B vitamins may be involved in the development of age-related macular degeneration (AMD). This investigation intended to examine the association between vitamin B6 catabolic status and the prevalence of AMD. Individuals ≥ 40 years old in the 2005 to 2008 National Health and Nutrition Examination Survey who had complete vitamin B6 measurement and AMD diagnostic data were included in this cross-sectional study. The catabolic status of vitamin B6 was evaluated using serum levels of pyridoxal 5’-phosphate (PLP) (the active form) and its metabolite 4-pyridoxic acid (4-PA). The analysis of 4-PA, PLP, and the 4-PA to PLP ratio (4-PA/PLP) used continuous variables and quartiles (Q1–Q4). The associations of 4-PA, PLP, and 4-PA/PLP with the prevalence of AMD were evaluated via weighted logistic regression, with odds ratio (OR) and 95% confidence interval (CI) estimates provided. Nonlinear relationships were explored utilizing restricted cubic splines. Of these 4202 included individuals, 549 were diagnosed with AMD and 3653 were non-AMD patients. High PLP levels (Q4 ≥ 55.475 nmol/L vs Q1: OR 95% CI = 0.69 0.48–0.97) were significantly associated with lower odds of AMD, whereas high 4-PA/PLP levels (Q3 0.668–0.976: OR 95% CI = 1.57 1.07–2.29; Q4 ≥ 0.976: OR 95% CI = 2.00 1.35–2.96) were related to higher odds of AMD. The associations of PLP levels (Q4: OR 95% CI = 0.49 0.32–0.76) and 4-PA/PLP levels (Q4: OR 95% CI = 2.18 1.27–3.75) with the prevalence of AMD were observed only in individuals aged ≥ 65 years and not in those aged .05). The restricted cubic splines curves demonstrated that the nonlinear relationships of 4-PA ( P overall = .002; P non-linear = .730) and PLP ( P overall < .001; P non-linear = .791) with the prevalence of AMD were not significant, whereas the levels of 4-PA/PLP ( P overall < .001; P non-linear < .001) had a significant nonlinear association with the prevalence of AMD. High 4-PA/PLP levels showed an association with high odds of AMD, suggesting that vitamin B6 catabolic status may influence the prevalence of AMD.
Tang et al. (Fri,) studied this question.