Association of MPOD Values With Blue Light.
Condition: Age Related Macular Degeneration
MeSH terms: Macular Degeneration
Study type: Observational

Summary: 
      This study aims to investigate in healthy adults 18-65 years of age the association of
      electronic device blue light exposure and macular pigment optical density (MPOD) considering
      usual dietary intake of lutein and zeaxanthin (L/Z) as confirmed by serum lutein and
      zeaxanthin concentrations.

      It is hypothesised in healthy adults 18-65 years of age:

        1. Higher usual daily electronic device blue light exposure will be negatively correlated
           with MPOD value.

        2. Usual dietary intake of L/Z will be positively correlated with MPOD value.

        3. L/Z concentration will be positively correlated with MPOD value.

        4. Usual dietary intake of L/Z will be positively correlated with plasma L/Z
           concentrations.

        5. Higher usual intake of L/Z will mitigate the effect of higher electronic device exposure
           on MPOD value.
    

Detailed description: 
      Exponential uptake of modern technology over the last 30 years (computers) and 10 years
      (smartphones) has resulted in remarkable increase in artificial blue light exposure amongst
      all age groups. This suggests the incidence of age-related macular degeneration (AMD) could
      be increasing significantly in the population in the years to come. It is unknown whether the
      extent of daily blue light exposure influences macular pigment optical density (MPOD) in
      young to middle age adults. Stringham et al. (2017) showed that, in 18-25 year old healthy
      adults, exposed to electronic devices over 6 hours daily, MPOD value and visual performance
      significantly improved after 6 months of lutein/zeaxanthin/meso-zeaxanthin supplementation.
      The findings of this project may inform on the risks of high exposure to electronic screens
      and the need to address with preventive measures the potential decline in MPOD and increased
      risk of AMD. The impact of usual dietary intake of macular xanthophylls on circulating
      concentrations and MPOD will be investigated. Findings may inform guidelines on recommended
      daily intake of these food constituents either through diet or supplementation.

      Data Management and Confidentiality of Data Collected:

      Consent is sought for extended use of the collected data which means it may be used in future
      research. For example, in the future if more sensitive methods for detecting L/Z, or other
      macular pigments become available, stored blood samples may be re-analysed. Furthermore, data
      may be used for subsequent statistical analysis and statistical analysis may be published in
      peer-reviewed journals, however no identifiable personal details will be published or used.
      Any personal information, such as full name and date of birth will remain confidential to
      only the study investigators at all times.

      All hard copy personal information and measures taken as part of the study protocol will be
      stored in locked filing cabinets when not in use, and will only be accessible to approved
      study investigators. Any electronic data collected for the study will be stored using the UQ
      Research Data Management system. Data will be de-identified through the use of participant ID
      numbers allocated at enrolment. Re-identification of participant information will only be
      accessible by study investigators. At the conclusion of the study, participant hard copy
      files and trial documents are kept in locked filing cabinets for a period of 15 years. After
      this time, records will be disposed of by a certified record destruction, such as shredding.

      Blood samples will be collected for research purposes, specifically for the measurement of
      plasma lutein and zeaxanthin concentrations. Collected samples will be stored as per the
      extended consent sought, held for up to 15 years. After this time, they will be destroyed via
      incineration. Collected plasma samples will only be identifiable via the participant study
      number allocated at enrolment. All publicly shared data or data used in publications will be
      in a non-identifiable form.

      Data recorded and maintained for this trial will be controlled in accordance with the
      national Privacy Principles and Privacy Act 1988.

      Sample Size:

      Sample size calculation was performed on the basis of a MPOD coefficient of variation of
      0.187 optical density units (ODU) measured in a sample of 5581 adults using the Macular
      Pigment Screener II (18). A minimum of 105 participants was calculated using a two tailed,
      random model, linear multiple regression with an alpha error probability: 0.05, power: 0.90,
      number of predictors: 4. This also allows for a 20% drop out rate.

      Statistical Tests:

      Analysis will be conducted using GraphPad Prism 8. Participants will be stratified by MPOD.

        1. Descriptive statistics will be performed.

        2. All data will be tested for normality of distribution using the D'Agostino-Pearson
           normality test.

        3. Based on the outcome of testing for normality of distribution, Spearman or Pearson's
           correlations will be used to test for correlation between the following variables.

             1. MPOD and daily hours of electronic device use.

             2. MPOD and usual dietary intake of lutein and zeaxanthin (L/Z).

             3. MPOD and serum L/Z concentration.

             4. Serum L/Z concentration and usual dietary intake of L/Z.

        4. Multiple linear regression will be used to test for correlation to MPOD with the
           following variables:

             1. Daily hours of electronic device use.

             2. Usual dietary intake of L/Z.

             3. Age

             4. Gender

      Results will be considered statistically significant if p<0.05.
    

Observational model: Cohort
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Healthy males and females, 18-65 years of age from Brisbane and surroudning areas,
        Australia.
      
Biospecimen description: 
      Plasma blood sample.
    
Keywords: macular pigment optical density; lutein; zeaxanthin; dietary intake; blue light