Daily total physical activity level and
health risk in Japanese: Results from a Large-scale Population-based Cohort
Study in
Manami Inoue
Epidemiology and Prevention Division, Research
Center for Cancer Prevention and Screening, National Cancer Center, 5-1-1
Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan
Physical activity is now regarded as one of
the most important targets for the prevention of premature death and other adverse
health outcomes. Physical activity has been assessed using various types of
activity category, such as leisure time activity, sports, occupational and
household work etc. From a public health point of view, the need for
comprehensive evaluation of these physical activities in the aggregate has been
recognized. However, the impact of daily total physical activity level on health
risk has not been fully clarified in non-Western, relatively lean populations.
For a better understanding of this issue, we recently reported the association
between daily total physical activity level (METs/day) and subsequent risk of
all cause and major causes of mortality and cancer incidence in a large-scale
population-based cohort study in Japan (JPHC Study) (Ann Epidemiol 2008;18:522-30,
Am J Epidemiol 2008;168:391-403). A total of 80,000 general Japanese aged 45-74
who responded to the questionnaire in 1995-1999 were followed for death and
cancer incidence. During follow-up, a total of 4,500 deaths and 4,300 newly
diagnosed cancer cases were recorded. Compared with subjects in the lowest quartile,
increased daily total physical activity was associated with a significantly
decreased risk of all-cause mortality in both sexes. A significantly decreased
risk was similarly observed for death from cancer and heart disease in both
sexes, and from cerebrovascular disease in women. Increased daily total
physical activity was also associated with a
significantly decreased risk of total cancer in both sexes. By site, a
decreased risk was observed for cancer of the colon, liver and pancreas in men,
and for stomach in women. These results suggest that higher daily total
physical activity level, either from occupation, daily life, or leisure time,
may be of benefit in preventing premature death and incidence of cancer, even
in relatively lean populations.
Key words: physical activity; population-based; cohort study;
mortality, cancer incidence