Date Published: June , 2018
Publisher: Makerere Medical School
Author(s): Christine Louw, De Wet Swanepoel, Robert H Eikelboom, Jannie Hugo.
Hearing loss prevalence data in South Africa is scarce, especially within primary health care settings.
To determine; (i) the prevalence of hearing disorders in patients ≥3 years of age attending two primary health care clinics, and (ii) the nature and characteristics of hearing disorders at these primary health care clinics.
A cross-sectional design was used at two primary health care clinics. Non-probability purposive sampling was used to screen participants at clinics for hearing loss with pure tone audiometry. A total of 1236 participants were screened (mean age 37.8 ±17.9 years). Diagnostic testing was available for confirmation of hearing loss on participants who failed the screening.
Hearing loss prevalence was 17.5% across both clinics. Most hearing losses were bilateral (70.0%) and were of a sensorineural nature (84.2%).
Hearing loss prevalence was comparable at both primary health care clinics. Participants 40 years and older were at significantly higher risk for hearing loss. The current study is the first attempt to establish hearing loss prevalence for primary health care clinics in South Africa.
Hearing loss is a major public health concern affecting more than 1.33 billion people globally in 20151. As one of the leading contributors to the global burden of disease, it currently ranks fifth on the global causes of years lived with disability index, higher than other chronic diseases such as diabetes or dementia1. A combination of factors is responsible for the upward trend in the global hearing loss epidemic. These include increased life expectancy leading to the number one cause of hearing loss, aging. The widespread use of ototoxic treatments for diseases such as cancer and tuberculosis, and occupational and recreational noise exposure without appropriate protection are other major contributors to the global burden of hearing loss2.
This research project was approved by the Institutional Research Board of the University of Pretoria, South Africa and was part of a larger community oriented primary care (COPC) project in Gauteng province in the City of Tshwane12.
A total of 1236 participants were included in the study (PHC 1: n=633; PHC: n=603) (Table 1). The mean age was 37.8 years (±17.9 years, range 3 – 97 years). Twenty six participants (22 adults, four children) at PHC clinic 1 and two participants (2 adults) at PHC clinic 2 were excluded from the study because the screening protocol was not completed due to operator error. Two other participants were omitted from the study group at PHC clinic 2 because their date of birth was not captured. Two hundred and sixteen (17.5%) participants failed the hearing screening (PHC 1 = 18.8%, PHC 2 = 16.1%). 4.8% participants failed in the 3–14 years category, whilst 10.5% and 25.4% failed in the 15 – 39 years and > 40 years categories respectively. Of the 216 participants who failed, 138 participants were tested diagnostically whilst 78 did not attend the diagnostic assessment.
Hearing loss prevalence data in Africa varies greatly. The current study revealed a hearing loss prevalence of 17.5% at two PHC clinics in underserved communities in the Tshwane area. This is slightly higher than the 12.35% prevalence reported in the Cape Town metropolitan area8 whilst it is very similar to an estimated range of 11.4% –20.3% for sub-Saharan Africa6. Different contexts such as school settings or population-based contribute to the prevalence variation. The current study investigated hearing loss prevalence at PHC clinics. Different hearing test techniques employed also contribute to the variation. Also, in studies where pure tone audiometry was used as the screening method, there was also a wide variation in the intensity cut-off criteria i.e. 25 dB HL, 30 dB HL, 35 dB HL7. Using a stricter screen intensity such as 25 dB HL will identify milder hearing losses, and will produce a higher prevalence whilst a pure tone cut off at 40 bB HL will result in a lower prevalence as only moderate and severe losses will be included. The cut off criteria in the current study was of 25 dB HL (children) and 35 dB HL (adults). These intensities were selected to identify disabling hearing loss in children (>30 dB HL) and adults (>40 dB HL)16; however there may have been a small percentage of adults with slight hearing loss (> 25 dB < 35 dB) that may have passed the hearing screening. A limitation of the study was that participants younger than three years of age were not included. Furthermore, the population was sampled purposively and not randomly taking into consideration power and precision. This was mainly due to the clinical time and human resource constraints of the research setting. Source: http://doi.org/10.4314/ahs.v18i2.16