Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light

Abstract

Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation Daniel P. Windred, Angus C. Burns, Martin K. Rutter, Chris Ho Ching Yeung, Jacqueline M. Lane, Qian Xiao, Richa Saxena, Sean W. Cain, Andrew J. K. Phillips. Personal light exposure patterns and incidence of type 2 diabetes: analysis of 13 million hours of light sensor data and 670,000 person-years of prospective observation. Lancet. 2024. doi: 10.1016/j.lanepe.2024.100943. Abstract Background Light at night disrupts circadian rhythms, and circadian disruption is a risk factor for type 2 diabetes. Whether personal light exposure predicts diabetes risk has not been demonstrated in a large prospective cohort. We therefore assessed whether personal light exposure patterns predicted risk of incident type 2 diabetes in UK Biobank participants, using ∼13 million hours of light sensor data. Methods Participants (N = 84,790, age (M ± SD) = 62.3 ± 7.9 years, 58% female) wore light sensors for one week, recording day and night light exposure. Circadian amplitude and phase were modeled from weekly light data. Incident type 2 diabetes was recorded (1997 cases; 7.9 ± 1.2 years follow-up; excluding diabetes cases prior to light-tracking). Risk of incident type 2 diabetes was assessed as a function of day and night light, circadian phase, and circadian amplitude, adjusting for age, sex, ethnicity, socioeconomic and lifestyle factors, and polygenic risk. Findings Compared to people with dark nights (0–50th percentiles), diabetes risk was incrementally higher across brighter night light exposure percentiles (50–70th: multivariable-adjusted HR = 1.29 [1.14– 1.46]; 70–90th: 1.39 [1.24–1.57]; and 90–100th: 1.53 [1.32–1.77]). Diabetes risk was higher in people with lower modeled circadian amplitude (aHR = 1.07 [1.03–1.10] per SD), and with early or late circadian phase (aHR range: 1.06–1.26). Night light and polygenic risk independently predicted higher diabetes risk. The difference in diabetes risk between people with bright and dark nights was similar to the difference between people with low and moderate genetic risk. Interpretation Type 2 diabetes risk was higher in people exposed to brighter night light, and in people exposed to light patterns that may disrupt circadian rhythms. Avoidance of light at night could be a simple and cost-effective recommendation that mitigates risk of diabetes, even in those with high genetic risk. Open access paper: thelancet.com

AI evidence extraction

Main findings

In 84,790 participants with ~13 million hours of light sensor data, brighter night light exposure was associated with higher risk of incident type 2 diabetes compared with dark nights (0–50th percentile): 50–70th aHR 1.29 (1.14–1.46), 70–90th aHR 1.39 (1.24–1.57), 90–100th aHR 1.53 (1.32–1.77). Lower modeled circadian amplitude (aHR 1.07 per SD, 1.03–1.10) and early/late circadian phase (aHR range 1.06–1.26) were also associated with higher diabetes risk; night light and polygenic risk independently predicted risk.

Outcomes measured

• incident type 2 diabetes

Limitations

• Observational (prospective cohort) design; causality cannot be established from the abstract alone
• Light exposure measured for one week may not represent long-term exposure patterns
• Exposure characterization is based on modeled circadian amplitude/phase from weekly light data (model assumptions not described in abstract)

{
    "study_type": "cohort",
    "exposure": {
        "band": null,
        "source": "personal light exposure (day and night) measured by wearable light sensors",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "one week of light sensor wear; mean follow-up 7.9 ± 1.2 years"
    },
    "population": "UK Biobank participants",
    "sample_size": 84790,
    "outcomes": [
        "incident type 2 diabetes"
    ],
    "main_findings": "In 84,790 participants with ~13 million hours of light sensor data, brighter night light exposure was associated with higher risk of incident type 2 diabetes compared with dark nights (0–50th percentile): 50–70th aHR 1.29 (1.14–1.46), 70–90th aHR 1.39 (1.24–1.57), 90–100th aHR 1.53 (1.32–1.77). Lower modeled circadian amplitude (aHR 1.07 per SD, 1.03–1.10) and early/late circadian phase (aHR range 1.06–1.26) were also associated with higher diabetes risk; night light and polygenic risk independently predicted risk.",
    "effect_direction": "harm",
    "limitations": [
        "Observational (prospective cohort) design; causality cannot be established from the abstract alone",
        "Light exposure measured for one week may not represent long-term exposure patterns",
        "Exposure characterization is based on modeled circadian amplitude/phase from weekly light data (model assumptions not described in abstract)"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "light at night",
        "night light exposure",
        "circadian disruption",
        "circadian amplitude",
        "circadian phase",
        "type 2 diabetes",
        "UK Biobank",
        "wearable light sensor",
        "prospective cohort",
        "hazard ratio",
        "polygenic risk"
    ],
    "suggested_hubs": []
}

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