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

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.