Iron Deficiency Associated with Hearing Loss Risk in Adolescents

Young Ho Kim, MD, PhD

Credit: Seoul National University

Microalbuminuria and functional iron deficiency were independently associated with hearing loss and high-frequency hearing loss among adolescent patients aged 10–19 years old, according to new research.

The investigative team from the Seoul National University College of Medicine noted the importance of identifying pediatric hearing loss for language development and learning in adolescence— the evaluation of renal and systemic diseases may be critical for the early detection of hearing loss.

However, the team identified no association between hearing loss and laboratory findings, including impaired estimated glomerular filtration rate (eGFR), hypertension, diabetes, anemia, obesity, serum triglyceride, or serum total cholesterol.

“Since microalbuminuria test is non-invasive, easy, and included in pediatric health screenings, suspecting a higher possibility of hearing loss in microalbuminuria individuals can lead to early hearing rehabilitation,” wrote the investigative team, led by Young Ho Kim, MD, PhD, the department of otorhinolaryngology-head and neck surgery at Seoul National University Boramae Medical Center.

Aging is the most common cause of hearing loss. Viral infection, metabolic disease, and noise can also cause hearing loss in adults—however, the causes of hearing loss in pediatric populations can be much different. Genetic diseases or exposures to pathogens, including toxoplasmosis, rubella, and cytomegalovirus, make up the largest group of congenital hearing loss.

Past research has investigated the association of hearing loss with other organ-related conditions or acquired systemic disease among pediatric populations. But, as Kim and colleagues indicated, these investigations are few, feature varying designs and outcomes, and involve fewer comorbidities than adult-focused trials.

The team conducted the present trial to assess the association between hearing loss and renal or systemic disease in a population of adolescents. Participants were chosen from the 5th Korea National Health and Nutrition Examination Survey from 2011 to 2012. They were adolescents aged 10–-19 years old with normal tympanic membrane status who had undergone a physical and laboratory examination and pure tone audiometry.

Mean hearing levels were identified after averaging hearing levels at frequencies of 0.5, 1, 2, and 3 kHz. A threshold of ≥15 dB of mean hearing levels in either ear helped the team determine hearing loss. High-frequency hearing loss was categorized as a mean hearing level of ≥15 dB in either ear at frequencies of 3, 4, and 6 kHz.

Albuminuria was defined as a urine albumin-to-creatinine ratio (UACR) of ≥30 mg/g. Among those defined as albuminuric, patients were classified into microalbuminuria (30 mg/g ≤UACR <300 mg/g) and macroalbuminuria (UACR >300 mg/g) groups. An impaired eGFR was defined as an eGFR of ≤60 mL/min/1.73 m2, while hypertension, diabetes, and obesity were determined based on a patient’s laboratory data.

Of 16,576 subjects in the 5th KHANES, a total of 1972 adolescents were selected for analysis. Approximately 1000 adolescents underwent physical and laboratory examinations, and 936 individuals with bilateral normal tympanic membranes were in the full analysis set.

Among the population, the prevalence of microalbuminuria was 3.53%. Specifically, the prevalence of hearing loss was 4.16% in the normal group, 8.14% in the low albuminuria group, and 18.18% in the microalbuminuria group, suggesting significant differences between patient groups (P = .002).

Upon analysis, those with microalbuminuria demonstrated a higher prevalence of hearing loss (odds ratio [OR], 5.12; P = .003) than the normal group. In addition, the prevalence of high-frequency hearing loss also exhibited significant differences (P = .012) between groups (normal: 9.43%; low albuminuria: 13.95%; microalbuminuria: 24.24%). The trend gradually increased with the increasing severity of albuminuria.

Individuals with impaired eGFR showed no hearing loss, high-frequency hearing loss, or microalbuminuria. Anemia was not associated with hearing loss or high-frequency hearing loss. The prevalence of hearing loss and high-frequency hearing loss showed no significant differences among those with hypertension, diabetes, or obesity or those without the disease.

Further, those with hearing loss or high-frequency hearing loss exhibited lower transferrin saturation (TSAT) levels than individuals without hearing loss (P = .002) or high-frequency hearing loss (P = .001). Meanwhile, high-frequency hearing loss was linked to lower ferritin levels (P = .017).

Considering these data, Kim and colleagues indicated iron deficiency may independently contribute to hearing loss, remaining consistent with previously described data on hearing loss and iron deficiency.

“If adolescents are diagnosed with iron deficiency, physicians may need to consider their increased risk of hearing loss,” Kim and colleagues wrote. “However, we could not demonstrate the association between hearing loss and anemia, a severe form of iron deficiency.”

References

1. _{Han SY, Kim YH. Microalbuminuria and Functional Iron Deficiency are Risk Factors for Hearing Loss in Adolescents. Laryngoscope. Published online February 5, 2024. doi:10.1002/lary.31317}