Prevalence of vitamin C deficiency and its association with stroke risk among U.S. adult population: A cross-sectional analysis spanning 15 years with over 13,000 participants.

Background: Stroke presents a significant global health challenge. Despite its potential for cardiovascular protection, the role of vitamin C (VTMC) in stroke risk remains contentious. Aim: This study aimed to assess VTMC deficiency in stroke patients and its association with stroke risk. Methods: We analyzed data from 13,339 adults aged 20 and above in the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2018, excluding those with missing serum VTMC and stroke status. We assessed the VTMC deficiency (<11.4 µmol/L) and stroke incidence association using multivariate weighted logistic regression, adjusting for demographics, BMI, medical history, smoking, and dietary VTMC intake. Results: Stroke rates in the NHANES cycles 2003-2006 and 2017-2018 were 2.8% (95% CI [2.3-3.4]) and 3.3% (95% CI [2.7-4.2]), respectively. VTMC deficiency was more common in individuals with a history of stroke, with rates of 3.6% (95% CI [2.2-5.8]) and 5.3% (95% CI [3-9.1]) compared to 2.7% (95% CI [2.3-3.3]) and 3.2% (95% CI [2.5-4.1]) in the nonstroke population. Nevertheless, VTMC deficiency was distinctly prevalent across diverse demographic and health-related subgroups. Multivariate analyses invalidated any statistically significant association between VTMC deficiency and stroke risk across all employed analytical models within both time intervals. Conclusions: Our study does not support a link between VTMC deficiency and increased stroke risk in U.S. adults. Substantial uncertainties persist regarding the use of VTMC for stroke-related oxidative stress, dosage, and delivery methods, requiring further clinical trials. Healthcare providers should carefully consider its prevalence in specific subgroups.