The English disease, as referred to by the Dutch, is rickets.
According to the provided reference:
Not so long ago, a lot of people were affected by rickets (what the Dutch refer to as 'the English disease'), a condition that causes bowed legs, spinal deformities and oral problems when the body cannot make enough vitamin D from sunlight.
In other words, when someone speaking Dutch refers to "the English disease," they are likely talking about rickets. Rickets is a disease primarily affecting children, caused by a deficiency in vitamin D, calcium, or phosphate. This deficiency leads to softening and weakening of bones, resulting in skeletal deformities. Common signs of rickets include bowed legs, spinal deformities, and dental problems.
