The impact of relationship type and closeness on mental health following suicide loss

BACKGROUND

Most research investigating the effect of suicide on loss survivors has been limited to first-degree family members. Few studies examine the impact of suicide on others outside the immediate family and the influence of relationship type and closeness on mental health.

METHODS

This study used data from a sample obtained through random digit dialing (n = 805) to assess exposure to suicide loss, relationship types, perceived closeness, and mental health symptoms (prolonged grief, depression, anxiety, and posttraumatic stress disorder).

RESULTS

Familial status, friend status, and higher perceived closeness were associated with prolonged grief, depression, and posttraumatic stress disorder, with the strongest adjusted associations observed for posttraumatic stress disorder and prolonged grief. In general, the magnitude of adjusted standardized associations for closeness and mental health symptoms was stronger than those observed for familial status and mental health symptoms and friend status and mental health symptoms.

CONCLUSION

Closeness, familial status, and friend status are associated with mental health symptoms experienced after suicide loss, but the magnitude of associations was strongest for closeness. Future studies should examine perceived closeness in addition to other factors related to relationship type and dynamics to assess the complexities of suicide bereavement reactions.

Associations between circulating proteins and risk of breast cancer by intrinsic subtypes: a Mendelian randomisation analysis

BACKGROUND

The aetiologic role of circulating proteins in the development of breast cancer subtypes is not clear. We aimed to examine the potential causal effects of circulating proteins on the risk of breast cancer by intrinsic-like subtypes within the Mendelian randomisation (MR) framework.

METHODS

MR was performed using summary statistics from two sources: the INTERVAL protein quantitative trait loci (pQTL) Study (1890 circulating proteins and 3301 healthy individuals) and the Breast Cancer Association Consortium (BCAC; 106,278 invasive cases and 91,477 controls). The inverse-variance (IVW)-weighted method was used as the main analysis to evaluate the associations between genetically predicted proteins and the risk of five different intrinsic-like breast cancer subtypes and the weighted median MR method, the Egger regression, the MR-PRESSO, and the MRLocus method were performed as secondary analysis.

RESULTS

We identified 98 unique proteins significantly associated with the risk of one or more subtypes (Benjamini-Hochberg false discovery rate < 0.05). Among them, 51 were potentially specific to luminal A-like subtype, 14 to luminal B/Her2-negative-like, 11 to triple negative, 3 to luminal B-like, and 2 to Her2-enriched-like breast cancer (n_total = 81). Associations for three proteins (ICAM1, PLA2R1 and TXNDC12) showed evident heterogeneity across the subtypes. For example, higher levels of genetically predicted ICAM1 (per unit of increase) were associated with an increased risk of luminal B/HER2-negative-like cancer (OR = 1.06, 95% CI = 1.03-1.08, BH-FDR = 2.43 × 10^-4) while inversely associated with triple-negative breast cancer with borderline significance (OR = 0.97, 95% CI = 0.95-0.99, BH-FDR = 0.065, P_{heterogeneity} < 0.005).

CONCLUSIONS

Our study found potential causal associations with the risk of subtypes of breast cancer for 98 proteins. Associations of ICAM1, PLA2R1 and TXNDC12 varied substantially across the subtypes. The identified proteins may partly explain the heterogeneity in the aetiology of distinct subtypes of breast cancer and facilitate the personalised risk assessment of the malignancy.