Kava use and risk of car crash injury: a population-based case control study in Fiji

Kava use and risk of car crash injury: a

population-based case control study in

Fiji

Iris Wainiqolo, Bridget Kool, Berlin Kafoa, Elizabeth Robinson, Eddie McCaig, Josephine Herman, Shanthi Ameratunga

2nd_{International Symposium on Drugs and Driving}

Wellington, New Zealand Wed 12 November 2014

Presenter: Iris Wainiqolo

Outline

•

Background

•

Aim

•

Method

•

Results

•

Implications for Injury Prevention

BACKGROUND

•

Burden of road traffic injuries (RTI) is largely borne by

low- and middle-income countries.

•

RTIs are a significant problem in the Pacific Islands

•

Contribution of alcohol and recreational drugs to

driver performance is well established

•

While the consumption of kava (

Piper methysticum)

is high in many Pacific Islands, it’s role in RTI has

received minimal attention

•

Widely consumed beverage in the Pacific (Polynesia,

Micronesia and Melanesia) used for ceremonial,

therapeutic, and recreational purposes.

•

Prepared from dried or green roots of

Piper methysticum

•

Active ingredient: ‘lipid-soluble’ kavalactones (18) of which

6 are commonly associated with observed effects

•

Action of kavalactones:

–

Strong interaction with GABA-A receptors which are plentiful in

the amygdala and hippocampus (sedative, anxiolytic, muscle

relaxation effects)

–

Inhibition of cytochrome P 450 (CYP 450) enzymes in the liver

responsible for hepatic metabolism of a large number of drugs

(caution with drug use)

Why is kava so popular in the islands?

•

“....

It gives a pleasant,

warm and cheerful, but

lazy feeling...” (Hocart,

1929)

•

“....The head is affected

pleasantly; you feel

friendly, not beer

sentimental; you cannot

hate with kava in you.

Kava quiets the mind;....”

(Lemert, 1967)

Why should kava use be a concern?

•

Widespread and regular use of kava and

increasing use of kava with alcohol

(“wash down”)

(

•

Negative effects:

–

Acute use: numbing effect in the mouth,

sedation

,

slow reaction/reflexes,

lethargic, lack of coordination (ataxia),

muscle weakness, reduced visual

attention

,

fatigue,

loss of appetite…

•

Fiji: Ban on kava drinking in Government

offices (PSC circular #22/2007)

•

No specific laws against kava drinking and

driving

– Long-haul trucks, cane trucks having ‘kava stops’ on roadsides are still common practice

Scientific evidence

What do we know about kava and crash?

•

Recent SR found no epidemiological studies examining the effect of kava

use on motor vehicle crash or injury

What then?

•

4 Experimental studies investigated the effect of kava on driving

ability/performance;

– 2 German and 2 Australian studies

– Use of computer test system or driving simulator

– All studies report no significant negative effect of kava on driving ability

– 1 study showed that kava in combination with alcohol had significant negative effects on visoumotor skills similar to that used in driving a vehicle.

– All experiments used Medicinal kava doses: 180 – 300 mg

•

Recreational kava doses such as that

used in the Pacific & amongst

Aborigines is 50-100x more potent (Cairney, Kava, Sarris)

AIM

To investigate the association between driving while

under the influence of kava and serious

METHOD

Controls

-

• Eligible vehicles

– A population-based sample of 4 –wheel

motor vehicles representative of ‘driving time’ on public roads in Viti Levu

Cases -

– All 4-wheel motor vehicles involved in a crash resulting in a road user (driver, passenger or pedestrian) dying or admitted to hospital for 12 hours or more

Case control analysis

– July 2005 – December 2006

– Multivariable unconditional logistic regression – Analyses conducted using STATA 12 software

RESULTS

- Participant characteristics

Variables

Cases

n=140 (%)

Controls

n=752 (%)

Age of drivers (in years)

15-24

25-34

35-44

45+

19 (13.6)

48 (34.3)

36 (25.7)

37 (26.4)

84 (12.9)

220 (31.8)

222 (29.3)

223 (25.9)

Gender

Female

Male

6 (4.3)

134 (95.7)

35 (6.8)

717 (93.2)

Ethnicity

iTaukei

Indo-Fijian

Other

42 (30.0)

96 (68.6)

2 (1.4)

154 (21.9)

551 (70.1)

47 (8.1)

RESULTS

-

Kava use

Variables

Cases

n=140 (%)

Controls

n=752 (%)

Acute kava use (previous 12 hrs)

No

Yes

108 (77.1)

32 (22.9)

698 (95.7)

54 (4.3)

Usual kava use (past 12 months)

None

Less than a month to monthly

Greater than monthly to daily

36 (25.7)

60 (42.9)

44 (31.4)

269 (44.7)

326 (39.3)

157 (16.0)

RESULTS

- Role of Kava use in RTI

–

Consuming kava within 12 hours of driving

associated with

three-fold increase

in odds of

crash involvement - Adjusted OR = 3.5

(95% CI, 1.47,

8.31)

–

Population Attributable Risk:

16%

(95% CI, 11-20%)

–

No significant interaction

for:

•

Acute kava use and acute alcohol use

IMPLICATIONS FOR INJURY PREVENTION

•

Acute kava use within 12 hours of driving

is

significantly associated with

serious

injury-involved 4-wheeled motor vehicle road

traffic crashes in Viti Levu, Fiji

•

Driving under the influence of kava requires

explicit attention in road safety strategies

in

the Pacific and in countries with large

kava-drinking Pacific populations (e.g. NZ, Australia,

the US)

GAPS IN KAVA RESEARCH

•

Future research - quantify

kava use (volume and

patterns) that pose the

greatest crash risk

•

Development of a test

(biochemical?) to detect

drivers under the

influence of kava

–

Use of compulsory

impairment test by Police

for mood altering

substances other than

alcohol

ACKNOWLEDGEMENTS

• TRIP Project Principal investigators - A/Professor Eddie McCaig, Professors Shanthi Ameratunga, Sitaleki Finau and Rod Jackson; Research Managers - Drs Iris

Wainiqolo, Berlin Kafoa, Josephine Herman and Robyn McIntyre; Research team -Mrs Mabel Taoi, Sr Asilika Naisaki, Mr Ramneek Goundar, Mr Ravi Reddy, Ms Litia Vuniduvu, and Mrs Nola Vanualailai.

• Fiji Ministry of Health, including the former Permanent Secretary Dr Lepani Waqatakirewa, doctors and nurses in divisional and sub divisional hospitals.

• Fiji Police Force Highway Unit and their branches in the Central and Western Divisions for assisting the team collect driver information in roadside surveys on Viti Levu roads.

• Fiji School of Medicine MBBS 6 students (2005-06) for their assistance in establishing the Fiji injury surveillance in hospitals (FISH) register.

• University of Auckland staff and postgraduate researchers who contributed to training and development of research outputs including Professor David Thomas and Robert Scragg, Dr Bridget Kool, Ms Cherie Lovell, Dr Roshini Peiris-John, Ms Naina Raj, Mr Dudley Gentles, and the biostatistical support provided by Mrs Elizabeth Robinson.

• Funding for the Project providing by an International Collaborative Research Grant awarded by the Wellcome Trust and the Health Research Council of New Zealand.