ESPE Yearbook of Paediatric Endocrinology

Brief summary: This study assessed the relation between the metabolic syndrome (MetS) and sensorineural hearing loss in children with obesity. Children with MetS were shown to have subclinical hearing loss compared to those without MetS.

Comment: Associations between obesity and hearing loss have been reported in several adult studies.¹ However, similar studies in adolescents have yielded conflicting results. The present study aimed to address this uncertainty by distinguishing among children with obesity, those with and without the MetS.

They studied 252 treatment-naive children (median age 12.5 years), living with obesity. One-third of them had MetS. All underwent otorhinolaryngological examinations, as well as tympanometry and audiometry tests. None experienced sensorineural hearing loss. However, a significantly higher rate of subclinical hearing loss (<15 dB) was detected among children with obesity plus MetS compared with those obesity without MetS. A considerable proportion showed one or more component of MetS, evidenced by clinical insulin resistance, hypertension, fasting hyperglycemia, and dyslipidemia in 77%, 43%, 34% and 22% of the children, respectively. However, subclinical hearing loss was not associated with any specific MetS component, suggesting the influence of a combination of factors. The absence of clinical hearing loss was explained by their young age, so possibly an association between MetS and hearing loss may become apparent with age.

Unfortunately, this is yet another less known complication of obesity and the metabolic syndrome which may further have impact on quality of life of obese people. The pathophysiological mechanism behind this association is unclear. A key hypothesis is vasoconstriction in the inner ear. Accordingly, strain on the capillary walls due to excess adipose tissue causes damage to the delicate inner ear system. Several studies have reported associations of hypertension, dyslipidemia and fasting hyperglycemia with pathological changes in the ear, and with increased rates of hearing loss.

References: 1. Rim HS, Kim MG, Park DC, Kim SS, Kang DW, Kim SH, Yeo SG. Association of metabolic syndrome with sensorineural hearing loss. J Clin Med. 2021 Oct 22;10(21):4866. doi: 10.3390/jcm10214866. PMID: 34768385; PMCID: PMC8584388. 2. Dhanda N, Taheri S. A narrative review of obesity and hearing loss. Int J Obes (Lond). 2017 Jul;41(7):1066–1073. doi: 10.1038/ijo.2017.32. Epub 2017 Feb 6. PMID: 28163314.