Below is an instruction from Human. Write a response.
    ### Instruction:
    How many people are affected by multiple sclerosis ?
    ### Response:
    An estimated 1.1 to 2.5 million people worldwide have multiple sclerosis. Although the reason is unclear, this condition is more common in regions that are farther away from the equator. In Canada, parts of the northern United States, western and northern Europe, Russia, and southeastern Australia, the condition affects approximately 1 in 2,000 to 2,400 people.
    