The learning difficulties are often school-related problems. Many times they show up as learning difficulties. There are many county public health programs, which have screening efforts where they will come out and evaluate your homes. We have had some cases in the Midwest recently. If you are concerned, you can ask your pediatrician to get a blood lead level on your child.
Early detection is key to avoiding the complications of lead poisoning.
Probably the most common health disorders in children are things like diabetes, asthma, and various forms of cancer. Obviously, cancer has more specific implications for survival and more complications related to the types of treatments that affect both lifestyle as well as daily functioning for children. I suspect diabetes is probably the most common. Many children with asthma do outgrow it to some extent. It probably depends on the type of asthma.