Olfaction and cardiovascular risk: a connection yet to be explored

Abstract

Introduction: Cardiovascular disease (CVD) is highly prevalent in the general population, especially in older age groups. Published studies associate loss of smell with comorbidities such as dyslipidemia, stroke, and heart failure. However, results are inconsistent, and the relationship between CVD and olfactory dysfunction remains unclear.
Objective: To evaluate the correlation between loss of smell, cardiovascular risk factors (CVRFs), and overall cardiovascular risk (CVR).
Material and methods: A retrospective study design, recruiting patients aged 40 years and older, observed on our Olfaction Clinic at a tertiary hospital between 2016 and 2024. CVRFs (sex, age, systolic blood pressure, total and HDL cholesterol, weight, height, smoking habits, and the presence of diabetes mellitus (DM)) were assessed. The degree of loss of smell was quantified using the Burghart Sniffin' Sticks Identification Test (0-16). CVR was calculated using the SCORE2, SCORE2-OP (patients >70 years), and SCORE2-DM (diabetic patients). A case-control study and correlation analysis between the identification score and the other variables were performed. The control group included age- and sex-matched individuals with no subjective loss of smell. Statistical analysis was performed using SPSS® 30.0 for MacOs.
Results: 119 patients were included (81 with changed sense of smell and 38 in the control group). The mean age was 61 ± 11 years, 79 were female; 16.8% had diabetes. The study group had a mean olfactory identification score of 8.4 ± 4 and a mean CVR of 7.7% ± 6%.Our results showed that our patients with olfactory dysfunction have significantly higher total cholesterol levels and a greater tendency to DM (p = 0.054), although this was not statistically significant. When subgroup analysis was applied and patients with smell loss due to sinonasal pathology were excluded, a statistically significant relationship was found between smell identification results and CVR (p = 0.031), as well as with total cholesterol (p = 0.044). No other statistically significant associations were found in the other variables evaluated.
Conclusion: This is the first study to explore the relationship between CVR and smell disorders in the Brazilian population. This study suggests an association between smell loss, elevated serum cholesterol, and increased CVR.