Single‐item chronotype is associated with dim light melatonin onset in lymphoma survivors with fatigue
Linske de Bruijn, Daniëlle E. J. Starreveld, Michael Schaapveld, Flora E. van Leeuwen, Eveline M. A. Bleiker, Nina E. Berentzen
Abstract
Chronotype is frequently assessed in human observational studies using various morningness-eveningness questionnaires. An alternative single-item chronotype question has been proposed for its reduced administration time and its accessibility to all types of populations. We investigated whether this single-item chronotype is associated with dim light melatonin onset, the "gold standard" for estimating the endogenous circadian phase. We used data from a randomised trial in 166 (non-)Hodgkin lymphoma survivors with cancer-related fatigue. All participants completed a questionnaire, including a single-item chronotype question. A subsample of 47 participants also provided saliva samples before sleep onset for melatonin measurement. Using multiple linear regression, we examined whether chronotype based on a single question was associated with dim light melatonin onset. The subsample of 47 participants had a mean age of 44.6 years. The mean (SD) dim light melatonin onset was at 8:42 (1:19) p.m. and the most common chronotype was more evening than morning person (29.2%). A gradual increase in dim light melatonin onset with later chronotype (i.e. evening preference) was observed, with a mean ranging from 7:45 p.m. in definite morning persons to 9:16 p.m. in definite evening persons. Our study shows that single-item chronotype is associated with dim light melatonin onset as a marker of the endogenous circadian phase of fatigued lymphoma survivors. This type of chronotype assessment can therefore be a useful alternative for more extensive morningness-eveningness questionnaires.