Walking and mortality in Japan: the Miyagi Cohort Study.
BACKGROUND
Although many studies in western populations demonstrated that time spent walking was associated with a reduced risk of all-cause mortality, data on Japanese has been sparse.


METHODS
In 1990, 20,004 men and 21,159 women in Miyagi Prefecture in rural northern Japan (40-64 year of age) completed a self-administered questionnaire including a question on time spent walking. Cox regression was used to estimate relative risk (RR) of mortality according to three levels of walking (30 minutes or less, between 30 minutes and one hour, and one hour or more), with adjustment for age, education, marital status, past history of diseases, smoking, drinking, body mass index, and dietary variables. During 11 years of follow-up, 1,879 subjects had died.


RESULTS
Time spent walking was inversely associated with risk of all-cause mortality: compared with men and women who walked one hour or more per day, multivariate RR (95% confidence intervals) was 1.06 (0.95-1.19) for subjects who walked between 30 minutes and one hour per day, and 1.16 (1.04-1.29) for subjects who walked 30 minutes or less per day (P for trend=0.007). Shorter duration of walking was associated with increased mortality among men who were never smokers (P for trend=0.081) and past smokers (P for trend=0.026), but not among currently smoking men (P for trend=0.751). We observed similar effect modification for women.


CONCLUSIONS
Time spent walking was associated with a reduced risk for all-cause mortality, especially among nonsmoking men and women.
Fujita
Kazuki
K
Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
Takahashi
Hideko
H
Miura
Chihaya
C
Ohkubo
Takayoshi
T
Sato
Yuki
Y
Ugajin
Takashi
T
Kurashima
Kayoko
K
Tsubono
Yoshitaka
Y
Tsuji
Ichiro
I
Fukao
Akira
A
Hisamichi
Shigeru
S
D000328:Adult; D015331:Cohort Studies; D005260:Female; D006306:Health Surveys; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends*; D016016:Proportional Hazards Models; D012307:Risk Factors; D013997:Time Factors; D016138:Walking