Research on noise-induced hearing loss in Sweden

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Research on noise-induced hearing loss in Sweden

• Ann-Christin Johnson
• PhD
• Karolinska Institutet
• Dept. Clinical Science, Intervention and
  Technique, Unit of Audiology
• and
• Center for Hearing and Communication Research

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What causes hearing loss?
Noise
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The noise problem

• Hearing disabilities in Sweden
• 15 of the population gt 1 million people
• Numbers are increasing
• 600 000 is lt 65 years old
• Hidden numbers - stigma
• Communication demands has increased in society
  and at work

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Noise cause hearing loss and annoyance

• Noise at Swedish workplaces
• 400 000 are exposed to noise at work gt85 dBA
• 1200 acknowledged noise-related work
  injuries/year
• 7 of all work injuries
• Increasing number of women since 1998
• Problems at work
• 16-25 of employees are disturbed by noise at
  least ¼ of the time
• 250 000 employees are disturbed by noise that
  mask communication

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Where is the noise and how loud is it?
Estimated by Ulf Landström, University of Gävle
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Research consortium at KI Hearing disability
in working life

• With focus on
• Work environment
• Risk factors
• Audiological epidemiology
• Different noise exposed populations
• Twin studies
• The Life-Gene project hearing
• Hearing and stress
• Experimental studies in animals
• Many different research groups

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Audiological epidemiology

• Military pilotsRetrospective study from medical
  records
• Presented on a poster
• Johnson AC, Hellstadius A and Rosenhall R
  Karolinska Institutet
• Hearing in young men military conscripts
• Presented in the afternoon session
• Follow-up study planned
• Muhr P and Rosenhall U Karolinska Institutet
• Cross-sectional study on different musicians
• Advanced hearing measurements
• Noise dosimetry and noise diaries
• Hagerman B, Lindblad AC, Svensson E Karolinska
  Institutet

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Audiological epidemiology

• Twin studies Hearing, work environment, age and
  genetic factors
• Questionnaires and audiometry from 1100 male
  twins from 1998
• Repeated data collection including genetic
  analyzes, 2009 -
• Planned study of female twins
• Analyzes of previously collected data
• Data collection
• Longitudinal data
• Genetics, work environment and age
• Å. Skjönsberg, R Bogo, N Pedersen, AC Johnson, M
  Svartengren Karolinska Institutet

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Audiological epidemiology

• Hearing Loss and Stress
• Data from a longitudinal Occupational Survey
• 10 000 answers
• Hearing problems (self-estimated) significantly
  associated with stress-related illness, sleeping
  problems, burn-out syndromes
• A sample, gt 300, of the population has been
  audiometrically tested
• Hasson D, Theorell T , Canlon B Karolinska
  Institutet

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Audiological epidemilogy

• The Life-Gene study
• Large population based, prospective study in
  lifestyle, health and genetics
• National Swedish study involving several
  universities
• 500,000 participants 0-45 years at baseline
• Including children and born into cohort
• Information collected at several occasions
• Including biobanks
• Includes also hearing screening and
  questionnaires
• Life Gene is lead by Nancy L Pedersen
  Karolinska Institutet
• Internet-based platform for self-test of hearing
• Under development
• Used for research with questionnaires

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Experimental studies in animals

• Some examples ..
• NIHL in animal models
• molecular and structural effects of noise
• susceptibility to noise
• influence of hereditary factors and gender
• New treatment strategies for NIHL
• pharmacological therapy
• cell and tissue transplantation (tissue
  engineering)
• gene therapy and stem cell technology
• Groups lead by M Ulfendahl, A Fridberger and B
  Canlon Karolinska Institutet

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Human noise studies in other universities in
Sweden

• The Noise Network
• Risk for hearing loss after combined exposure to
  noise and vibrations
• Longitudinal study in industrial workers
• Burström L et al University of Umeå
• Noise in pre-schools Health and preventions
• Intervention study with pre- and after
  measurements of hearing, questionnaires, noise
  levels and cortisol
• Kjellberg A, Landström U et al University of
  Gävle
• Noise in office landscapes
• Experimental and intervention studies on normal
  hearing and hearing impaired persons
• Hygge S et al University of Gävle

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Human Noise studies in other universities in
Sweden

• The Linné center for Hearing and Deafness - HEAD
• Universities of Linköping and Örebro
• MP3 players. Use and hearing loss risk in young
  people
• Presented in the afternoon session
• Kähäri K University of Örebro
• Hearing impaired in working life. Influence of
  cognition, noise and work load
• Lyxell B et al - University of Linköping
• Many other projects on Hearing, Deafness and
  Cognition
• Rönnberg J, Lyxell B et al - University of
  Linköping
• Möller C, Danermark B et al University of
  Örebro
• Genetic influence on workplace related hearing
  loss
• Carlsson P-I et al - University of Örebro

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Genetic influence on workplace-related hearing
impairmentA series of studies lead by Per-Inge
Carlsson from the University of Örebro

• Carriers of mutations Connexin 26 heterozygotes
• Are these carriers more susceptible to noise
  exposure?
• Genetic, environmental factors and noise
  susceptibility
• Selection from large group N1261 - Looking at
  the
• Most damaged - Noise susceptible group (10) 103
• Least damaged - Noise resistant group (10) 112
• Blood samples for genetic analyses
• Differences between noise susceptible and noise
  resistant groups were investigated
• Connexin26 mutations do not contribute to noise
  susceptibility
• More smokers in noise susceptible group
• Genetic variation in the protective antioxidant
  system can influence noise susceptibility
• Genetic variation (SNP) in genes involved in the
  potassium recycling system might contribute to
  noise susceptibility

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Groups with interaction

• Several larger groups that work together
• FAS-center at KI
• Noise network in several places
• Linné-center HEAD in Örebro and Linköping
• Interaction between the groups
• Started and will hopefully develop the noise
  research further

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Acknowledgements

• The following scientists from the Karolinska
  Institutet are also involved in the consortium on
  
• Hearing Disabilities in Working Life and Society
• Gunnel Backenroth-Ohsako,
• Barbara Canlon
• Björn Hagerman
• Nancy L. Pedersen
• Ulf Rosenhall
• Åsa Skjönsberg
• Thöres Theorell
• Mats Ulfendahl
• A special thanks to
• Per-Inge Carlsson and his colleagues for the
  material from the genetic studies

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Questions ?!
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References

• PER-INGE CARLSSON, ERIK BORG, LARS GRIP, NIKLAS
  DAHL, MARIE-LOUISE BONDESON. Variability in
  noise susceptibility in a Swedish population The
  role of 35delG mutation in the Connexin 26 (GJB2)
  gene. Audiological Medicine 2004 2 123-130
• Per-Inge Carlsson, Lut Van Laer, Erik Borg,
  Marie-Louise Bondeson, Melissa Thys, Erik Fransen
  and Guy Van Camp. Variability in noise
  susceptibility among Swedish industrial workers.
  The influence of genetic variation in oxidative
  stress genes. Hearing Research 2005 1-2, 87-96
• Carlsson P-I, Fransen E, Stenberg E, Bondeson
  M-L. The influence of genetic factors, smoking
  and cardiovascular diseases on human noise
  susceptibility. Audiological Medicine 2007 1
  1-6
• Van Lear L, Carlsson P-I, Ottschytsch N, E Borg
  et al. The contribution of genes involved in
  potassium recycling in the inner ear to
  noise-induced hearing loss. Human mutation.
  27(8)786-95 2006
• Konings A, Van Lear L, Pawelczyk M, Carlsson P-I,
  E Borg et al. Association between variations in
  CAT and noise induced hearing loss in two
  independent noise-exposed populations. Human
  molecular genetics. 16(15)1872-83, 200