Inflammation and hearing status in mid-childhood and mid-life: a population-based cross-sectional study

Polygenic Risk Scores and Hearing Loss Phenotypes in Children

Importance

Monogenic causes of childhood hearing loss are well established, as are polygenic risk contributions to age-related hearing loss. However, an untested possibility is that polygenic risk scores (PRS) also contribute to childhood hearing loss of all severities, alongside environmental and/or monogenic causes.

Objective

To examine the association between a PRS for adult hearing loss and childhood hearing loss phenotypes.

Design, Setting, and Participants

This cross-sectional study used a unique population-based dataset spanning normal hearing to profound loss, combining 2 contemporaneous population cohorts in Australia. This included the Child Health CheckPoint, a national population-based cross-sectional study nested within the Longitudinal Study of Australian Children, and the Victorian Childhood Hearing Longitudinal Databank (VicCHILD), a statewide population-based longitudinal data bank open to every child with congenital hearing loss in Victoria, Australia. The analysis took place from March to August 2023.

Exposures

Genotype data were generated from saliva- or blood-derived DNA using global single-nucleotide variations arrays. Based on genotype data, PRS was computed using published UK Biobank genome-wide association study results for self-reported hearing difficulty in individuals aged 40 to 69 years.

Main Outcomes and Measures

Hearing outcomes were classified by laterality (bilateral, unilateral), severity (mild, moderate, severe or worse) and types (sensorineural, conductive, mixed, auditory neuropathy, atresia). Analyses included multinominal logistic regressions of PRS with hearing outcomes.

Results

Overall, 1488 CheckPoint study children (49.8% boys, aged 11-12 years) and 527 VicCHILD study children (55.2% boys, aged 0-13 years) with hearing and genotype data were included. A 1-SD increment in PRS was associated with higher odds of mild (odds ratio [OR], 1.3; 95% CI, 1.0-1.6), moderate (OR, 5.1; 95% CI, 3.2-8.1), and severe or worse (OR, 5.3; 95% CI, 3.9-7.3) unilateral hearing loss compared with normal hearing. Similarly, the PRS was associated with increased odds of mild, moderate, and severe or worse bilateral hearing loss (per-SD ORs, 3.9-6.6) and all hearing loss types (per-SD ORs, 8.5-10.6).

Conclusions and Relevance

In this cross-sectional study, a PRS initially developed for adult hearing difficulty was associated with wide-ranging childhood hearing loss phenotypes, partly explaining hearing phenotype variations despite shared genetic and environmental factors (eg, preterm birth). Large-scale studies with objectively defined hearing phenotypes are crucial for refining PRS and predicting high-risk children.

Association between the systemic immune-inflammation index and hearing loss: A cross-sectional study of NHANES 2005 to 2018

The relationship between systemic inflammation and hearing loss (HL) remains unclear. To investigate the association between the systemic immune-inflammation index (SII) and objective HL, this study was performed. Participants from the National Health and Nutrition Examination Survey (NHANES) spanning from 2005 to 2018 were analyzed. Two types of hearing loss were investigated: speech-frequency hearing loss (SFHL) and high-frequency hearing loss (HFHL). The SII score was constructed using the levels of peripheral neutrophil (N), lymphocyte (L), and platelet (P), and was defined as P multiplied by N/L (in units of 109/L). Weighted multivariable logistic regression and subgroup analysis were used to examine the relationship between HL and high-SII group (≥330 × 109/L). A total of 6428 participants were included in the study. This study found that the high-SII group was positively associated with a higher risk of HL (OR: 1.29, 95% CI: 1.05-1.57, P < .05) and HFHL (OR: 1.24, 95% CI: 1.05-1.46, P < .05), but not significant for SFHL (OR: 1.13, 95% CI: 0.94-1.37, P > .05). Subgroup analysis showed that this association was similar in different age groups. Finally, sensitivity analysis confirmed the robustness of the association. In the full model, increasing SII index per SD was associated with HL (OR: 1.17, 95% CI: 1.09-1.26, P < .001) and HFHL (OR: 1.13, 95% CI: 1.06-1.21, P < .001). The significance of SFHL was not detected with the increasing SII index (OR: 1.13, 95% CI: 0.94-1.37, P > .05). SII score was associated with HL and HFHL in the general adult population of the United States, but was not significantly correlated with SFHL.

Longitudinal urinary neopterin is associated with hearing threshold change over time in independent older adults

Low-grade chronic inflammation is associated with many age-related conditions. Non-invasive methods to monitor low-grade chronic inflammation may improve the management of older people at risk of poorer outcomes. This longitudinal cohort study has determined baseline inflammation using neopterin volatility in monthly urine samples of 45 independent older adults (aged 65-75 years). Measurement of neopterin, an inflammatory metabolite, enabled stratification of individuals into risk categories based on how often in a 12-month period their neopterin level was raised. Hearing was measured (pure-tone audiometry) at baseline, 1 year and 3 years of the study. Results show that those in the highest risk category (neopterin raised greater than 50% of the time) saw greater deterioration, particularly in high-frequency, hearing. A one-way Welch's ANOVA showed a significant difference between the risk categories for change in high-frequency hearing (W (3, 19.6) = 9.164, p = 0.0005). Despite the study size and duration individuals in the highest risk category were more than twice as likely to have an additional age-related morbidity than those in the lowest risk category. We conclude that volatility of neopterin in urine may enable stratification of those at greatest risk of progression of hearing loss.

Association of Polygenic Risk Scores for Hearing Difficulty in Older Adults With Hearing Loss in Mid-Childhood and Midlife: A Population-Based Cross-sectional Study Within the Longitudinal Study of Australian Children

Importance

Although more than 200 genes have been associated with monogenic congenital hearing loss, the polygenic contribution to hearing decline across the life course remains largely unknown.

Objective

To examine the association of polygenic risk scores (PRSs) for self-reported hearing difficulty among adults (40-69 years) with measured hearing and speech reception abilities in mid-childhood and early midlife.

Design, Setting, and Participants

This was a population-based cross-sectional study nested within the Longitudinal Study of Australian Children that included 1608 children and 1642 adults. Pure tone audiometry, speech reception threshold against noise, and genetic data were evaluated. Linear and logistic regressions of PRSs were conducted for hearing outcomes. Study analysis was performed from March 1 to 31, 2022.

Main Outcomes and Measures

Genotypes were generated from saliva or blood using global single-nucleotide polymorphisms array and PRSs derived from published genome-wide association studies of self-reported hearing difficulty (PRS1) and hearing aid use (PRS2). Hearing outcomes were continuous using the high Fletcher index (mean hearing threshold, 1, 2, and 4 kHz) and speech reception threshold (SRT); and dichotomized for bilateral hearing loss of more than 15 dB HL and abnormal SRT.

Results

Included in the study were 1608 children (mean [SD] age, 11.5 [0.5] years; 812 [50.5%] male children; 1365 [84.9%] European and 243[15.1%] non-European) and 1642 adults (mean [SD] age, 43.7 [5.1] years; 1442 [87.8%] female adults; 1430 [87.1%] European and 212 [12.9%] non-European individuals). In adults, both PRS1 and PRS2 were associated with hearing thresholds. For each SD increment in PRS1 and PRS2, hearing thresholds were 0.4 (95% CI, 0-0.8) decibel hearing level (dB HL) and 0.9 (95% CI, 0.5-1.2) dB HL higher on the high Fletcher index, respectively. Each SD increment in PRS increased the odds of adult hearing loss of more than 15 dB HL by 10% to 30% (OR for PRS1, 1.1; 95% CI, 1.0-1.3; OR for PRS2, 1.3; 95% CI, 1.1-1.5). Similar but attenuated patterns were noted in children (OR for PRS1, 1.1; 95% CI, 0.8-1.2; OR for PRS2, 1.2; 95% CI, 1.0-1.5). Both PRSs showed minimal evidence of associations with speech reception thresholds or abnormal SRT in children or adults.

Conclusions and Relevance

This population-based cross-sectional study of PRSs for self-reported hearing difficulty among adults found an association with hearing ability in mid-childhood. This adds to the evidence that age-related hearing loss begins as early as the first decade of life and that polygenic inheritance may play a role together with other environmental risk factors.

Infant inflammation predicts childhood emotional and behavioral problems and partially mediates socioeconomic disadvantage

BACKGROUND

Emotional and behavioral problems (EBP) are common in children. Environmental factors like socioeconomic disadvantage influence EBP pathogenesis and can trigger inflammation. However, the link between early inflammation-EBP in children is unclear. We investigated the associations between i) infant inflammatory biomarkers and subsequent EBP and ii) early life environmental factors and EBP and assessed whether infant inflammation mediated these associations.

METHODS

Inflammatory biomarkers glycoprotein acetyls (GlycA) and high-sensitivity C-reactive protein (hsCRP) were quantified at birth and 12 months in a population-derived birth cohort, the Barwon Infant Study. Early life factors including demographic, prenatal, and perinatal factors were collected from antenatal to the two-year period. Internalizing and externalizing problems at age two were measured by the Child Behavior Checklist. Prospective associations were examined by multivariable regression analyses adjusted for potential confounders. Indirect effects of early life factors on EBP through inflammation were identified using mediation analyses.

RESULTS

Elevated GlycA levels at birth (GlycAbirth) were associated with greater internalizing problems at age two (β = 1.32 per SD increase in GlycA; P = 0.001). Inflammation at birth had a stronger magnitude of effect with later EBP than at 12 months. GlycAbirth partially mediated the associations between lower household income (6%), multiparity (12%) and greater number of older siblings (13%) and EBP. Patterns were less evident for hsCRP or externalizing problems.

CONCLUSIONS

GlycAbirth was positively associated with EBP at age two and partially mediated the association between several indicators of socioeconomic disadvantage and EBP. Prenatal and perinatal inflammation may be relevant to early neurodevelopment and emotional health.

Associations of Retinal Vessel Caliber With Hearing Status in Childhood and Midlife: A Cross-Generational Population-Based Study

Importance

Microvascular phenotypes, which can be assessed using retinal imaging, may be informative about the life course pathogenesis of hearing loss.

Objective

To investigate whether differences in retinal vessel caliber (specifically wider venules and narrower arterioles) are associated with hearing threshold and hearing loss in mid-childhood and midlife.

Design, Setting, and Participants

A population-based cross-sectional study (Child Health CheckPoint) was nested within the Longitudinal Study of Australian Children. A total of 1281 children and 1255 attending parents were assessed using retinal microvasculature and air conduction audiometry data at a main assessment center in 7 large cities in Australia.

Main Outcomes and Measures

Air conduction audiometry was used to calculate the high Fletcher index (mean threshold of 1, 2, and 4 kHz), and bilateral hearing loss was defined as a high Fletcher index greater than 15 dB hearing level in the better-hearing ear. Retinal arteriolar and venular caliber were measured from fundus photographs using validated computer-based software. Linear and logistic regression quantified the associations of retinal vessel caliber with hearing threshold and hearing loss, respectively.

Results

Of the 1281 included children (mean age, 11.4 years; 49.1% boys), the mean (SD) high Fletcher index was 7.9 (5.8) dB hearing level. Of the 1255 included adults (mean age, 43.8 years; 86.6% women), the mean (SD) high Fletcher index was 13.0 (6.8) dB hearing level; 109 of 1281 children (8.5%) and 328 of 1255 adults (26.1%) had hearing loss. In adults, each 1-SD (18.6-μm) wider retinal venular caliber (worse) was associated with higher (worse) hearing threshold at lower individual frequencies (eg, 2 kHz: β = 0.63; 95% CI, 0.10-1.17) and overall high Fletcher index (eg, 2 kHz: β = 0.52; 95% CI, 0.07-0.96), as well as a 1.20-fold (95% CI, 1.03-1.40) higher odds of hearing loss. In children, patterns of venular associations were similar but smaller and less certain. Narrower retinal arteriolar caliber (worse) was associated with a 1.16-fold (95% CI, 1.00-1.37) higher odds of hearing loss in adults (per 1-SD [14.0-μm] narrower arteriolar caliber) but not in children.

Conclusions and Relevance

Adverse retinal microvascular characteristics are associated with hearing loss by midlife, with venular associations possibly emerging by age 11 to 12 years. Microvascular health may contribute to the pathogenesis of hearing loss across the life course, warranting replication and mechanistic studies to inform causal inference and prevention efforts.

Cannabinoids, Inner Ear, Hearing, and Tinnitus: A Neuroimmunological Perspective

Cannabis has been used for centuries for recreational and therapeutic purposes. Whereas, the recreative uses are based on the psychotropic effect of some of its compounds, its therapeutic effects range over a wide spectrum of actions, most of which target the brain or the immune system. Several studies have found cannabinoid receptors in the auditory system, both at peripheral and central levels, thus raising the interest in cannabinoid signaling in hearing, and especially in tinnitus, which is affected also by anxiety, memory, and attention circuits where cannabinoid effects are well described. Available studies on animal models of tinnitus suggest that cannabinoids are not likely to be helpful in tinnitus treatment and could even be harmful. However, the pharmacology of cannabinoids is very complex, and most studies focused on neural CB1R-based responses. Cannabinoid effects on the immune system (where CB2Rs predominate) are increasingly recognized as essential in understanding nervous system pathological responses, and data on immune cannabinoid targets have emerged in the auditory system as well. In addition, nonclassical cannabinoid targets (such as TRP channels) appear to play an important role in the auditory system as well. This review will focus on neuroimmunological mechanisms for cannabinoid effects and their possible use as protective and therapeutic agents in the ear and auditory system, especially in tinnitus.