Prevalence and risk factors of smell dysfunction - a comparison between five German population-based studies

BACKGROUND

The prevalence of olfactory impairment increases with age and is known to be an early sign of different neurodegenerative diseases. Only few population-based studies examined the prevalence of olfactory impairment and comparisons across studies are scarce. Aim of this analysis was to compare the prevalence and determinants of normosmia across five population based studies in Germany.

METHODOLOGY

Data from five population-based, cross-sectional studies were included. They were independently conducted and used the same test system (Sniffin' Sticks Screening 12) to measure olfactory function. This system consists of 12 odor-dispensing felt-tip pens; the task is a forced-choice selection among four alternative odors per pen. Sociodemographic information and comorbidities were assessed in face-to-face interviews. Univariate, descriptive statistics and multivariable logistic regression models stratified by study, were performed to determine risks, i.e. prevalence odds ratios, associated with olfactory function.

RESULTS

The prevalence of normosmic participants varied considerably across studies. Olfactory function was lower in men, decreased with age, and increased with higher education. Several individual comorbidities and a comorbidity index were associated with olfactory dysfunction. Recognition performance for three of the 12 pens was especially low in all studies.

CONCLUSION

Four factors, well known to describe population composition, contribute to explain differences in the prevalence of olfactory function between studies when the same test system is used. Our results indicate that comorbidities and educational level should always be considered when test systems based on smell recognition are used in population-based studies.

[Gene therapy in rheumatoid arthritis: new aspects]

Rheumatoid arthritis (RA) is a chronic and systemic inflammatory disease of unknown aetiology that is characterized by the progressive destruction of articular structures. The accumulation of inflammatory cells in the joint and the transformation of the healthy synovial membrane into a hyperplasic and aggressive pannus tissue constitute important steps in the pathology of RA. The synthesis and secretion of inflammatory factors such as cytokines and chemokines as well as the release of matrix degrading enzymes play a decisive role and have, therefore, become of interest for novel therapeutic strategies, among the gene therapy. This article summarizes the principles and current developments of gene therapy in RA and gives an overview about available vector systems and target genes.