Determinants and Consequences of Hearing Impairment and Tinnitus: Netherlands Longitudinal Study on Hearing

Chapter 1 comprises an overview of current insights into the pathophysiology and consequences of hearing loss and tinnitus, of which specifically the consequences they have for work-related health. It also explains the study design of the Netherlands Longitudinal Study on Hearing (NL-SH). Chapter 2 describes the 10-year change in hearing ability among NL-SH participants, considering factors such as age, education, sex, and lifestyle factors like alcohol use and smoking. The results showed an average decline of 0.89 dB signal-to-noise ratio (SNR) over a decade. The decline was more pronounced in older age groups (51 to 60 and 61 to 70 years) compared to younger ones (i.e. 18 to 30, 31 to 40, and 41 to 50 years). Additionally, participants with a history of smoking experienced a faster decline in speech recognition in noise during the follow-up period. Chapter 3 investigates the association between cardiovascular disease (CVD) risk factors and speech recognition in noise over time. Specifically, interactions between CVD risk factors on the longitudinal change in hearing ability were analyzed. CVD risk factors are known to cluster and interact, increasing the cumulative risk for CVD. However, we found that none of the CVD risk factors or two-way interactions of CVD risk factors were significantly associated with a decline in the speech reception threshold in noise over time. In a cross-sectional analysis using all measurement rounds, obesity, rheumatoid arthritis, and hypertension were associated with overall higher (more unfavorable) speech reception thresholds. In Chapter 4, we analyzed the potential association between beta blocker use and hearing ability in adults and examined whether this effect is dose-dependent. Hearing ability was not affected by beta blockers, but this result is not conclusive for all types of beta blockers as the study involved mostly beta-1 selective agents and no non-selective beta blockers. In Chapter 5 we analyzed the longitudinal association between changes in speech recognition in noise and the need for recovery after work (NFR), job demand, and job control, using 5-year measurement intervals. Decreased hearing ability was associated with increased NFR, but no significant associations with job demand or job control were found. The uptake of hearing solutions during the same period did not significantly impact NFR. In the study in Chapter 6, we analyzed potential risk factors for the development of tinnitus 5 years later. Further, we aimed to identify risk factors associated with annoyance caused by new-onset tinnitus. Higher levels of somatization and a history of smoking were associated with the development of tinnitus 5 years later. Increased levels of anxiety and poor speech recognition ability in noise were associated with higher levels of tinnitus annoyance in new-onset tinnitus. Chapter 7 investigates the relationship between tinnitus and NFR and whether the level of tinnitus annoyance affects NFR. After adjusting for confounding factors, tinnitus was not associated with NFR. Similarly, higher levels of tinnitus annoyance did not significantly impact NFR after adjustments.