Meibomian Gland Dysfunction and Sex as Risk Factors of Dry Eye Disease in a Cohort of Norwegian 65-year-Olds: A Cross-Sectional Study

Purpose: Dry eye disease (DED) is a multifactorial condition characterized by the loss of ocular surface homeostasis, causing discomfort and ocular symptoms. Higher age, female sex, and meibomian gland dysfunction (MGD) are some of the reported risk factors for DED. However, age-specific studies of DED are rare. This study aimed to determine the prevalence of DED and MGD in a cohort of Norwegians in their mid-60s. Additionally, to investigate potential sex-related differences in the prevalence of DED and MGD. Methods: For this cross-sectional study, a random sample of 137 demographically homogeneous Norwegian residents of Oslo in their mid-60s was recruited. Participants completed the Ocular Surface Disease Index (OSDI) dry eye symptom questionnaire and underwent clinical dry eye examinations. DED was defined as OSDI ≥ 13, accompanied by fluorescein break-up time (FBUT) < 10s and/or ocular surface staining (OSS) ≥ 1. The presence of MGD was defined as a score of 1 for both meibum quality (MQ) and meibum expressibility (ME) or a score > 1 for either MQ or ME. Results: The overall prevalence for DED was 20.4% [95% CI: 14.0 to 28.2], and for MGD was 90.5% [95% CI: 84.3– 94.9]. No significant sex differences were observed for either condition. MGD was highly prevalent among both DED and non-DED participants: all individuals with DED (n = 28) had MGD, while among those without DED (n = 109), prevalence was 88.1% (males: 85.7%; females: 90.0%). No significant correlation was found between MGD and sex (rs ([137] = [0.075], p = 0.413). In the whole cohort, OPI and FBUT correlated positively with ME (rs ([132] = [0.437] and rs ([132] = [0.296], both p < 0.001) and negatively with OSS (rs ([132] = [− 0.315] and rs ([132] = [0.423], both p < 0.001) and lid margin abnormality (rs ([130] = [− 0.222], p = 0.011; rs ([132] = [0.234], p = 0.007). FBUT correlated also positively with tear production (rs ([128] = [0.308], p < 0.001). A more frequent use of topical ocular lubricant was found among females (p = 0.043). In the symptomatic group, females had significantly lower OPI and FBUT values (p = 0.046 and 0.027, respectively). Among symptomatic participants, categorized as mild (OSDI 13– 22), moderate (OSDI 23– 32), and severe (OSDI 33– 100), only in the severe group did females show higher OSDI scores ( p= 0.042) but lower OSS ( p= 0.031) compared to males. Conclusion: In this cohort of Norwegians in their mid-60s, DED and MGD were highly and equally prevalent among both sexes. The high prevalence of these conditions underscores the need to raise awareness of DED and MGD within the young elderly population. Keywords: dry eye disease, meibomian gland dysfunction, sex differences, young elderly, prevalence, age-specific