Trends in the Prevalence of Cerebral Palsy in Children Born Between 1988 and 2007 in Okinawa, Japan

Aim: This study aimed to describe trends in CP prevalence among children born between 1988 and 2007 in Okinawa, Japan.

Method: This study was conducted during two time periods, Period I (from 1988 to 1997) and Period II (from 1998 to 2007), using data from the local CP registration system. We assessed cerebral palsy gestational age and birth weight specific trends in prevalence and analyzed these with Poisson regression analysis.

Results: Overall crude CP prevalence was 1.88 per 1000 live births. Approximately 70% of children with CP were born preterm or with low birth weight (LBW). Overall CP prevalence increased in Period I and decreased significantly in Period II (P<0.05). Additionally, CP prevalence among children born with a birth weight between 1000 and 1999g increased in Period I and decreased significantly in Period II (P<0.05). A significant decrease was found among the children born between 1995 and 2007 with a gestational age between 28 and 31weeks (P<0.01).

Conclusions: There was a decrease in CP prevalence from 1998 to 2007, especially among LBW children and preterm infants. The high CP proportions among LBW and preterm infants are unique features of the population of Okinawa, Japan.