Impact Of Everyday Light Exposure Patterns On Health

NCT06908395 | Completed DMC

• 1 other identifier: EK 24-324
• Study Type: interventional
• Target: 62
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of the present study is to characterize everyday light conditions of younger and older adults and to consider them in relation to cardiovascular, metabolic and psychological health. An ambulatory assessment approach will be used over 12 days, measuring physiological parameters and daily thoughts, behaviors and experiences of different age groups using wearable technologies (e.g., light sensors, activity trackers, continuous glucose monitors) and smartphone-based self-reports (e.g., mood, vitality). At the beginning of the study, the degeneration of the lens and retina of the participants is objectively quantified by ophthalmologists. On the last two days, participants will spend one working day in dim light and another in bright light in randomized order under the same measurement protocol as before in order to experimentally assess their sensitivity to light and its health effects.

Conditions

Healthy Male and Female Subjects; Healthy Elderly

Keywords

Spectral diet; ambulatory assessment; daylight; m-path; eye degeneration; lense yellowing; continuous glucose monitoring; healthy aging; light sensitivity; melanopic EDI

Outcome Measures

Primary Outcomes (2)

• Mean melanopic EDI (lux) from 09:00 to 17:00 h (daytime in European winter months)

  Measured via light loggers (ActLumus) worn as a necklace

  Over the 10-day ambulatory assessment period

• Mean melanopic EDI (lux) 2 hours before individual bedtime

  Measured via light loggers (ActLumus) worn as a necklace

  Over the 10-day ambulatory assessment period

Secondary Outcomes (10)

• Lense degeneration

  Baseline

• Macular and retinal thickness

  Baseline

• Interstitial glucose levels

  Over the 10-day ambulatory assessment period, and specifically levels of day 11 and day 12 between 8:30 and 17:00 h upon controlled office lighting

• Systolic and diastolic blood pressure

  09:00, 10:30, 12:00, 13:00, 14:30, 16:00 and 17:00 on day 11 and 12

• Heart rate

  09:00, 10:30, 12:00, 13:00, 14:30, 16:00 and 17:00 h on day 11 and 12

Other Outcomes (1)

• Digital food photo diary

  continuously throughout the 12-day study period

Study Arms (2)

10 days ambulatory assessment + 1 office day in bright light + 1 office day in dim light

EXPERIMENTAL

Day 11 is spent under laboratory conditions in bright (1250 lux) office lighting from 08:30 to 17:00 h. Day 12 is spent under laboratory conditions in dim (10 lux) office lighting from 08:30 to 17:00 h.

Other: 10-day ambulatory assessment in everyday life combined with two laboratory office days

10 days ambulatory assessment + 1 office day in dim light + 1 office day in bright light

EXPERIMENTAL

Day 11 is spent under laboratory conditions in dim (10 lux) office lighting from 08:30 to 17:00 h. Day 12 is spent under laboratory conditions in bright (1250 lux) office lighting from 08:30 to 17:00 h.

Other: 10-day ambulatory assessment in everyday life combined with two laboratory office days

Interventions

10-day ambulatory assessment in everyday life combined with two laboratory office days OTHER

Participants undergo a 10-day ambulatory assessment period wearing a continuous glucose monitor and a light logger as a necklace as well as completing short questionnaires through a smartphone app at regular intervals every day. On the first day, participants also undergo an extensive eye examination. Day 11 and 12 are spent in either dim or bright office lighting in randomized order.

10 days ambulatory assessment + 1 office day in bright light + 1 office day in dim light; 10 days ambulatory assessment + 1 office day in dim light + 1 office day in bright light

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age: 18-35 or 60-80 years old
• Voluntary participation, signed consent form
• Owns an Android or iOS Smartphone compatible with the m-Path App
• Generally healthy (self-reported)
• Non-smoker for at least 12 months (self-reported)

You may not qualify if:

• Pregnancy (for female participants) (self-reported)
• Night-shift worker
• Eye diseases (e.g. glaucoma, age-related macular degeneration, diabetic retinopathy conditions after retinal detachment / retinal blood vessel occlusions)
• Pseudophakic eyes
• Psychological disorders: insomnia, depression, bipolar disorder and generalized anxiety disorder
• Wearing specially-filtered glasses

Sponsors & Collaborators

• RWTH Aachen University: lead

Study Sites (1)

University hospital at RWTH Aachen

Aachen, 52074, Germany

Location

MeSH Terms

Conditions

Photophobia

Condition Hierarchy (Ancestors)

Vision Disorders; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Jan-Frieder Harmsen, PhD

  RWTH Aachen University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: This study is designed as an observatory field study of characterizing younger and older adults' everyday life over 10 days continuously through wearables and smartphone-based self-reports. In a randomized cross-over design, the 11th and 12th day will be spent in either bright (1250 lux) or dim office lighting (10 lux).

Study Record Dates

• First Submitted: March 20, 2025
• First Posted: April 3, 2025
• Study Start: November 18, 2024
• Primary Completion: June 30, 2025
• Study Completion: June 30, 2025
• Last Updated: July 10, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: The study protocol is available from the 20th of March 2025 onwards for at least 5 years.
• Access Criteria: The study protocol can be requested via email to study officials.

Locations

DE (1)