
 
(16.5 - 23.3)
(10.6 - 18.0)
 
(9.7 - 14.5)
(5.5 - 10.6)
 
Perpetrator
4.5
1.8
***
6.1
2.0
***
2.8
0.2
***
 
(3.2 - 5.9)
(1.0 - 2.5)
 
(4.1 - 8.2)
(0.8 - 4.0)
 
(1.6 - 4.0)
(0.0 - 1.2)
 
Witness
35.1
20.7
***
40.0
27.5
***
23.6
16.2
**
 
(32.0 - 38.2)
(18.4 - 23.0)
 
(35.9 - 44.2)
(22.9 - 32.4)
 
(20.4 - 26.7)
(13.0 - 19.8)
 
Yelling and heavy pranks
         
Victim
29.9
19.1
***
34.5
22.7
***
22.7
13.5
***
 
(26.9 - 32.9)
(16.8 - 21.3)
 
(30.6 - 38.7)
(18.4 - 27.4)
 
(19.6 - 25.8)
(10.5 - 16.9)
 
Perpetrator
26.0
10.3
***
33.5
14.6
***
14.1
4.4
***
 
(23.2 - 28.9)
(8.6 - 12.0)
 
(29.5 - 37.6)
(11.1 - 18.7)
 
(11.5 - 16.7)
(2.8 - 6.7)
 
Witness
54.6
42.4
***
64.0
40.1
***
48.2
33.9
***
 
(51.3 - 57.9)
(39.6 - 45.3)
 
(59.9 - 68.0)
(34.9 - 45.3)
 
(44.5 - 52.0)
(29.6 - 38.3)
 
Unarmed aggression
         
Victim
26.3
19.1
***
30.2
20.2
***
20.6
16.8
 
 
(23.4 - 29.1)
(16.8 - 21.3)
 
(26.4 - 34.2)
(16.1 - 24.7)
 
(17.6 - 23.6)
(13.6 - 20.5)
 
Perpetrator
25.2
20.0
**
28.4
20.2
***
21.4
17.9
 
 
(22.3 - 28.0)
(17.7 - 22.3)
 
(24.7 - 32.3)
(16.1 - 24.7)
 
(18.4 - 24.5)
(14.6 - 21.6)
 
Witness
34.6
25.7
***
39.1
27.7
***
27.9
22.3
*
 
(31.5 - 37.7)
(23.2 - 28.1)
 
(35.0 - 43.3)
(23.1 - 32.7)
 
(24.6 - 31.2)
(18.6 - 26.3)
 
During life time
         
Armed threat
         
Victim
27.3
14.8
***
26.9
27.7
 
14.8
14.7
 
 
(24.4 - 30.1)
(12.7 - 16.8)
 
(23.3 - 30.8)
(23.1 - 32.7)
 
(12.2 - 17.4)
(11.7 - 18.2)
 
Perpetrator
4.1
0.7
***
3.6
4.8
 
0.7
0.6
 
 
(2.8 - 5.3)
(0.2 - 1.1)
 
(2.1 - 5.2)
(2.8 - 7.5)
 
(0.1 - 1.3)
(0.1 - 1.8)
 
Witness
46.5
33.8
***
49.7
41.5
*
33.3
34.7
 
 
(43.2 - 49.8)
(31.1 - 36.5)
 
(45.5 - 54.0)
(36.3 - 46.8)
 
(29.8 - 36.9)
(30.5 - 39.2)
 
Severe threat
         
Victim
10.2
7.7
*
9.4
11.5
 
7.1
8.4
 
 
(8.3 - 12.2)
(6.2 - 9.2)
 
(7.0 - 11.8)
(8.4 - 15.3)
 
(5.2 - 8.9)
(6.1 - 11.3)
 
Perpetrator
1.1
0.3
*
1.3
0.8
 
0.4
0.2
 
 
(0.4 - 1.8)
(0.0 - 0.7)
 
(0.3 - 2.2)
(0.2 - 2.4)
 
(-0.1 - 0.9)
(0.0 - 1.2)
 
Witness
31.0
20.2
***
32.2
29.1
 
20.1
20.3
 
 
(28.0 - 34.0)
(17.9 - 22.4)
 
(28.3 - 36.3)
(24.5 - 34.1)
 
(17.1 - 23.0)
(16.8 - 24.2)
 
Unarmed robbery
         
Victim
22.1
21.0
 
22.2
21.8
 
21.0
21.1
 
 
(19.4 - 24.8)
(18.7 - 23.3)
 
(18.8 - 25.9)
(17.7 - 26.5)
 
(18.0 - 24.0)
(17.5 - 25.0)
 
Perpetrator
4.2
0.6
***
5.4
2.2
**
0.7
0.4
 
 
(2.9 - 5.5)
(0.2 - 1.0)
 
(3.5 - 7.3)
(1.0 - 4.4)
 
(0.1 - 1.3)
(0.1 - 1.5)
 
Witness
30.5
21.6
***
35.0
23.5
***
22.4
20.4
 
 
(27.5 - 33.5)
(19.3 - 23.9)
 
(31.0 - 39.1)
(19.2 - 28.3)
 
(19.4 - 25.5)
(16.9 - 24.3)
 
Armed physical aggression
         
Victim
12.5
3.8
***
11.0
14.8
 
4.2
3.2
 
 
(10.4 - 14.7)
(2.7 - 4.9)
 
(8.5 - 13.9)
(11.3 - 19.0)
 
(2.7 - 5.7)
(1.8 - 5.2)
 
Perpetrator
3.7
0.4
***
3.6
3.9
 
0.6
0.2
 
 
(2.5 - 5.0)
(0.1 - 0.8)
 
(2.1 - 5.2)
(2.2 - 6.5)
 
(0.0 - 1.1)
(0.0 - 1.2)
 
Witness
42.1
26.5
***
43.0
40.6
 
25.2
28.2
 
 
(38.9 - 45.3)
(24.0 - 29.0)
 
(38.9 - 47.3)
(35.5 - 45.9)
 
(22.0 - 28.4)
(24.2 - 32.5)
 
Sexual aggression
         
Victim
3.1
8.1
***
4.0
1.7
*
9.3
6.3
 
 
(2.0 - 4.2)
(6.5 - 9.7)
 
(2.3 - 5.6)
(0.6 - 3.6)
 
(7.2 - 11.4)
(4.3 - 8.9)
 
Perpetrator
2.3
0.3
***
3.3
0.8
**
0.4
ND
NA
 
(1.3 - 3.3)
(0.0 - 0.5)
 
(1.8 - 4.7)
(0.2 - 2.4)
 
(-0.1 - 0.9)
  
Witness
15.7
8.5
***
19.2
10.4
***
8.9
8.0
 
 
(13.3 - 18.1)
(6.9 - 10.1)
 
(16.0 - 22.7)
(7.4 - 14.0)
 
(6.8 - 11.0)
(5.7 - 10.8)
 
 
n = 910
n = 1185
 
n = 553
n = 357
 
n = 709
n = 475
 
Medellin, Colombia. 2003 - 2004
*P < 0.05 ** p < 0.01 *** p < 0.001
ND: No data
NA: Does not apply
The prevalence of victimization and aggression by verbal violence, fraud/deception, yelling and heavy pranks, and sexual aggression was greater among those in a partnership, regardless of the sex of the respondent. Men were more likely than women to be unarmed perpetrators and victims of unarmed aggression. We found no differences by sex between those currently in a partnership and those not with respect to reporting having been a victim or perpetrator of threats with or without a weapon, robbery, and armed aggression (Table 6).
We found no significant differences in yelling and heavy pranks, severe threats, robbery, armed aggression and sexual violence by socio economic status (SES) among both men and women. The proportion of women perpetrators by fraud/deception and verbal aggression decreases as SES increases. Among men, a direct relationship was observed between being a victim of fraud/deception and SES, and an inverse relationship between being a victim of unarmed violence and SES. There were no significant differences in incidence of sexual aggression and sexual victimization by SES independent of sex (Table 7).
Table 7
Prevalence per 100 (95% CI) of being a victim, perpetrator and witness of different forms of violence, by socioeconomic status and sex (12 to 60 years of age).
Types of violence
Men
P value
Women
P value
 
Low
Middle
High
 
Low
Middle
High
 
During past year
        
Verbal aggression
        
Victim
30.4
33.5
30.0
 
28.6
23.6
23.0
 
 
(26.0 - 35.1)
(28.9 - 38.3)
(20.8 - 40.6)
 
(24.6 - 32.9)
(20.1 - 27.4)
(16.7 - 30.3)
 
Perpetrator
28.2
27.2
32.2
 
25.3
20.8
11.8
**
 
(23.9 - 32.8)
(22.9 - 31.8)
(22.8 - 42.9)
 
(21.5 - 29.4)
(17.5 - 24.5)
(7.3 - 17.8)
 
Witness
61.0
64.1
75.6
*
58.1
54.4
59.0
 
 
(56.1 - 65.8)
(59.2 - 68.7)
(65.4 - 84.0)
 
(53.5 - 62.5)
(50.1 - 58.7)
(51.0 - 66.7)
 
Defraud or deceive
        
Victim
13.7
20.4
21.1
*
12.2
8.9
9.9
 
 
(10.5 - 17.5)
(16.6 - 24.6)
(13.2 - 31.0)
 
(9.5 - 15.5)
(6.6 - 11.6)
(5.8 - 15.6)
 
Perpetrator
3.7
6.1
1.1
 
3.1
0.9
0.6
*
 
(2.1 - 6.0)
(4.0 - 8.8)
(0.0 - 6.0)
 
(1.8 - 5.1)
(0.1 - 1.7)
(0.0 - 3.4)
 
Witness
33.8
34.2
44.4
 
24.1
17.2
22.4
*
 
(29.2 - 38.6)
(29.6 - 39.0)
(34.0 - 55.3)
 
(20.3 - 28.1)
(14.1 - 20.6)
(16.2 - 29.6)
 
Yelling and heavy pranks
        
Victim
29.7
29.9
31.1
 
21.2
18.5
14.9
 
 
(25.3 - 34.3)
(25.5 - 34.5)
(21.8 - 41.7)
 
(17.6 - 25.1)
(15.3 - 22.0)
(9.8 - 21.4)
 
Perpetrator
28.7
24.3
22.2
 
11.8
10.1
6.2
 
 
(24.3 - 33.3)
(20.2 - 28.7)
(14.1 - 32.2)
 
(9.1 - 15.0)
(7.7 - 13.0)
(3.0 - 11.1)
 
Witness
52.7
55.1
61.1
 
43.8
42.4
38.5
 
 
(47.7 - 57.6)
(50.2 - 60.0)
(50.3 - 71.2)
 
(39.3 - 48.3)
(38.2 - 46.7)
(31.0 - 46.5)
 
Unarmed aggression
        
Victim
30.1
24.0
18.9
 
21.8
17.3
16.8
 
 
(25.7 - 34.9)
(20.0 - 28.5)
(11.4 - 28.5)
 
(18.2 - 25.7)
(14.2 - 20.8)
(11.4 - 23.5)
 
Perpetrator
27.9
23.8
18.9
 
22.6
19.4
14.3
 
 
(23.6 - 32.6)
(19.8 - 28.2)
(11.4 - 28.5)
 
(19.0 - 26.6)
(16.1 - 23.0)
(9.3 - 20.7)
 
Witness
37.7
31.6
34.4
 
29.7
22.3
24.8
*
 
(33.0 - 42.6)
(27.1 - 36.3)
(24.7 - 45.2)
 
(25.6 - 34.0)
(18.9 - 26.1)
(18.4 - 32.3)
 
During life time
        
Armed threat
        
Victim
23.5
30.3
30.0
 
12.4
15.9
18.0
 
 
(19.5 - 28.0)
(25.9 - 35.0)
(20.8 - 40.6)
 
(9.6 - 15.7)
(12.9 - 19.2)
(12.4 - 24.8)
 
Perpetrator
4.2
4.6
1.1
 
1.7
ND
ND
NA
 
(2.4 - 6.6)
(2.8 - 7.1)
(0.0 - 6.0)
 
(0.7 - 3.2)
   
Witness
43.1
48.3
53.3
 
34.2
33.8
32.9
 
 
(38.3 - 48.1)
(43.4 - 53.2)
(42.5 - 63.9)
 
(30.0 - 38.7)
(29.8 - 37.9)
(25.7 - 40.8)
 
Severe threat
        
Victim
12.0
9.2
6.7
 
7.9
6.8
9.9
 
 
(9.0 - 15.6)
(6.6 - 12.4)
(2.5 - 13.9)
 
(5.6 - 10.7)
(4.7 - 8.9)
(5.8 - 15.6)
 
Perpetrator
1.5
1.0
  
0.2
0.4
0.6
 
 
(0.5 - 3.2)
(0.3 - 2.5)
ND
 
(0.0 - 1.2)
(-0.1 - 0.9)
(0.0 - 3.4)
 
Witness
31.9
30.6
28.9
 
24.0
17.0
19.3
*
 
(27.4 - 36.6)
(26.2 - 35.3)
(19.8 - 39.4)
 
(20.2 - 28.0)
(14.0 - 20.5)
(13.5 - 26.2)
 
Unarmed robbery
        
Victim
19.1
23.8
27.8
 
20.1
19.9
27.3
 
 
(15.4 - 23.3)
(19.8 - 28.2)
(18.9 - 38.2)
 
(16.6 - 24.0)
(16.6 - 23.5)
(20.6 - 34.9)
 
Perpetrator
5.1
3.9
1.1
 
1.5
  
NA
 
(3.2 - 7.8)
(2.2 - 6.2)
(0.0 - 6.0)
 
(0.6 - 3.0)
ND
ND
 
Witness
26.0
35.0
30.0
 
22.4
20.7
22.4
 
 
(21.8 - 30.6)
(30.3 - 39.8)
(20.8 - 40.6)
 
(18.8 - 26.4)
(17.3 - 24.3)
(16.2 - 29.6)
 
Armed physical aggression
        
Victim
12.5
13.3
8.9
 
4.8
3.0
3.7
 
 
(9.5 - 16.1)
(10.2 - 17.0)
(3.9 - 16.8)
 
(3.0 - 7.1)
(1.5 - 4.4)
(1.4 - 7.9)
 
Perpetrator
4.2
3.9
1.1
 
1.0
  
NA
 
(2.4 - 6.6)
(2.2 - 6.2)
(0.0 - 6.0)
 
(0.3 - 2.4)
ND
ND
 
Witness
42.2
41.7
43.3
 
28.4
26.4
21.1
 
 
(37.3 - 47.1)
(36.9 - 46.7)
(32.9 - 54.2)
 
(24.4 - 32.7)
(22.7 - 30.3)
(15.1 - 28.2)
 
Sexual aggression
        
Victim
2.5
3.6
3.3
 
6.6
8.9
9.9
 
 
(1.2 - 4.5)
(2.1 - 5.9)
(0.7 - 9.4)
 
(4.6 - 9.2)
(6.6 - 11.6)
(5.8 - 15.6)
 
Perpetrator
2.2
2.7
1.1
 
0.4
0.2
ND
 
 
(1.0 - 4.1)
(1.3 - 4.7)
(0.0 - 6.0)
 
(0.1 - 1.5)
(-0.2 - 0.5)
  
Witness
7.7
8.3
11.8
***
3.8
4.2
5.9
***
 
(5.5 - 10.4)
(6.1 - 11.0)
(7.3 - 17.8)
 
(2.6 - 5.1)
(3.0 - 5.3)
(3.6 - 9.1)
 
 
n = 408
n = 412
n = 90
 
n = 482
n = 542
n = 161
 
Medellin, Colombia. 2007
*P < 0.05 ** p < 0.01 *** p < 0.001
NA: Does not apply
ND: No data

Discussion

The most frequent studies about violence in representative community samples address the issue of victimization. The United Nations Interregional Crime and Justice Research Institute (UNICRI) has carried out several victimization surveys in representative samples of persons 16 years of age or older in urban populations in different continents. Unfortunately, it is impossible to compare the results from the present survey with those of the UNICRI surveys, since the UNICRI data refer to the last year, while items on the most severe forms of violence in the present survey refer to the respondent's lifetime [1520]. The populations with the highest risk of victimization were men (except for robbery and sexual assault), young people, and those without a partner. Our findings with respect to being a victim of armed robbery and aggression with blunt objects and firearms are consistent with the victimization range reported by the ACTIVA survey carried out by the Pan American Health Organization in several Latin American cities and Madrid, Spain [2123]. It is also worth noting that the armed assault figures reported in the current study are higher than the ones observed in the Epidemiologic Catchment Area Study of the U.S. National Institute of Mental Health, which states that "110 per 10,000 respondents sampled had ever used a weapon like a stick, knife or gun in a fight since the age of eighteen" [24].
There are few population studies that include witnessing violence. United States youth and their parents reported witnessing a homicide (6% and 3%), stabbing (19% and 4%) or shooting (26% and 7%) at markedly different degrees [25]. Violence witnessing ranges vary greatly among U.S. youngsters according to the group studied. For instance, Buka et al. state that youth living in American cities witnessed a great deal of violence in their communities, and that children and adolescents who report having witnessed murder ranged from a low of 1% in a "resort" group--middle- and upper-class, predominantly Caucasian youth to 47% in a low-income, predominantly African-American community. Variability was less in studies assessing predominantly low-income, urban youth, where witnessing murder was reported by one-quarter of the participants. The proportion who reported witnessing stabbings in their lifetime ranged from 9% in an affluent sample to 56% among the central-city summer camp population. The percentage of those witnessing a shooting sometime during their life ranged from 4% to 70%; among urban youth surveyed [26]. In Ontario, Canada, 34% of the population reported having been witness to aggression without a weapon during the last year, which is substantially lower than the percentage of the current study (42%) [27].
This study shows that aggression, victimization and being witness to violence are not randomly distributed in the population, but rather that certain groups are indeed more likely to have experience with one or more of these phenomena. These data are useful in defining appropriate aggression prevention policies, by calling attention to the observation that perpetrators are most likely to be young males from middle and low socioeconomic strata who have attended high school. It is also important to know the characteristics of victims, which tend to be young men with higher education --except when it comes to sexual violence--with the specific type of aggression varying in accordance with socioeconomic status. This study shows that there are more victims per perpetrator for the most severe forms of violence than for the less severe, which is in accordance with the reports that severe perpetrators make up around 5% of the population, but are responsible of 50% or more of the worst aggressions [28].
It would be advantageous for authorities to include, along with victims' characteristics, an extensive report of perpetrators' profiles in the epidemiologic surveillance system for violence. Victimization studies allow more precise estimation of the magnitude and distribution of the different forms of violence. Aggression studies allow identification of risk and protective factors associated with perpetrators, which should be the primary public health concern insofar as it is the perpetrators that produce violence and not the victims. This in turn enables the design of evidence-based policy for violence prevention and the promotion of coexistence, as has been done in Medellin and the surrounding metropolitan area. We also suggest that the UNICRI surveys include information on perpetrators and, if possible, on witnesses.
The figures we present for Medellin are indicative of a reduction in the majority of types of violence when compared with data from a similar study of 2003-2004 [4]. However, it is prudent to point out that this research, like all cross-sectional survey studies, has its limitations. Responses may have been affected by recall bias and feelings of uneasiness produced by answering questions of such seriousness in residential areas marked by high levels of aggression. It must also be noted that the sample did not include institutionalized individuals such as those found in jails, prisons, the military, and convents. Some of these groups are reportedly much more likely to report episodes of violence and victimization than are non-institutionalized residents. However, the statistical effect of including these groups in the analysis cannot be verified. Thus, caution must be exercised when drawing conclusions; the results cannot be generalized to institutionalized populations. Nonetheless, we speculate that the indices of violence reported in this study are underestimated due to the non-inclusion of these populations.
The strengths of the study are also worth highlighting. The current study casts light on an important phenomenon in a developing country. Secondly, it allows for the international comparison of data, since it employs the WHO global population standard (15-60 years of age) in the calculation of adjusted rates (Table 2). The fact that the 9% no-response rate was lower than that usually reported in this type of study and that the lack of answers was not concentrated in any particular group allows us to deduce that the conclusions are not overly biased. This study estimates the prevalence proportions of having been a witness, as well as a victim and perpetrator, which gives new perspectives on the knowledge of the distribution of violence in communities, since cross-sectional surveys carried out on random population samples tend to focus on the study of victims. The formulation of public policies for the prevention and control of violence would be better founded on scientific evidence that includes the distributions and characteristics of perpetrators and witnesses as well those of victims.

Conclusions

Despite having registered a nearly 90% decline in homicides over the last fifteen years, Medellin continues to have one of the highest rates of homicide in Latin America. Aggression is not randomly distributed. Men reported the highest prevalence of being victims, perpetrators and witnesses in all forms of violence, except for robbery and sexual violence. The number of victims per perpetrator was positively correlated with the severity of the type of violence. The highest victimization proportions over the previous twelve months occurred among minors. Perpetrators are typically single males of lower socioeconomic strata.
Periodic surveys should be included in systems for epidemiological monitoring of violence, not only of victimization but also on perpetrators, in order to both quantify the magnitude of different forms of violence and estimate risk and protective factors that can help in the formulation of policies for violence prevention. To this end, UNICRI could include information on the characteristics of aggression and perpetrators in its surveys.

Acknowledgements

This study was financed by Area Metropolitana del Valle de Aburrá and the University of Antioquia, Contract 500-2006.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

LFD conceived the study, and leaded its design and coordinated its implementation and helped to draft the manuscript; AR participated in its design and coordination and was responsible to draft the manuscript, and NM participated in the design of the study and performed the statistical analysis.
All authors read and approved the final manuscript
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