Dataset Information

Hearing Impairment Overview in Africa: the Case of Cameroon.

ABSTRACT: The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on HI in Cameroon, published from inception to 31 October, 2019, with no language restrictions. Reference lists of included studies were also scrutinized, and data were summarized narratively. This study is registered with PROSPERO, number CRD42019142788. We screened 333 records, of which 17 studies were finally included in the review. The prevalence of HI in Cameroon ranges from 0.9% to 3.6% in population-based studies and increases with age. Environmental factors contribute to 52.6% to 62.2% of HI cases, with meningitis, impacted wax and age-related disorder being the most common ones. Hereditary HI comprises 0.8% to 14.8% of all cases. In 32.6% to 37% of HI cases, the origin remains unknown. Non-syndromic hearing impairment (NSHI) is the most frequent clinical entity and accounts for 86.1% to 92.5% of cases of HI of genetic origin. Waardenburg and Usher syndromes account for 50% to 57.14% and 8.9% to 42.9% of genetic syndromic cases, respectively. No pathogenic mutation was described in GJB6 gene, and the prevalence of pathogenic mutations in GJB2 gene ranged from 0% to 0.5%. The prevalence of pathogenic mutations in other known NSHI genes was <10% in Cameroonian probands. Environmental factors are the leading etiology of HI in Cameroon, and mutations in most important HI genes are infrequent in Cameroon. Whole genome sequencing therefore appears as the most effective way to identify variants associated with HI in Cameroon and sub-Saharan Africa in general.

SUBMITTER: Wonkam Tingang E

PROVIDER: S-EPMC7073999 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Hearing Impairment Overview in Africa: the Case of Cameroon.

Wonkam Tingang Edmond E Noubiap Jean Jacques JJ F Fokouo Jean Valentin JV Oluwole Oluwafemi Gabriel OG Nguefack Séraphin S Chimusa Emile R ER Wonkam Ambroise A

Genes 20200222 2

The incidence of hearing impairment (HI) is higher in low- and middle-income countries when compared to high-income countries. There is therefore a necessity to estimate the burden of this condition in developing world. The aim of our study was to use a systematic approach to provide summarized data on the prevalence, etiologies, clinical patterns and genetics of HI in Cameroon. We searched PubMed, Scopus, African Journals Online, AFROLIB and African Index Medicus to identify relevant studies on ...[more]

PMID: 32098311

Similar Datasets

Project description:Hearing impairment (HI) is a silent planetary health crisis that requires attention worldwide. The prevalence of HI in South Africa is estimated as 5.5 in 100 live births, which is about 5 times higher than the prevalence in high-income countries. This also offers opportunity to drive progressive science, technology and innovation policy, and health systems. We present here a systematic analysis and review on the prevalence, etiologies, clinical patterns, and genetics/genomics of HI in South Africa. We searched PubMed, Scopus, African Journals Online, AFROLIB, and African Index Medicus to identify the pertinent studies on HI in South Africa, published from inception to April 30, 2021, and the data were summarized narratively. We screened 944 records, of which 27 studies were included in the review. The age at diagnosis is ∼3 years of age and the most common factor associated with acquired HI was middle ear infections. There were numerous reports on medication toxicity, with kanamycin-induced ototoxicity requiring specific attention when considering the high burden of tuberculosis in South Africa. The Waardenburg Syndrome is the most common reported syndromic HI. The Usher Syndrome is the only syndrome with genetic investigations, whereby a founder mutation was identified among black South Africans (MYO7A-c.6377delC). GJB2 and GJB6 genes are not major contributors to nonsyndromic HI among Black South Africans. Furthermore, emerging data using targeted panel sequencing have shown a low resolution rate in Black South Africans in known HI genes. Importantly, mutations in known nonsyndromic HI genes are infrequent in South Africa. Therefore, whole-exome sequencing appears as the most effective way forward to identify variants associated with HI in South Africa. Taken together, this article contributes to the emerging field of planetary health genomics with a focus on HI and offers new insights and lessons learned for future roadmaps on genomics/multiomics and clinical studies of HI around the world.

Project description:BackgroundThe prevalence of HIV-associated neurocognitive disorders (HAND), especially HIV-associated dementia (HAD) is influenced by several risk factors. The prevalence as well as risk factors for HAD are not well known in sub-Saharan Africa (SSA). We have shown that the International HIV Dementia Scale (IHDS) is a useful screening tool for HAND in Yaoundé [Njamnshi AK, Djientcheu VdP, Fonsah JY, Yepnjio FN, Njamnshi DM, Muna WFT. The IHDS is a useful screening tool for HAD/Cognitive Impairment in HIV-infected adults in Yaoundé-Cameroon. Journal of Acquired Immune Deficiency Syndromes 2008;49(4):393-397], but no study in Cameroon has yet investigated the risk factors for HAND or HAD.Patients and methodsA cross-sectional study was conducted in Yaoundé, the capital of Cameroon from September to December 2006. One hundred and eighty-five HIV-positive subjects were included. Diagnosis of HAND was done using the IHDS with a score < or = 10 considered as abnormal. Age, sex, level of education, IV drug use, body mass index (BMI), CDC clinical stage, CD4 counts, hemoglobin levels, administration of highly active antiretroviral therapy (HAART) and type of regimen used, were considered in univariate analysis, with level of significance set at P < or = 0.05. A binary logistic regression was used to determine independent risk factors.ResultsThe following factors were independent predictors of HAND: advanced clinical stage (OR=7.43, P=0.001), low CD4 count especially CD4 < or = 200 cells/microL (OR=4.88, P=0.045) and low hemoglobin concentration (OR=1.16, P=0.048).ConclusionThis first study of the risk factors for HAND in Yaoundé-Cameroon shows findings similar to those described in other studies. These results call for rapid action by policy makers to include HAND prevention strategies such as providing early universal access to HAART based on these risk factors, in the management of HIV patients at risk of HAND in resource-limited settings of SSA like ours.

Dataset Information

Hearing Impairment Overview in Africa: the Case of Cameroon.

Publications

Hearing Impairment Overview in Africa: the Case of Cameroon.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets