This study aims to investigate the association of vitamin D (VD) knowledge, behavior, and attitude with BMI status among Saudi adults. This cross-sectional online survey included a total of 774 participants (M/F: 239/535). Knowledge about the overall sources of VD was highest in OB participants in correctly identifying sunlight (95.1%; p < 0.001) while significantly more OW participants answered food (83.1%; p = 0.04) and fortified food (66.5%; p = 0.02). However, 18.9% of OB participants also wrongly identified air as a VD source and this was significantly higher than in other groups (p = 0.03). OW participants were 50% less likely to identify salmon and fish oil (odds ratio, OR 0.5 (95% Confidence interval, CI 0.4-0.7); p < 0.01) and 40% more likely to identify chicken (OR 1.4 (1.0-1.9); p < 0.05) as dietary sources of VD than controls. On the other hand, OB participants were almost three times more likely to know that sunlight exposure is the main source of VD than controls (OR 2.65 (1.2-6.0); p < 0.05). In conclusion, while VD knowledge overall was apparently high in Saudi adults regardless of BMI status, the quality of knowledge among OB and OW individuals appear inconsistent, particularly in terms of identifying the right VD sources. Public health awareness campaigns should include the correction of VD misconceptions so that high-risk populations are able to make well-informed decisions in achieving optimal VD levels.
Keywords: BMI; Saudi Arabia; attitude; behavior; knowledge; sun exposure; vitamin D.