Normative data for the Vietnamese smell identification test

Tai Ngoc Tran; Thuong Huyen Thi Dang; Truc Thanh Thai; Uyen Le Ngoc Ha; Hien Thi Le; Thuy Thu Thi Nguyen; Hai Thi Nguyen; Anh Ngoc Thi Nguyen; Khang Chung Ngoc Vo; Thanh Vinh Nguyen; Thanh van Nguyen; Quang Xuan Ly; Khang Vinh Nguyen; Daniel Truong

doi:10.1016/j.prdoa.2023.100222

Normative data for the Vietnamese smell identification test

Clin Park Relat Disord. 2023 Oct 17:9:100222. doi: 10.1016/j.prdoa.2023.100222. eCollection 2023.

Authors

Affiliations

¹ Movement Disorder Unit, Neurology Department, University Medical Center, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam.
² Department of Medical Statistics and Informatics, Faculty of Public Health, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam.
³ ENT Department, University Medical Center, University of Medicine and Pharmacy at Ho Chi Minh City, Viet Nam.
⁴ The Parkinson and Movement Disorder Institute, Fountain Valley, CA 92708, USA.
⁵ Department of Psychiatry and Neuroscience, University of California Riverside, Riverside, CA, USA.

Abstract

Introduction: The 12-item Vietnamese smell identification test (VSIT) has been developed to evaluate the olfactory function of the Vietnamese population. This study aimed to investigate the normative value of the VSIT in different age groups and sexes.

Methods: This cross-sectional study was conducted at Ho Chi Minh University Medical Center, Vietnam. All participants were evaluated for odor identification ability using the VSIT. We included healthy participants aged 18 years or older with no history of olfactory disturbances.

Results: A total of 391 healthy volunteers were recruited with a mean age of 45.80 years (SD: 17.62; range: 18-86; female: 63.4 %). The tenth percentile of scores on the 0-12 VSIT scale was 8.3 in participants aged 18-29 years, 9.0 in 30-39 years, 8.0 in 40-49 years, 7.8 in 50-59 years, 7.9 in 60-69 years and 6.0 in over 70 years. Young adults (18-39 years old) had better olfactory identification ability than older adults (over 50 years), p < 0.001. There was a significant main effect of sex on VSIT score (p = 0.02), suggesting that females outperformed males. Sensitivity to 8 odors were negatively correlated with age: lemon, garlic, banana, coffee, mango, guava, apple and watermelon (p < 0.05 in all cases) whereas four odors were age-independent including orange, fish sauce, soy sauce, and fish.

Conclusion: Normative data provide guidance for assessing individual olfactory function. However, there were significant sex and age effects on olfactory identification scores on the VSIT. Therefore, future studies should be conducted to better adjust for those confounders mentioned above.

Keywords: Hyposmia; Normative data; Olfaction; Smell identification test.