Suicide Prevention in the USAF
Suicide is an important cause of death in the general population of
most Western countries, e.g. the eleventh leading cause of death with
3,681 deaths among Canadians in 1997 (1). Suicide within Western military
forces usually occurs at lower rates than in the same age-sex group in the
general population (2); however, individual suicides and increasing
suicide trends tend to evoke substantial concern among military
commanders. Therefore, we commend Knox et al (3) for their report on the
effects of a suicide prevention program instituted in the United States
Air Force (USAF).
However, we have the following concerns:
a. while there is a decline of 33% in the mean suicide rate for the
USAF between 1990-1996 compared to 1997-2002, the suicide trend in the
general US population is not mentioned. Comparing 1990 to 2000, US rates
(4) declined by 17%, 23%, 12%, 18% and 22% among, respectively, the whole
population, 15-24 year olds, 25-44 year olds, males and black males.
Hence, the decline seen in the USAF may reflect, in whole or in part, the
b. the trend in suicide rates for the period prior to 1990 is not
reported. While suicide rates may have an overall temporal trend, in
smaller populations, rates tend to fluctuate over shorter periods of time
(5); hence, following such rates over longer periods is usually necessary
to confirm substantial changes in the trend. In Fig 1, the suicide rate
in the USAF was already declining in 1996 (before the preventive program
was put in place) and 1997 (before the program was fully implemented).
Further, in Fig 1, after the nadir in 1999, there may be an impending
fluctuation to increasing suicide rates, e.g. the rate in 2001 is the same
as in 1990. An alternative explanation for the decline in the USAF
suicide rates may lie in shorter term fluctuations; and
c. without a more robust study design, for example, including a
control population that does not receive the intervention, it is
impossible to address the contribution of confounders and biases.
Overall, we do not believe that this report provides substantial
evidence that the USAF program played an important role in the decrease in
the suicide rate. The first statement in the Box (page 1378) remains
true, i.e. "there is a lack of evidence for the effectiveness of broadly
based community level suicide prevention programs".
1. Statistics Canada. Selected leading causes of death by sex, 1997
2. Wong A, Escobar M, Lesage A, Loyer M, Vanier C, Sakinofsky I. Are
UN peacekeepers at risk for suicide? Suicide Life Threat Behav 2001;31:103
3. Knox KL, Litts DA, Talcott W, Feig JC, Caine ED. Risk of suicide
and related adverse outcomes after exposure to a suicide prevention
programme in the US Air Force: cohort study. Br Med J 2003;327:1376-8
4. Fried VM, Prager K, MacKay AP, Xia H. Chartbook on Trends in the
Health of Americans. Health, United States, 2003. Hyattsville, Maryland:
National Center for Health Statistics. 2003.
5. Hourant LL and Warrack AG. Suicide in the US Marine Corps, 1990-
1996. Mil Med 1999;164;551-55.
No competing interests were declared by any author.
Martin Tepper* (corresponding and lead author)
Senior Medical Advisor, Communicable Disease Control Program
Head, Epidemiology Section
Senior Medical Advisor, Epidemiology Section
Deputy Chief of Staff
Senior Medical Advisor, Occupational and Environmental Health Program
Senior Advisor, Pest Management/Entomology, Communicable Disease Control
* Force Health Protection
Director General Health Services
Department of National Defence, 1745 Alta Vista Drive, Ottawa, Ontario, Canada, K1A 0K6
Competing interests: No competing interests