Are neighbourhood social fragmentation and suicide associated in New Zealand? A national multilevel cohort study.
BACKGROUND
Studies of the association between neighbourhood fragmentation and suicide have yielded varied results, and none has simultaneously adjusted for neighbourhood fragmentation, neighbourhood deprivation and individual-level factors.


METHODS
A multilevel analysis of a 3-year cohort study was carried out using probabilistic linkage of census and mortality records, and two measures of neighbourhood fragmentation. A total of 2.8 million respondents to the 1996 New Zealand census were followed up for 3 years for mortality (1101 suicide deaths in the analysis), aged from 20 to 74 years at follow-up.


RESULTS
No consistent association was observed between either measure of neighbourhood social fragmentation and suicide, after controlling for individual-level confounders and neighbourhood deprivation. There was some evidence of a U-shaped relationship between neighbourhood fragmentation and suicide, especially for the Congdon(NZ) index. There was no evidence of an association for a nine-variable index that captured family-type variables as well as the usual attachment-type variables. Neighbourhood deprivation remained as an important predictor of suicide rates.


CONCLUSIONS
This paper highlights the importance of understanding both the measure and the wider national context when considering neighbourhood effects on suicide.
Collings
S
S
Social Psychiatry and Population Mental Health Research Unit, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand. sunny.collings@otago.ac.nz
Ivory
V
V
Blakely
T
T
Atkinson
J
J
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009520:New Zealand / Q000453:epidemiology; D011610:Psychosocial Deprivation; D012044:Regression Analysis; D012111:Residence Characteristics; D012307:Risk Factors; D012944:Social Support; D013405:Suicide / Q000706:statistics & numerical data*