Figures & data
Figure 1. Overview of the Betula project, showing the samples and test waves from which data were drawn for the different set of analyses.
![Figure 1. Overview of the Betula project, showing the samples and test waves from which data were drawn for the different set of analyses.](/cms/asset/bb747b03-4a91-4887-8b94-f79965fea7b4/cije_a_1973969_f0001_b.gif)
Table 1. Characteristics and background variables for the study samples used in the different analyses.
Table 2. Mean values and standard deviations for the outcome variables used in the different analyses.
Table 3. Estimated regression parameters (β) and 95% confidence intervals (95% CI) on odor identification and detection and rate of change of these scores over time. The fully adjusted model was adjusted for age, sex, education, APOE-ε4 status, and smoking habits. Rate of change is defined as the difference in test score from the participants' first test occasion. All models using rate of change as outcome variable were also adjusted for baseline performance (*p < 0.05, **p < 0.01, ***p < 0.001).
Data availability statement
Data from the Betula project cannot be made publicly available due to ethical and legal restrictions. However, access to these original data is available upon request from the corresponding author (J.A.) and after approval by the Steering Group of the Betula project (https://www.umu.se/en/betula). Access to data by qualified investigators is subject to scientific and ethical review and must comply with the European Union General Data Protection Regulations (GDPR)/all relevant guidelines. The completion of a data transfer agreement (DTA) signed by an institutional official will be required.