gms | German Medical Science

Since 1993 the diagnoses, age and gender of all inpatients in Germany are documented by the National Center of Health Statistics (Wiesbaden) according to the International Classification of Diseases (ICD). We received the data of all inpatients in whom otosclerosis (ICD-9:387; ICD-10:H80) was surgically confirmed between 1993 and 2007 (n=77,087; females=48,473, males=28,614; female/male ratio= 1.69:1). In 1993 there were 5626, in 2007 there were 4369 inpatients (-23%). The decline among female patients was -21%, among male patients it was -24%. As well the population (+1.1%) as the number of ENT-specialists (+23%) increased between 1993 and 2007, so that the decline of clinical cases cannot be due to a decrease of population or ENT-specialists.

The 77,087 inpatients were devided in different female and male age groups (15–25,26–35,36–45,46–55,56–65 etc) . When investigating the change of frequency of the different age groups a striking difference between patients younger and older than 35 years of age is obvious. The change of frequency among patients younger than 35 years is -52.7%, among patients older than 35 years it is -13%. The age around 35 is marking a break!

How this observation can be explained? There is not yet a more efficient alternative to stapes surgery for remediation of hearing loss as a result of otosclerosis.Hearing aids appeal to only a small percentage of surgical candidates and especially younger patients are usually refusing hearing aids.What else has influenced the decline of the disease in younger patients? Since otosclerosis is accepted as an inflammatory disease associated with a persistent measles infection and measles immunisation was introduced in Germany around 35 years ago, it is evident that measles vaccination has influenced the clinical penetrance of the disease. By the present investigation the temporal relationship between the application of immunisation and the decline in surgical cases has been established, as suggested by Vrabek & Coker in 2004 [Ref. 1]. To explain the 13% decline in inpatients older than 35 years is rather difficult: This decline may be due to “herd immunity”. Herd immunity describes a type of immunity that occurs when the vaccination of a portion of the population (or herd) provides protection to unprotected individuals. According to WHO the estimated Herd Immunity Threshold for measles is 83%, that means that if 83% of a population is vaccinated or has immunisation, the spread of the disease is effectively stopped.