Suicide is the third-leading cause of death among US adolescents. Environmental and lifestyle factors play a crucial role in influencing suicidal behavior and can inform risk classification. However, quantifying and incorporating these factors into risk assessment poses significant challenges for clinical translation. A recent study aimed to quantify the aggregate contribution of these factors to youth suicide attempt risk classification.

Study Design and Participants

This cohort study included three youth samples:

1. Adolescent Brain Cognitive Development (ABCD) Study:
   
   
   • 11,564 participants
   • Mean age: 12.0 years
   • 52.2% male
   • 3.0% reported suicide attempts
   • 1,154 environmental/lifestyle factors
2. UK Millennium Cohort Study (MCS):
   
   
   • 9,000 participants
   • Mean age: 17.2 years
   • 51.0% female
   • 7.3% reported suicide attempts
   • 2,864 environmental/lifestyle factors
3. Children’s Hospital of Philadelphia Emergency Department (CHOP-ED):
   
   
   • 19,800 participants
   • Mean age: 15.3 years
   • 65.3% female
   • 10.4% reported suicide attempts
   • 36 environmental/lifestyle factors

Methodology

An exposome-wide association study (ExWAS) approach was used to identify risk and protective factors. Logistic regression models were applied to test associations and model fit of exposomic scores with suicide attempts in independent data.

Exposomic Scores

A single-weighted exposomic score was developed by summing significant risk and protective environmental/lifestyle factors. This score was used to evaluate its association with self-reported suicide attempts.

Key Findings

ABCD Study

In the ABCD discovery subsample:

• 99 Risk and Protective Exposures: Identified as significantly associated with suicide attempt.
• Exposomic Score Association: The score was significantly associated with suicide attempt in an independent ABCD testing subsample (OR, 2.2; 95% CI, 2.0-2.6; P < .001).
• Variance Explained: The score explained 17.6% of the variance in suicide attempts, over and above the variance explained by age, sex, race, ethnicity (2.8%), and family history of suicide (6.3%).

MCS and CHOP-ED Cohorts

Findings were consistent across the MCS and CHOP-ED cohorts:

• MCS Cohort: The exposomic score explained 22.6% of the variance in suicide attempts.
• CHOP-ED Cohort: The exposomic score explained 19.3% of the variance in suicide attempts.

Risk Comparison

Youth in the top fifth quintile of the exposomic score were substantially more likely to have made a suicide attempt compared to those at the median quintile:

• ABCD Study: OR, 4.3; 95% CI, 2.6-7.2
• MCS Cohort: OR, 3.8; 95% CI, 2.7-5.3
• CHOP-ED Cohort: OR, 5.8; 95% CI, 4.7-7.1

Conclusion

The results suggest that exposomic scores of suicide attempt provide a generalisable method for risk classification that can be applied in diverse samples from clinical or population settings.

Source: JAMA Network