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Changing Prevalence of Cerebral Palsy. Coleen Boyle, Ph.D. National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention. What impacts the rate of CP in very preterm infants?. Birth rate (live births/1000) Birth weight/preterm birth distribution
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Changing Prevalence of Cerebral Palsy Coleen Boyle, Ph.D. National Center on Birth Defects and Developmental Disabilities Centers for Disease Control and Prevention
What impacts the rate of CP in very preterm infants? • Birth rate (live births/1000) • Birth weight/preterm birth distribution • Survival in preterm/vlbw infants • Prevalence of CP in preterm survivors
Factor #1: Birth rate • Birth rate has decrease since 1960s, but number of reproductive age women has increased • Changes in birth rate do not change rate; but will change absolute number of case children
Cerebral Palsy in Atlanta, Atlanta, 1975 - 1991 1975 -1977 1981 -1985 1986 -1991 No. live birth/yr No. case children Cp rate 21,144 36 1.7 26,127 52 1.8 36,457 77 2.0
Factor #2: Birthweight/preterm birth distribution The rate of very preterm births (<32 weeks GA) in the U.S. has increased 9% from 1981 to 1999 (1.81% of all births in 1981 to 1.98% in 1999) Whites – 12% (1.37 1.57) Blacks – unchanged (4.13 4.13)
Factor #3: VLBW/Preterm Infant Survival Critical factor because this group is at highest risk of CP and other disability
Woods et al, 2000 - RESULTS • Development – 19% with Bayley >3 SD; 11% 2-3 SD • Neuromotor – 10% with severe disabilities 14% other disabilities • Sensory- 2% blind; 2% deaf; 5% no speech
Factor # 4: Prevalence of CP in preterm survivors • Impact of prenatal factors: role of inflammation, infection • Impact of antenatal care/intervention? • corticosteriods; surfactant; others
Rates of CP in Neonatal Survivors Source: Stanley, Blair & Alberman, 2000
Table. Prevalence of moderate or severe CP in singleton weighing < 1500 g born in 4 northern California counties No. of children with CP No. of singleton survivors <1500 g Prevalence per 1000 survivors <1500 g 1983-1985 <1000 g 1000-1499 g Total 15 27 42 266 616 882 56 44 48 1988-1989 208 429 637 77 35 49 <1000 g 1000-1499 g Total 16 15 31 1990-1994 560 1108 1668 48 23 32 <1000 g 1000-1499 g Total 27 26 53 Source: Grether: J Pediatr, 136; 2000:133
70 59 60 50 40 36 30 20 19 19 20 13 13 8 7 7 10 3 0 0 79-84 84-89 89-94 % Dying CP Blindness Bayley MDI <68 Outcome at 1 yr in infants weighing 501 – 800 gm, North Carolina Source: O’Shea et al. Pediatrics 1998:101
80 67 70 62 60 50 44 40 30 20 6.5 5.9 6.0 10 0 % Survivors and Prevalence of CP in Infants <1500 g, Atlanta, 1975-1991 births Percent 1975 - 77 1981 - 85 1986 - 91
Prevalence of CP <1500 g survivors, Atlanta, 1975 –1991, by race white 8 7.5 black 7.0 7 6.4 6.1 5.8 6 5.0 5 Percent 4 3 2 1 0 1975 - 77 1981 - 85 1986 - 91
Characteristics of CP in infants <1500 g, Atlanta, 1975 - 1991 % Isolated CP % Spastic diplegia 1975 – 1977 1981 – 1985 1986 - 1991 41 46 51 7 36 32
Trends in CP – Conclusions • Factor 1: Birth rate stable; rise in the number of reproductive age women • Factor 2: Proportion of very preterm births has increased • Factor 3: Infant mortality in very preterm infants continues to improve • Factor 4: Increase - mid to late 1980’s; decrease in early 1990’s