Internal consistency and factor structure of Jenkins Sleep Scale: cross-sectional cohort study among 80 000 adults

: Juhola Juhani, Arokoski Jari PA, Ervasti Jenni, Kivimäki Mika, Vahtera Jussi, Myllyntausta Saana, Saltychev Mikhail

Publisher: BMJ PUBLISHING GROUP

: 2021

: BMJ Open

: BMJ OPEN

: ARTN e043276

: 11

: 1

: 5

: 2044-6055

DOI: https://doi.org/10.1136/bmjopen-2020-043276

: https://research.utu.fi/converis/portal/detail/Publication/53365149

ObjectivesTo assess the internal consistency and construct validity of the Finnish translation of the Jenkins Sleep Scale (JSS) in a large healthy working-age population with diverse work characteristics.
DesignSurvey-based cross-sectional cohort study.
SettingSurvey conducted by an institute of occupational health.
ParticipantsEmployees of 10 towns and 6 hospital districts.
Primary and secondary outcome measures The internal consistency defined by a Cronbach's alpha. Exploratory and confirmatory factor analyses to evaluate the construct structure of the JSS.
ResultsOf 81 136 respondents, 14 890 (18%) were men and 66 246 (82%) were women. Their average age was 52.1 (13.2) years. Of the respondents, 41 823 (52%) were sleeping 7 or less hours per night. The mean JSS total score was 6.4 (4.8) points. The JSS demonstrated high internal consistency with an alpha of 0.80 (lower 95% confidence limit 0.80). Exploratory factor analysis supported a one-factor solution with eigenvalue of 1.94. Confirmatory factor analysis showed that all four items were positively correlated with a single common factor explaining 44%-61% of common factor's variance.
ConclusionsThe Finnish translation of JSS was found to be a unidimensional scale with good internal consistency. As such, the scale may be recommended as a practicable questionnaire when studying sleep difficulties in a healthy working-age population.

e043276.full.pdf