Iodine deficiency French, the term "crétin des Alpes" also became current, since the condition was observed in remote valleys of the Alps in particular. The word "cretin" appeared in English in 1779. While reporting recent progress towards overcoming iodine-deficiency disorders worldwide, "The Lancet" noted: "According to World Health Organization, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age." A conclusion was made that the single most preventable cause of intellectual disability is that of iodine deficiency. There is preliminary evidence that iodine deficiency enhances the sensitivity of breast tissue to estrogen. In rats treated with
Vitamin A deficiency Vitamin A deficiency Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues. It is common in poorer countries, but rarely is seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD. Xerophthalmia, keratomalacia, and complete blindness can also occur since vitamin A has a major role in phototransduction. The three forms of vitamin A include retinols, beta-carotenes, and carotenoids. Vitamin A deficiency is the leading cause of preventable childhood blindness, and is critical to achieving Millennium Development Goal 4 to reduce child mortality. About 250,000 to