[The association between subjective symptoms and lifestyle habits among junior high school students a cross-sectional survey in Kumamoto, Japan]

Abstract

Objectives: This study aimed to examine the association between subjective symptoms and lifestyle habits among junior high school students by using a cross-sectional survey.

Methods: The survey was conducted during May-November 2012. The study subjects were 1229 adolescents (527 boys and 702 girls, age 12-13 years) from 10 junior high schools in Kumamoto Prefecture, Japan. Data from 1182 students (500 boys and 682 girls; response rate 96.2%) were used for the analyses. School nurses measured students' body weights and heights. A self-administered questionnaire examining dietary intake (FFQW82), subjective symptoms (12 items), lifestyle habits (18 items), and diet- and health-related topics (9 items) was used. The 4 categories of each of the 12 subjective symptoms were classified into dichotomous variables (1=always or sometimes; 0=occasionally or never). The subjective symptom score was calculated as a total score by summing up the dichotomous variables for the 12 subjective symptoms. Associations were examined using a chi-square test, Student's t-test, Wilcoxon rank sum test, and a stepwise regression model. The structure of factors was examined by factor analysis (varimax rotation) and associations among the question items were examined by principal component analysis. A significance level of 5% (two-sided) was applied and SAS ver. 9.3 software was used for the analyses.

Results: Students' body weights and heights were mostly at or near national averages. The ratio of energy intake at breakfast, lunch, and dinner for the 1-day total energy intake (kcal) was respectively 2:3:4, indicating decreased energy intake at breakfast. The percent energy (%E) from fat of the 1-day total energy intake was 29%E for boys and 30%E for girls. Using regression models, we found that the following lifestyle factors were significantly related to fewer subjective symptoms: "balanced diet," and "sleeping 6 hours or more per day" were for boys and girls, "regularly eating three meals a day," "strong appetite," and "having relaxation time" for girls. However, the following factors were significantly related to more subjective symptoms: "eating hurriedly," and "2 hours or more of watching television or playing video games" were for boys and girls, "cooking meals or sweets" for boys, "eating snacks and nighttime meals," and "eating dinner after 9 p.m.," and "preparing bento (boxed lunches)" for girls. Dietary intake was not significantly related to subjective symptoms.

Conclusion: Findings from this study suggest that subjective symptoms are associated with lifestyle habits among junior high school students.