Nocturia is a common urinary symptom that is often associated with a negative impact on quality of life. Its definition, however, is controversial as many patients do not consider waking up once during the night to urinate as problematic. The International Continence Society (ICS) defines nocturia as the complaint of waking up one or more times to urinate. Prevalence studies are strongly influenced by the reference value used, with a reference value of 1 episode per night or 2 episodes per night resulting in different specific and overall prevalence rates for lower urinary tract symptoms (LUTS).
There are four underlying causes of nocturia: an increase in urine production throughout the 24-hour period, an increase in nighttime urine production, a decrease in bladder capacity, and a sleep disorder. Age is the main risk factor for both sexes, with prevalence higher in men than in women among the elderly. For example, in a study of a Finnish community, men aged 70-79 had a 155-fold higher risk of nocturia than men under 30 years old. In the BACH study, which included 5,506 adults aged 30-79 years, the overall prevalence was 28.4%, but was 41.2% in the sample restricted to those over 60 years old. Ethnic and racial factors may also play a role, but existing studies have several confounding variables and associated comorbidities, so the relationship is not clear. The BACH study found a 90% increased likelihood of African Americans reporting nocturia, even after controlling for sociodemographic factors. The OAB-POLL study also found an increased prevalence of nocturia in African Americans.
Nocturia is important due to the literature that robustly associates it with decreased quality of life and increased daytime fatigue, decreased concentration, reduced work performance, and increased accident risk. It is also associated with other diseases, including hip fracture, cardiovascular morbidity and mortality, depression, endocrine, immunological and metabolic disorders.

As a part of a broader project titled "Mictional Evaluation in an African Country", the data utilized in this study was collected. From 2014 to 2017, a sample of male residents of São Tomé and Príncipe, aged 30 years or above, was selected and stratified by district and age for the purpose of data collection. The participants completed the International Prostate Symptom Score (IPSS), the Visual Analogue Scale for Urinary Symptoms (VASUS), and underwent free-flow uroflowmetry.

The analysis of question 7 of the IPSS reveals a statistically significant correlation with age for all three reference values used. The graphic shows that for all age groups, the prevalence of one or more episodes of nocturia is very high (88.2%) and tends to increase with age until it reaches values close to 100% in individuals aged 70 years or older.

Regarding the impact of nocturia on quality of life, it was found that only for one or more episodes per night, there is a statistically significant correlation, but this relationship is inverse, meaning that the presence of one or more episodes of nocturia seems to be associated with better quality of life. For the other reference values, there doesn't seem to be a correlation between nocturia and quality of life.

The results indicate that nocturia is one of the most important determinants for the increase in prevalence of LUTS. In fact, it contributes to approximately 40% of the final IPSS score and is the only question where the first response option ("None" / "0 episodes") is not the most frequent. The prevalence of nocturia is high, particularly for lower reference values. The prevalence of nocturia using 2 episodes per night as a cut-off is as high or higher than that found in the literature for 1 or more episodes. Prevalence decreases as the number of episodes per night increases and increases with age, resulting in near 100% prevalence for the oldest age group.
Despite the high relative weight of nocturia in the IPSS score, its impact on quality of life does not seem to be relevant. The authors' perception in the field is that, despite a high number of nighttime urinations, they did not reflect a decrease in quality of life and were perceived as normal.

Based on the analysis of the data presented, it is clear that nocturia has a significant impact on the prevalence of lower urinary tract symptoms (LUTS). In fact, it is one of the most important determinants contributing to the overall IPSS score. However, despite its high prevalence, nocturia does not seem to have a significant impact on the quality of life of individuals experiencing it. This can be explained by sociocultural differences and should be taking in account when planning to address LUTS men with different backgrounds. 
In conclusion, while the high prevalence of nocturia is a cause for concern, it is essential to focus on understanding the impact of this symptom on quality of life and to develop effective interventions to manage and treat it.