The Effect of Ethnicity on Human Axillary Odorant Production

Abstract

Previous findings from our laboratory highlighted marked ethnic differences in volatile organic compounds (VOCs) from cerumen among individuals of Caucasian, East Asian, and African-American descent, based, in part, on genetic differences in a gene that codes for a transport protein, which is a member of the ATP-binding cassette transporter, sub-family C, member 11 (ABCC11). In the current work, we hypothesized that axillary odorants produced by East Asians would differ markedly from those obtained from individuals of European or African descent based on the pattern of ethnic diversity that exists in ABCC11. Using gas chromatography/mass spectrometry (GC/MS) we examined differences in axillary odorant VOCs among 30 individuals of African-American, Caucasian, and East Asian descent with respect to their ABCC11 genotype. While no qualitative differences in the type of axillary odorants were observed across ethnic groups, we found that characteristic axillary odorants varied quantitatively with respect to ethnic origin. We propose that ABCC11 is not solely responsible for predicting the relative amounts of volatiles found in axillary secretions and that other biochemical pathways must be involved.

Keywords: Analytical chemistry; Axillary odor; Ethnicity/race; Genetics; Volatile organic compounds.

Fig. 1

ABCC11 genotype (rs17822931) of 30 male donors with respect to ethnicity/race.

Fig. 2

Comparison of short-chain volatile acids detected in axillary sweat samples collected from East Asian, Caucasian, and African-American donors. Variation across the three donor groups was nearly significant (F_(16,42) = 1.76, P = 0.07).

Fig. 3

a 3-Methyl-2-hexenoic acid (3M2H) comparison revealing significant differences (P = 0.009, Kruskal-Wallis test) in the relative amounts of the characteristic axillary odorant, E-3M2H, among the three donor groups (also, see text for a significant interaction generated by a repeated measures ANOVA). b Comparison of 7- and 2-octenoic acid detected in axillary sweat samples from East Asian, Caucasian, and African-American donors. For 7-octenoic acid, differences in the distributions across the three groups of donors was suggestive (Jonckheere-Terpstra test for ordered alternatives; P = 0.065; across the three groups, this test has more statistical power than the Kruskal–Wallis test).

Fig. 3

a 3-Methyl-2-hexenoic acid (3M2H) comparison revealing significant differences (P = 0.009, Kruskal-Wallis test) in the relative amounts of the characteristic axillary odorant, E-3M2H, among the three donor groups (also, see text for a significant interaction generated by a repeated measures ANOVA). b Comparison of 7- and 2-octenoic acid detected in axillary sweat samples from East Asian, Caucasian, and African-American donors. For 7-octenoic acid, differences in the distributions across the three groups of donors was suggestive (Jonckheere-Terpstra test for ordered alternatives; P = 0.065; across the three groups, this test has more statistical power than the Kruskal–Wallis test).

Fig. 4

Percentage of donors from whom 3H3M was detected in axillary secretions. Chi Square analysis revealed a significant difference across groups (Χ² = 10.05, P = 0.007).