The 24-h frequency-volume chart in adults reporting no voiding complaints: defining reference values and analysing variables.

OBJECTIVE

To determine the variables (e.g. voiding frequency, voided volumes, urine production) and their mutual relationships and differences between age groups and genders, using a frequency-volume chart (FVC) in an adult population (representing all age groups) who denied having any voiding complaints.

SUBJECTS AND METHODS

In all, 1152 men and women aged > 20 years completed a 24-h FVC; registration started with the first voided volume in the morning and concluded with the first voided volume the next morning. The time of voiding and volume were both recorded, and bedtime hours noted. Each participant claimed to have no voiding complaints. The statistical analysis was aimed at discerning the relationships between the FVC variables, gender and age.

RESULTS

There was a linear increase in mean 24-h voiding frequency and nocturia in men, from 6.0 and 0.5 in the third decade to 8.5 and 1.6 in those aged > 70 years. Contrary to men, in women the mean 24-h frequency declined slightly in the older decades; it increased from 6.9 in the third to 8.2 in the sixth, declining to 7.8 in those aged > 70 years. Nocturia in women increased linearly, although slower than in men, from 0.7 in the third decade to 1.4 in those aged > 70 years. The mean volume/void decreased significantly in both genders, from 313 to 209 mL in men, and from 274 to 240 mL in women. The mean 24-h volume was 1718 and 1762 mL in men and women, respectively. For both genders there was a strong linear association between 24-h urine production and voided volumes.

CONCLUSION

The volume/void and maximum voided volume decreased significantly with age in both sexes, but more prominently in men. As a result, in men the frequency increased with age, probably reflecting subclinical changes associated with the development of prostatic enlargement. In contrast to men the frequency in women increased initially and decreased in the older groups. A higher 24-h urine production was associated with a higher mean volume/void.