Iodine condition seems to occur mainly in people over forty, and the risk appears higher when iodine deficiency is severe and the initial rise in iodine intake is high. In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency gives rise to hypothyroidism, symptoms of which are extreme fatigue, goitre, mental slowing, depression, weight gain, and low basal body temperatures. Iodine deficiency is the leading cause of preventable intellectual disability, a result that occurs primarily when babies or small children are rendered hypothyroidic by a
Complement deficiency Complement deficiency Complement deficiency is an immunodeficiency of absent or suboptimal functioning of one of the complement system proteins. Because there are redundancies in the immune system, many complement disorders are never diagnosed, some studies estimated that less than 10% are identified. "Hypocomplementemia" may be used more generally to refer to decreased complement levels while "secondary complement disorder" means decreased complement levels that are not directly due to a genetic cause but secondary to another medical condition. The following symptoms (signs) are consistent with complement deficiency in general: Vaccinations for encapsulated organisms (e.g., "Neisseria meningitidis" and "Streptococcus pneumoniae") is crucial