Leg extension power is a pre-disaster modifiable risk factor for post-traumatic stress disorder among survivors of the Great East Japan Earthquake: a retrospective cohort study.
BACKGROUND
Post-traumatic stress disorder (PTSD) is a common psychological problem following natural disasters. Although pre-disaster risk factors are important for early detection and proactive support, the examination of such has been limited to sociodemographic factors, which were largely unaffected by the disasters. We examined the association between pre-disaster physical functioning and lifestyle and PTSD symptoms five months after the earthquake in the Great East Japan Earthquake survivors who were participating in a pre-existing cohort study.


METHODS
We designed a retrospective cohort study of a cooperative association in Sendai from August 2010 to August 2011. In 2010, lifestyle, physical condition, and sociodemographic factors were examined by self-reported questionnaires completed by 522 employees of this organization. We also measured the leg extension power of all the participants. PTSD symptoms were evaluated by the Japanese version of the Impact of Event Scale-Revised (IES-R-J) following the earthquake of 2011.


RESULTS
In multivariate linear regression analysis, leg extension power (β = -0.128, P = 0.025), daily drinking (β  = 0.203, P = 0.006), and depressive symptoms (β  = 0.139, P = 0.008) were associated with total score of the IES-R-J among men. Moreover, for the IES-R-J subscale, leg extension power was also negatively associated with Intrusion (β = -0.114, P = 0.045) and Hyperarousal (β = -0.163, P = 0.004) after adjusting for all other significant variables. For women, hypertension (β  = 0.226, P = 0.032) and depressive symptoms (β  = 0.205, P = 0.046) were associated with the total score of the IES-R-J.


CONCLUSIONS
Leg extension power is a potentially modifiable pre-disaster risk factor among men for attenuating the severity of PTSD symptoms associated with great disasters such as the Great East Japan Earthquake among men.
Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.
Haruki
H
Momma
Department of Epidemiology, School of Public Health, Tianjin Medical University, Tianjin, People's Republic of China.
Kaijun
K
Niu
Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
Yoritoshi
Y
Kobayashi
Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
Cong
C
Huang
Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
Atsushi
A
Otomo
Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
Masahiko
M
Chujo
School of Nursing in Miyagi University, Sendai, Japan.
Hiroko
H
Tadaura
Division of Biomedical Engineering for Health and Welfare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan; Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
Ryoichi
R
Nagatomi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking; D055866:Earthquakes; D005260:Female; D006801:Humans; D007564:Japan; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D012189:Retrospective Studies; D012307:Risk Factors; D057566:Self Report; D013313:Stress Disorders, Post-Traumatic / Q000209:etiology* / Q000523:psychology; D013315:Stress, Psychological; D017741:Survivors / Q000523:psychology*; D055815:Young Adult