Funded by the National Institute on Alcohol Abuse and Alcoholism (R37- AA10908)

Population Attributable Risk, Intimate Partner Violence and Drinking

Raul Caetano, M.D., Ph.D.

Susie Mikler, M.P.H., Ph.D.

University of Texas School of Public Health

Objectives of this Presentation

Briefly discuss the application of the population attributable risk in assessing population level alcohol control policies to prevent intimate partner violence.

Prevalence of IPV

Male to Female Partner

Violence (MFPV)

Female to Male Partner

Violence (FMPV)

1975: 12% 1975: 11.6%

1985: 11.6% 1985: 12.4%

1992: 9% (minor) 1992: 9% (minor)

1992: 2% (severe) 1992: 4.5% (severe)

Prevalence of Violence: 1995 National Study of Couples

79%

13%

8%

No IPV Moderate Severe

Violence, drinking and alcohol policy

• As suggested by Room and Rossow (2000) it is important to consider different types of violence: domestic, bar and street, collective (e.g., war atrocities).

• The association between alcohol and IPV in general population data are not strong and not always consistent.

• This is probably due to the nature of IPV (mostly moderate) and drinking (mostly light) in these data.

• The effect of alcohol-related policies on IPV is difficult to estimate because the Population Attributable Risk (PAR) is dependent on the definition of exposure.

Population Attributable Risk

PAR = It – Io/It x 100

It: Incidence among the exposedIo: Incidence among the non-exposed

Rate of disease in the total population that is attributable to the exposure

Estimates in the Literature

• 33% of assaults (Lenke)

• 50% of convicted assaults (Skog & Bjorks, 1988)

• 69% of homicides, 47% of assaults (Norstrom, 1998)

• Positive relationship with per capita consumption in aggregate studies

Population Attributable Risk %

IPV MFPV FMPV

Drinking

Perp/Victim 19 25 0

Perp 28 0

Binge

Perp/Victim 27 32 17

Perp 27 4

If Exposure Is Drinking in the Event

• Alcohol exposed IPV cases are those among drinkers drinking in the event.

• IPV cases among drinkers not drinking in the event are not exposed. In U.S. data, about 70% of MFPV and 80% of FMPV events by drinkers had no drinking in the event.

Other Considerations

• Violence literature has not considered a measure such as “drink 6 hours before” the event, which has been used in the injury field.

• Consider culture: expectancies about alcohol effects.• Consider drinking patterns: how much binge and

intoxication?• Consider population assumptions about the relationship

between drinking and intimate partner violence.• Consider then the scientific and political uses of the PAR.

Other Considerations

• Consider that PAR may vary across population subgroups because strength of association alcohol/IPV varies.

• There are no specific alcohol-control policies to prevent intimate partner violence (or domestic violence).

• Policies should not be justified by IPV prevention alone, but should based on the general prevention of violence and other problems.

• Policy effectiveness may have to be assessed by aggregate-level studies.

The End

Alcohol and Intimate Partner Violence

Issues for consideration: Is this association causal and if so which mechanisms

underlie it.Many aggressive events are not associated with alcohol. It is difficult to establish a temporal relationship

between drinking and aggression.Alcohol and aggression may be both associated with a

third factor (e.g., Impulsivity).The association may be due to expectancies about the

effect of alcohol.

Overall Design

1995 National Survey of Couples

1635 Couples Interviewed

555 Whites, 358 Black, 527 Hispanics

85% Response rate

2000 Follow-up National Survey of Couples

1392 couples reinterviewed,

1136 intact couples.

406 White, 232 Black and 387 Hispanic couples

72% Response rate

Other Methodological Features

Multistage area household probability sample.

Both partners interviewed separately.

Male-to-Female-Partner Violence (MFPV) and female-to-male partner violence (FMPV) measured with the Conflict Tactics Scale.

Upper-bound estimate used; violence considered to have occurred if either partner reports event.

Other Methodological Features

1995: Interviews of about 1 hour with main respondents and of about 20 minutes with partner. 2000: Interviews of about 1 hour with both

Interviews conducted by trained interviewers. Standardized questionnaire used (close ended). Bilingual interviewers (Spanish/English) available

on request. Spanish questionnaire available on request.

Items in the Conflict Tactics Scale

Threw something (at him/her) (moderate) Pushed, grabbed or shoved (moderate) Slapped (moderate) Kicked, bit or hit (severe) Hit or tried to hit with something (severe) Beat up (severe) Choked (severe) Burned or scalded (severe) Forced sex (severe) Threatened with a knife or gun (severe) Used a knife or gun (severe)

Data Coverage

Alcohol consumption was assessed with a series of questions covering quantity and frequency of drinking wine, beer and spirits in the past 12 months.

Sociodemographic factors: Gender, age, income, education, marital status, place of birth, religion, employment status, occupation, number of children <17 at home, relationship length.

Data Coverage

Psychosocial factors: Childhood history of parent-perpetrated violence, witnessing violence between parents, approval of marital aggression, impulsivity, risk taking.

Acculturation. Drug use. Residential addresses matched to Census Tract

number. 1990 Census data appended to the geocoded sample in 1995.

Cross-Sectional Results

Overall Rates of Male to Female Partner Violence

21

12

16

23

30

17

0

5

10

15

20

25

30

35

40

45

Any MFPV* Any FMPV

White

Black

Hispanic

Chi-square across ethnic groups: * p < .01

*

*

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

WhiteBlack

Hispanic

* Chi-square across ethic groups: p < .05

Type of Male to Female Partner Violence

Push Slap Kick BurnBeatHitWith

ChokeThrow Threat/Knife or

Gun

Sex Use/Knife or

Gun

*

*

* *

Moderate 10% Severe 4%

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

WhiteBlack

Hispanic

* Chi-square across ethnic groups: p < .05

Type of Female to Male Partner Violence

Push Slap Kick BurnBeatHitWith

ChokeThrow Threat/Knife or

Gun

Sex Use/Knife or

Gun

* *

*

* *

Moderate 11% Severe 7%

Unidirectional and Bidirectional Intimate Partner Violence

0

10

20

30

40

50

60

70

MFPV FMPV Both

WhiteBlackHispanic

Male to Female Partner Violenceby Drinking Patterns

6

10

14

11

16

31

41

15

19

24

18

1317

7

17

0

5

10

15

20

25

30

35

40

45

Abstain Infrequent Less Frequent Frequent Frequent HeavyDrinker

White

Black

Hispanic

Chi-square: p:ns

Female to Male Partner Violenceby Drinking Patterns

12

19

5051

79

3229

20

33

1515

24

27

2517

0

10

20

30

40

50

60

70

80

90

Abstain Infrequent Less Frequent Frequent Frequent HeavyDrinker

White

Black

Hispanic

Chi-square: Black - p<.001, Hispanic - p<.05

Odds Ratios from Multiple Logistic Regression on Male to Female Partner

Violence

White Black Hispanic

Male Alcohol Problems

- 10.33 (4.44-24.03) -

Female Alcohol Problems

- 5.40 (1.97-14.81) -

Variables in the analysis: Income, education, employment, age, marital status, number of children, relationship length, impulsivity, volume of alcohol consumption.

Odds Ratios from Multiple Logistic Regression on Female to Male Partner

Violence

White Black Hispanic

Male AlcoholProblems

- 2.84 (1.17-6.89) -

Female AlcoholProblems

6.57 (1.87-23.06) 6.61 (2.50-17.51) -

Variables in the analysis: Income, education, employment, age, maritalstatus, impulsivity, volume of alcohol consumption.

Other factors associated with Intimate Partner Violence

Risk factors for MFPV: Young age, lower income, unemployment, childhood physical abuse, approval of aggression, alcohol problems, neighborhood poverty.

Risk factors for FMPV: Young age, childhood physical abuse, alcohol, number of children, approval of aggression, alcohol problems, neighborhood poverty.

Longitudinal Results

Initial Research Questions

What is the prevalence of IPV across ethnic groups in 1995 and 2000?

What is the stability, remission and incidence of IPV across ethnic groups?

What is the course of IPV (no violence to moderate to severe violence) across ethnic groups?

What are the predictors of stability, remission and incidence?

Non-Response Analysis

Non-respondents were more likely to be: Younger men (18-29), unemployed men, women 40 to 49.

Women who experienced abuse during their childhood were less (OR=0.6) likely to be among non-respondents.

Gender-specific multivariate logistic regression models accounted for only 5% of the variance in survey participation.

Prevalence of Intimate Partner Violence: 1995 and 2000 (1)

17

10

27

22

2624

0

5

10

15

20

25

30

1995 2000

White

Black

Hispanic

(1) Intact Couples Only

* *

* Chi-square: p>.01

Stability and Incidence of Intimate Partner Violence (1)

38

6

51

14

57

14

0

10

20

30

40

50

60

Stability Incidence

White

Black

Hispanic

(1) Intact Couples Only

*

**

•*Chi-square: Hispanic vs. White, p>.01•**chi-square: p>.01

Odds Ratios from Multinomial Logistic Regression: Alcohol Problems a

Incidence

Re: No violence

Recurrence

Re: No violence

Male Alcohol

Problems

1.2 (0.2-5.4) 1.8 (0.6-5.9)

Female Alcohol Problems

0.1 (0.01-.6)* 1.7 (0.6-5.2)

* Significant at p<.05a Also controlling for: drug use, childhood victim., parental violence, impulsivity, attit. toward violence, age, income, education, emplm. status, marital status, length of relationship, ethnicity, weekly N drks, 5 or +.

2000 Status of 1995 Non-Violent Couples

94

5 1

87

121

86

112

0102030405060708090

100

No Violence Moderate SevereViolence

WhiteBlackHispanic

66

26

8

59

30

10

58

37

4

0

10

20

30

40

50

60

70

No Violence Moderate SevereViolence

WhiteBlackHispanic

2000 Status of 1995 Couples with Moderate Violence

2000 Status of 1995 Couples with Severe Violence

52

43

5

39

27

35

28

49

23

0

10

20

30

40

50

60

No Violence ModerateViolence

SevereViolence

WhiteBlackHispanic*

*chi-square: p>.03

Odds Ratios from Logistic Regression: 1995 Alcohol-Related Predictors of 2000 MFPV

White Black HispanicMen N drinks ** .9 (.8 - 1.1) 1.0 (.9 - 1.2)

Women N drinks .3 (.1 - .7)* 1.1 (.9 - 1.4) **

Men 5+ .4 (.1 – 1.3) .6 (.2 – 1.8) 1.2 (.6 – 2.7)

Women 5+ 3.6 (1.1 –12.1)* 2.7 (.5 – 15.7) .6 (.3 – 1.5)

Men’s Problems 3.0 (.7 – 12.4) 2.9 (.4 – 20.2) 1.2 (.5 – 3.3)

Women’s Problems ** 3.6 (.6 – 21.1) 2.0 (.4 – 10.5)

Also controlling for: childhood victim., parental violence, impulsivity, attit. toward violence, age, income, education, marital status, MFPV and FMPV in 95.

* p<.05; **variable failed criteria for inclusion: p=.25

Odds Ratios from Logistic Regression: 1995 Alcohol-Related Predictors of 2000 FMPV. a

White Black HispanicMen N drinks 1.2 (1.1 – 1.3)* ** **

Women N drinks ** ** **

Men 5+ .2 (.1 – 1.2) 2.6 (.7 – 10.0) .9 (.4 – 1.8)

Women 5+ 3.3 (.6 – 18.3) 1.9 (.4 – 9.7) 1.3 (.6 – 2.6)

Men’s Problems .9 (.3 – 3.0) 1.7 (.3 – 8.4) 1.1 (.4 – 2.9)

Women’s Problems ** 3.0 (.4 – 25.5) 1.7 (.4 – 7.0)

a Also controlling for: childhood victim., parental violence, impulsivity, attit. toward violence, age, income, education, marital status, MFPV and FMPV in 95.

* p<.05; ** variable failed criteria for inclusion: p =.25

Goodness of fit indices

Hu and Bentler (1999)

• Comparative Fit Index (CFI)

– Between .90 and .95< : Acceptable fit

– >.95 : Good fit

• Root Mean Square Error of Approximation (RMSEA)

– RMSEA < 0.05 Close fit

– RMSEA > .05 ≤ 0.08 Reasonable fit

– RMSEA > 0.1 Poor fit

• Ratio of chi-square to degrees of freedom (χ2 / df) = 2

IPV 1995

Male Alcohol Problems

IPV 2000

Female Alcohol Problems

Female 5 plus drinks

Female Alcohol Problems

Female 5 plus drinks

Male Alcohol Problems

Male 5 plus drinks

Figure 1. Paths for the core set of associations in the model – WHITES1995 2000

Female Alc. Vol.Female Alc. Vol.

Male Alc. volume Male Alc. volume Male 5 plus drinks

0.66 *

049 *

0.14

0.35 *

0.38 *

0.41 *

0.71 *

0.42 *

0.10 *

0.42 *

0.05 0.06

0.48 *

0.12 *0.09

0.16 *0.39 *

0.39 *

0.01

- 0.14 *

0.19 *

0.27 *

0.32 *0.15 *

0.07

0.060.31 *

0.13 *

0.13 *

CFI = .879CFI = .879

χχ 2 = 462.2 2 = 462.2

df = 238, df = 238, p=.0000 p=.0000

RMSEA = RMSEA = 0.0510.051

IPV 1995

Male Alcohol Problems

IPV 2000

Female Alcohol Problems

Female 5 plus drinks

Female Alcohol Problems

Female 5 plus drinks

Male Alcohol Problems

Male 5 plus drinks

Figure 2. Paths for the core set of associations in the model – BLACKS1995 2000

Female Alc. Vol.Female Alc. Vol.

Male Alc. volume Male Alc. volume Male 5 plus drinks

0.63 *

0.38*

0.13

0.42 *

0.66*

0.36 *

0.66 *

0.48 *

0.16

0.51 *

0.21*0.03

0.39 *

0.04

0.29 *

0.190.43

0.43 *

- 0.06

- 0.07

0.34 *

0.27 *

0.23 *0.22 *

0.18 *

0.110.08

0.09

0.08 *

CFI = .766CFI = .766

χχ 2 = 592.3 2 = 592.3

df = 238, df = 238, p=.0000 p=.0000

RMSEA = RMSEA = 0.0890.089

IPV 1995

Male Alcohol Problems

IPV 2000

Female Alcohol Problems

Female 5 plus drinks

Female Alcohol Problems

Female 5 plus drinks

Male Alcohol Problems

Male 5 plus drinks

Figure 3. Paths for the core set of associations in the model – HISPANICS1995 2000

Female Alc. Vol.Female Alc. Vol.

Male Alc. volume Male Alc. volume Male 5 plus drinks

0.32 *

0.31*

0.29 *

0.46 *

0.17

0.36 *

0.43 *

0.46 *

0.11

0.49 *

0.20*-0.07

0.40 *

0.025

- 0.045

0.260.33 *

0.43 *

0.06

0.01

0.44 *

0.62 *

0.27 *0.19 *

0.11

0.110.12

0.01

0.10 *

CFI = .888, CFI = .888,

χχ 2 = 430.6 2 = 430.6

df = 238, df = 238, p=.0000 p=.0000

RMSEA= RMSEA= 0.0490.049

Cross-sectional Associations

White (n=366) Black (n=190) Hispanic (n=344)

Paths Estimated 1995 2000 1995 2000 1995 2000

Male Volume Alc Problems * * NS * NS *

Male Binge Alc Problems * * * * * *

Male Alc Problems IPV NS * * NS * NS

Male Binge IPV NS NS NS NS NS NS

Female Volume Alc Problems * NS NS NS NS NS

Female Binge Alc Problems * * NS NS * NS

Female Alc Problems IPV NS NS * * NS NS

Female Binge IPV * Negative * NS NS NS NS

Correlations

Male Volume & Binge * * * * * *

Female Volume & Binge * * * * * *

Male and Female Volume * * * * * *

Summary of Longitudinal Results

Most couples reporting IPV at baseline do not report IPV five years later.

The likelihood of reporting IPV five years later is related to the severity of IPV at baseline. This is equally true of MFPV and FMPV.

Summary of Longitudinal Results

Male weekly N. of drinks is associated with incidence.

Male and female (Blacks only) alcohol problems associated with IPV.

Hispanics are more likely than Whites to report incident IPV (OR=2.9, 1.2-7.1).

Blacks are 3 times more likely than Whites to report IPV in both 1995 and 2000 (OR=2.9, 1.2-6.9).

Predictors of Intimate Partner Violence

Moderate

Severe

Sociodem. Char.

Personality Char.

Relationship Char.

Personal History

Situational Factors

Contextual Factors

Cultural Factors

Alcohol Problems

Psychiatric Diagnoses

Alcohol Dependence

Drug Dependence

VIOLENCE

Intimate Partner Violence: A Longitudinal Perspective

Violence ContinuumModerate Severe

No Violence

Time

Couple’s Level of Agreement in Reporting Intimate Partner Violence (Kappa)

Violent Act Male to Female Female to Male

Threw somethingPushed, grabbed, or shovedSlappedKicked, bit, of hitHit or tried to hit with somethingBeat upChokedBurned or scaldedForced sexThreatened with knife or gunUsed knife or gun

Any violence

.36

.49

.38

.35

.23

.22

.30*

.15**

.39

.40

.45

.34

.34

.28

.00

.28

.00

.16

.13*

.36

* Not calculated, 2 or more cells very close to 0.

Rates of Intimate Partner Violence in the U.S.: Lower and Upper Bound Estimates

56

8

14

18

21

0

5

10

15

20

25

MFPV FMPV ANY

Lower Bound

Upper Bound

Two Different Ways to Report the Prevalence of Intimate Partner Violence

MFPV Only

FMPV Only Both

No

MFPV

FMPV

No

Proportional Representation of MFPV Only, FMPV Only and Bidirectional Violence Among IPV Cases

17 919

39

30

35

4461

46

0%10%20%30%40%50%60%70%80%90%

100%

White Black Hispanic

BothFMPVMFPV

Overall Rates of Intimate Partner Violence Among U.S. Hispanics by Acculturation

1413

20

34

18 18

0

5

10

15

20

25

30

35

Any MFPV Any FMPV*

Low

Medium

High

* Chi-square: p <.01

*

Odds ratios and from Multiple Logistic Regression: Acculturation and IPV.

Male to Female Female to Male

(Ref: Low/Low)

Medium/Medium 3.71 (1.42-9.71) 10.92 (3.96 – 30.12)

Low/Medium 3.17 (1.01 – 9.96) 9.14 (2.43 – 34.38)

High/Medium 3.14 (1.06 – 9.31) 4.93 (1.15 – 21.13)

High/High 5.59 (1.29 – 24.36)

Variables in the analysis: Income, education, age, marital status, childhoodvictimization, approval of aggression, drinking patterns, impulsivity.

Association Between IPV and Expectancies

How likely to be aggressive?

Violence No violence

No/not much chance

16% 13%

Strong/very strong chance

19% 7%

OR (Strong/very strong vs. no: 3.2 (1.3-7.9). Controlling for gender, age, ethnicity, income, attitudes towards IPV, impulsivity, excuses.

malcprob 2000

ipv 1995

malcvol 2000

ipv 2000

falcvol 2000

falcprob 2000

falcvol 1995

falcprob 1995

malcvol 1995

malcprob 1995

mchildabuse (0.042)fchildabuse(0.128) *mattitudes (0.183) *fattitudes (0.010)mimpul (0.128) *fimpul (0.075) freqrelig (0.045) *relength (-0.093) *

mhispus medu incomemarry memploy mimpul

fhispus fedu incomemarry fimpul

faccult 1995

femploy

Hispanic (including birth place and acculturation)

-0.379

4.6400.265

-6.384 *

3.09

1 *

-0.4

10

4.858 *

-0.008

0.045

-0.079

0.19

9

0.002

-0.0

16 *

0.009 *

0.019 *

0.034

0.082

0.238 *

0.379 *

0.00

7 *

0.284 *

0.014 *

0.045

0.410 *

0.000

-0.00

4

0.053

0.37

0 *

0.17

3 0.755 *

-0.127

maccult 2000

maccult 1995

faccult 2000

0.822 *

0.839 *

0.077

0.062

0.117 *

0.03

2

Potential Courses for Violence Type: 1995 to 2000

No

FMPV BothMFPV

1995

2000

Number of Respondents Eligible for Reinterview in 2000 Follow up Eligible Individuals for 2000 Follow-up Survey N = 3,270

Dead or IncapacitatedN = 124

Capable of Re-interviewN = 3,146

InterviewedN = 2,577

Not InterviewedN = 569

Excluded from the Analysis N = 35

Excluded from the Analysis N = 5

Final Respondents included in the Analysis N = 2,542

Final Non-Respondents in the Analysis N = 564

Proportion of Incident and Stable Cases of IPV in 2000 among All IPV Cases by Ethnicity

Black

40

15

4560

Incidence Chronic Severe Moderate

Hispanic

44

12

4456

Incidence Chronic Severe Moderate

White

32

59

27

41

Incidence Chronic Severe Moderate

Prevalence of MFPV and FMPV in 1995 and 2000

118

1310

1821

24 25

17

22 21 20

0

5

10

15

20

25

30

MFPV 95 MFPV 2000 FMPV 95 FMPV 2000

WhiteBlackHispanic

Odds Ratios from Multinomial Logistic Regression: Drinking Variables a

Incidence

Re: No violence

Recurrence

Re: No violence

Male weekly N. of drinks (5)

1.1 (1.0-1.2)* 1.1 (1.0-1.2)

Female 5+ less once a month

1.5 (0.3-7.7) 3.8 (1.3-10.6)*

Female 5+ at least once a month

1.5 (0.1-29.7) .7 (0.1-5.2)

* p<0.05, **p<0.01

a Also controlling for: female and male alc. prob, drug use, childhood victim., parental violence, impulsivity, attit. toward violence, age, income, education, emplm. status, marital status, length of relationship, ethnicity.

Stability and Incidence of MFPV and FMPV 1995 - 2000

39

6

44

6

05

101520253035404550

Stability Incidence

MFPVFMPV

2000 Status of 1995 Non-Violent Couples

94

5 1

94

5 10

102030405060708090

100

No Violence Moderate SevereViolence

MFPVFMPV

2000 Status of 1995 Couples with Moderate Violence

61

36

3

63

31

6

0

10

20

30

40

50

60

70

No Violence Moderate SevereViolence

MFPVFMPV

2000 Status of 1995 Couples with Severe Violence

58

28

14

45

34

21

0

10

20

30

40

50

60

70

No Violence Moderate SevereViolence

MFPVFMPV