Vitamin A serum levels do not correlate well with liver stores. Carotenemia may be confused with jaundice. It is also reported high with some cases of diabetes mellitus, myxedema, chronic nephritis, nephrotic syndrome, liver disease, hypothyroidism, type I, IIA, and IIB hyperlipoproteinemia, and in a group of amenorrheic hypogonadotropic women. An inverse relationship between serum β-carotene and the risk of bronchogenic squamous cell carcinoma is reported. The highest carotene levels are found in the serum of faddists ingesting large amounts of vegetables. Oral leukoplakia responds well to β-carotene therapy. Low β-carotene levels are associated with oral contraceptives and smoking.