大学新入生における行動変容ステージモデルを導入した身体活動と抑うつ症状の関連

抄録

Background: An inverse relationship between physical activity and depressive symptoms has been reported in adolescents, but this has not been confirmed in university students. Motivational readiness to physical activity could be an important key to reducing the risk of depressive symptoms in university students who have few opportunities to exercise.

Objectives: The purpose of this study was to clarify the association between physical activity, including the concept of motivational readiness, and depressive symptoms in university freshmen.

Methods: This study was a cross-sectional survey among 886 university freshmen（540 male and 346 female, mean age: 18.4±0.6 years）. Physical activity was evaluated using a questionnaire developed by Okazaki combined the American College of Sports Medicine and American Heart Association guidelines with the stages-of-change model. Participants were sorted into 7 groups based on the results of a modified version of this questionnaire. The severity of depressive symptoms was assessed with the total score on the Japanese version of the Patient Health Questionnaire-9（PHQ-9）, and the presence of depressive symptoms was determined with a total score of 10 or above. Our online questionnaire on multifactor lifestyle for university students was used to obtain data on the confounding factors of depressive symptoms（eating behavior, sleep, stress）. Data were analyzed using a multivariate logistic regression model.

Results: The percentages of physical activity in each group were as follows: 9.5% in the pre-contemplation group（PreCG）, 25.6% in the contemplation group（CG）, 27.9% in the preparation group（PG）, 7.2% in the low physical activity group（LPAG）, 15.6% in the high living activity group（HLAG）, 4.3% in the high sports activity group（HSAG）, and 9.9% in the high physical activity group（HPAG）. The prevalence of depressive symptoms was 12.7%. After adjusting for sex and related confounders mentioned above, the CG, PG, LPAG, HLAG, HSAG, and HPAG had odds ratios of 0.39（95% CI＝0.19, 0.83）, 0.38（95% CI＝0.18, 0.81）, 0.28（95% CI＝0.09, 0.81）, 0.23（95% CI＝0.09, 0.56）, 0.45（95% CI＝0.11, 1.60）, and 0.37（95% CI＝0.14, 0.98）for likelihood of having depressive symptoms, compared to the PreCG（p for trend＝0.05）.

Conclusions: This study showed that the odds ratio of depressive symptoms was the lowest in the HLAG. Decreased odds ratios were also found in the CG and PG, which did not engage in regular physical activity. These results indicate that contemplation of physical activity and regular physical activity may have similar effects on preventing depressive symptoms in university freshmen. The causal relationship between physical activity and depressive symptoms in university freshmen must be clarified using a longitudinal study.