Long-term cumulative light exposure from the natural environment and sleep: A cohort study

Marko Elovainio, Kaisla Komulainen, Jari Lipsanen, Timo Partonen, Anu Katriina Pesonen, Laura Pulkki-Råback, Tiina Paunio, Mika Kähönen, Jussi Vahtera, Marianna Virtanen, Reija Ruuhela, Christian Hakulinen, Olli Raitakari

    Research output: Contribution to journalArticleScientificpeer-review

    7 Citations (Scopus)


    We analysed (A) the association of short-term as well as long-term cumulative exposure to natural light, and (B) the association of detailed temporal patterns of natural light exposure history with three indicators of sleep: sleep duration, sleep problems, and diurnal preference. Data (N = 1,962; 55% women; mean age 41.4 years) were from the prospective Young Finns Study, which we linked to daily meteorological data on each participant’s neighbourhood natural light exposure using residential postal codes. Sleep outcomes were self-reported in 2011. We first examined associations of the sleep outcomes with cumulative light exposure of 5-year, 2-year, 1-year, and 2-month periods prior to the sleep assessment using linear and Poisson regression models adjusting for potential confounders. We then used a data-driven time series approach to detect clusters of participants with different light exposure histories and assessed the associations of these clusters with the sleep outcomes using linear and Poisson regression analyses. A greater cumulative light exposure over ≥1 year was associated with a shorter sleep duration (β = −0.10, 95% confidence interval [CI] −0.15 to −0.04), more sleep problems (incident rate ratio [IRR] 1.04, 95% CI 1.0–1.07) and diurnal preference towards eveningness (β = −0.09, 95% CI −0.14 to −0.03). The data-driven exposure pattern of “slowly increasing” light exposure was associated with fewer overall sleep problems (IRR 0.93, 95% CI 0.88–0.98) compared to a “recently declining” light exposure group representing the “average-exposure” group. These findings suggest that living in an area with relatively more intense light exposure for a longer period of time influences sleep.

    Original languageEnglish
    Article numbere13511
    JournalJournal of Sleep Research
    Issue number3
    Early online dateNov 2021
    Publication statusPublished - 2022
    Publication typeA1 Journal article-refereed


    • area
    • depression
    • mechanisms
    • neighbourhood
    • population
    • risk

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

    • Cognitive Neuroscience
    • Behavioral Neuroscience


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