Introduction

What is nocturia?

Nocturia is a condition when a patient wakes up multiple times at night to urinate. Only those occasions are classified as nocturia when the patient gets up from sleep and then sleeps back after the urination, also referred to as voids.^1,3 Both upper and lower urinary tract infection (UTI) cases can be associated with nocturia. Still, the condition is most commonly seen with lower urinary tract symptoms, affecting the prostate and the bladder.² 

As nocturia causes frequent disruptions to sleep, it can be a disturbing urinary condition for the patients, while also being one of the most common ones. If untreated, nocturia can cause long-term sleep deprivation and consequently a negative impact on cognitive performance.^1,2 

The causes and influencing factors of nocturia

The causes of nocturia generally have multiple factors associated with urinary and non-urinary conditions that may influence its development. These include: 

Urinary conditions associated with nocturia

• Lower urinary tract symptoms (LUTS), including an overactive bladder (OAB) and benign prostatic obstruction (BPO)
• Neurogenic voiding dysfunction
• Polyuria (overproduction of urine)
• Bladder tumours^2,3

Non-urinary conditions associated with nocturia

• Heart failure 
• Diabetes linked to impaired insulin production leading to kidney dysfunction
• Hypoalbuminemia, meaning impaired albumin in the body
• Sleep apnoea
• Chronic pain
• Depression
• Inadequate fluid intake² 

The consensus is that nocturia typically results from one or a combination of the following three factors, which may arise from the conditions mentioned above: 

• Nocturnal polyuria: Excess urine production overnight
• Global polyuria: Excess urine production throughout the day and night
• Reduced bladder’s storage capacity^1,2

Some researchers suggest that sleep disorders could be a fourth potential factor contributing to nocturia. However, the exact relationship between sleep disorders and nocturia is not yet fully understood, as it's unclear whether sleep disorders cause nocturia or if nocturia leads to sleep disturbances.^1,2 

The prevalence of this condition is highly underestimated as many people are either embarrassed to share about it or brush it off as normal in milder cases.^2,7 However, the demographic trends seen from the available reports show a gradual increase in the incidence rate across all age groups.²

Nocturia in different age groups 

Nocturia in children 

When it comes to nocturia, most studies have been done in adults in their twenties onwards. Children might suffer from an overactive bladder (OAB), which results in a similar array of symptoms as in adults, including an urgency to urinate (which differs from a simple urge), urinary frequency, and nocturia. The important differentiating factor is that in children, impaired bladder function or urine overproduction often also leads to nocturnal enuresis, also known as “wetting the bed”. 

Under the age of 5, this phenomenon is considered normal, however, above that age, nocturnal incontinence is usually investigated. Whether the condition arises from mental or especially physical causes, early diagnosis and appropriate treatment are key to preventing exacerbation of the underlying condition behind nocturnal enuresis.⁵

Nocturia in young adults 

Nocturia in young adults (between 20 and 40 years of age) is less prevalent than in the elderly but still affects a large fragment of the population. For instance, 4-18% of females in their 20s and 30s are affected by having more than two voids/night, while the same is true for 2-17% of males of the same age range, as reported in a review of 43 studies.⁶ Another survey involving almost twenty-thousand adults across five countries reported nocturia as the most prevalent LUTS with 13-17% of adults below the age of 40 years reporting two or more voids.^2,7

The prevalence of nocturia in this age group is not the only concern. Studies showed that nocturia has the most detrimental effect on daytime functioning in young adults, and it even has a more substantial possible negative impact on health and mortality in young adults than in any other age group.^2,4,6 

Nocturia in middle-aged adults

Most studies compare the rate of nocturia in younger adults to the elderly population, while middle-aged adults can get left out of the spotlight. However, as expected, the percentage of people within this age group (40-60 years old) falls between the results of young adults and the elderly. This means approximately between 8-30% of middle-aged adults have two or more voids at night.²

It must also be noted that nocturia is significantly more prevalent in women in the earlier stages of life, however, around 50 years of age, the results from the two sexes become more comparable (most likely with less efficient prostate function).^2,4

Nocturia in the elderly

With less efficient prostate and kidney function and a weakened bladder, patients older than 60 years have the highest chances of developing nocturia. By the age of 80, between 80-90% of patients report at least one void during the night, with nearly half experiencing two or more episodes.⁸ The same review that evaluated the prevalence in young adults based on 43 studies also found that 28-62% of women in their 70-80s experience nocturia, while in men, this number slightly reduces to 29-59%.^2,6

Diagnosis and management

Diagnostic approaches

Diagnosing nocturia itself is easy, however, identifying the combination of underlying conditions resulting in this symptom is a challenge. The most valuable diagnostic tool to screen for the potentially triggering underlying pathology is the 24-hour monitoring of the patient's urination, including the frequency and volume. Based on this assessment, both polyuria and bladder storage deficiency can be easily identified based on the total urine volume and the occasional volume, respectively.² 

Additionally, monitoring the patient’s fluid intake, along with evaluating kidney function, cardiac function, and serum glucose and haemoglobin levels, can help identify any underlying pathologies.^1,2 

Management techniques

The treatment of nocturia itself is not necessary unless the patient is significantly bothered by the frequent awakenings. Most people consider it a natural part of ageing, however, in more severe cases, it might be beneficial to apply practices that lower the number of voids to 1-2 occasions per night. This includes:

• Limiting fluid intake throughout the day, and especially in the last 2 hours before sleep
• Limiting protein and salt intake
• Avoiding alcohol and caffeine intake, as well as smoking 
• Increasing daily physical exercise
• Performing pelvic floor muscle exercises¹

Additionally, treating the underlying conditions responsible for nocturia with the appropriate medications will help limit the number of voids and, thus, improve the sleeping experience.² 

Summary

The term nocturia refers to the need to urinate multiple times during the night and is a major cause of sleep disruption in a large fragment of the adult population. While its prevalence increases with age, nocturia impacts individuals differently across all age groups. In children, it is often intervened with other urinary symptoms like nocturnal enuresis (bed wetting). Young adults, though less frequently affected, may experience significant disruptions to daily life in cognitive performance when nocturia occurs. Middle-aged individuals see an increasing prevalence, with the elderly being most commonly affected.

The causes of nocturia are multifaceted, ranging from urinary tract issues to systemic conditions. Diagnosis typically involves comprehensive evaluation, including 24-hour urination monitoring. Management strategies encompass lifestyle modifications such as diet and muscle-strengthening exercises, as well as therapies targeted at the underlying causes.

Understanding nocturia's impact across different age groups is crucial for effective diagnosis and treatment. While often considered a normal part of ageing, severe cases can significantly affect quality of life. Recognising symptoms and seeking appropriate care allows for effective management of nocturia, improving overall well-being. As research progresses, a personalised approach to nocturia management, considering age-specific and other demographic factors, remains key to improving outcomes for those affected by this common urinary condition.