20171023 Suicide by Pesticide Poisoning: a Priority for Suicide Prevention by Prof. David Gunnell

Suicide by pesticide poisoning: a priority
for suicide prevention
Professor David Gunnell FMedSci
University of Bristol, UK
Population Health Sciences

Think of a 15 year old girl you know…..

(source: Eddleston and Phillips BMJ 2004)
A 15 year old girl drank 20% paraquat after an
argument and fight with her 11 year old brother…
She told doctors she had not known it was paraquat
and in her distress had simply grabbed the nearest
bottle in the house and drunk it. She died from
cardio-respiratory arrest 2 days after admission.
Now imagine this was her……

100,000 people

Outline
• Background – epidemiology, industry involvement
and prevention approaches
• The evidence
Regulation – bans
Regulation - sales regulation
Locked boxes
• Impact on crop yields

Source: FAO statistics
http://www.fao.org/faostat/en/#data/RT
[accessed 12 June 2017]
Market projected to be worth US ($) 71 billion by 2018
Trends in global pesticide imports
1990-2014 (US $(1000))

Source: FAO statistics
http://www.fao.org/faostat/en/#data/RT
[accessed 6 October 2017]
0
50000
100000
150000
200000
250000
300000
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
ImportValue–1000USDollars
Year
Trends in pesticide imports 1990-
2014, Taiwan
Pesticides

1 in 5-7 of all suicides worldwide
110,000-168,000 deaths per year
Over 1 million deaths in the last
decade.
In 2016 in Taiwan pesticides
accounted for 467 (12.4%) suicides
Mostly in low and middle income
countries
Global burden of pesticide poisoning mortality:
systematic review

Easy access to pesticides for self-poisoning

來源：全國自殺防治中心
2012 全球平均
world average:
11.4 per 100,000
83-105年全國自殺死亡人數 / 死亡率
Number and rate of suicide in Taiwan, 1994-2016
105年自殺人數：3765人自殺，增加90人
105年標準化自殺率：12.3/10萬人，增加1.7%
There were 3765 suicides in 2016 (a rise of 90 over 2015) and
suicide rate was 12.3 per 100,000 (a 1.7% rise compared to
2015)
Number of suicide
Crude rate
Age-stand. rate
1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014

507 480 484
537
493 475 494 483 478 462 448 466 468 479 467
0
200
400
600
800
1000
1200
1400
1600
1800
2002 2004 2006 2008 2010 2012 2014 2016
每年自殺人數Annualsuicidenumber
每年自殺人數依方法別 2002-2016
Number of suicide by method
(1) 上吊 hanging
(2) 燒炭 charcoal
(3) 農藥
pesticide
(4) 墜落 fall
(5) 溺水 drowning
農藥中毒是第三位自殺方式
Pesticide poisoning is the third common
suicide method
來源：
衛生
福利
105年：農藥自殺467人，占全部自殺12.4%
巴拉刈是主要致死農藥，造成194人死亡
每19名自殺當中就有一人死於巴拉刈中毒
There were 467 pesticide suicides in 2016, accounting for
12.4% of total suicides.
Paraquat was the main pesticide involved, accounting for
194 suicides or one in 19 of all suicides.
Thanks to Shu-Sen Chang for slide

There are huge differences in toxicity /
case fatality for different pesticides
• Paraquat >50%
• Aluminium Phosphide >50%
• Organophosphate/ organochlorine and other
pesticides
• Monocrotofos 35%
• Endosulfan 28%
• Chlorpyrifos 8%
• Glyphosate 2%
• Carbofuran 1%
• Paracetamol (acetaminophen) <0.5%
Sources: Ganeshamoorthy 1985; Siwach 1988; Eddleston 2005; Rao 2005; Gunnell 1997 , Dawson 2010

Commonest substance No. hospital No. deaths
in self-poisoning admissions per year per year
England Paracetamol 40,000 100
Sri Lanka Pesticides 20,000 2,000
Gunnell et al 1996; Roberts et al 2003
Most frequently ingested poisons: England and Sri Lanka

Approaches to prevention
Regulation:
• Outright ban
• Sales restrictions (reduced concentration / limit availability to particular
occupations / licenced purchasers)
Safe storage (lockable boxes / village stores);

Restricting access to commonly used, high-lethality suicide
methods leads to falls in overall suicides

UK domestic gas: % of carbon monoxide in domestic gas: UK 1955-74
0
2
4
6
8
10
12
14
1955 1960 1965 1970 1975
Kreitman N Brit. J. Prev. Soc. Med. (1976), 30, 86-93
Year
Evidence from the UK and USA

England & Wales: sex-specific suicide
rates by mode of death
Kreitman N Brit. J. Prev. Soc. Med. (1976)30,86-93
Male Female
Total: all methods
Total: all methods
Non-carbon monoxide
Non-carbon monoxide
Carbon monoxide Carbon monoxide
year
Suicide rate
year

Access to methods: account of suicide attempt
by Jerry Lewis
He was preparing to kill himself and feeling for the trigger
of his gun when “Thank God I heard my children
laughing and running through the hall. That snapped me
out of it. The suicide impulse lasted only a moment – but
that’s all it takes.”
(source: Farmer RDT 1988)

Age-adjusted suicide rates by mechanism, United States vs. New
Jersey, 1999 – 2001 (Hempstead, 2006)
Age-adjustedrateper100,000population

WHO, 2014
Key messages (page 9)…
“An effective strategy for
preventing suicides and suicide
attempts is to restrict access to
the most common means
including pesticides, firearms and
certain medications.”

Should the most toxic pesticides be banned?

Challenge to banning pesticides – influence of
pesticide manufacturers

Pesticide industry influence
• Regular meets with Government Agricultural extension services (provide farmer
education) to encourage upscaling their preferred approaches
• Funding researchers and influential bodies
• Free distribution of locked boxes (sometimes without padlocks)
• Production of promotional videos encouraging the use of locked boxes
• Co-funding workshops at suicide prevention conferences focusing on boxes
• Focus on challenges of regulation – black market / substitution

Dilemmas in preventing suicides by pesticide
poisoning
•Is it possible to enforce sales bans / regulations?
•Are safe storage/locked box approaches effective and sustainable?
•Will ‘method substitution’ occur to more lethal methods of suicide?
•Will changes in pesticide use impact on crop yield?

The evidence: bans and sales
regulations

Systematic review: Lancet
Global Health 2017

Findings….
• Identified 27 studies carried out in sixteen countries.
• Impact of bans evaluated in 6 countries (South Korea,Taiwan,
Greece, Jordan, Sri Lanka, and Bangladesh)
• Impact of sales restrictions evaluated in 5 countries (Denmark, India,
Ireland, UK and USA)

Interventions evaluated
• Import or sales ban
• Sales restricted to licensed retailers
• Sales restricted to farmers / occupational
use
• Non-specific restrictions to sales
• Ban on sale of pesticides in small
containers
• Dilution of pesticide concentration

Findings….
• In 5 of the 6 countries where bans studied there were reductions in
pesticide suicides and, in three countries, falls in overall suicide
mortality.
• Sales restrictions were followed by falls in pesticide suicides in 3 of
the 5 countries; impacts on overall suicides unclear.

Impact of paraquat regulation in S Korea: 2011-12
2013 vs 2011
•Pesticide suicide mortality halved
•Pesticide mortality falls accounted
for 56% of the decline in S Korea’s
overall suicide decline
Cha et al Int J Epid 2016

Suicide trends in Sri Lanka: impact of pesticide
regulation
Knipe et al Lancet Global Health 2017
Estimated number of
deaths
Prevented 1995-
2015 – 90,000

Suicide and suicide attempt rates in Sri Lanka
1880-2005
0
5
10
15
20
25
30
35
40
45
50
1880 1886 1892 1898 1904 1910 1916 1922 1928 1934 1940 1946 1952 1958 1964 1970 1976 1982 1988 1994 2000

斯里蘭卡禁用劇毒農藥後自殺率下降
Trends in suicide in Sri Lanka
33
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
0
5
10
15
20
25
30
35
標準化自殺率/10萬人
農藥自殺率預測值全部自殺率預測值
農藥自殺率實際值全部自殺率實際值
2008-2011禁用三種劇毒農藥
Ban on three toxic pesticides
2015年農藥自
殺率減少51%
(937人)
51% drop in pesticide
suicides in 2015 (937
deaths avoided)
2011-2015：
農藥自殺率下降 50% drop in pesticide suicides
全部自殺率下降 21% drop in overall suicides
其它方法自殺率微增 2% rise in other suicides
Thanks to Shu-Sen Chang for slide

Trends in “unnatural”deaths in Bangladesh 1996-2014
WHO Class I
products
banned in 2000.
Other arrows
mark timing of
other
regulations

Paraquat imports and suicide in Western
Samoa 1956-1988 (Bowles 1995)
Year

"Bureau of Animal and Plant Health Inspection and Quarantine formally announced the
schedule to ban two pesticide products containing paraquat.“ (5th Oct 2017)
Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture, Taiwan.
(2017-10-05). from http://www.baphiq.gov.tw/view_news.php?id=13445.

UN Sustainable Development Goals (SDG)
Suicide rate is a SDG indicator (3.4.2)

3. The evidence: locked boxes

1. Rural China
• 2 intervention (received boxes) and 8
control townships. Use promoted every 6
months
2. Rural Sri Lanka
• Lock boxes issued to all farming
households (570) in in 2 villages; two
control villages
3. Tamil Nadu, India
• Locked central storage facility in two
villages; two control villages

RCT evidence: Pearson et al Lancet 2017
53,000 households, (223,000
people)
•Over 3 years follow-up the
incidence of pesticide self-poisoning
(RR 0.93, 95%CI 0.80, 1.08) and
overall suicide (RR 1.22, 95%CI 0.88
to 1.68) did not differ between
intervention and control villages

Challenges with lock boxes:
•Highlight whereabouts of
Pesticides
•Many kept unlocked (75-80%
in China in year 2) (WHO 2016)
•Increased access to pesticides
in the home
•Non-sustainable: boxes &
locks need replacing

4. Do bans affect crop yields?

Manuweera et al 2008
Yields of cereals, pulses and roots/tubers in South Asian countries between 1980 - 2005

Cereals
1980 1985 1990 1995 2000 2005
0
1000
2000
3000
4000
Bangladesh
India
Pakistan
Sri Lanka
Year
kg/hectare
Pulses
1980 1985 1990 1995 2000 2005
0
200
400
600
800
1000
Year
kg/hectare
Roots & tubers
1980 1985 1990 1995 2000 2005
0
5000
10000
15000
20000
Year
kg/hectare
Manuweera et al 2008
Yields of cereals, pulses and roots/tubers in South Asian
countries between 1980 - 2005

禁用劇毒農藥沒有影響農作產量
Sri Lanka’s 2008-2011 bans on 3 pesticides: no
evidence for an impact on crop yield
45
0
10
20
30
40
50
60
70
80
90
100
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
稻米產量（bushel/acre）
秋冬春季
夏季
2008-2011禁用三種劇毒農藥
Ban on three toxic pesticides

Conclusions
• 110,000 + suicides from pesticide poisoning per year
• In Taiwan Pesticides account for 12.4% of suicides; paraquat is the
main pesticide involved
• Bans appear to be most effective approach – if target key pesticides
(frequent use / high mortality)
• No evidence of significant substitution
• No evidence of impact on crop yield
• The recently announced ban on the two registered paraquat
formulations has potential to substantially reduce suicide in Taiwan

Acknowledgements
Bristol: Dee Knipe, Chris Metcalfe, Prianka Padmanathan
Edinburgh: Michael Eddleston, Melissa Pearson
Denmark: Flemming Konradsen
Sri Lanka: Ravindra Fernando
Taiwan: Shu-Sen Chang
Canada: Emma Mew
China: Michael Phillips, Shiwei Liu
South Korea: Won-Jin Lee, Eun Shil Cha
Australia: Andrew Page

THANK YOU
谢谢
David Gunnell University of Bristol,
UK
d.j.gunnell@bristol.ac.uk

WHO region % suicides due to pesticides Estimated no. pesticide
suicides
Africa (LMIC) 3.5% 2,100
Americas (LMIC) 8.8% 3,100
E Mediterranean (LMIC) 7.1% 2,100
European (LMIC) 0.9% 300
SE Asia (LMIC) 11.3% 35,500
W Pacific (LMIC) 48.3% 63,300
All High Income Countries 1.7% 3,300
WORLD TOTAL 13.7% 109,700

20171023 Suicide by Pesticide Poisoning: a Priority for Suicide Prevention by Prof. David Gunnell

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20171023 Suicide by Pesticide Poisoning: a Priority for Suicide Prevention by Prof. David Gunnell