Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study

Abstract Background Vitamin D deficiency is highly prevalent among Japanese female university students. Vitamin D deficiency is associated with physical and mental health problems, including sleep disorders. This study aimed to clarify the relationship between vitamin D deficiency and sleep and ment...

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Main Authors: Nodoka Yamashita, Shioka Ishii, Yoriko Kotoku, Takuya Shuo, Hiromi Eto, Hideaki Kondo
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Journal of Physiological Anthropology
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Online Access:https://doi.org/10.1186/s40101-025-00403-9
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author Nodoka Yamashita
Shioka Ishii
Yoriko Kotoku
Takuya Shuo
Hiromi Eto
Hideaki Kondo
author_facet Nodoka Yamashita
Shioka Ishii
Yoriko Kotoku
Takuya Shuo
Hiromi Eto
Hideaki Kondo
author_sort Nodoka Yamashita
collection DOAJ
description Abstract Background Vitamin D deficiency is highly prevalent among Japanese female university students. Vitamin D deficiency is associated with physical and mental health problems, including sleep disorders. This study aimed to clarify the relationship between vitamin D deficiency and sleep and mental health problems among Japanese female university students. Methods Participants were 224 female university students. Blood levels of 25-hydroxyvitamin D [25(OH)D] were measured using liquid chromatography-tandem mass spectrometry for vitamin D assessment. Mental health was assessed using the K6. Sleep–wake status as a factor related to mental health was assessed using the Athens Insomnia Scale (AIS) and Munich ChronoType Questionnaire. Loneliness was assessed using the Three-Item Loneliness Scale. Factors predicting mental health problems with a K6 score ≥ 5 were explored using the Mann–Whitney U test, Fisher’s exact probability test, and classification and regression tree (CART) analysis. Results The median (interquartile range) serum 25(OH)D concentration was 14.5 (11.8–18.3) ng/mL. Of the participants, 80.8% had vitamin D deficiency (25(OH)D < 20 ng/mL), and 26.3% had severe vitamin D deficiency (25(OH)D < 12 ng/mL). In total, 41.1% had mental health problems with a K6 score of ≥ 5. Although there was no significant association between vitamin D deficiency and sleep–wake problems, vitamin D deficiency was more prevalent among those with K6 scores ≥ 5 (P = 0.02). Compared to those with K6 < 5, those with K6 ≥ 5 had significantly higher Loneliness and AIS scores (P < 0.001), greater social jetlag (P = 0.03), shorter sleep duration on weekdays (P = 0.03), and lower serum 25(OH)D concentration (P = 0.02). In the CART analysis, the algorithm was set in the order of Loneliness score ≥ 6, AIS score ≥ 7, social jetlag ≥ 150 min, and serum 25(OH)D concentration < 14 ng/mL, and the target accuracy (95% confidence interval: CI) was 76.5 (70.3–81.9)%, and sensitivity and specificity (95% CI) were 62.2 (51.4–72.2)% and 86.3 (79.2–91.6)%, respectively. Conclusions Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency were associated with mental health problems among Japanese female university students.
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spelling doaj-art-b2ba3fde9f6946658d9fe56efc816cb82025-08-20T03:46:16ZengBMCJournal of Physiological Anthropology1880-68052025-07-0144111110.1186/s40101-025-00403-9Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional studyNodoka Yamashita0Shioka Ishii1Yoriko Kotoku2Takuya Shuo3Hiromi Eto4Hideaki Kondo5Graduate School of Biomedical Sciences, Nagasaki UniversityGraduate School of Biomedical Sciences, Nagasaki UniversityDepartment of Reproductive Health, Institute of Biomedical Sciences, Nagasaki UniversityFaculty of Health and Medical Sciences, Hokuriku UniversityDepartment of Reproductive Health, Institute of Biomedical Sciences, Nagasaki UniversityDepartment General Medicine, Nagasaki University HospitalAbstract Background Vitamin D deficiency is highly prevalent among Japanese female university students. Vitamin D deficiency is associated with physical and mental health problems, including sleep disorders. This study aimed to clarify the relationship between vitamin D deficiency and sleep and mental health problems among Japanese female university students. Methods Participants were 224 female university students. Blood levels of 25-hydroxyvitamin D [25(OH)D] were measured using liquid chromatography-tandem mass spectrometry for vitamin D assessment. Mental health was assessed using the K6. Sleep–wake status as a factor related to mental health was assessed using the Athens Insomnia Scale (AIS) and Munich ChronoType Questionnaire. Loneliness was assessed using the Three-Item Loneliness Scale. Factors predicting mental health problems with a K6 score ≥ 5 were explored using the Mann–Whitney U test, Fisher’s exact probability test, and classification and regression tree (CART) analysis. Results The median (interquartile range) serum 25(OH)D concentration was 14.5 (11.8–18.3) ng/mL. Of the participants, 80.8% had vitamin D deficiency (25(OH)D < 20 ng/mL), and 26.3% had severe vitamin D deficiency (25(OH)D < 12 ng/mL). In total, 41.1% had mental health problems with a K6 score of ≥ 5. Although there was no significant association between vitamin D deficiency and sleep–wake problems, vitamin D deficiency was more prevalent among those with K6 scores ≥ 5 (P = 0.02). Compared to those with K6 < 5, those with K6 ≥ 5 had significantly higher Loneliness and AIS scores (P < 0.001), greater social jetlag (P = 0.03), shorter sleep duration on weekdays (P = 0.03), and lower serum 25(OH)D concentration (P = 0.02). In the CART analysis, the algorithm was set in the order of Loneliness score ≥ 6, AIS score ≥ 7, social jetlag ≥ 150 min, and serum 25(OH)D concentration < 14 ng/mL, and the target accuracy (95% confidence interval: CI) was 76.5 (70.3–81.9)%, and sensitivity and specificity (95% CI) were 62.2 (51.4–72.2)% and 86.3 (79.2–91.6)%, respectively. Conclusions Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency were associated with mental health problems among Japanese female university students.https://doi.org/10.1186/s40101-025-00403-9InsomniaLonelinessMental health25-hydroxyvitamin DSocial jetlagVitamin D
spellingShingle Nodoka Yamashita
Shioka Ishii
Yoriko Kotoku
Takuya Shuo
Hiromi Eto
Hideaki Kondo
Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
Journal of Physiological Anthropology
Insomnia
Loneliness
Mental health
25-hydroxyvitamin D
Social jetlag
Vitamin D
title Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
title_full Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
title_fullStr Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
title_full_unstemmed Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
title_short Loneliness, insomnia symptoms, social jetlag, and vitamin D deficiency in relation to mental health problems in Japanese female university students: a cross-sectional study
title_sort loneliness insomnia symptoms social jetlag and vitamin d deficiency in relation to mental health problems in japanese female university students a cross sectional study
topic Insomnia
Loneliness
Mental health
25-hydroxyvitamin D
Social jetlag
Vitamin D
url https://doi.org/10.1186/s40101-025-00403-9
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