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ObjectiveTo evaluate the associations of grip strength with retinal or choroidal thickness in patients with type 2 diabetes mellitus without retinopathy.DesignObservational study-cross-sectional design.Setting and participantsThis study included the Chinese patients with type 2 diabetes without retinopathy registered in the community health system in Guangzhou, China.MeasuresThe grip strength in both hands were measured by using a dynamometer. The retinal and choroidal thickness in macular region stratified by Early Treatment Diabetic Retinopathy Study (ETDRS) sectors were measured by a swept-source optical coherence tomography.ResultsA total of 1029 patients were included. Both retinal thickness and choroidal thickness decreased with the lower quartile of grip strength. Regression analyses indicated that the average retinal and choroidal thickness increased by 0.14 µm (95% CI: 0.03 to 0.25 µm, p=0.011) and 0.57 µm (95% CI: 0.03 to 1.11 µm, p=0.037), respectively, for each additional kilogram of grip strength following adjustment for age and sex. Further adjustments were made for axial length, haemoglobin A1c, length of time the patient had diabetes, insulin usage, height, weight and systolic and diastolic blood pressure, which resulted in an average retinal and choroidal thickness increase of 0.13 µm (95% CI: 0.02 to 0.24 µm, p=0.024) and 0.65 µm (95% CI: 0.13 to 1.16 µm, p=0.013), respectively, for each additional kilogram of grip strength. Consistent results were obtained in the analyses in ETDRS 9 sectors.ConclusionLower hand grip strength was found to be significantly associated with thinner retinal and choroidal layers in patients with diabetes. Grip strength may provide a useful and easily administered indicator of retinal status in patients with diabetes.

PurposeTo assess the association between physical activity, sleep duration, sitting time, and alterations of posterior segment structures with swept-source optical coherence tomography (SS-OCT).MethodsPatients with diabetic retinopathy (DR) were recruited, and diabetic patients without retinopathy (non-DR) who matched for age and duration of diabetes were used as control. The physical activity, siting time, and sleep duration were obtained by using standardized questionnaire. OCT parameters included: retinal nerve fibre layer (RNFL) thickness, ganglion cell inner plexiform layer (GC-IPL) thickness, retinal thickness, and choroidal thickness (CT). Linear regression was conducted to analyse the association.ResultsEach group included 116 diabetic patients. Average macular CT was positively correlated with metabolic equivalents (MET) only in the DR group, independent of age, gender, and other potential confounding factors (β = 1.163, P = 0.006). Average macular CT was also positively correlated with sleep duration only in the non-DR group, independent of age, gender, and other potential confounding factors (β = 10.54, P = 0.031). No correlation was found between MET, sleep duration, and other OCT parameters. Sitting time was not significantly correlated with OCT parameters either.ConclusionsPhysical activity and sleep duration are both positively correlated with macular choroidal thickness; this suggests that more time in physical activity and sleep benefit the retina, while there was no association between sedentary time and OCT parameters. Further studies are warranted to clarify the underlying mechanisms and the role of physical activity and sleep in CT alterations and DR.

ObjectiveTo determine the relationship between grip strength and retinal or choroidal thickness in Chinese patients with type 2 diabetes mellitus.DesignObservational study-cross-sectional design.Setting and ParticipantsThe study was conducted among diabetes patients without retinopathy registered in the community health system in Guangzhou, China.MeasuresGrip strength was measured twice for each hand with a dynamometer in kilograms (kg). The retinal and choroidal thickness in macular Early Treatment Diabetic Retinopathy Study (ETDRS) sectors were measured by commercial swept-source optical coherence tomography (SS-OCT; DRI OCT-2 Triton; Topcon, Tokyo, Japan).ResultsA total of 1,029 patients were included in the study. Both retinal thickness and choroidal thickness increased with the higher quartile of grip strength. Regression analyses indicated that the average retinal and choroidal thickness increased by 0.14 μm (95%CI: 0.03-0.25 μm, P=0.011) and 0.57 μm (95%CI: 0.03-1.11 μm, P=0.037) for each additional kg of grip strength following adjustment for age and gender. Further adjustments were made for axial length, HbA1c, length of time the patient had diabetes, insulin usage, height, weight and systolic and diastolic blood pressure, which resulted in an average retinal and choroidal thickness increase of 0.13 μm (95%CI: 0.02-0.24 μm, P=0.024) and 0.65 μm (95%CI: 0.13-1.16 μm, P=0.013) for each additional kg of grip strength. Consistent results were obtained in the analyses in ETDRS 9 sectors.ConclusionGreater hand grip strength was found to be significantly associated with thicker retinal and choroidal layers in diabetic patients. Grip strength may provide a useful indicator of retinal health in diabetic patients. Further studies are needed to determine directionality and causality, and to examine whether improving muscle strength has a positive effect on retinal and choroidal thickness.Article summaryStrengths and limitations of this studyGrip strength is an indicator of upper limb muscle function and tension, and it is one of the important indicators of aging in the human population. This is one of the few studies to examined the relationship between grip strength and retinal thickness and choroidal thickness in a large sample size of patients with diabetes mellitus.Greater hand grip strength was found to be significantly associated with thicker retinal and choroidal thickness in diabetic patients, and grip strength may provide an easily-administered marker of retinal health in diabetic patients.Causal inferences could not be inferred due to the cross-sectional design of the study.The dynamic changes in grip strength and their impact on retinal and choroidal thickness are warranted to be explored in longitudinal studies.