 [ Symptoms ] what causes tendonitis in multiple joints  specifically tendonitis in the thumb wrist peronials of foot and lower leg and now shoulder [ Disease ] lactose intolerance is more common in some ethnic groups than in others the national institute of diabetes and digestive and kidney diseases estimates that up to 75 of all adult african americans and native americans and 90 of asian americans are lactose intolerant as people age their bodies produce fewer lactase enzymes so most people do not have symptoms until they are adults most people inherit the condition from their parents lactose intolerance is not very common in children under two years of age unless the child has a lactase deficiency because of an injury to the small intestine if you think your infant or child may be lactose intolerant talk to your child is pediatrician