In a univariate analysis, low plasma 25 (OH)D3 levels at baseline were significantly associated with TB-co-infection, low Karnofsky score, low body mass index, low plasma cholesterol level, low hemoglobin level, low albumin, high viral load, high CYP3A activity (as measured by 4β-hydroxycholesterol to cholesterol ratio), and high serum alkaline phosphatase. This evidence concerns the gene CYP3A4 and tuberculosis.