Itai-Itai disease is caused by chronic poisoning of

Itai-Itai disease is a painful condition that primarily affects the bones and kidneys.

It was first identified in Japan in the Toyama Prefecture in the early 20th century.

The term "Itai-Itai" literally means "ouch-ouch" in Japanese, referring to the extreme pain suffered by patients.

The disease was caused by chronic cadmium poisoning, which occurred due to prolonged consumption of rice and water contaminated by cadmium from mining and industrial runoff.

Cadmium accumulation leads to osteomalacia (softening of the bones), fractures, and kidney failure.

Hence, Cadmium is the correct answer.