A study published in The Ocular Surface by researchers at the Oslo University Hospital in Oslo, Norway, evaluated the connection between sedentary behavior (SB) and dry eye disease (DED) caused by low-grade inflammation.
Give me some background.
The cross-sectional study assessed 48,418 participants from Lifelines, an ongoing prospective, population-based cohort study examining the health and health-related behaviors of over 167,000 people living in the northern Netherlands.
Participants of the Lifelines study were included by general practitioners or self-enrollment between 2006 and 2013, and will be followed for at least 30 years.
Tell me more.
The Lifelines study evaluated DED using the Women’s Health Study (WHS) dry eye questionnaire given to participants between 2014 and 2017.
Physical activity (PA) was recorded with a separate questionnaire, collecting information on commuting, leisure time and sports, household work, employment, and school.
Sedentary behavior was measured using the Marshall Sitting Questionnaire, which evaluated sitting time across five areas: transportation, work, television watching, at-home computer use, and leisure.
Let’s hear about the study.
Investigators analyzed the relationship between SB and DED using logistic regressions, correcting for age, sex, body mass index, smoking status, demographics, and 48 comorbidities.
Researchers also assessed any potential modifying effect of PA, with repeated analyses—excluding the most computer-intensive domains—to evaluate SB independently from screen exposure.
Results?
The study found that DED was present in 9.1% of participants, and each hour of daily SB time increased the odds of having DED by 1.5% (odds ratio [OR] 1.015 per hour/day, 95% confidence interval [CI] 1.005-1.024, P=0.004).
Additionally, the association between SB and DED was only significant for those with less than the World Health Organization’s (WHO) recommended PA (OR 1.022, 95% CI 1.002-1.042, P=0.076).
According to WHO, adults should perform >150 minutes of moderate or >75 minutes of vigorous PA per week.
Anything else?
When excluding computer-related sitting (and thus, digital screen use), the relationship between SB and DED was no longer significant (OR 1.009, 95% CI 0.996-1.023, P=0.19).
Further, several disorders associated with DED were linked to increased SB, including type 2 diabetes, depression, and connective tissue disease.
Take home?
Researchers concluded that the significant association between SB and DED risk was only significant when involving computer-related sitting time.
As a result, digital screen use should be considered a potential major factor (the confounder) when linking SB and DED together.