569059 research-article2015

JIVXXX10.1177/0886260515569059Journal of Interpersonal ViolenceRalo et al.


Prevalence of Family Violence and Associated Factors Among In-School Adolescents in São Paulo, SP, Brazil

Journal of Interpersonal Violence 1­–16 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0886260515569059 jiv.sagepub.com

Janaina Maria Ralo,1 Neia Schor,1 Carlos Mendes Tavares,2 and Valter Silva3

Abstract Family violence is a social and public health issue across the world for many populations and affects many different types of people, for example, children, women, and vulnerable adults. Adolescents are one of the main victims of this important phenomenon. This article estimates the prevalence of family violence in adolescents and associated factors. The study was carried out in 2012 with a probability and representative sample of 656 adolescents aged between 11 and 17 years who were enrolled at public schools located in the extreme South of the city of São Paulo. The association was tested by the proportion test, Pearson’s chi-square or Fischer’s exact test, and Poisson regression adjusted by robust variance estimation, considering a level of significance of 5%. Among adolescents, 38.9% reported having been victims of family violence. Women were victimized with higher frequency (44.1%). The factors associated with prevalence of family violence were being of the female sex (prevalence ratio [PR] = 1.47; 95% confidence interval [CI] = [1.20, 1.80]) and living only with the father (PR = 1.52; 95% CI = [1.11, 2.08]).


de São Paulo, Brazil da Integração Internacional da Lusofonia Afro-Brasileira, Redenção, Brazil 3Universidade Federal de São Paulo, São Paulo, Brazil 2Universidade

Corresponding Author: Janaina Maria Ralo, Avenida Miguel Stéfano, 400 apto 85 Saúde São Paulo CEP 04301-000, Brazil. Email: [email protected]


Journal of Interpersonal Violence 

The prevalence of adolescents who were victims of family violence is high; however, special attention must be paid to women and adolescents who live only with their father—they were established, in this study, as a risk group. Epidemiological studies of this nature are important to reveal the reality of family violence and to aid the construction of intersectoral public policies to promote health, prevent violence, and foster a peaceful culture. Keywords domestic violence, adolescent, population’s characteristics, alcohol consumption, illicit drugs

Introduction Violence has become one of the most serious social and public health problems across the world (Krug, Mercy, Dahlberg, & Zwi, 2002). Although its contribution to mortality by external causes is low, family violence is an expressive problem that causes severe and long-lasting consequences for individuals, families, and the society (Peden, Oyegbite, & Ozanne-Smith, 2008). According to World Health Organization (WHO; Peden et al., 2008), violence can be defined as the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, which either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment, or deprivation. In addition, it is divided into typologies according to characteristics of those who commit them: self-directed, collective, and interpersonal, in which the violence occurs between family members. It can be committed inside and outside the home by any member of the family who is in a power relationship with the victim. It also includes people who are playing the role of father or mother, even if there are no blood ties (Azevedo & Guerra, 1989; Day, Lisieux, Zoratto, 2003). The term family violence is interpreted by many as violence between partners and occurs only in the home setting. However, family violence can include events that occur outside the home environment and from an expanded family, that is, grandparents, aunts and uncles, cousins, stepfathers, and stepmothers, all living nearby or in the same household. In addition, family violence is the official term used by Medical Subject Headings (MeSH) as a controlled vocabulary for the purpose of indexing journal articles and books under the theme. It is manifested in several forms and with different severity levels, and it can be classified according to the following natures: physical, sexual, and psychological violence, and negligence (Brasil, 2001; Peden et al., 2008).

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An inquiry carried out in 2008 (Brasil, 2010) at urgency and emergency services in 22 cities distributed in 15 states of Brazil using data derived from the Notification/Investigation Form for Domestic, Sexual, and/or other types of Violence has shown that 27% (n = 2,389) of the registered cases occurred among individuals aged 10 to 19 years; the highest proportion was identified among women (28.8%; n = 1,798). In the majority of cases, there was only one perpetrator (69.4%) of the male sex (66.3%) who had a close relationship with the victim, usually a spouse (14.1%), friend (14.0%), father (8.3%), or mother (8.6%). Alcohol consumption by the perpetrator was observed in 29.6% of the occurrences, ranging from 22.7% among men to 30.3% among women. Studies have shown that the consequences of the exposure to family violence include an increased chance of reproducing transgressive and violent behaviors, early initiation into sexual life and risk behavior, and a higher chance of presenting depressive symptoms (Avanci, Assis, & Oliveira, 2008; Bordin, Silvestre, Nascimento, & Duarte, 2006; Teixeira & Taquette, 2010). The majority of studies about family violence in minors focuses on phase childhood, without taking into account its specificities; in addition, they use specific groups—such as victims assisted in health care services, shelters, and organizations such as the Child Protective Services, and pregnant adolescents—or are restricted to one of the typologies of violence (Ferriani, Bertolucci, & Silva, 2008; Marinheiro, 2003). Other studies, through the qualitative methodological approach, are limited to the evaluation of health care services or to the health care professional’s responsibility for the notification of cases of family violence (Brito, Zanetta, & Mendonça, 2005; Saliba, Garbin, Garbin, & Dossi, 2007). Thus, it is possible to state that studies that investigate the prevalence of family violence among adolescents in its completeness are still scarce; this scarcity contributes to social invisibility, as this is a phenomenon that is installed in the intimacy of family life and is based on the establishment of abusive power relationships. Therefore, the present study aimed to identify the prevalence of family violence and to estimate related factors among inschool adolescents.

Method This is a cross-sectional study with a probability sample that is representative of adolescents studying at public schools located in the extreme South region of the city of São Paulo, and it was carried out during the period from May to August 2012. The criterion for inclusion in the research was being regularly enrolled in the eighth or ninth grades of elementary school or in the first


Journal of Interpersonal Violence 

grades of high school. These grades were chosen because they encompass adolescents who are in an intermediate phase of adolescence: They are neither in the extreme of childhood, nor in the borders of youth (Conselho Nacional dos Direitos da Criança e do Adolescente [National Council for the Rights of the Child and the Adolescent][CONANDA], 1990; Peden et al., 2008). Furthermore, it was expected that they had a higher degree of understanding of the data collection instrument in terms of reading and filling it in. A probability sampling technique with a single-stage sampling plan was used (cluster sampling). It included division by schools with a draw (in all the selected schools) of classes by year of study and the subsequent listing of all students who had the characteristics of interest to the study. Sample size was calculated based on the percentage of adolescents who were victims of family violence, estimated at 50%, with sampling error estimated at 4% and with a 95% CI. The prevalence of 50% was chosen because national studies provide data of health and police notification of violence (BRAZIL, 2010); they did not offer certainty about accuracy due to underreporting. Moreover, the prevalence of 50% ensures the largest possible sample. The calculated sample size corresponded to 600 adolescents, and 15% were added to this figure to include the possibility of loss of sample. Thus, the final planned sample comprised 690 adolescents. The study’s aim, the procedure, the voluntary nature of participation, and the guarantee of anonymity of individual information were explained to all the participants. The parents or guardians were requested to sign a consent document that had been previously approved by the Research Ethics Committee of the School of Public Health of the Universidade de São Paulo, under the opinion no. 121/12, on June 4, 2012. A self-administered questionnaire was used, in which the majority of the questions were closed and there were some open ones. The questions were based on studies validated in the academic environment (Schraiber, Latorre, & França-Junior, 2010; Tavares, 2009; Vital, 2010), and this type of questionnaire has proved to be highly efficient in studies of special groups (Schraiber, D’oliveira, França-Junior, & Grupo de estudos em População, Sexualidade e Aids, 2008). The questionnaire was administered during class time for an average of 40 min. The study’s dependent variable was victimization by family violence, according to the adolescent’s report, in the 6 months prior to the research as there was a higher chance that they would recall the event to avoid memory biases. It was inferred from the marking of at least one of the affirmatives of the question: “Mark with an X if in the last six months someone in your home treated you in the following way” and defined as “family violence.” The event was categorized as true if there were one or more answers marked, and the event was categorized as false if the item “no one in my home treated me

Ralo et al.


like this in the last six months” was marked. The exposure factors (i.e., independent variables) were the following: sex, age, skin color/race, religion, housing conditions, number of inhabitants, cohabitation, and use of alcohol and drugs by family members. The descriptive analysis was presented by absolute (n) and relative (%) frequencies. Differences in the proportions between the groups of victimized and non-victimized adolescents by family violence were first compared in relation to each factor individually by means of Pearson’s chi-square test or Fischer’s exact test. Subsequently, these groups were compared in relation to the diverse associated factors. To calculate the PR, a 95% CI was used as well as the obtention of multiple analysis; PR is the analogous surrogate of relative risk for cross-sectional studies and it was determined by PRs between victims and non-victims. The associated factors that presented values of p < 20% in the univariate analysis were included in the multiple Poisson regression model and were adjusted by robust variance estimation. A significance level of 5% was adopted.

Results Among the 690 adolescents included, there was 5% of loss of sample due the following reasons: incorrect answers to the instrument and/or adolescents who refused to participate in the study. These losses were not statistically important so as to negatively affect the representativeness of the sample, because they were within what had been predicted by the sample calculation (i.e., 600 adolescents plus 15%). Therefore, the final sample was representative and encompassed 656 adolescents effectively studied. A little more than 1/3 of the in-school adolescents reported that they had been victims of family violence, and this was more frequent among female adolescents who stated being aged between 14 and 15 years and who lived with their parents (Table 1). When the relationship between adolescent and perpetrator was established, it was verified that siblings were perpetrators of violent acts more frequently (Figure 1). Both in the univariate and in the multiple models, the factors associated with family violence were being of the female sex and cohabiting only with the father (Tables 2 and 3).

Discussion This is one of the few Brazilian studies that have identified the magnitude of family violence in its diverse typologies among in-school adolescents and the


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Table 1.  Distribution of the In-School Adolescents According to Family Violence and Possible Associated Variables—City of São Paulo (Extreme South Region), SP, Brazil, 2012. Non-Victim Variable Sex (n = 649)a  Male  Female  Total Age (n = 647)a   11 to 13   14 to 15   16 to 17  Total Skin color/race (n = 656)  White   Mixed ethnicity (Black and White)  Yellow  Indigenous  Othersb  Black  Total Religion (n = 653)a   Has a religionc   Does not have a religiond  Total Housing conditionse (n = 656)   Has access to the 3 resources   Does not have access to the 3 resources together  Total Number of inhabitants (n = 655)a   Less than 3   3 to 4   5 to 6   More than 6  Total Cohabitation (n = 656)   Father and mother   Just the mother   Just the father   None of the parents  Total









186 212 398

68.9 55.9 61.3

84 167 251

31.1 44.1 38.7

270 379 649

41.6 58.4 100.0

209 171 12 392

64.3 57.2 52.2 60.6

116 128 11 255

35.7 42.8 47.8 39.4

325 299 23 647

50.2 46.2 3.6 100.0

103 179

60.6 60.5

67 117

39.4 39.5

170 296

25.9 45.1

21 10 30 58 401

52.5 47.6 71.4 66.7 61.1

19 11 12 29 255

47.5 52.4 28.6 33.3 38.9

40 21 42 87 656

6.1 3.2 6.4 13.3 100.0

288 111 399

61.9 59.0 61.1

177 77 254

38.1 41.0 38.9

465 188 653

71.2 28.8 100.0

283 118

62.1 59.0

173 82

37.9 41.0

456 200

69.5 30.5








13 159 175 54 401

72.2 64.4 57.8 62.1 61.2

5 88 128 33 254

27.8 35.6 42.2 37.9 38.8

18 247 303 87 655

2.7 37.7 46.3 13.3 100.0

282 103 10 6 401

64.5 56.9 41.7 42.9 61.1

155 78 14 8 255

35.5 43.1 58.3 57.1 38.9

437 181 24 14 656

66.6 27.6 3.7 2.1 100.0


p .001*       .135         .312               .492       .459    



Ralo et al. Table 1.  (continued) Non-Victim Variable



Alcohol consumption among family members (n = 656)  No  Yes  Total Drug use among family members (n = 656)  No  Yes  Total


Total %




p .983

228 173 401

62.6 59.2 61.1

136 119 255

37.4 40.8 38.9

364 292 656

55.5 44.5 100.0


375 26 401

60.9 65.0 61.1

241 14 255

39.1 35.0 38.9

616 40 656

93.9 6.1 100.0



referring to adolescents who did not answer the variable in question were excluded. not know or did not answer. Evangelical/Protestant, Spiritist. dI do not have a religion but I believe in God; I do not believe in God. eConcerning access to the resources: water, electricity, and sewage. *p < .05 by Pearson’s chi-square test or by Fischer’s exact test. bDoes



Prevalence (%)





32.7 22.7



0 Father Mother Siblings Othersa Perpetrators of the violence as reported by adolescentsb

Figure 1.  Prevalence of victimization by family violence according to relationship with the perpetrators. City of São Paulo (extreme South region)—SP, Brazil, 2012. aOthers:


grandparents, uncles and aunts, cousins, stepfather/stepmother. choice question reported by adolescents.


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Table 2.  Estimations of the Univariate Poisson Regression Model With Robust Variation for Family Violence—City of São Paulo (Extreme South Region), SP, Brazil, 2012. Family Violence Variable Sex   Male (reference)  Female Age   11 to 13 years (reference)   14 to 15 years   16 to 17 years Cohabitation   Father and mother (reference)   Just the mother   Just the father   None of the parents Skin color/race   White (reference)   Mixed ethnicity (Black and White)  Yellow  Indigenous  Others  Black Religion   Has a religion (reference)   Does not have a religion Resources   Has access to the 3 resources (reference)   Does not have access to the 3 resources together Number of inhabitants   3 to 4 (reference)   Less than 3   5 to 6   More than 6 Alcohol consumption among family members   No (reference)  Yes Drug use among family members   No (reference)  Yes


95% CI



[1.15, 1.75]


1.20 1.34

[0.99, 1.46] [0.85, 2.10]

  .069* .204

1.21 1.64 1.61

[0.99, 1.50] [1.15, 2.36] [1.01, 2.58]

  .069 .007* .047*

1.00 1.21 1.33 0.72 0.85

[0.79, 1.27] [0.83, 1.75] [0.85, 2.08] [0.43, 1.21] [0.60, 1.20]

  .980 .330 .214 .219 .349


[0.87, 1.32]



[0.88, 1.32]


0.78 1.19 1.06

[0.36, 1.67] [0.96, 1.47] [0.78, 1.46]

  .523 .117 .698


[0.89, 1.31]



[0.58, 1.37]


Note. PR = prevalence ratio; CI = confidence interval. *p ≤ .20 by univariate Poisson regression, with robust variance.


Ralo et al. Table 3.  Estimation of the Multiple Poisson Regression Model With Robust Variance for Family Violencea—City of São Paulo (Extreme South Region), SP, Brazil, 2012. Family Violence Variable Sex   Male (reference)  Female Age   11 to 13 years (reference)   14 to 15 years   16 to 17 years Cohabitation   Father and mother (reference)   Just the mother   Just the father   None of the parents


95% CI



[1.20, 1.80]

Prevalence of Family Violence and Associated Factors Among In-School Adolescents in São Paulo, SP, Brazil.

Family violence is a social and public health issue across the world for many populations and affects many different types of people, for example, chi...
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