Relative and attributable risks for moderate to profound bilateral sensorineural hearing impairment associated with lower birth weight in children 3 to 10 years old
K. Van Naarden et P. Decoufle, Relative and attributable risks for moderate to profound bilateral sensorineural hearing impairment associated with lower birth weight in children 3 to 10 years old, PEDIATRICS, 104(4), 1999, pp. 905-910
Objective. To determine the prevalence, relative risks, and attributable fr
actions for congenital bilateral sensorineural hearing impairment in relati
on to lower birth weight among children born in the 1980s and living in the
metropolitan Atlanta area from 1991 through 1993.
Methods. We used the population-based, active case ascertainment Metropolit
an Atlanta Developmental Disabilities Surveillance Program that conducts su
rveillance in the five-county metropolitan Atlanta area. Hearing impairment
was defined as a bilateral, pure-tone hearing loss at frequencies of 500,
1000, and 2000 Hz averaging 40 dBs or more, unaided, in the better ear. Cas
e children, 3 to 10 years of age, with sensorineural loss of presumed conge
nital origin were included in these analyses (n = 172). Prevalence rates an
d relative risks were computed for various birth weight categories by heari
ng level, sex, race, the presence or absence of coexisting developmental di
sabilities, and gestational age. Attributable fractions were calculated for
low birth weight and very low birth weight children by race.
Results. The overall prevalence rate of presumed congenital bilateral senso
rineural hearing impairment was 5.3 cases per 10 000 3-year survivors. The
prevalence was 4.1 per 10 000 among children weighing greater than or equal
to 4000 g, 3.7 per 10 000 among those weighing 3000 to 3999 g, 6.6 per 10
000 among those 2500 to 2999 g, 12.7 per 10 000 among those 1500 to 2499 g,
and 51.0 per 10 000 among those <1500 g. There was virtually no difference
in birth weight-specific rates of hearing impairment across three hearing
levels. The presence of coexisting developmental disabilities was associate
d with a much stronger inverse trend with birth weight. Black children weig
hing <2500 g had much higher rates of hearing impairment than comparable wh
ite children. The overall percentage of moderate to profound congenital bil
ateral sensorineural hearing loss in the entire study population that was a
ttributable to children weighing <2500 g or <1500 g was estimated to be 18.
9% and 9.4%, respectively. Prematurity did not alter the magnitude of risk
among children weighing <2500 g.
Conclusions. The results presented here provide recent estimates of the rat
es, relative risks, and attributable fractions for congenital bilateral sen
sorineural hearing impairment by birth weight among children in the United
States. The elevated relative risks among children weighing 2500 to 2999 g
and 1500 to 2499 g may have implications for future newborn hearing screeni
ng criteria.