Background
In spite of the accumulating evidence in western countries, which indicate the relationship between environmental factors and physical activity, few studies on this topic have been reported in Japan. While environmental factors vary in countries, evidence from a variety of cultures is more informative and important for understanding the determinants of physical activity.
Objective
The objective of this study was to examine, among Japanese adults, the association of perceived environmental factors and walking.
Method
This study was conducted by a cross-sectional design including a convenient sample of 497 Japanese adults aged from 20 to 74 years old (mean age +/- SD: 41.6+/-12.4, male: 61.4%, mean BMI +/- SD: 22.6 +/- 3.1). Participants were asked to answer self-administered questionnaires regarding their physical activity and perceived environment. For the assessment of physical activity, the short version of the International Physical Activity Questionnaire (IPAQ) was used. In this study, total walking time in the last week for any purpose (minutes/week) was examined as the dependent variable. For the assessment of environment as an independent variable, the IPAQ environment module consisting of 11 items (types of residence, access to destinations, access to transits, existence of sidewalks, bicycle facilities, access to recreational facilities, nighttime crime rate, walking safety related to traffic, social environment, aesthetics and household motor vehicles) was used. Original questionnaires were translated into Japanese, and then two translators, who were prohibited from seeing the original version, translated the Japanese version back to English. The IPAQ committee approved the back-translated English version of the questionnaire. Reliability of the 11 items by test-retest with a 10-day interval were between r=0.80 to r=0.99 depending on the items. For data analyses, a series of logistic regression models were used to examine the association between environmental factors and walking. A person walking more than 150 minutes per week was defined as an active walker. Response categories of environmental scales were converted into dichotomous variables. The odds ratios of active walkers were calculated adjusted for age, sex and education level.
Result
Total walking time was 225 +/- 374 minutes (mean +/- SD). Forty-three percent of participants were reported to have walked more than 150 minutes in the last week. Logistic regression analyses revealed that three of eleven environmental factors are significantly related to walking. The odds ratios (95% confidential interval, p value) of active walkers who reported their neighborhood as “single-family residence or low-storey apartment dominant”, as “not many destinations within easy walking distance” and as “having few sidewalks” were 0.546 (0.352-0.848, p=0.007), 0.609 (0.390-0.951, p=0.029) and 0.587 (0.401-0.859, p=0.006), respectively.
Discussion
In this study, IPAQ, which was developed for international comparison, was used for the assessment of environmental factors and walking. It is important that the relationships between environmental factors and physical activity were observed, using an internationally-standardized questionnaire, among people from a culture different from western countries. Because of limitations such as cross-sectional study design, perceived measures and convenient samples, further studies targeting the Japanese population are needed.
Conclusion
The association of walking for 150 minutes a week and three perceived environmental factors: type of residence, access to destinations and existence of sidewalks, was observed among Japanese adults.
