Suicidal Inclination and Lifestyle Factors in Miyazaki City Junior High School Students

抄録

Purpose: The present study aimed to explore relationships between suicidal inclination and lifestyle and behavioral factors in junior high school students (aged 12–15 years).

Methods: A total of approximately 3,000 junior high school students (grades 7-9) living in the city of Miyazaki, Miyazaki Prefecture were recruited by random sampling from a citywide total of the 10,642 students. A questionnaire was mailed to 2,996 students. The questionnaire covered personal and lifestyle factors including sex, eating habits, sleep habits, chronic diseases, Internet use, illicit substances use, and menstruation. Suicidal inclination was measured using the Scale of Suicidal Inclination for junior high school students and its subscales. Scores of the subscales were compared between males and females. Students were divided into low and high groups for each subscale and association of the personal and lifestyle factors with each subscale was examined using logistic regression.

Results: Responses were obtained from 537 students out of 2,996 (17.9%). Out of the 537 students, 54 were excluded from the analysis due to invalid, missing, or implausible data. A total of 213 boys (44.1%) and 270 girls (55.9%) were studied. Most students (42.9%) reported less than 7–8 hours of sleep per night, with girls reporting shorter sleep duration than boys (p=0.001). A sex difference in suicidal inclination was observed for depressive mood, which was higher in girls. Multivariate analysis showed that suicidal inclination was mostly associated with sleep duration in boys, and sleep duration, interest in illicit substances, and menstruation in girls. The multivariate analysis of lifestyle factors and high subscale scores found that “bedtime,” “sleep duration/quality of sleep,” “chronic diseases,” “interest in illicit substances,” and “time using the Internet” showed some association with suicidal inclination in both boys and girls.

Conclusions: In addition to confirming previously identified risk factors, the present study suggests that additional risk factors are “whether dinner is eaten alone” for boys, and “grades,” “experience of dieting,” and “irregularity of menstrual cycle” for girls. To identify high-risk individuals effectively, screening for suicide prevention in junior high school students should consider sex-based characteristics. The present study also demonstrated relationships between suicide and lifestyle factors that should be considered by the government when developing public health policy and suicide prevention interventions.