Table 1.
Studies assessing the association between hearing loss and metabolic syndrome.
| Author (Year) | Study Design | N | Age (Years) | Associated Variables | Conclusions |
|---|---|---|---|---|---|
| Kang S.H. et al. (2015) [9] | Cross-sectional | 16,554 | 50.4 ± 16.6 (men) 49.2 ± 16.4 (women) |
MetS or CKD/Hearing thresholds | MetS is associated with hearing thresholds in women; and CKD is associated with hearing thresholds in men and women. Subjects with MetS or CKD should be closely monitored for hearing impairment. |
| Sun Y.-S. et al. (2015) [3] | Cross-sectional | 2100 | ≤65 | MetS components/SNHL | Significant associations between the number of components of metabolic syndrome and hearing thresholds in US adults, with the strongest association between low HDL and hearing loss. |
| Kang S.H. et al. (2015) [18] | Cross-sectional | 8198 | 54.7 ± 9.9 | WHR/HL | WHR may be a surrogate marker for predicting the risk of hearing loss resulting from metabolic syndrome. |
| Bener A. et al. (2016) [19] | Cross-sectional | 459 | 20–59 | DM, HTN/HL | Adults with DM and hypertension showed greater hearing impairment in a highly endogamous population. Diabetic patients with hearing loss were likely to have high blood glucose and other risk factors like hypertension, retinopathy, nephropathy, and neuropathy. |
| Kim S.H. et al. (2016) [20] | Cross-sectional | 61,052 | 42.33 ± 7.49 (normal) 49.89 ± 9.32 (HL) |
BMI/HL | Underweight and severe obesity were associated with an increased prevalence of hearing loss in a Korean population. |
| Kang S.H. et al. (2016) [21] | Cross-sectional | 7449 | 53.2 ± 10.7 56.7 ± 11.0 59.8 ± 10.8 |
HbA1c/HL | HbA1c level was associated with hearing impairment in nondiabetic individuals. |
| Lee H.Y. et al. (2016) [22] | Retrospective | 16,779 | ≥19 | MetS components/SNHL | Metabolic syndrome itself was not an independent risk factor for hearing impairment. Among its individual components, only increased fasting plasma glucose was independently associated with hearing impairment. |
| Aghazadeh-Attari J. et al.(2017) [12] | Cross-sectional | 11,114 | 20–60 | MetS components/SNHL | Possible associations between different components of MetS (obesity, hypertension, hypertriglyceridemia, high fasting glucose levels, and waist circumference) and SNHL in a population of West Azerbaijan drivers. |
| Jung D.J. et al. (2017) [23] | Cross-sectional | 18,004 | >40 | TG/HDL ratio/SNHL | High TG/HDL-C ratio was associated with hearing impairment in a Korean population |
| Nwosu J. N. et al. (2017) [24] | Case-control | 416 | 26–80 years | DM/HL | High prevalence of hearing loss among diabetic adults at University of Nigeria Teaching Hospital, Enugu. Hearing loss was predominantly sensorineural and often mild to moderate in severity. |
| Lee Y. et al. (2017) [25] | Retrospective | 2602 | 57.6 ± 7.3 | Factors relevant abdominal fats (FRAs)/ Age-related hearing loss (ARHL) |
FRAs were associated with frequency-specific hearing losses according to sex. DM and visceral adipose tissue (VAT) are particularly important role for hearing. |
| Kim T.S. et al. (2017) [8] | Prospective | 1381 | >50 | MetS components/ age-related hearing impairment (ARHI) |
MetS is associated with age-related hearing impairment in women aged ≥ 50 years. At 5-year follow-up, high-frequency hearing loss tended to be greater in women with than without MetS, suggesting the need for hearing evaluation in older women with MetS. |
| Han X. et al. (2018) [7] | Cross-sectional | 18,824 | 61.1 ± 7.6 66.6 ± 7.2 71.0 ± 7.7 |
MetS components/SNHL | MetS, including its components central obesity, hyperglycemia, and low HDL-C levels, is positively associated with hearing loss. |
| Jung D.J. et al. (2019) [11] | Cross-sectional | 17,513,555 | >40 | MetS components/SNHL | Among the components of MetS, low HDL and high TG levels were especially associated with hearing loss. Rather than assessing MetS, each MetS component should be evaluated individually. |
| Shim H.S. et al. (2019) [10] | Cross-sectional | 28,866 | all age groups | MetS components/SNHL | MetS may be associated with hearing loss, especially in subjects who meet four or five of the diagnostic criteria for MetS. |
| Hu H. et al. (2020) [26] | Prospective cohort | 48,549 | 20–64 | BMI (w/o Waist circumference)/SNHL |
Overweight and obesity are associated with an increased risk of hearing loss, with metabolically unhealthy status conferring an additional risk. |
| Kim J. et al. (2021) [27] | Cross-sectional | 10,356 | 40–80 | MetS components/HL | MetS is associated with high-frequency hearing loss in subjects exposed to noise. |
Abbreviations: MetS, metabolic syndrome; CKD, chronic kidney disease; SNHL, sensorineural hearing loss; HL, hearing loss, DM, diabetes mellitus; HTN, hypertension; BMI, body mass index; WHR, waist hip ratio; HDL, high density lipoprotein; TG, triglyceride.