Associations of lifestyle factors with quality of life (QOL) in Japanese children: a 3-year follow-up of the Toyama Birth Cohort Study

PURPOSE: To examine the associations between lifestyle factors and quality of life (QOL) among Japanese children. METHODS: Participants were 7794 children (3869 boys and 3925 girls) aged 9-10. They completed a questionnaire regarding lifestyles at baseline survey and were followed up for 3 years. In the follow-up survey, QOL was evaluated using a Japanese version of the COOP charts. Children rated their QOL as one of five response categories. Subjects rated as 'very well' or 'pretty good' were considered to have good QOL, and the remainder was assumed to have poor QOL. Logistic regression analysis was performed to evaluate the relationship between lifestyles or changes in lifestyles and QOL. In the multivariate analysis model, age, sex, body mass index (BMI), and lifestyle factors were simultaneously entered. RESULTS: During the follow-up period, children became more sedentary. Compared to children participating in physical activity 'very often' at baseline, those who exercised 'almost never' were more likely to have poor QOL [OR (95% CI): 1.92 (1.26-2.93)]. Children who developed or maintained undesirable lifestyles had high OR for poor QOL. Compared to children taking breakfast 'often' during the follow-up period, those changing from 'often' to 'seldom' or those taking breakfast 'seldom' were more likely to have poor QOL [1.61 (1.24-2.07), 2.05 (1.03-4.09), respectively]. When compared with children maintaining their participation in physical activity 'often', those who changed from 'often' to 'seldom' and those who kept 'seldom' were more likely to have poor QOL [2.10 (1.84-2.39), 2.21 (1.88-2.59), respectively]. CONCLUSIONS: This study shows that unfavourable lifestyles in childhood are associated with poor QOL in early adolescence. Early intervention could be worth considering to keeping desirable lifestyles during childhood.