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Abstract:
Background: Light exposure is essential for our health and well -being, driving various non-visual processes, including circadian photoentrainment, melatonin suppression and the modulation of alertness. An unexplored dimension of light exposure is that it is partially controlled by our behavior. Here, we present a novel instrument to capture light exposure-related behavior: the Light Exposure Behaviour Assessment (LEBA).
Methods: An expert panel prepared an initial item pool (n = 48 items). Responses, consisting of rating the frequency of engaging in a given behavior on a five-point Likert scale, were collected using a fully anonymous, geographically unconstrained online survey (n = 690 complete responses across 74 countries and 28 time zones). Five different attention - check items were included in the survey to ensure high data quality. We applied a psychometric analysis strategy based on Classical Test Theory and Item Response Theory (IRT) to develop and validate the LEBA instrument. Results: In the exploratory factor analysis (EFA) on an initial subset of our sample (n = 428), a five-factor latent structure with 25 items was obtained (F1: wearing blue light filters; F2: spending time outdoors; F3: using phone and smart watch in bed; F4: using light before bedtime; F5: using light in the morning and during daytime). A subsequent confirmatory factor analysis (CFA) was performed on another independent subset of participants (n = 262) to assess structural validity. The final CFA analysis yielded a five-factor latent structure with 23 items (CFI = 0.95, TLI = 0.95 and RMSEA = 0.06). The five factors’ internal consistency reliability coefficient ordinal alpha ranged between 0.52 and 0.96, indicating sufficient to good internal consistency. The full scale also showed adequate internal consistency (McDonald’s Omega = 0.73). Our model also exhibited the highest level of invariance–residual invariance between native and non-native English speakers (CFI = 0.95, TLI = 0.95, RMSEA = 0.05). Finally, we used IRT on the complete sample (n = 690) to develop a short form of LEBA (18 items), excluding five items carrying low information to distinguish individuals in terms of their attitude towards light hygiene.
Conclusion: The psychometric properties of both forms of LEBA indicate the potential usability for measuring individuals’ general light exposure-related behavior at a large scale. The LEBA instrument may offer a scalable solution to characterize persons based on their engagement in these behaviors, which may help to develop interventions for optimizing personal light exposure. Adaptations of LEBA into Bangla and German are currently in preparation. The LEBA instrument will be available under the open -access CC-BY-NC-ND license (https://leba-instrument.org/ accessed on 28 February 2022).
