During follow-up questionnaire 1B adult Lifelines participants completed questionnaires from the Pittsburgh Sleep Quality Index. Researchers from Erasmus MC used these questions to calculate the Pittsburgh Sleep Quality Index (PSQI), Munich Chronotype Questionnaire (MCTQ), and Epworth Sleepiness Scale (ESS). This syntax has been checked by Lifelines and some bugs have been removed (sections: Lifestyle & environment (Sleep quality (PSQI, Chronotype (MCTQ), Sleepiness (ESS)) and secondary & linked variables).
The sleep indices can be requested in the Lifelines catalogue or by email (data@lifelines.nl). When this data has been used in your research, you will have to include a reference to the the following paper:
The PSQI is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. Where nineteen questions generate seven 'component' scores. The sum of these scores gives the global PSQI score (Buysse et al., 1989).
The seven 'component' scores were calculated according to the scoring instructions that can be found in the Buysse et al., 1989.
Afterwards, the global PSQI score was calculated by adding the seven component scores (cut-off: max 1 missing component score). This calculation included a weighing component as well, entailing that in case of six components the global PSQI score has been mulitplied by 7/6.
Result: >121,000 calculated PSQI scores (>109,000 with no missing component score).
Remarks researcher:
Label English | Label Dutch | Code | Variable | Assessment | Age |
PSQI component 1: quality | PSQI component 1: kwaliteit | psqi_componentscore_adu_c_1 | PSQIcomponent1 | 1B | 18+ |
PSQI component 2: latency | PSQI component 2: latency | psqi_componentscore_adu_c_2 | PSQIcomponent2 | 1B | 18+ |
PSQI component 3: sleep duration | PSQI component 3: slaapduur | psqi_componentscore_adu_c_3 | PSQIcomponent3 | 1B | 18+ |
PSQI component 4: habitual sleep efficiency | PSQI component 4: gewone slaap efficiëntie | psqi_componentscore_adu_c_4 | PSQIcomponent4 | 1B | 18+ |
PSQI component 5: disturbances | PSQI component 5: verstoringen | psqi_componentscore_adu_c_5 | PSQIcomponent5 | 1B | 18+ |
PSQI component 6: use of sleeping medication | PSQI component 6: gebruik van slaapmedicatie | psqi_componentscore_adu_c_6 | PSQIcomponent6 | 1B | 18+ |
PSQI component 7: daytime dysfunction | PSQI component 7: disfunctie overdag | psqi_componentscore_adu_c_7 | PSQIcomponent7 | 1B | 18+ |
Global PSQI score (weighted for maximum 1 component missing) | PSQI-score (gewogen voor maximaal 1 ontbrekend onderdeel) | psqi_globalscore_adu_c_1 | PSQIscore_1miss | 1B | 18+ |
Global PSQI score, dichotomized into good versus poor sleep quality | PSQI-score, gedichotomiseerd in goede versus slechte slaapkwaliteit | psqi_qualityscore_adu_c_1 | PSQIscore_1miss_dich | 1B | 18+ |
The MTCQ is a questionnaire that assesses sleep and wake behavior on work and free days (Roenneberg et al., 2012). MCTQ provides measures of midpoint of sleep on free days (MSF), and MSF corrected for sleep debt accumulated during the week (MSFsc).
For an overview of the used formulas for the Munich Chronotype estimation we refer to the supplementary material of the article from Roenneberg et al., 2012 and the provided syntax on the workspace. In the end, the social jetlag has been calculated for >104,000 participants.
1. Exclusion criteria for further analyses include:
2. The questionnaire did NOT include specific questions for shift workers
Label English | Label Dutch | Code | Variable | Assessment | Age |
Sleep duration on free days | Slaapduur op vrije dagen | mctq_sdfree_adu_c_1 | SDf | 1B | 18+ |
Sleep duration on workdays | Slaapduur op werkdagen | mctq_sdwork_adu_c_1 | SDw | 1B | 18+ |
Average sleep duration across the week | Gemiddelde slaapduur gedurende de week | mctq_sdweek_adu_c_1 | SDweek | 1B | 18+ |
Mid-Sleep time on free days | Tijdstip mid-slaap op vrije dagen | mctq_msfree_adu_c_1 | MSF | 1B | 18+ |
Mid-Sleep time on free days corrected for 'oversleep' on free days | Tijdstip mid-slaap op vrije dagen, gecorrigeerd voor 'overslapen' op vrije dagen | mctq_msfreecorrected_adu_c_1 | MSFsc | 1B | 18+ |
Mid-Sleep on work- and on free days | Mid-Sleep on work- and on free days | mctq_msw_adu_c_1 | MSW | 1B | 18+ |
Social jetlag | Sociale jetlag | mctq_socialjetlag_adu_c_1 | SJL | 1B | 18+ |
Absolute social jetlag | Absolute sociale jetlag | mctq_socialjetlagabs_adu_c_1 | absSJL | 1B | 18+ |
The eight ESS item scores provide estimates of eight different situational sleep propensities (SSPs) for a person, while the total ESS score gives an estimate of a more general characteristics, the person's 'average sleep propensity' (ASP), across a wide range of activities in their daily lives (ESS website).
Calculation of the ESS score was executed in three steps:
Result: >95,000 calculated ESS scores.