Hi,
A wide centre hair parting is generally an indication of diffuse hair thinning. The common causes are common balding (androgenetic alopecia), telogen effluvium (hair loss due to more hairs being pushed into the sleeping phase of the hair growth cycle; caused by recent illness, crash dieting, pregnancy, etc), underlying chronic illness (e.g. thyroid disease, iron deficiency), underlying acute illness (e.g. systemic lupus erythematosus).
It is best that you consult your doctor so that a thorough evaluation may be done to determine the root cause. Effective treatment will need to be directed at the most likely cause of your hair loss.
Hope this helps!