Monday, April 25, 2011

Altitude a Risk Factor for Suicide

"Two recent preliminary studies that found a positive correlation between altitude and suicide relied on the average or highest state altitude, or the elevation of the state capital city, to represent the altitude of the entire state.

Positive Correlation

However, US states vary greatly in altitude, and this method severely minimizes this variation, Dr. Brenner's team points out. Because counties vary considerably less in altitude than an entire state, they reexamined the altitude-suicide link at a county level.

The investigators included all 2584 US counties in their analysis. They examined county-specific mortality data for 20 years (1979-1998) and determined altitude for each county using the US Geologic Survey.

During the study period, among 42,868,100 total deaths, there were 596,704 suicide deaths (1.4%).

There was a negative correlation between county altitude and all-cause mortality (r = −0.31; P < .001), yet a "strong positive correlation" between county altitude and suicide rate (r = 0.50; P < .001). Positive correlations were seen for both firearm-related suicides (r = 0.40; P < .001) and non–firearm-related suicides (r = 0.31; P < .001).

Prior reports of increased suicide rates in the US mountainous region have fueled speculation that the excess may be due to greater access to firearms, increased isolation, or reduced income. But even after controlling for these variables, the positive correlation between altitude and suicide still exists, they report."

Tuesday, April 5, 2011

Genetic Linkage Study Finds Gene Associated with Suicide

Defendants should not be asked to pay for genetic abnormalities.

"A new study in patients with bipolar disorder (BPD) strongly suggests a genomewide association between attempted suicide and a region on chromosome 2 containing the ACP1 gene.

Expression of this gene, which influences a lithium-regulated pathway, is also elevated in BPD individuals who complete suicide, according to the study, which was published online March 22 in Molecular Psychiatry.

Suicide risk is greater in individuals with alcoholism, depression, or BPD. However, previous work has shown that offspring of mood-disordered and suicidal parents are at higher risk (12%) of attempting suicide than offspring of similar but nonsuicidal parents (2%).

The present genomewide association study looked for genetic associations with suicidal behavior in BPD individuals with or without a history of attempted suicide. Diagnosis of BPD was based on criteria in the Diagnostic and Statistical Manual of Mental Disorders (Third Edition Revised) or Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition).

Single nucleotide polymorphisms (SNPs) were analyzed in 1201 BPD individuals who had attempted suicide and 1497 who had not. Initial genotyping found 2507 SNPs associated with suicide attempts at P < .001, with strongest association (P = 1.09 × 10−6) at a locus on chromosome 2 (2p25)."