Goitre related to hypermetabolism, (increased metabolism), excessive thyroid hormone, an increase in oxygen consumption, metabolic changes in protein metabolism, immunologic stimulation of diffuse goitre, and ocular changes (exophthalmos). Hypothyroid individuals may have weight gain despite poor appetite, cold intolerance, constipation and lethargy. However, these symptoms are often non-specific and make diagnosis difficult. A goitre may be classified either as nodular or diffuse. Nodular goitres are either of one nodule (uninodular) or of multiple nodules (multinodular). Worldwide, the most common cause for goitre is iodine deficiency, usually seen in countries that do not use iodized salt. Selenium deficiency is also considered a
Vitamin A deficiency Organization (WHO), VAD is under control in the United States, but in developing countries, VAD is a significant concern. Globally, 65% of all children aged 6 to 59 months received two doses of vitamin A in 2013, fully protecting them against VAD (80% in the least developed countries). The common cause of blindness in developing countries is Vitamin A deficiency (VAD). The WHO estimated in 1995 that 13.8 million children to have some degree of visual loss related to VAD. Night blindness and its worsened condition, xerophthalmia, are markers of Vitamin A deficiency (VAD) and collections of keratin in the