# Interaction Between Smoking and Olfactory Function on Frailty: A Population‐Based Cross‐Sectional Study

## TL;DR

Smoking and poor sense of smell together increase the risk of frailty in older adults more than either factor alone.

## Contribution

This study reveals a synergistic interaction between smoking and olfactory dysfunction in increasing frailty risk.

## Key findings

- Smoking and altered olfactory function are independently linked to higher frailty risk.
- The combination of smoking and olfactory dysfunction leads to the highest odds of frailty.
- Sensory screening and behavioral risk assessment are important for early frailty detection in smokers.

## Abstract

Frailty is a multidimensional syndrome characterized by decreased physiological reserves and is closely associated with aging‐related adverse outcomes. Although smoking and olfactory dysfunction are individually associated with frailty, their potential interactions have not been thoroughly investigated.

We used data from the National Health and Nutrition Examination Survey (NHANES) 2011–2014, which included 5192 participants. Smoking status and self‐reported olfactory function were assessed using standardized questionnaires. Frailty was defined using a 36‐item Frailty Index (FI), with FI > 0.2 indicating frailty. Multivariate logistic regression models were used to examine the independent and joint associations of smoking and olfactory function with frailty, after adjusting for demographic and lifestyle covariates. Interaction and stratified analyses were also performed.

Current smoking status and altered olfactory function were independently associated with an increased risk of frailty. In fully adjusted models, nonsmokers had a lower odds of frailty compared with smokers (odds ratio [OR] = 0.41, 95% confidence interval [CI]: 0.29–0.58), and participants with normal olfactory function had a lower odds of frailty than those with altered olfactory function (OR = 0.57, 95% CI: 0.48–0.69). A significant interaction was observed between smoking and olfactory function (P interaction = 0.001). The highest odds of frailty were found in participants who smoked and had altered olfactory function (OR = 2.49, 95% CI: 1.88–3.31).

Our findings revealed a synergistic association between smoking, altered olfactory function, and frailty risk. This interaction in relation to the healthcare of older people highlights the importance of sensory screening and behavioral risk assessment in the early identification of frailty, especially in smokers.

Smoking and altered olfactory function were independently associated with an increased risk of frailty.A significant interaction was observed between smoking and olfactory function, suggesting a stronger effect of olfactory alterations on the frailty risk among smokers than among nonsmokers.Participants with both risk factors—altered olfactory function and current smoking—had the highest likelihood of frailty.

Smoking and altered olfactory function were independently associated with an increased risk of frailty.

A significant interaction was observed between smoking and olfactory function, suggesting a stronger effect of olfactory alterations on the frailty risk among smokers than among nonsmokers.

Participants with both risk factors—altered olfactory function and current smoking—had the highest likelihood of frailty.

With regards to the healthcare of older people, the interaction between smoking and altered olfactory function highlights the importance of sensory screening and behavioral risk assessment in the early identification of frailty, especially in smokers.