Factors associated with odour identification in older Indonesian and white Australian adults

Background and aims: Among older adults, olfactory dysfunction is associated with cognitive impairment, lower quality of life, and increased mortality. While age is a risk factor for olfactory dysfunction, other risk factors are less well understood, and may vary between ethno-regional groups. This study investigated how associations between odour identification (OI) and various risk factors, as well as cognition and language ability, differed or were similar in two distinct ethno-regional groups of older adults.

Methods: This cross-sectional study used data from two cohorts: 470 Indonesians (aged 67.4 ± 7.4 years) and 819 white Australians (aged 78.7 ± 4.8 years). Univariate and multivariate analyses explored whether OI test scores were associated with age, sex, education, cholesterol levels, apolipoprotein E ε4 status, smoking, diabetes, hypertension and depression scale scores, or with Mini-Mental State Examination (MMSE) and language test performance.

Results: Univariate analyses identified some factors associated with OI scores in both Indonesians and white Australians, including older age and smoking with lower scores, and MMSE and language test performance with higher scores. Multivariate analyses yielded different and mutually exclusive patterns of associations in the two ethno-regional groups, with language test scores significantly associated with higher OI scores in Indonesians, and age, being male, smoking, having diabetes and higher depression scale scores significantly associated with lower OI scores in white Australians.

Conclusion: Ethno-regional differences may need consideration in the attempt to fully understand associations between OI and negative outcomes like dementia and mortality, and interventions for olfactory dysfunction might need to be tailored to specific ethno-regional groups. However, the difference in mean age between cohorts is a limitation of this study, and future studies should aim to compare populations with similar age distributions.