Low Evidence for Tinnitus Risk Factors: A Systematic Review and Meta-analysis

Abstract

Aims/Hypothesis Identifying risk factors for tinnitus could facilitate not only the recommendations for prevention measures, but also identifying potential pathways for new interventions. This study reports the first comprehensive systematic review of analytical observational studies able to provide information about causality (i.e., case–control and cohort designs). Methods A literature search of four electronic databases identified epidemiological studies published on tinnitus and different exposures. Independent raters screened all studies, extracted data, and evaluated study quality using the Newcastle–Ottawa Scale. Reported relative risks (RR), hazard ratios (HR), odds ratios (OR), and prevalence ratios (PR) with 95% confidence intervals (CI) were used to compute crude estimates of RR for tinnitus risk factors. Results From 2389 records identified, a total of 374 articles were read as full text (24 reviews, 301 cross-sectional studies, 42 cohort studies, and 7 case–control studies). However, from 49 case–control and cohort studies, only 25 adequately reported risk ratios. Using the findings from these studies, positive causal associations were found for various hearing-related factors (i.e., unspecified hearing loss, sensorineural hearing loss, occupational noise exposure, ototoxic platinum therapy, and otitis media). Evidence was also found for a number of non-otological risk factors including temporo-mandibular joint disorder, depression, chronic obstructive pulmonary disease, and hyperlipidemia. Negative associations indicating preventative effects were found for diabetes and high alcohol consumption. No associations were found for low alcohol consumption, body mass index, head injury, heart failure, hypertension, leisure noise exposure, migraine, rheumatoid arthritis, sex, smoking, stroke, and whiplash. However, with the exception of unspecified hearing loss, these findings resulted from pooling no more than 4 studies, illustrating that the vast majority of the associations still remain inconclusive. Conclusions These systematic review and meta-analysis confirm a number of otological and non-otological risk factors for tinnitus. By highlighting major gaps in knowledge, our synthesis can help provide direction for future research that will shed light on the pathophysiology, improve management strategies, and inform more effective preventions.

Serum Vitamin D Concentration Is Lower in Patients with Tinnitus: A Meta-Analysis of Observational Studies

“…A pooled analysis of eleven studies (totaling over 17,000 patients) revealed that the levels of Vit D were significantly lower in patients with both acute (mean difference: −10.6; 95% CI, −19.3 to −2.0) and chronic (mean difference: −3.6; 95% CI, −7.0 to −0.2) otitis media compared to the healthy control population, yielding to a pooled mean difference of −6.26 (95% CI, −10.5 to −2.0) in all patients with otitis media. Such relationship between low Vit D and otitis media may hence justify a concomitantly increased risk of developing tinnitus, as shown in the meta-analysis published by Biswas et al [ 23 ], who concluded that patients with otitis media have an over 60% enhanced risk of developing tinnitus (relative risk [RR], 1.63; 95% CI, 1.61–1.65). Besides otitis, low Vit D levels may also be causally associated with benign paroxysmal positional vertigo.…”

Initial Response to Combination Therapies for Tinnitus: Lessons Learned From a Retrospective Analysis

“…In addition, the relationship between migraine, tinnitus, and cerebral blood flow patterns suggests that migraine may worsen the underlying mechanisms of chronic tinnitus, emphasizing the relevance of migraine treatment (32). Identifying risk factors for tinnitus, including hearing-related and nonotological factors, underscores the significance of addressing these factors in treatment and prevention, potentially reducing its co-occurrence with migraine (33). Taken together, these studies emphasize the potential benefits of integrating migraine treatment strategies into tinnitus management, considering the shared pathophysiology and symptom overlap between the two conditions (34,35).…”

The Role of Diet in Tinnitus Onset: A Hospital-Based Case-Control Study from Italy

“…Despite its high prevalence and debilitating consequences [ 2 ], the available epidemiological data on its risk factors are inadequate. Above all, there is a distinct paucity of large, well-conducted analytical studies, i.e., case-control or cohort studies, that quantify the association between putative risk factors and the onset of tinnitus [ 2 , 3 ]. Currently, tinnitus management often involves education and counselling, with a general recommendation of a healthy diet; modifiable lifestyle risk factors for tinnitus, of which diet is an example, should be identified and addressed to prevent and manage tinnitus symptoms [ 4 ].…”

“…Currently, tinnitus management often involves education and counselling, with a general recommendation of a healthy diet; modifiable lifestyle risk factors for tinnitus, of which diet is an example, should be identified and addressed to prevent and manage tinnitus symptoms [ 4 ]. In a recent systematic review and meta-analysis of tinnitus risk factors, Biswas and colleagues [ 3 ] revealed the scant evidence on exposures causally related to tinnitus. The review found hearing loss, temporo-mandibular joint disorder, depression, chronic obstructive pulmonary disease, and hyperlipidaemia to be tinnitus risk factors.…”

“…The review found hearing loss, temporo-mandibular joint disorder, depression, chronic obstructive pulmonary disease, and hyperlipidaemia to be tinnitus risk factors. Most of this evidence comes from cross-sectional studies, i.e., study designs unable to infer causality; of 374 articles analysed, only 49 were case-control or cohort studies [ 3 ]. Among those analytical studies, besides a few investigations on alcohol drinking or obesity, only the Nurses’ Health Study II evaluated diet (specifically caffeine intake) as a potential risk factor for tinnitus [ 5 ].…”