Design and methods of the prevalence and pharmacogenomics of tenofovir nephrotoxicity in HIV-positive adults in south-western Nigeria study.

BACKGROUND: Individuals of African descent are at higher risk of developing kidney disease than their European counterparts, and HIV infection is associated with increased risk of nephropathy. Despite a safe renal profile in the clinical trials, long-term use of tenofovir disoproxil fumarate (TDF) has been associated with proximal renal tubulopathy although the underlying mechanisms remain undetermined. We aim to establish the prevalence of and risk factors for TDF-induced kidney tubular dysfunction (KTD) among HIV-I and II individuals treated with TDF in south-west Nigeria. Association between TDF-induced KTD and genetic polymorphisms in renal drug transporter genes and the APOL1 (Apolipoprotein L1) gene will be examined. METHODS: This study has two phases. An initial cross-sectional study will screen 3000 individuals attending the HIV clinics in south-west Nigeria for KTD to determine the prevalence and risk factors. This will be followed by a case-control study of 400 KTD cases and 400 matched controls to evaluate single nucleotide polymorphism (SNP) associations. Data on socio-demographics, risk factors for kidney dysfunction and HIV history will be collected by questionnaire. Blood and urine samples for measurements of severity of HIV disease (CD4 count, viral load) and renal function (creatinine, eGFR, phosphate, uric acid, glucose) will also be collected. Utility of urinary retinol binding protein (RBP) and N-acetyl-beta-D-glucosaminidase (NAG) levels as surrogate markers of KTD will be evaluated. Genomic DNA will be extracted from whole blood and SNP analyses performed using the rhAMP SNP genotyping assays. Statistical analysis including univariate and multivariate logistic regression analyses will be performed to identify factors associated with KTD. DISCUSSION: In spite of TDF being the most commonly used antiretroviral agent and a key component of many HIV treatment regimens, it has potential detrimental effects on the kidneys. This study will establish the burden and risk factors for TDF-induced KTD in Nigerians, and explore associations between KTD and polymorphisms in renal transporter genes as well as APOL1 risk variants. This study may potentially engender an approach for prevention as well as stemming the burden of CKD in sub-Saharan Africa where GDP per capita is low and budgetary allocation for health is inadequate.

Spectrum of DNA variants for non-syndromic deafness in a large cohort from multiple continents.

Hearing loss is the most common sensory deficit in humans with causative variants in over 140 genes. With few exceptions, however, the population-specific distribution for many of the identified variants/genes is unclear. Until recently, the extensive genetic and clinical heterogeneity of deafness precluded comprehensive genetic analysis. Here, using a custom capture panel (MiamiOtoGenes), we undertook a targeted sequencing of 180 genes in a multi-ethnic cohort of 342 GJB2 mutation-negative deaf probands from South Africa, Nigeria, Tunisia, Turkey, Iran, India, Guatemala, and the United States (South Florida). We detected causative DNA variants in 25 % of multiplex and 7 % of simplex families. The detection rate varied between 0 and 57 % based on ethnicity, with Guatemala and Iran at the lower and higher end of the spectrum, respectively. We detected causative variants within 27 genes without predominant recurring pathogenic variants. The most commonly implicated genes include MYO15A, SLC26A4, USH2A, MYO7A, MYO6, and TRIOBP. Overall, our study highlights the importance of family history and generation of databases for multiple ethnically discrete populations to improve our ability to detect and accurately interpret genetic variants for pathogenicity.

Novel domain-specific POU3F4 mutations are associated with X-linked deafness: examples from different populations.

BACKGROUND: Mutations in the POU3F4 gene cause X-linked deafness type 3 (DFN3), which is characterized by inner ear anomalies. METHODS: Three Turkish, one Ecuadorian, and one Nigerian families were included based on either inner ear anomalies detected in probands or X-linked family histories. Exome sequencing and/or Sanger sequencing were performed in order to identify the causative DNA variants in these families. RESULTS: Four novel, c.707A>C (p.(Glu236Ala)), c.772delG (p.(Glu258ArgfsX30)), c.902C>T (p.(Pro301Leu)), c.987T>C (p.(Ile308Thr)), and one previously reported mutation c.346delG (p.(Ala116ProfsX26)) in POU3F4, were identified. All mutations identified are predicted to affect the POU-specific or POU homeo domains of the protein and co-segregated with deafness in all families. CONCLUSIONS: Expanding the spectrum of POU3F4 mutations in different populations along with their associated phenotypes provides better understanding of their clinical importance and will be helpful in clinical evaluation and counseling of the affected individuals.

Evaluation of serum antioxidants in age-related hearing loss.

BACKGROUND: Age-related hearing loss (ARHL) has been linked to the shift in the pro-oxidant/antioxidant ratio. Our objectives were to assess serum levels of retinol and zinc among the elderly individuals and to correlate the levels with hearing threshold. METHODS: Prospective study of apparently healthy individuals aged ≥60 years of age. Participants had complete clinical history, physical examination and pure tone average conducted. Blood samples were collected for determination of serum levels of retinol and zinc. Mann-Whitney U test was used to compare retinol and zinc values. Pearson's correlation test was used to determine the relationship between hearing threshold and serum levels of retinol and zinc. RESULTS: Among 126 elderly participants with mean age 67 ± 2.7 years; the mean pure tone average for air conduction was 29.3 ± 1.6 dBHL while the mean bone conduction was 36.5 ± 1.8 dBHL. The median values of serum retinol and zinc levels in the elderly participants who had hearing loss in the speech frequencies were 52 and 83.3 µg/L, respectively, while among participants with normal hearing threshold, values were 50 and 89.9 µg/L, respectively (p = 0.59 and 0.99, respectively). For the high frequencies, the median value of serum retinol and zinc levels among the elderly participants with normal hearing threshold was 70.3 and 99.9 µg/L, while among those with hearing loss, it was 46.9 and 83.2 µg/L, respectively (p = 0.000 and 0.005, respectively). CONCLUSION: Serum retinol and zinc levels were significantly lower among elderly with hearing loss involving the high frequencies. This is added evidence to extant literature on the possible role of antioxidants in the development of ARHL and suggests further study on the effect of antioxidants supplementation in the control of ARHL which is presently controversial and inconclusive.

Corrigendum to "WCN24-1105 PHARMACOGENETIC RISK FACTORS FOR TENOFOVIR-INDUCED KIDNEY TUBULAR DYSFUNCTION AMONG HIV-POSITIVE ADULT NIGERIANS" [Kidney International Reports Volume 9, Issue 4, Supplement, April 2024, Page S339].

[This corrects the article DOI: 10.1016/j.ekir.2024.02.699.].

Predictors of Taste Dysfunction and Its Severity Among Patients With Chronic Kidney Disease.

BACKGROUND: Patients with chronic kidney disease (CKD) often complain of taste dysfunction. The prevalent taste dysfunction among patients with CKD predisposes them to malnutrition, poor quality of life, and worsen disease prognoses. To appropriately treat the taste dysfunction in this group of patients, it's imperative that factors that predict taste dysfunction and its severity are identified for prompt treatment. AIM: To identify factors associated with taste dysfunction and its severity among patients with CKD. MATERIALS AND METHODS: This was a hospital-based case-control study of adult patients with CKD at the University College Hospital, Ibadan, Nigeria. The control group was made up of age- and gender-matched healthy volunteers with no clinical and laboratory evidence of CKD. Relevant clinical and social data obtained include demographics, symptoms, and signs of taste dysfunction and its risk factors. The 4 basic taste modalities namely sweet, sour, bitter, and salt taste senses of the participants were tested with validated "taste strips." Factors that predict taste dysfunction were identified among the spectrum of the disease. RESULTS: There were 100 patients with CKD and 100 healthy controls, age ranges between 19 and 86 years (mean ± standard deviation [SD] = 46.3 ± 13.9 years) and 20 and 85 years (mean ± SD = 43.4 ± 14.9 years), respectively. There was no statistically significant difference between cases and control gender distribution (P = .57). Hypogeusia was found in 27.0% of patients with CKD, while total taste function score of all the control was within normal range. Increasing duration of CKD was identified as a predictor of taste dysfunction among patients with CKD (odds ratio: 4.889, P = .038). The stages of CKD had no statistically significant relationship with the severity of taste dysfunction (P = .629). CONCLUSION: The prevalence of taste dysfunction among patients with CKD was high and this showed significant correlation with increasing duration of CKD; in contrast, the severity of CKD is not significant in the development of taste dysfunction.

Prevalence of insomnia and impact on quality of life among community elderly subjects with tinnitus.

OBJECTIVES: We sought to determine the prevalence of insomnia and its impact on the quality of life (QoL) among community elderly subjects (at least 65 years of age) with subjective tinnitus. METHODS: After household selection with multistage stratified area probability sampling, face-to-face interviews were used to obtain self-reports of subjective tinnitus and insomnia, and QoL was assessed with the WHOQoL-Bref instrument. RESULTS: Among 1302 elderly subjects, there were 183 subjects (109 female and 74 male) with tinnitus. Among those with tinnitus, insomnia was encountered in 95 (51.9%) and was found to be significantly more common among those with tinnitus than among those without (378 of 1119, or 33.8%; p = 0.002). The insomnia symptoms included difficulty in maintaining sleep in 73.4% of subjects, difficulty in falling asleep in 70.0%, early morning wakefulness in 64.3%, nonrestorative sleep in 35.1%, and daytime sleepiness in 34.7%. Univariate analysis revealed difficulty with falling asleep (p = 0.01) and early morning wakefulness (p = 0.05) to be significantly associated with tinnitus among the symptoms. Student's t-test and logistic regression analysis revealed significant deterioration in the total QoL and in the physical, psychological, social, and environmental QoL domains among elderly subjects who had tinnitus with insomnia as compared with those without insomnia. CONCLUSIONS: We believe that insomnia is significantly more common among elderly subjects with tinnitus than among those without, and that its presence further depreciates the QoL in these elderly individuals.

Correlation between serum immunoglobulin G and hearing threshold among elderly subjects with age-related hearing loss.

BACKGROUND AND PURPOSE: This study was based on the hypothesis that suboptimal immune response and low serum immunoglobulin G (IgG) may predispose to age-related hearing loss (ARHL), and the objective was to determine the serum levels of IgG and hearing thresholds of apparently healthy elderly subjects and assess their correlation. METHOD: This prospective study involved 126 participants ≥ 60 years old who were found to be free of any medical conditions. Pure-tone averages for both the speech (500-2,000 Hz) and high frequencies (3,000-8,000 Hz) and serum IgG levels were determined. Using 30 dB as cut-off for hearing loss, the correlation with serum IgG was assessed. RESULTS: There were 59 males and 67 females with a mean age ± SD of 67.0 ± 2.7 years. Speech frequency hearing loss was seen in 30.2%, while high-frequency hearing loss accounted for 74.6%. In the speech frequencies, the mean ± SD of serum IgG among subjects with normal hearing was 11.3 ± 3.9 g/l, while among those with hearing loss it was 8.3 ± 3.3 g/l (p = 0.01). In the high frequencies, the mean ± SD values of serum IgG among the subjects with normal hearing was 11.1 ± 2.3 g/l, while among those with hearing loss it was 8.7 ± 1.9 g/l (p = 0.01). CONCLUSION: Low serum IgG may be a contributory factor to the development of ARHL among the elderly. However, a longitudinal study involving intervention with immunoglobulin supplementation may further confirm this role.

The role of retinol in the etiology and outcome of suppurative otitis media.

Vitamin A deficiency is still a serious public health problem affecting an estimated 127 million preschool children. The resulting immunological dysfunctions lead to increased risks of respiratory tract infections, diarrhoeal diseases and blindness, among others. The aim of this study is to determine the significance of the role of serum retinol in the etiology of acute suppurative otitis media (ASOM) and its chronicity (CSOM). In a prospective follow-up of patients with ASOM for 6-9 months, serum retinol determination was done using the high performance liquid chromatography. Participants comprised 358 ASOM and 52 control subjects. Six-month follow-up was achieved in 264 subjects (74%); of these, there was persistence of otorrhoea (CSOM) in 116, while 148 had resolved ASOM. Of the 264 subjects, 146 were males and 118 were females, between the ages of 6 months and 9 years and a mean of 7 years (SD = 2.32), whereas the control subjects comprised 29 males and 22 females, between the ages of 6 months and 11 years and a mean of 7.8 years (SD = 3.6). The range of serum retinol in the ASOM subjects was 1.63-2.64 microg/L, mean of 1.53 microg/L, median value of 2.61 microg/L and (SD = 0.16). Among control subjects, the range was 2.5-2.8 microg/L, mean of 2.58 microg/L and median value of 2.61 microg/L (SD = 0.14) (Table 1). The range of serum retinol in the resolved ASOM subjects was 1.61-2.63 microg/L, mean of 2.07 microg/L and median value of 2.09 microg/L (SD = 0.16) while the CSOM subjects ranged between 0.8-2.86 microg/L, mean of 1.58 microg/L and median value of 1.28 microg/L, (SD = 0.48) (Table 2). Univariate analysis using unpaired t test to compare the mean serum retinol revealed significant difference between ASOM and control (P = 0.0000) and between resolved ASOM and CSOM (P = 0.0000). In conclusion, hyporetinolaemia was a significant etiological factor in the etiology ASOM and CSOM, suggesting retinol supplementation as one strategy in control of SOM.

The inner ear in patients with nasal allergy.

BACKGROUND: The endolymphatic sac has been proposed as a target organ responsible for inner-ear symptom in allergic subjects. This is a report of inner-ear symptoms in patients with nasal allergy. METHOD: Retrospective review of record charts of patients with known nasal allergy presenting to the otorhinolaryngology out-patient department of the University College Hospital, Ibadan in 5 years. RESULT: Ear symptoms were found in 95/144 (66%) subjects with nasal allergy. This comprises of 41 males and 44 females (M: F = 1:1). Of these, itching of the external ear canal, hearing loss and tinnitus accounted for 63 (66%), 55 (58%) and 39 (41%), respectively, while vertigo was found in 12 (13%). Peripheral vestibular signs of imbalance were seen in 11/95. The audiological assessment of 73 subjects revealed normal pure-tone average in 43 (59%), and sensorineural hearing loss (SHL) in 17 (23.3%). The severity of SHL was mild in 6/17, moderate in 7 and moderate-to-severe in 4. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were elevated in 10/15 (67%) and 6/15 (40%), while the skin sensitivity test showed reactions to dust in 32, cold in 25, cockroach in 7, perfume in 11, vegetable oil in 1 and insecticide in 2. The clinical diagnoses were idiopathic tinnitus in 25 (26.3%), Idiopathic SHL in 17 (18%), cochlear hydrop in 6 (6%) and autoimmune inner-ear disease in 6 (6%). CONCLUSION: This report suggests some peculiar predisposition to inner-ear pathology in patients with nasal allergy. However a longitudinal assessment of cochleovestibular features of nasal allergy subjects will help in its validation.

Serum and middle ear immunoglobulins in suppurative otitis media.

BACKGROUND AND PURPOSE: Despite the increasing occurrence of suppurative otitis media (SOM), the content of immunoglobulin fractions in the middle ear secretion (MES) has still not been determined. METHOD: The serum and MESwere analyzed for IgG and M using enzyme-linked immunoassay. RESULT: The subjects and controls were 30 males and 22 females, between 6 months and 9 years old, with a mean age of 6 years (SD = 3.26). The patient group included 20 chronic SOM (CSOM) and 17 acute SOM (ASOM) cases, and sera of 15 subjects made the control group. The mean serum IgG levels were for controls 1,051 mg/dl, ASOM 666.1 mg/dl and CSOM 1,321.1 mg/dl; the MES levels were for ASOM 203.4 mg/dl and CSOM 511.5 mg/dl. The mean serum IgM levels were for controls 35 mg/dl, ASOM 64.1 mg/dl and CSOM 40 mg/dl; the MES levels were for ASOM 22.59 mg/dl and CSOM 3.44 mg/dl. The mean MES:serum ratios for IgG and IgM were between 0.1 and 0.4 in ASOM and CSOM. The ratio of serum IgG levels of controls to ASOM cases was 0.66 while that of controls to CSOM was 1.3. The corresponding ratios of IgM were 1.6 and 0.88. Multivariate analysis revealed a significant correlation between serum IgG levels of ASOM and CSOM (p = 0.043) and MES IgG (p = 0.02) in ASOM and CSOM but no correlation between serum IgG levels in controls and ASOM (p = 0.25), serum IgM levels in controls and CSOM (p = 0.62) and serum IgM levels in controls and ASOM (p = 0.73), ASOM and CSOM (p = 0.064) and MES IgM levels of ASOM and CSOM (p = 0.06). CONCLUSIONS: Monitoring of the serum and MES IgG in ASOM may provide a useful index to assess the possibility of progression to chronicity. This forms a database for the immunological status of SOM patients.

Sinonasal malignancies: a 10-year review in a tertiary health institution.

Sinonasal malignancy is a cause of otorhinolaryngologic morbidity and mortality in West Africa. However, there is a dearth of information in the literature on its clinicopathologic presentation in West Africa. It is our aim to determine the prevalence of sinonasal malignancy and highlight the clinicopathologic features in our environment. A 10-year retrospective review of cases with histologically diagnosed malignant sinonasal tumors in University College Hospital, Ibadan, Oyo State, Nigeria was carried out. There were 82 cases-56 (68.29%) males and 26 (31.71%) females-whose ages ranged from 4-69 years. Epistaxis, rhinorrhea and nasal blockage were seen in all patients; other symptoms were facial [76 (93%)], oral cavity [48 (59%)], ophthalmic [33 (40%)] and [otologic 21 (25%)]. Squamous cell carcinoma accounted for 69/75 (92%) of epithelial tumors, and malignant lymphoma accounted for 4/7 (57%) of nonepithelial tumors. Advanced disease was the predominant presentation in our series, stage 3 in 59 (79%) and stage 4 in 12 (16%) cases. Therefore, health education on early presentation to hospitals and efforts at early detection of the disease are needed in order to achieve cure. Industrial workers should always wear face masks to protect their nasal cavity.

Clinical and demographic risk factors associated with chronic suppurative otitis media.

BACKGROUND: The incidence of chronic suppurative otitis media (CSOM) is high worldwide but increasing occurrence of complications appear peculiar to West Africa. However, knowledge of associated risk factors is sparse, we report the sociodemographic risk factors of CSOM with the aim of control of the disease and complications; and possible preventive strategies. METHOD: This is a survey of children with CSOM in five sites spread in two suburban cities in two states in Nigeria. Questionnaire was administered on the informants followed by examination of the children. RESULT: Of the 189 children, 114 (60%) had developed ear suppuration before 6 months of age, the number of attacks within the previous 18 months ranged between 2-12 with average of 7. Sociodemographic risk factors included low socioeconomic class in 153 (81%), 136 (72%) live in congested houses with more than 10 people and 79 (42%) belonged to families with more than 5 children. Indoor-cooking and infant daycare attendance were 117 (62%) while supine bottlefeeding was 115 (61%) and 34 (18%) of subjects had smoking father. The clinical risk factors were upper respiratory tract infection (URI) 85 (45%), allergy 53 (28%), adenoid 54 (28%) and malnutrition 65 (34%). The univariate analysis revealed that low social class (OR=7.33, CI=4.18-12.83, P=0.0001), malnutrition (OR=3.57, CI=1.88-6.76, P=0.00001), bottlefeeding (OR=2.93, CI=1.63-5.28, P=0.0001), indoor-cooking (OR=1.35, CI=0.88-2.10, P=0.161) and high number of people in a household (OR=0.59, CI=0.34-0.98, P=0.04) are significant in development of OM; while multivariate logistic regression analysis showed malnutrition (OR=3.48, CI=1.633-7.425, P=0.001), low social status (OR=7.74, CI=4.15-14.43, P=0.0001) and indoor-cooking (OR=2.34, CI=1.18-4.66, P=0.014), second table. Parental smoking, daycare attendance, allergy, adenoiditis/adenoidal hypertrophy and upper respiratory tract infection were not found significant. CONCLUSION: Low socioeconomic class, malnutrition, congestion from high number of children in the household and bottlefeeding constitute significant risk factor. The early onset of disease (<6 months) may suggest a prenatal predisposition. We need further research for the understanding of the biologic effect of these factors while this remains a database for prevention and control of disease.

Hearing threshold in patients with chronic renal failure.

OBJECTIVE: To determine the pattern of hearing loss among patients with chronic renal failure (CRF). METHODS: This is a case control study carried out jointly by the Otorhinolaryngology and Nephrology Departments of the University College Hospital Ibadan, Nigeria between December 2004 and March 2006. Consecutive CRF patients who satisfied the inclusion criteria were recruited, the patients had not had hemodialysis prior to inception of the study. Parameters like age, gender, duration of illness and blood pressure were recorded and pure tone audiometry was carried out. The data was analyzed using the Statistical Package for Social Sciences. RESULTS: Thirty-three CRF patients and 28 healthy controls (34 males and 27 females) were used. The age range was 16-72 years, mean of 45.30 (SD 16.20). Sensorineural hearing loss was found in 67% of CRF and 32% of controls. The mean hearing threshold of CRF was 47.42 (SD 18.55) while the controls was 35 db, unpaired t-test (value -5.155) and Pearson correlation p=0.0008, r=0.614 showed the difference was significant. There was a correlation between duration of renal disease and hearing threshold p=0.00387 (r=0.73). There was no correlation between the hearing threshold and the diastolic blood pressure p=0.056 dosage of diuretics p=-0.155 (r=0.12) and creatinine level of the patients p=0.35 (r=0.31). CONCLUSION: Sensorineural hearing loss is common among patients with CRF and related to the duration of renal disease, we recommend periodic audiological assessment incorporated in the care of these patients.

Childhood hearing loss; a need for primary health care.

INTRODUCTION: Essential health care for children is the care of the ear. METHODS: A cross-sectional descriptive study of 155 children with hearing loss. RESULTS: A total of 155 pupils with hearing impairment and their parents were interviewed; 77(49.7%) males and 78(50.3%) females, age ranged from 6 to 15years (mean 9.11 ± 2.5 years). None of the participants had neonatal hearing screening. Parents detected the hearing loss at a mean age of 2.3 ± 1.1years. Initial care was given by community health workers and general medical practitioners, only 21 participants had otolaryngological consultation and none had audiological rehabilitation. Barriers to accessing services were financial constraints, poor awareness and non-availability of otolaryngological service for the hearing impaired in the communities. CONCLUSION: Hearing impaired children in Nigeria have poor access to ear care. There is a need to create awareness of otological services and incorporate ear-care into the primary health care.

Prevalence and correlates of dizziness in the Ibadan Study of Ageing.

Dizziness is common among older people, but little is known about its prevalence and risk factors in the sub-Saharan population. We conducted a cross-sectional study to determine the prevalence of dizziness and its sociodemographic, lifestyle, and clinical correlates in 1,299 subjects--551 men (42.4%) and 748 women (57.6%), aged 65 years and older (mean: 77.3 ± 6.3)--who lived in the Yoruba-speaking areas of Nigeria. Among this group, 318 persons reported dizziness, which represents a prevalence of 24.5%. Univariate analysis of sociodemographic and lifestyle variables revealed that low economic status (p = 0.05) and smoking (p = 0.01) were significantly correlated with dizziness; however, on logistic regression analysis, only smoking (p = 0.01) was found to be significant. Neither sex (p = 0.07), age (p = 0.71), area of residence (p = 0.34), education level (p = 0.74), nor alcohol consumption (p = 0.44) had a significant correlation with dizziness. On multivariate modeling, significant clinical correlates in patients with dizziness included self-reports of a history of suppurative otitis media (p = 0.01), head injury (p = 0.03), and recurrent rhinosinusitis (p = 0.01); no significant correlation was seen between dizziness and hypertension, transient ischemic attack, and diabetes. Finally, balance testing conducted in a subset of 1,006 subjects revealed poor balance in 93 of 250 persons with dizziness (37.2%) and in 189 of 756 subjects without dizziness (25.0%) (p = 0.01). Logistic regression analysis of sex and age revealed that the probability of poor balance was 1.5 times greater among those persons with dizziness. We conclude that the high incidence of dizziness among community-dwelling elderly and its significant correlations with remediable medical conditions suggest the need for policy formulation for the care of the elderly in Nigeria.

Common genes for non-syndromic deafness are uncommon in sub-Saharan Africa: a report from Nigeria.

INTRODUCTION: Little is known about the molecular epidemiology of deafness in sub-Saharan Africa (SSA). Even in Nigeria, the most populous African nation, no genetic studies of deafness have been conducted. This pioneering work aims at investigating the frequencies of gene mutations relatively common in other parts of the world (i.e. those in GJB2, GJB6, and mitochondrial DNA) among subjects from Nigeria with hearing loss (HL) with no evidence of acquired pathology or syndromic findings. In addition, we review the literature on the genetics of deafness in SSA. METHOD: We evaluated 81 unrelated deaf probands from the Yoruba tribe residing in Ibadan, a suburban city in Nigeria, for the aetiology of their deafness. Subjects underwent genetic testing if their history was negative for an environmental cause and physical examination did not find evidence of a syndrome. Both exons of GJB2 and mitochondrial DNA flanking the 1555A>G mutations were PCR-amplified followed by Sanger sequencing. GJB6 deletions were screened via quantitative PCR. RESULT: We identified 44 probands who had nonsyndromic deafness with no environmental cause. The age at study time ranged between 8 months and 45 years (mean=24 years) and age at onset was congenital or prelingual (G mutations were not found among this initial cohort of the deaf in Nigeria. This makes imperative the search for other genes in the aetiology of HL in this population.

Neonatal hearing screening in a rural/sub-urban community in Nigeria, sub-Saharan Africa-a preliminary report.

INTRODUCTION: The implementation of Neonatal Hearing Screening (NHS) program is still at the preliminary stage particularly in developing countries despite the burden of permanent congenital and early-onset hearing impairment. There has been an earlier report of NHS in a city in Nigeria, however, this is a report of a preliminary NHS carried in a rural/sub-urban area in Nigeria. METHOD: This prospective study, which took place between October 2009 and April 2010, involved all newborns delivered at the University College Hospital, Ibadan and the Bilal Missionary Maternity, Agodi, Ibadan, a small maternity service located in Agodi community serving predominantly low socioeconomic class people. All the neonates delivered during the study period were included in the screening. The screening was performed within 72 h of delivery using automated auditory brainstem response (AABR) and repeated after 6 weeks among those with referral result. Subsequently the neonates were referred to diagnostic audiology. RESULT: Among the 453 newborns (231 males and 222 female), AABR screening showed referral, in 43.7% of neonates. At first screening, 224 (49.4%) were referred while 229 (50.6%) passed, however, during the post-natal period 40/229 (17.5%) reported for second screening, out of these 26 showed pass to the screening. This gave a total pass of 255/453 (56.3%). The presence of maternal pre-ecclampsia (P = 0.05) was found to be a significant morbidity factor associated with referral in the screening, while parental socioepidemiological variables; and the neonates' birthweight, gestational age and APGAR score were not. CONCLUSION: The proportion of referral on hearing screening encountered was far higher than previously reported, however, continuation of infant screening in future should be comprehensive with viral and genetic analysis in order to address the issue of aetiologic diagnosis; in addition, the implementation should factor the high drop out from the first stage screening in order to substantiate the findings in our region.

Correlation between plasma levels of radical scavengers and hearing threshold among elderly subjects with age-related hearing loss.

CONCLUSION: Low plasma melatonin is significant in the development of high frequency hearing loss (HL) among the elderly. OBJECTIVE: To determine the correlation between hearing threshold and the plasma melatonin and ascorbic acid (vitamin C). METHODS: This was a cross-sectional study involving 126 apparently healthy elderly subjects, 59 males and 67 females, aged >60 years. Subjects underwent pure tone audiometry and plasma melatonin and vitamin C were assayed using high-performance liquid chromatography. RESULTS: The mean ± SD of plasma melatonin among the subjects with normal hearing (NH) (0-30 dB) and those with HL in the speech frequencies was 18.3 ± 3.6 µg/L and 16.4 ± 4.7 µg/L, respectively. In the high frequencies the values were 17.7 ± 6.2 µg/L and 13.1 ± 6.4 µg/L for NH and HL, respectively. For vitamin C, the mean ± SD among subjects with NH and those with HL in the speech frequencies were 1.2 ± 0.2 µg/L and 1.0 ± 0.1 µg/L, respectively. In the high frequencies, the values were 1.0 ± 0.2 µg/L and 0.9 ± 0.3 µg/L for NH and HL, respectively. Among subjects with high frequency HL, Spearman's correlation revealed significant correlation between increasing hearing threshold and melatonin (correlation coefficient = -0.30, p = 0.01), but not for vitamin C (correlation coefficient = -0.12, p = 0.22). Linear regression, adjusting for age, still revealed significant correlation between the melatonin (correlation coefficient = -0.03, p = 0.00) and hearing threshold in the high frequencies.

Age-related hearing loss, vitamin B12, and folate in the elderly.

OBJECTIVE: Determine the correlation between the hearing threshold and the serum levels of vitamin B12 (cobalamin) and folic acid among elderly subjects (> 60 years) with age-related hearing loss (ARHL). STUDY DESIGN: Cross-sectional. SETTING: Community. SUBJECTS AND METHODS: Subjects included elderly who were found apparently healthy following repeated examination by physicians. The pure tone average (PTA) for the speech and high frequencies, and the serum folate and cobalamin were determined and the correlation found. RESULTS: The mean ± SD values of serum folate among the subjects with normal PTA in the speech frequencies (0-30 dB) was 412.3 nmol/L ± 17.6 nmol/L, while among those with hearing loss (HL), it was 279.1 nmol/L ± 17.2 nmol/L (P = 0.01). In the high frequencies, the mean ± SD values among the subjects with normal PTA was 426.3 nmol/L ± 17.6 nmol/L, while among those with HL, it was 279.14 nmol/L ± 171.2 nmol/L. The serum cobalamin among the subjects with normal PTA within the speech frequencies was 49.7 pmol/L ± 9.4 pmol/L, while among those with speech-frequency HL, it was 42.6 pmol/L ± 10.2 pmol/L. However, for high frequencies, the mean ± SD values among the subjects with normal PTA was 47.4 pmol/L ± 7.3 pmol/L, while among those with HL, it was 41.3 pmol/L ± 9.2 pmol/L. Spearman's correlation revealed that low folate (correlation coefficient = -0.27, P = 0.01) and cyanocobalamin (correlation coefficient = -0.35, P = 0.02) were significantly associated with increasing hearing threshold in the high frequencies. After adjusting for age, serum folate (correlation coefficient = -0.01, P = 0.01) was significant, while vitamin B12 (correlation coefficient = -0.01, P = 0.74) was not. CONCLUSION: Serum folate was significantly lower among elderly with ARHL. Trials on nutritional supplementation may substantiate the role of serum folate in ARHL.