Posttraumatic stress and lifestyles are associated with natural killer cell activity in victims of the Hanshin-Awaji earthquake in Japan.
BACKGROUND
The relationships among mental health status, lifestyle, and natural killer (NK) cell activity, which plays important roles in the immune surveillance of tumors and viral infections, were investigated in victims of the Hanshin-Awaji Earthquake.


METHODS
About 1 and 1/3 years after the earthquake, 155 male workers who experienced the event were administered questionnaires concerning their unhealthy mental status, such as symptoms of posttraumatic stress disorder (PTSD), lifestyles, and demographic variables. Peripheral blood was taken from all of them to measure NK cell activity.


RESULTS
Subjects who had PTSD symptoms showed lower NK cell activity than those without symptoms. Subjects with positive lifestyles showed higher NK cell activity than those with poor or moderate lifestyles. When subjects were divided into four groups by lifestyle and PTSD symptoms, subjects with positive lifestyles and few or no PTSD symptoms showed the highest NK cell activity among the four groups. The other three groups were subjects with positive lifestyles but many PTSD symptoms; subjects with poor or moderate lifestyles and many PTSD symptoms; and subjects with poor or moderate lifestyles and few or no PTSD symptoms.


CONCLUSIONS
PTSD symptoms and lifestyles were associated with NK cell activity in the earthquake victims.
Inoue-Sakurai
C
C
Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, Yamada-oka 2-2, Suita, Osaka, 565-0871, Japan.
Maruyama
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S
Morimoto
K
K
D000328:Adult; D000428:Alcohol Drinking; D004032:Diet; D004190:Disasters; D015444:Exercise; D006801:Humans; D007564:Japan; D007694:Killer Cells, Natural / Q000276:immunology*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012907:Smoking; D013313:Stress Disorders, Post-Traumatic / Q000209:etiology* / Q000276:immunology; D013315:Stress, Psychological / Q000175:diagnosis; D011795:Surveys and Questionnaires