Cohort profile: Netherlands Longitudinal Study on Hearing (NL-SH).

PURPOSE: The Netherlands Longitudinal Study on Hearing (NL-SH) was set up to examine associations of hearing ability with psychosocial, work and health outcomes in working age adults.

PARTICIPANTS: Inclusion started in 2006 and is ongoing. Currently the sample comprises 2800 adults with normal and impaired hearing, aged 18-70 years at inclusion. Five-year follow-up started in 2011, 10-year follow-up in 2016 and 15-year follow-up in 2021. All measurements are web-based. Participants perform a speech-in-noise recognition test to measure hearing ability and fill out questionnaires about their hearing status, hearing aid use, self-reported hearing disability and coping, work status and work-related outcomes (work performance, need for recovery), physical and psychosocial health (depression, anxiety, distress, somatisation, loneliness), healthcare usage, lifestyle (smoking, alcohol), and technology use.

FINDINGS TO DATE: The NL-SH has shown the vast implications of reduced hearing ability for the quality of life and health of working-age adults. A selection of results published in 27 papers is presented. Age-related deterioration of hearing ability accelerates after the age of 50 years. Having a history of smoking is associated with a faster decline in hearing ability, but this relationship is not found for other cardiovascular risk factors. Poorer hearing ability is associated with increased distress, somatisation, depression and loneliness. Adults with impaired hearing ability are more likely to be unemployed or unfit for work, and need more time to recuperate from work effort.

FUTURE PLANS: Participant data will be linked to a national database to enable research on the association between hearing ability and mortality. Linking to environmental exposure data will facilitate insight in relations between environmental factors, hearing ability and psychosocial outcomes. The unique breadth of the NL-SH data will also allow for further research on other functional problems, for instance, hearing ability and fall risk.

TRIAL REGISTRATION NUMBER: NL12015.029.06.