In a new study published in Translational Vision Science and Technology, researchers investigated the relationship between accelerometer-measured daily behaviors and refractive status with depressive disorders.
Give me some background first.
Depression is a mood disorder impacting more than 300 million individuals globally.
- To note: Previous studies have identified an association between depression and vision impairment, which may have been due to a reduction in social connectedness and hindered ability to participate in pleasurable activities.
Now, talk about the study.
Investigators conducted a cohort study that utilized data from the United Kingdom (UK) Biobank. They included participants with baseline mean spherical equivalent (MSE) and 7-day accelerometer measurements.
Note: Compared with traditional questionnaires, accelerometer tests use definite assessment criteria and provide objective measurements, which are less vulnerable to recall bias.
- The refractive status of participants was categorized as hyperopia and non-hyperopia.
Who was included in the study?
A total of 20,607 participants were included in the final analysis and comprised of:
- 55.71% females
- Mean age of 56.52 years
- Mean baseline MSE of −0.56 ± 2.78 D
How was the study conducted?
Four daily behaviors were recorded between 2013 and 2015:
- Moderate to vigorous intensity physical activity (MVPA)
- Light physical activity (LPA)
- Sedentary
- Sleep
Note: 24-hour behavior patterns were also assessed.
Depression cases were defined through:
- Questionnaires
- Hospital records
- Over 10 years of follow up
Findings?
Among 20,607 individuals:
- Every 0.5-diopter increase in MSE was associated with a 6% higher risk of depressive disorders
- Hyperopia participants were at a higher risk than non-hyperopia participants
- Odds ratio (OR), 1.14; 95% confidence interval (CI), 1.05–1.23; P = 0.001
- Hyperopia participants were at a higher risk than non-hyperopia participants
Mediation analyses showed:
- MVPA and sleep partially mediated the relationship between MSE and depressive disorders
- With 35.2% of the association between moderate to high hyperopia and depression mediated by MVPA
Tell me more.
Additionally:
- MVPA and sleep time significantly correlated with depressive disorders, with ORs of 0.79 and 1.14, P< 0.05
- MSE showed significant correlations with all four daily behaviors (as noted above)
- The effects of MVPA and sleep duration on MSE and depressive disorders varied throughout the day
Limitations?
The study authors noted its cross-sectional design, as well as the device-based methods being limited in horizontal locomotion.
- What this means: They are unable to distinguish between types of physical activity and sedentary behavior.
Go on …
Lastly, the study utilized the UK Biobank, which the authors stated was representative of a predominantly White and high-income country.
- Why this matters: This limited the generalizability of results
Expert opinion?
The authors stated, “Future interventions to restore normal vision while also targeting MVPA and normal sleeping patterns may cater more holistically toward an aging population to decrease the risk and burden of depression.”
Take home.
The study found that older adults who have higher MSE (especially hyperopia) may have:
- Lower levels of MVPA
- Longer sleep durations
- Higher depression risk
“Physical activity and sleep may significantly mediate the relationship between MSE and depressive disorders”, the authors concluded.