Association of Metabolic Syndrome with Macular Thickness and Volume in Older Adults: A Population-Based Optical Coherence Tomography Study.

Background: To explore the associations of the metabolic syndrome (MetS) and individual components with macular thickness and volume among rural-dwelling Chinese older adults. Methods: This population-based cross-sectional study included 705 participants (age ≥60 years) derived from the MIND-China study. In 2018-2019, we collected data through face-to-face interview, clinical examination, optical coherence tomography (OCT) examination, and blood test. We measured macular thickness and volume using spectral-domain OCT. MetS was defined following the International Diabetes Federation (IDF) criteria, the IDF/American Heart Association (AHA) criteria, the National Cholesterol Education Program-Adult Treatment Panel III criteria, and the Chinese Diabetes Society (CDS) criteria. Data were analyzed with multivariable general linear models. Results: MetS was significantly associated with thinner macula in central (multivariable-adjusted β = -5.29; 95% confidence interval: -9.31 to -1.26), parafoveal (-2.85; -5.73 to 0.04) and perifoveal regions (-4.37; -6.79 to -1.95) when using the IDF criteria, in the perifoveal regions (-3.82; -6.18 to -1.47) when using the IDF/AHA criteria, and in the central region (-5.63; -10.25 to -1.02) when using the CDS criteria, and with reduced macular volume when using the IDF (-0.16; -0.26 to -0.07) and IDF/AHA (-0.13; -0.22 to -0.04) criteria. In the parafoveal region, the IDF-defined MetS was significantly associated with thinner retina in men (β = -6.25; -10.94 to -1.56) but not in women. Abdominal obesity (-2.83; -5.41 to -0.25) and elevated fasting blood glucose (-2.65; -5.08 to -0.21) were associated with thinner macular thickness in the perifoveal region. Conclusion: MetS is associated with macular thinning and reduced macular volume among rural-dwelling older adults, and the associations vary by the defining criteria of MetS.