The estimated prevalence of hypospadias in Hokkaido, Japan.
BACKGROUND
Hypospadias is one of the most common congenital anomalies in the world. Recently, increases in the prevalence of hypospadias have been reported in various countries including Japan. In this study, we examined whether the prevalence of hypospadias in Hokkaido, Japan, increased or not, using standardized diagnostic criteria. We also investigated the degree of its severity.


METHODS
We calculated prevalence of hypospadias using hospital records of hypospadias repair in Hokkaido. The prevalence from 1985 through 1997 by dividing the number of patients obtained from hospital records by the number of births.


RESULTS
The average prevalence of hypospadias in Hokkaido was 3.9 per 10,000 births, and did not significantly change (p=0.7). The average proportions of distal, proximal and chordee alone were 56.7%, 39.6% and 3.7%, respectively. The decrease in the proportion of the proximal type was statistically significant (p=0.05) for the entire time period, whereas the proportion of the distal type did not have a significant upward trend for the observed 13 years (p=0.1).


CONCLUSIONS
No significant changes in the prevalence of hypospadias existed in Hokkaido.
Kurahashi
Norie
N
Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Murakumo
Masashi
M
Kakizaki
Hidehiro
H
Nonomura
Katsuya
K
Koyanagi
Tomohiko
T
Kasai
Setsuko
S
Sata
Fumihiro
F
Kishi
Reiko
R
D002648:Child; D002675:Child, Preschool; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007021:Hypospadias / Q000145:classification / Q000453:epidemiology* / Q000601:surgery; D007223:Infant; D007564:Japan / Q000453:epidemiology; D008297:Male; D015995:Prevalence; D012042:Registries; D012720:Severity of Illness Index; D013521:Urologic Surgical Procedures, Male / Q000706:statistics & numerical data