**Background:** Dry eye syndrome (DES) is a common ocular condition characterized by tear film instability and ocular surface damage, with higher prevalence in women, especially those over 40. Emerging evidence suggests dietary nutrients may influence DES risk, but specific relationships in older Korean women are underexplored. This study aimed to assess DES prevalence and its association with daily dietary nutrient intake in this population.
**Methods:** Data were obtained from the 8th Korea National Health and Nutrition Examination Survey (KNHANES 2019), a nationally representative cross-sectional survey. The study included 92,888 women aged 40 and above (mean age 63.35 ± 8.86 years). DES diagnosis was based on structured interview-based surveys following ophthalmologist-established criteria. Dietary intake was assessed using a personalized 24-hour recall method, covering 21 nutrients including macronutrients, minerals, and vitamins. Nutrient adequacy was referenced against Korean Dietary Reference Intakes (KDRI) 2020. Socio-demographic and health variables (age, BMI, education, income, occupation, near-work activity, menopause, systemic diseases) were collected. Multivariate logistic regression was used to calculate adjusted odds ratios (OR) for DES associated with each nutrient, controlling for age, BMI, education, income, occupation, near work, menopause, and systemic diseases (rheumatoid arthritis, osteoporosis, diabetes, thyroid disease). Statistical significance was set at p < 0.05.
**Key Results:** The overall prevalence of DES was 7.7%, with the highest prevalence in women aged 50-59 (63.1% of DES cases). In adjusted models, protective factors included higher household income (OR 0.67) and outdoor work (OR 0.61), while risk factors included age 50-59 (OR 1.81), being underweight (OR 1.74), higher education (OR 1.52), and 1-3 hours of near work (OR 1.46). Systemic diseases associated with increased DES risk included rheumatoid arthritis (OR 1.54), osteoporosis (OR 1.47), diabetes (OR 1.41), and thyroid disease (OR 1.41). Menopause also increased risk (OR 1.31).
Regarding dietary nutrients, after full adjustment, the following were inversely associated with DES (all p < 0.0001): dietary fiber (adjusted OR 0.72), protein (OR 0.84), omega-3 fatty acids (OR 0.90), water (OR 0.76), calcium (OR 0.82), phosphate (OR 0.87), potassium (OR 0.88), magnesium (OR 0.87), vitamin A (OR 0.78), carotene (OR 0.82), vitamin C (OR 0.73), and vitamin E (OR 0.86). Conversely, higher intakes of carbohydrates (OR 1.23), sugar (OR 1.30), fat (OR 1.25), cholesterol (OR 1.32), sodium (OR 1.18), iron (OR 1.28), and zinc (OR 1.26) were associated with increased DES risk (all p < 0.0001). No significant associations were found for omega-6 fatty acids or vitamin D.
**Clinical Implications:** This study provides evidence that specific dietary nutrients may influence DES risk in Korean women aged 40 and above. Nutrients with anti-inflammatory and antioxidant properties (e.g., omega-3 fatty acids, vitamins A, C, E) appear protective, while high intakes of carbohydrates, fats, and certain minerals may increase risk. These findings suggest that dietary modification could be a potential strategy for DES prevention and management, particularly in this demographic. However, due to the cross-sectional design and reliance on self-reported dietary data, causality cannot be established. The authors recommend future randomized controlled trials and longitudinal studies to confirm these associations and develop specific dietary guidelines. The study highlights the need for a comprehensive approach to DES management that includes dietary assessment and counseling, especially in postmenopausal women and those with systemic conditions like rheumatoid arthritis or thyroid disease.