Angiotensin-converting enzyme polymorphism and completed suicide: an association in Caucasians and evidence for a link with a method of self-injury

Abstract

Background/aims: An association between the II genotype of the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and suicide was found among Japanese men. Our purpose was to replicate this finding in Caucasians and explore other putative genotypic associations among suicides.

Methods: The ACE genotypes were studied by a 2-stage PCR method in 150 completed suicides and 165 age- and sex-matched controls.

Results: We found an increase in the frequency of the ACEI allele among male victims of suicide compared to male controls (odds ratio, OR = 1.69, p < 0.006), female suicides (OR = 2.01, p = 0.006) and pooled controls (OR = 1.77, p = 0.001). Analysis of genotype distribution showed that the codominant model had the best fit (p = 0.7) whereas the recessive model could be rejected (p = 0.04). Among males we found an association between the number of the ACE I allele and the method of suicide: OR = 17.98, p(corrected) = 0.00003, for jumping from a height; OR = 0.36, p(corrected) = 0.048, for hanging. We also observed a trend for a negative effect of the number of copies of the ACE I allele on prevalence of depression (OR = 0.36, p = 0.013) and a trend for an effect on age at death (p = 0.021).

Conclusions: Our results suggest that low ACE activity associated with the I allele is a risk factor for suicide, especially in a subset of males. This may be of concern given the widespread use of drugs lowering ACE activity.