The linear association between vitamin B12 and diabetic retinopathy in type 2 diabetic patients: a cross-sectional study.
To examine the association between serum vitamin B12 levels and the prevalence of diabetic retinopathy (DR) among adults with type 2 diabetes mellitus (T2DM).
This study performed a secondary analysis of a cross-sectional dataset from the Department of Endocrinology, Guangdong Provincial People's Hospital (Dec 2017-Nov 2018). A total of 413 adults with T2DM were included, with DR adjudicated by board-certified ophthalmologists. Serum vitamin B12 was the exposure. Multivariable logistic regression assessed the vitamin B12 and DR association, alongside generalized additive models (GAMs) with smooth splines to explore nonlinearity. Prespecified subgroup and interaction analyses were conducted by sex, age, diabetes duration, blood pressure, lipid profile, and renal function.
After multivariable adjustment, each 100 μmol/L increase in vitamin B12 was significantly associated with a higher risk of DR (OR = 1.49, 95% CI: 1.12-1.99, p = 0.0067). Participants in the highest tertile of vitamin B12 (≥398 μmol/L) exhibited a substantially elevated risk of DR compared with those in the lowest tertile (OR = 11.83, 95% CI: 1.79-78.19, p = 0.0103). GAM indicated a linear positive association. No significant interactions were detected across prespecified subgroups (all P for interaction >0.05).
Higher serum vitamin B12 levels were independently and linearly associated with greater DR prevalence in adults with T2DM. However, temporal ordering and causality cannot be established.
This study performed a secondary analysis of a cross-sectional dataset from the Department of Endocrinology, Guangdong Provincial People's Hospital (Dec 2017-Nov 2018). A total of 413 adults with T2DM were included, with DR adjudicated by board-certified ophthalmologists. Serum vitamin B12 was the exposure. Multivariable logistic regression assessed the vitamin B12 and DR association, alongside generalized additive models (GAMs) with smooth splines to explore nonlinearity. Prespecified subgroup and interaction analyses were conducted by sex, age, diabetes duration, blood pressure, lipid profile, and renal function.
After multivariable adjustment, each 100 μmol/L increase in vitamin B12 was significantly associated with a higher risk of DR (OR = 1.49, 95% CI: 1.12-1.99, p = 0.0067). Participants in the highest tertile of vitamin B12 (≥398 μmol/L) exhibited a substantially elevated risk of DR compared with those in the lowest tertile (OR = 11.83, 95% CI: 1.79-78.19, p = 0.0103). GAM indicated a linear positive association. No significant interactions were detected across prespecified subgroups (all P for interaction >0.05).
Higher serum vitamin B12 levels were independently and linearly associated with greater DR prevalence in adults with T2DM. However, temporal ordering and causality cannot be established.