Heart rate and suicide: findings from two cohorts of 533 000 Taiwanese and 75 000 Norwegian adults.
OBJECTIVE
To investigate the association of resting heart rate with suicide in two large cohorts.


METHODS
The MJ cohort (Taiwan) included 532 932 adults from a health check-up programme (1994-2008). The HUNT cohort (Norway) included 74 977 adults in the Nord-Trøndelag County study (1984-1986), followed up to 2004. In both cohorts heart rate was measured at baseline, and suicide was ascertained through linkage to cause-of-death registers. Risk of suicide was estimated using Cox proportional hazards models.


RESULTS
There were 569 and 188 suicides (average follow-up period of 8.1 and 16.9 years) in the MJ and HUNT cohorts respectively. Sex- and age-adjusted hazard ratio for every 10 beat increase in heart rate per minute was 1.08 (95% Confidence Interval 1.00-1.16) and 1.24 (1.12-1.38) in the MJ and HUNT cohorts, respectively. In the MJ cohort this association was confined to individuals with a history of heart diseases vs. those without such a history (P for interaction = 0.008). In the HUNT cohort the association did not differ by history of heart diseases and was robust to adjustment for health-related life style, medication use, and symptoms of anxiety and depression.


CONCLUSIONS
Elevated resting heart rate may be a marker of increased suicide risk.
Institute of Health Behaviors and Community Sciences, and Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan.|Hong Kong Jockey Club Centre for Suicide Research and Prevention, The University of Hong Kong, Hong Kong SAR, China.|Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong SAR, China.
S-S
SS
Chang
Department of Public Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.|Forensic Department and Research Centre, Bröset St. Olav's University Hospital Trondheim, Trondheim, Norway.
J H
JH
Bjørngaard
China Medical University Hospital, Taichung, Taiwan.|Institute of Population Health Science, National Health Research Institutes, Miaoli, Taiwan.
M K
MK
Tsai
Faculty of Health Sciences, Nord-Trøndelag University College (HiNT), Levanger, Norway.|Institute of Neuromedicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
O
O
Bjerkeset
China Medical University Hospital, Taichung, Taiwan.|Institute of Population Health Science, National Health Research Institutes, Miaoli, Taiwan.
C P
CP
Wen
Hong Kong Jockey Club Centre for Suicide Research and Prevention, The University of Hong Kong, Hong Kong SAR, China.|Department of Social Work and Social Administration, The University of Hong Kong, Hong Kong SAR, China.
P S F
PS
Yip
MJ Health Management Institution, Taipei, Taiwan.
C K
CK
Tsao
School of Social and Community Medicine, University of Bristol, Bristol, UK.
D
D
Gunnell
D000328:Adult; D015331:Cohort Studies; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016016:Proportional Hazards Models; D012307:Risk Factors; D013405:Suicide / Q000706:statistics & numerical data*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
Norway; Taiwan; The Hunt Study; cohort study; heart rate; suicide