Quantitative measurement of odor detection thresholds using an air dilution olfactometer, and association with genetic variants in a sample of diverse ancestry

Anthropology, University of Toronto, Toronto, Canada
Anthropology, University of Toronto, Mississauga, Canada
DOI
10.7287/peerj.preprints.529v1
Subject Areas
Anthropology, Evolutionary Studies, Genetics
Keywords
Scentroid SM110C, olfactory detection threshold, general olfactory sensitivity (GOS), genetic association, genetic marker.
Copyright
© 2014 Cook et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Cook GR, Krithika S, Edwards M, Kavanagh P, Parra EJ. 2014. Quantitative measurement of odor detection thresholds using an air dilution olfactometer, and association with genetic variants in a sample of diverse ancestry. PeerJ PrePrints 2:e529v1

Abstract

Genetic association studies require a quantitative and reliable method for odor threshold assessment in order to examine the contribution of genetic variants to complex olfactory phenotypes. Our main goal was to assess the feasibility of a portable Scentroid air dilution olfactometer for use in such studies. Using the Scentroid SM110C and the SK5 n-butanol Sensitivity Kit (IDES Canada Inc.), n-butanol odor thresholds were determined for 182 individuals of diverse ancestry (mean age: 20.4 ± 2.5 years; n = 128 female; n = 54 male). Threshold scores from repeat participants were used to calculate a test-retest reliability coefficient, which was statistically significant (r = 0.754, p < 0.001, n = 29), indicating that the Scentroid provides reliable estimates of odor thresholds. In addition, we performed a preliminary genetic analysis evaluating the potential association of n-butanol odor thresholds to six single-nucleotide polymorphisms (SNPs) putatively involved in general olfactory sensitivity (GOS). The results of multiple linear regression analysis revealed no significant association between the SNPs tested and threshold scores. However, our sample size was relatively small, and our study was only powered to identify genetic markers with strong effects on olfactory sensitivity. Overall, we find that the Scentroid provides reliable quantitative measures of odor detection threshold and is well suited for genetic studies of olfactory sensitivity.

Author Comment

This submission has been accepted for publication in PeerJ.

Supplemental Information

Comparison of n-butanol olfactory threshold score distributions for participants of East Asian, European and South Asian ancestry (n = 60, 55 and 58, respectively)

DOI: 10.7287/peerj.preprints.529v1/supp-2

Power analysis results in a range of beta (ppb) values and allele frequencies for the genetic association testing of SNPs and olfactory sensitivity, assuming an additive model

DOI: 10.7287/peerj.preprints.529v1/supp-3