NIDCD Outcomes Research in Children with Hearing Loss
December 12 and 13, 2006
Bethesda, Maryland
Related Pages:
Statistical Report: Prevalence of Hearing Loss in U.S. Children, 2005
I. Background
Hearing loss (HL) can be assessed using subjects' responses to questions or through objective audiometric examinations. The summary below is based primarily on exam measures; however, rates of hearing difficulty as judged by parents or youths in the National Health Interview Survey (NHIS)1 are also reported.
Definitions
PTA4 is the pure-tone average of air-conduction thresholds at 0.5, 1, 2, & 4 kHz
- Normal hearing — PTA4 < 15 dB HL, both ears
- “Mild” hearing loss — 15 dB HL < PTA4 < 30 dB HL
- “Moderate” hearing loss — 30 dB HL < PTA4 < 45 dB HL
- “Severe” hearing loss — 45 dB HL < PTA4 < 75 dB HL
- “Profound” hearing loss — PTA4 > 75 dB HL
U.S. children's hearing examination data
- National Health & Nutrition Examination Survey II (NHANES II), 1976–1980
- National Health & Nutrition Examination Survey III (NHANES III), 1988–1994
NHANES examination surveys are broad, multi-purpose surveys conducted on subjects within selected age ranges across the lifespan.2 The NHANES target population is the civilian, non-institutionalized U.S. population. The sample size for audiometry in children, 6 to 19 years old, was 7,119 in NHANES II and 6,166 in NHANES III. Prevalence rates for combinations of better/worse ear HL were generally similar in these two nationally representative surveys.
II. Exam measures for children, ages 6 to 19 years
The prevalence of profound bilateral HL was 0.75 per 1,000 and 0.57 per 1,000 in NHANES II and NHANES III, respectively, which corresponded to national estimates of 39,063 and 27,764 children. Since the number of U.S. children, 6 to 19 years old, increased to 57.5 million in 2005, applying these two prevalence rates to the 2005 population yields estimates of 43,000 and 33,000 with profound bilateral HL.
The prevalence of severe HL (better ear; excluding profound bilateral HL) was 0.51 per 1,000 and 0.28 per 1,000 in NHANES II and NHANES III, respectively, which corresponded to 26,772 and 13,660 children. Adjusting for the 2005 population increase, the estimates are 30,000 and 16,000 with severe HL (better ear).
The prevalence of moderate HL (better ear; excluding severe or profound bilateral HL) increased to 2.37 per 1,000 and 1.66 per 1,000 in NHANES II and NHANES III, respectively, which corresponded to 124,000 and 81,000 children. Adjusting for the 2005 population increase, the estimates are 136,000 and 96,000 with moderate HL (better ear).
The prevalence of mild HL (better ear; excluding moderate, severe or profound bilateral HL) increased to 1.37% and 1.38% in NHANES II and III, respectively, which corresponded to 720,000 and 670,000 children. Adjusting for the 2005 population increase, the estimate is 791,000 with mild HL (better ear).
Except for children with profound bilateral hearing loss, the total estimate in 2005 is likely 903,000 to 957,000 children with mild, moderate, or severe HL (better ear), ages 6 to 19 years.
The estimates above are for children with HL in both ears; however, some children have normal hearing in their better ear while having HL in their other (worse) ear. The prevalence of “unilateral” mild, moderate, or severe HL in worse ear and normal hearing in better ear was 4.9% and 5.7% in NHANES II and NHANES III, respectively, which corresponded to 2.6 and 2.8 million children. Adjusting for the 2005 population increase, the estimates are 2.8 and 3.0 million with mild, moderate, or severe unilateral HL (worse ear).
III. Exam measures for children, ages 0 to 5 years
In 2005, 25 million U.S. children were 0 to 5 years of age. Since nationally representative hearing examination data are lacking for children in this age range, incidence statistics3 derived from States with newborn hearing screening programs are used as a surrogate. The following illustrates the calculation: given an incidence rate in 2004 for newborn HL of 1.11 per 1,000 live births, then 0.00111 X 3.95 million U.S. births = 4,385. After multiplying by 6 years (i.e., ages 0 to 5 years), the estimate is 26,310 children with HL since birth. After adjusting for other known etiologies (CMV, meningitis, injuries, etc.) of acquired early childhood HL, the overall estimate is at least 30,000 children with HL (primarily moderate, severe, or profound HL) below 6 years of age.
IV. Interview measures for children, ages 0 to 19 years
Each year the NHIS asks about the hearing of children: Which statement best describes your child's hearing (without a hearing aid)? a) good, b) little trouble, c) lot of trouble, or d) deaf. Since 1997, 12,000 to 15,000 children have been sampled annually. The mean prevalence of “deaf” is 0.81 per 1,000, corresponding to 67,000 children reported as deaf. The mean prevalence of “lot of trouble” hearing is 3.1 per 1,000, corresponding to 260,000 children with “lot of trouble” hearing. The mean prevalence of a “little trouble” hearing is 2.97%, corresponding to 2.5 million children with a “little trouble” hearing.
Source: Epidemiology & Statistics Program, NIDCD, 11/2006
1. The National Health Interview Survey (NHIS) is one of the major data collection programs of the National Center for Health Statistics (NCHS), CDC. For further information: www.cdc.gov/nchs/nhis.htm.
2. The Division of Health Examination Statistics (DHES), NCHS, CDC has conducted a series of health and nutrition surveys since the early 1960s, see: www.cdc.gov/nchs/nhanes.htm.
3. The Early Hearing Detection and Intervention (EHDI) Programs are sponsored by the Centers for Disease Control and Prevention (CDC) and the Maternal and Child Health Bureau, Health Resources and Services Administration (HRSA). Annually, statistics for the hearing screening programs in States and U.S. Territories are posted on the EHDI webpage: http://www.cdc.gov/ncbddd/hearingloss/ehdi-programs.html.