Associations of olfactory dysfunction with anthropometric and cardiometabolic measures: Findings from the 2013-2014 national health and nutrition examination survey (NHANES)

We examined associations of olfactory dysfunction with anthropometric and cardiometabolic measures in a nationally representative sample of US adults. In the 2013-2014 National Health and Nutrition Examination Survey (NHANES), 3,815 participants, 40 years and older, completed a standardized taste and smell protocol, which consisted of an 8-item odor identification test and a chemosensory questionnaire. Measured dysfunction was incorrect identification of >= 3 of 8 odors; self-reported dysfunction was affirmative response to either a recent smell problem, worse ability since age 25, or phantosmia. Survey-weighted linear regression models tested associations of olfactory dysfunction with body mass index (BMI), waist circumference (WC), blood pressure, serum total cholesterol (TC) with fractions, triglycerides, and glucose levels. Models were adjusted for age, race, education, physical activity, self-reported general health condition, smoking history, and income-to-poverty ratio, stratifying by sex and age group (middle-age 40-64 years; older >= 65 years). Relative to normal, measured olfactory dysfunction was associated with lower BMI [beta = -1.6 (95% CI: -3.2, -0.01)] in older men. In middle-age women, dysfunction was associated with higher BMI and WC, whether assessed by examination [beta's for BMI = 3.1 (0.6, 5.5), WC = 5.0 (0.3, 9.8)] or self-report [beta's for BMI = 2.5 (0.6, 4.3), WC = 6.1 (2.2, 9.9)]. Measured dysfunction was associated with significantly higher TC [beta = 12.8 (7.5, 18.1)] and LDL [beta = 18.1 (9.1, 27.2)] among older men, but significantly lower TC [beta = -15.0 (-25.0, -5.7)] and marginally lower LDL [beta = -12.0 (-25.0, 1.2)] among older women. Between measured dysfunction and fasting glucose, the association was inverse [beta = -7.9 (-13.0, -2.6)] among middle-age men, but positive [beta = 15.6 (1.5, 29.7)] among older women. No significant associations were observed with blood pressure levels. In conclusion, among US adults >= 40 years, olfactory dysfunction is associated with anthropometric and glucose and lipid levels, with associations varying by sex and age group.