Can the Determination of Salivary Cotinine Level Be a New Method in Diagnosis and Follow-up of Childhood Tinnitus?

Abstract

Background: There are many risk factors for childhood tinnitus such as hearing loss, exposure to high pitch sound, and passive smoking. Cotinine (C) is one of the metabolites of nicotine and is an important biochemical marker that reveals the objective and numerical indication of smoking exposure. Although there is a study investigating the role of urinary C levels in the etiology of tinnitus (T), the role of salivary C levels has not yet been elucidated. Objectives: Therefore, this study aimed to investigate the risk factors of idiopathic subjective T in children in terms of passive smoking and whether the salivary C level can be used as a novel marker for monitoring and follow-up of T. Methods: We retrospectively studied 1,245 children aged 7-15 years with T. We excluded 830 patients (66.5%) whose total tinnitus diagnosis was confirmed due to organic causes such as middle ear pathology and hearing loss. The remaining 415 (33.5%) patients with subjective T and 200 healthy individuals constituted the study and control groups. Complete blood counts, routine biochemical tests, and salivary C levels of children with T and controls were measured and their parents were also evaluated. Results: In univariate analysis, parents' C, children's C, ALP, and erythrocyte levels were significantly associated with T (P < 0.001 in all). Regarding laboratory values, erythrocyte and serum ALP levels were significantly associated with T (P < 0.001 in both) in univariate analysis (OR, 0.99; 95% CI, 0.98 to 0.99 for erythrocyte and OR, 157.04; 95% CI, 44.7 to 551.6 for serum ALP level). No significant relationships were found between other parameters. These four parameters that were found to be significant in the univariate analysis showed meaningful associations with T in multivariate analysis (P < 0.01 for parents C and P < 0.001 for other parameters). It was also observed that as the C levels increased in the parents, the C level also increased in children. Conclusions: There is a significant correlation between salivary C levels and parental salivary C levels in children. This suggests that the salivary C be used for evaluating the etiology of T in children and monitoring children with T exposed to cigarette smoke.

Objective and Measurable Biomarkers in Chronic Subjective Tinnitus

“…A study in pediatric patients with tinnitus showed that the patient’s saliva cotinine, parents’ saliva cotinine, alkaline phosphate (ALP), and erythrocytes increased the risk of tinnitus. In addition, the higher the parental saliva cotinine level, the higher was the saliva cotinine level in pediatric patients with tinnitus [ 119 ].…”

Limited Link of Common Blood Parameters with Tinnitus

“…Two of the forty-nine studies included in the meta-analysis from 2021 [11] on biomarkers of tinnitus comprised measurements of the erythrocyte levels. Resuli [65] demonstrated that the erythrocyte and serum ALP levels were significantly associated with tinnitus in children exposed to cigarette smoke. The association of red blood cell counts (and alkaline phosphatase levels/urine cotinine) in smokers with tinnitus was observed by Lee and Kim [66].…”

Vertigo and Dizziness in Children

“…The first mention of paediatric cases of BPPV was by Basser in 1964 [31]. He noted the occurrence of BPPV in 17 patients (male and female) who were all younger than 4 years old.…”