Other Causes of frequent urination:
o Multiple Sclerosis
o Parkinson's Disease
o Diabetes Insipidus:
A disease that is caused by insufficient secretion of vasopressin by the pituitary gland or by a failure of the kidneys to respond to circulating vasopressin and that is characterized by intense thirst and a high urine output.
o Interstitial Cystitis:
A chronic idiopathic cystitis characterized by painful inflammation of the subepithelial connective tissue of the bladder.
o Diabetes Insipidus:
A disease that is caused by insufficient secretion of vasopressin by the pituitary gland or by a failure of the kidneys to respond to circulating vasopressin and that is characterized by intense thirst and a high urine output. - Nephrogenic
o Excessive intake of a high solute load (e.g.  mannitol therapy in the hospital, or use of radiocontrast materials for radiology procedures)
o Salt wasting kidney diseases (such as Bartter's Syndrome)

Frequent Urination in Men:
o Benign Prostatic Hyperplasia (men)
o Cystoceles Prolapse (falling in) of the pelvic floor
o Prostate Cancer
o Urethral Strictures
o Damage form prostate surgery

Frequent Urination in Elderly:
o Atrophic Urethritis
o Central (brain) dysfunction
o Congestive Heart Failure (CHF):
A heart that is unable to maintain adequate circulation of blood in the tissues of the body or to pump out the venous blood returned to it by the venous circulation.
o Delirium:
An usually acute mental disturbance marked by confusion, disordered speech, and hallucinations.
o Diabetes
o Drugs
o Infections
o Psychological
o Medications (e.g. diuretics, Lithium)