What causes an overactive bladder?
An estimated 16 percent of the adult American population has overactive bladder (OAB), but the true number is unknown.
Overactivity of a muscle in the bladder wall is considered to be the main cause of OAB. Stimulants like caffeine and alcohol can also cause symptoms.
A variety of physical conditions and lifestyle habits can influence the chances of developing OAB. It is often the result of a combination of factors where no single cause may be determined.
Within the body, OAB is often the result of spasms in the detrusor muscle, the main muscle of the urinary bladder wall.
When the brain senses the bladder is about half full, it usually sends out nerve signals. These cause the pelvic floor and sphincter muscles to relax while the detrusor contracts, squeezing out urine.
In people with OAB, detrusor muscle contractions occur at random. This leads to a sudden urge to urinate, even when there's very little urine in the bladder. Depending on how the urinary sphincter muscles reacts, urine leakage can occur.
Nerve damage and neurocognitive disorders have long been known to cause OAB symptoms by interfering with nerve signalling.
Some definitions of OAB include neurological causes. Others refer to the symptoms as the result of nervous system conditions affecting the bladder.
Research is still being conducted to better understand the role of the nervous system in OAB.
One 2015 study found that the brain of one person might react to the sensation of the bladder filling differently to another person. This could mean that treatment options need to be tailored individually to be effective.
If the detrusor muscle contracts at random, it may cause leakage or the sudden urge to urinate, even if the bladder is nearly empty.
Common OAB causes include:
- pelvic organ prolapse
- catheter use
- stretched or weakened pelvic muscles
- low estrogen levels, especially after menopause
- enlarged prostate
- giving birth via the vagina
- bladder abnormalities such as bladder stones or tumors
- nerve damage
- Parkinson's disease, stroke, and multiple sclerosis
- decreased thinking ability or related diseases, including Alzheimer's disease
- hip surgery or hip problems
- stretched or weakened bladder muscles
- incomplete bladder emptying
- structural problems with the bladder
While OAB can impact anyone at any age, the likelihood of developing the condition increases greatly with age.
Despite being so common among older adults, OAB is not simply a part of aging. If someone's OAB symptoms become severe or disrupt everyday life, they should see a doctor.
Anything that puts excess weight on or restricts the bladder can increase the risk of developing OAB.
Activities may also increase the risk of OAB if they weaken or damage the pelvic floor, urinary, or sphincter muscles. Conditions that limit the use of pelvic and abdominal muscles may have the same effect.
The relationship between race and ethnicity is still unclear. However, one study found higher prevalence rates of OAB among African American and Hispanic adults compared with other groups.
Common OAB risk factors include:
- being overweight or excess belly fat
- gestational diabetes
- frequent or chronic urinary tract infections
- long-term constipation
- long-term dehydration or overhydration
- chronic coughing
- medications that cause a clear increase in urination or fluid intake
Though many OAB cases aren't reported, available data indicates the condition affects a large portion of adults globally.
An estimated 40 percent of American women and 30 percent of American men are thought to experience OAB symptoms.
Some people with OAB feel the need to urinate several times a night, interrupting their sleep.
At least 30 million American adults consider their OAB symptoms bothersome to everyday activity. The direct costs of OAB in the United States are similar to those of breast cancer and osteoporosis, totaling more than $12 billion annually.
Most OAB cases are marked by three main symptoms: urinary urgency, urinary frequency, and urge urinary incontinence (UUI).
Urinary urgency describes a sudden and uncontrollable desire to urinate even when the bladder isn't full. In some cases, this urgency can make it difficult to reach a bathroom in time, leading to UUI.
Urinary frequency describes the need to urinate an abnormally high amount of times throughout the day and night. Urinating eight or more times daily without excessive fluid intake may be a sign of urinary frequency and OAB.
Around half of those with OAB also experience UUI, or urine leakage. Other common OAB symptoms include bed-wetting and the need to urinate several times during the night.
OAB tends to affect men and women equally but differences in anatomy influence aspects of the condition.
A similar proportion of American women with OAB are estimated to have UUI alongside urgency and frequency.
However, less than 3 percent of American men with OAB report this combination. Men with OAB may experience higher rates of nocturia than women.
The physical symptoms of OAB can also lead to emotional and mental symptoms including depression.
Similarly, fear of an accident, or being far from a bathroom, can cause social anxiety in those with OAB. In more severe cases, people with OAB may avoid social situations or change their daily routine altogether.
Many people with OAB also suffer a loss of self-esteem and the desire for intimacy. Sleep loss, due to frequent nighttime urination, is another common symptom of OAB.
Medication and minimally invasive surgery options exist to treat OAB although the first line of treatment can often be lifestyle changes.
Many factors like smoking, diet, and being overweight increase the likelihood of developing OAB and the severity of symptoms. The lifestyle changes that are recommended for preventing and managing OAB are essentially the same.
OAB prevention and management options include:
- staying hydrated but not overhydrated
- losing weight
- treating chronic constipation through medication or diet
- pelvic floor muscle exercises, including Kegels
- treating urinary and bladder infections
- quitting smoking to reduce coughing
- regular exercise
Many foods and drinks worsen OAB symptoms. Making a few dietary changes will often reduce symptoms greatly.
Caffeine, alcohol, and salty foods can act as a diuretic, increasing urine output and trips to the bathroom.
Spicy and acidic foods irritate the bladder lining, causing discomfort and typically increasing the need for more bathroom visits. Dehydration also allows bladder irritants closer contact with the bladder lining, making their effect more intense.
Spicy foods can irritate the bladder lining and increase the need to urinate.
Foods and drinks to avoid include:
- spicy foods
- salty foods
- caffeinated foods and drinks such as coffee, tea, and chocolate
- items with artificial sweeteners
- acidic foods and drinks
- citrus fruits and juices
- tomatoes including juice, whole fruit, and sauces
- cranberry juice and whole fruit
- vinegar based products
- soda and carbonated drinks
Onions can also irritate the bladder. These can be cooked or replaced with shallots to lessen the effect.
Condiments like soy sauce, ketchup, and mustard, are high in salt, sugar, and acidity. Preservatives in processed foods like takeout meals and deli meats are also known bladder irritants.
People with severe cases of OAB or symptoms of the condition may need to treat these suggestions as rules that they want to adhere to.
To avoid complications, people with severe OAB are often advised to cook meals at home as much as possible.