Hearing Loss Prevalence High in Children, Adults with Sickle Cell Disease

Hearing loss was more prevalent among children and adults with sickle cell disease (SCD) and sickle cell traits (SCTs) compared to a matched control group with normal hemoglobin, according to new research.

The comparative cross-sectional trial was performed across four departments in an SCD outpatient clinic in a tertiary hospital in Nigeria. Audiometry was used for the assessment of hearing loss, with all participants receiving comprehensive ear and hearing assessments for sensorineural hearing loss.

“Our findings are instructive because they highly suggest hearing loss associated with sickle cell anemia commences earlier in life,” wrote the investigative team, led by Professor Titus Sunday Ibekwe, MBBS, department of otorhinolaryngology at the University of Abuja. “The SCTs also showed a significant numerical increase in hearing loss compared with the control, though not as strong as the SCD. This supports early routine hearing screening in children, especially those with SCD and SCT.”

SCD and its traits are genetically inherited disorders of the red blood cell, common among the people of Black race. Global estimates of the prevalence of SCD in Africa were 1.12%, compared with 0.04% in Europe and 0.11% globally, in 2018. The inherited disorders have been linked to an increased risk of injections, vaso-occlusive crises, and end-organ damage, including the cochlea if left unmanaged.

A vaso-occlusive crisis affecting the cochlea can lead to a wide array of hearing impairments, particularly high-frequency sensorineural hearing loss. Those with SCTs are generally stable due to heterozygous genetic formation, but it is possible to develop vaso-occlusive crisis leading to hearing loss. However, there is a lack of research in a population with SCD or SCTs and an overall shortage of data on neurological sequelae, particularly among at-risk African populations.

The cross-sectional study in Nigeria investigated the association between SCD or SCT diagnosis and hearing impairment, with controls drawn from normal hemoglobin (HbAA) genotype-confirmed individuals. Pure-tome audiometry (PTA) was categorized according to the WHO classification of hearing loss and tympanometry.

In total, the sample size consisted of 212 participants: 106 participants with SCD (HbSS) and its traits (HbAs) and 106 HbAA control participants, matched for age and sex. The analysis included 124 children aged 6 months to 17 years and 88 adults aged 18 to 55 years. Of the cohort group, HbSS comprised 80 and HbAS comprised 26 participants, representing 160 and 52 ears, respectively.

Approximately 2 of 8 (25%) children with HbAS experienced hearing impairment compared with 18.8% of children with HbAA, but the hearing impairment affected the right ear only. However, children with HbSS ears showed a statistically significant difference in hearing impairment compared with control (30.8% vs. 18.8%; P = .035). Asymmetrical hearing loss between the right and left ear was identified in both cohorts and control groups—a majority of hearing impairment was found in the right ears compared with the left.

Further hearing loss analysis revealed more adults with HbAS (36.1%) and HbSS (30%) exhibited hearing impairment affecting both ears when compared with HbAA (11%). In contrast to the children cohort, most adults experienced hearing impairment in the left ear.

Ibekwe and colleagues indicated the prevalence of hearing loss was significantly high in both children and adults with HbAS and HbSS compared with the matched group group—however, no significant difference was identified when children were compared to adults.

Overall, the likelihood of hearing impairment was higher in HbSS (odds ratio [OR], 2.48 [95% CI, 1.51 - 4.14; P = .0004) and HbAS (OR, 2.28 [95% CI, 1.1 - 4.58]; P = .02) participants than those with HbAA. These differences did not remain statistically significant when adjusted for the frequency of hospitalization, crises, blood transfusion, and routine drugs in HbAS, but did remain significant in those with HbSS (P = .03).

“This strongly suggests that the HbSS genotype has a more significant relationship with hearing loss, while the HbAS genotype is a weaker factor but strengthened by the predisposing factors,” investigators wrote.

References

1. _{Ibekwe TS, Rogers C, Ramma L. Comparing Hearing Loss in Children with Adults Living with Sickle Cell Disease and Sickle Cell Traits. Niger J Clin Pract. 2024;27(1):74-81. doi:10.4103/njcp.njcp_763_23}