Scientific Reports · 4 authors, 1 centre
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This nationwide Korean study found that sarcopenia (low muscle mass) is significantly associated with senile blepharoptosis (drooping upper eyelid). Individuals with lower muscle mass index had higher odds of blepharoptosis, independent of age, obesity, and metabolic comorbidities. The findings suggest that systemic muscle loss may impair eyelid function and vision, highlighting blepharoptosis as a potential visible marker for sarcopenia.
**Background:** Sarcopenia, an age-related progressive loss of skeletal muscle mass and function, is increasingly recognized as a contributor to disability and reduced quality of life. Senile blepharoptosis (drooping of the upper eyelid) is a common age-related condition that impairs vision and causes cosmetic concerns. The levator palpebrae superioris muscle is a skeletal muscle composed of approximately 85% type II fibers, which are preferentially affected by sarcopenic changes such as atrophy and fatty infiltration. Despite this biological plausibility, no prior study had examined the relationship between sarcopenia and blepharoptosis. This study aimed to investigate the association using a large, nationally representative Korean dataset.
**Methods:** Data were drawn from the KNHANES 2008–2011, a population-based cross-sectional health survey. Of 37,753 total subjects, 11,553 participants aged 40–79 years (5,159 men, 6,394 women) who completed both ophthalmologic examination and dual-energy X-ray absorptiometry (DXA) were included after excluding those with anophthalmos, facial palsy, or thyroid disease. Muscle mass was quantified using the muscle mass index (MMI), defined as appendicular skeletal muscle mass (ASM, kg) divided by body mass index (BMI, kg/m²). Sarcopenia was defined as the lowest MMI quintile (Q1) within each sex. Blepharoptosis was defined as marginal reflex distance 1 (MRD1) < 2 mm in the worse eye. Levator function was measured in millimeters and categorized as good (≥12 mm), fair (8–11 mm), or poor (≤7 mm). Multivariate logistic regression was used to assess associations, adjusting for age, hypertension, diabetes, smoking, cataract surgery history, and obesity (BMI > 25 kg/m²).
**Key Results:** The mean age of participants with blepharoptosis was significantly higher than those without (men: 62.8 vs. 56.4 years; women: 65.3 vs. 56.0 years; both p < 0.001). Mean MMI was significantly lower in the blepharoptosis group (men: 0.86 vs. 0.90 kg/kg/m²; women: 0.57 vs. 0.60 kg/kg/m²; both p < 0.001). A clear inverse linear trend was observed: lower MMI quintiles had progressively higher blepharoptosis prevalence (p for trend < 0.001 in both sexes). In fully adjusted models (Model 3: age, hypertension, diabetes, smoking, cataract surgery, obesity), MMI remained significantly associated with blepharoptosis in men (OR 0.17 per unit MMI; 95% CI 0.07–0.39; p < 0.001) but was borderline in women (OR 0.40; 95% CI 0.14–1.14; p = 0.086). Sarcopenia (lowest MMI quintile) was significantly associated with blepharoptosis in the total population after full adjustment (OR 1.18; 95% CI 1.04–1.34; p = 0.012). This association was significant in men (OR 1.22; 95% CI 1.01–1.47; p = 0.038) but not in women (OR 1.17; 95% CI 0.98–1.39; p = 0.085). When stratified by levator function, sarcopenia was significantly associated with blepharoptosis in those with fair-to-good levator function (≥8 mm; OR 1.19; 95% CI 1.04–1.37; p = 0.013) but not in those with poor levator function (≤7 mm; OR 1.00; 95% CI 0.65–1.53; p = 0.992). Additionally, lower MMI was linearly associated with worse levator function (p for trend < 0.001). In contrast, BMI showed no association with blepharoptosis in men (p for trend = 0.359) and a positive association in women (p for trend < 0.001), suggesting sex-specific differences in the relative contribution of sarcopenia versus adiposity.
**Clinical Implications:** This is the first study to demonstrate an independent association between sarcopenia and senile blepharoptosis in a large, nationally representative sample. The findings suggest that systemic muscle loss contributes to eyelid dysfunction, likely through sarcopenic changes (fat infiltration and type II fiber atrophy) in the levator palpebrae superioris muscle. The association persisted after adjusting for age and metabolic comorbidities, indicating that sarcopenia itself—not just aging or obesity—is a risk factor for blepharoptosis. Clinically, blepharoptosis may serve as a visible, easily assessed screening marker for sarcopenia, particularly in patients who cannot perform standard sarcopenia assessments (e.g., handgrip test, chair stand test). The study also highlights that men with blepharoptosis may be more likely to have underlying sarcopenia rather than obesity-related mechanical ptosis. Limitations include the cross-sectional design (precluding causal inference), lack of muscle strength measurements (e.g., handgrip), and restriction to a Korean population, which may limit generalizability to other ethnicities.