Socioeconomic Status & Permanent Hearing Loss

Anne Greville PhD

Greville Consulting

Auckland, New Zealand

Audiological Society of Australia biennial conferencePerth, WAMay 19, 2006

Thanks to…

• The Deafness Research Foundation of New Zealand for support of the project

• The National Audiology Centre for access to the deafness database & assistance with sourcing addresses

• Simon Jellie of e-Spatial for help in geo-coding the data.

Why look at SES?

• Kubba, MacAndie, Ritchie & MacFarlane Is deafness a disease of poverty? The association between socio-economic deprivation & congenital hearing impairmentInt J Audiol 43:123-5 (2004)

Children in Glasgow born 1985-94

Kubba et al, Glasgow

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1 2 3 4 5 6 7

Proportion of population

Prevalence/1000 births

• Fortnum, Marshall & SummerfieldEpidemiology of the UK population of hearing-impaired children, including characteristics of those with & without cochlear implants – audiology, aetiology, comorbidity & affluenceInt J Audiol 41:170-9 (2002)

Fortnum et al, UK

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1 2 3 4 5 6 7 8 9 10

Methodology

• Hearing impaired & deaf children notified to the National Audiology Centre’s database

• Limited to children born 1992 – 1999.

• Children with acquired or unilateral hearing loss & those born overseas excluded.

Sample

• 828 children

• 696 children with unambiguous addresses

• 693 children were geocoded into unique meshblocks (approx 100 people)

• Decile ratings available for meshblocks

Socioeconomic Measure• NZ Dep2001 Index of Deprivation

Salmond & Crampton (2002)• Based on:

– incomeemploymentcommunicationtransportsupportqualificationsliving spaceowned home

• SES Measure: deciles 1-10 (10 most deprived)

• Fairly even distribution into tenths of total population

• For children < 15 years, 13% are in decile 10, 8% decile 5

• Over 20% of Maori population in decile 10

• 40% of Pacific Island population in decile 10

Birth year

0

20

40

60

80

100

120

140

1992 1993 1994 1995 1996 1997 1998

Birth year

Number of deaf children per decile

y = 2.5189x2 - 15.63x + 58.283

R2 = 0.9285

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10

Decile and age (at 2001)

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10

Decile

Children born 1992-6

Children born 1997-9

Deafness prevalence & deprivation

0

0.5

1

1.5

2

2.5

3

3.5

4

1 2 3 4 5 6 7 8 9 10

Deprivation Index

Pre

vale

nce

/100

0

Children born 1997-9

Children born 1992-6

Overall

Ethnicity

0

20

40

60

80

100

120

140

160

180

1 2 3 4 5 6 7 8 9 10

Unknown

Pacific Id

Other

Maori

European

Asian

H/Loss moderate or greater

0

10

20

30

40

50

60

70

80

90

1 2 3 4 5 6 7 8 9 10

Unknown

Pacific Id

Other

Maori

European

Asian

y = 28.667x0.0788

R2 = 0.1584

y = 2.3084e0.3649x

R2 = 0.9744

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10

Maori

non-Maori

Power (non-Maori)

Expon. (Maori)

H/Loss moderate or greater

y = 0.6783x1.5526

R2 = 0.8115

y = 15.19x0.1611

R2 = 0.3686

0

5

10

15

20

25

30

35

40

45

50

1 2 3 4 5 6 7 8 9 10

Maori

non-Maori

Power (Maori)

Power (non-Maori)

Maori deaf children cf Maori population

0%

5%

10%

15%

20%

25%

30%

35%

40%

1 2 3 4 5 6 7 8 9 10

Maori deaf children

Total Maori population

Cause of deafness

0

20

40

60

80

100

120

140

160

180

200

1 2 3 4 5 6 7 8 9 10

Unknown

Other

Multiple

Low birthweight

Jaundice

Family history

Facial malformation

Congenital infection

Asphyxia

Cause of deafness among Maori children

0

20

40

60

80

100

120

1 2 3 4 5 6 7 8 9 10

Unknown

Other

Multiple

Low birthweight

Jaundice

Family history

Facial malformation

Congenital infection

Asphyxia

Household income levels

Ethnic group Mean household income

($,000)

Asian 51.3

European 50.6

Pacific Island 44.0

Other 41.4

Maori 39.1

Overall 44.9

Conclusions

• In New Zealand, there is no apparent effect of SES on congenital hearing loss for ethnic groups other than Maori

• Among the Maori children, unknown cause & family history are the major causal factors

… and…

• Does a family history of deafness in Maori mean that the family is more likely to live in a low SES area?

• Maori deaf/hearing impaired children are more likely to live in a low income household than are deaf children from other ethnic groups.

Thank you