Aging and Chronic Disease
Objectives : To assess the associations between smell function and adiposity and cardiometabolic measures in a nationally representative sample of US adults.
Methods : In the 2013-2014 NHANES, 3,527 adults ≥40 years, completed the NHANES Taste and Smell Exam. Smell function was assessed with an 8-item odor identification test. Participants smelled and identified each odorant by selecting one of four descriptors. Smell impairment was defined as incorrect identification of ≥3 (of 8) odors. Survey-weighted linear regression models estimated cross-sectional associations of smell function with adiposity (body mass index (BMI), waist circumference (WC)) and cardiometabolic measures (total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, fasting plasma glucose (FPG), and systolic (SBP) and diastolic blood pressure (DBP)). Models were adjusted for age, race, education, physical activity, self-reported health status, smoking history, and income-poverty ratio, and stratified by sex and age group (40-64 years vs. ≥65 years).
Results : In US adults ≥40 years, smell function was significantly associated with several adiposity and cardiometabolic measures in adjusted models, with significant interactions by sex and age. Compared to normal smell, smell impairment was significantly associated with higher BMI [β= 3.0; 95% CI: 0.6, 5.4)] and WC [β= 5.0; 95% CI: 0.3, 9.8] among women < 65 years; conversely among men ≥ 65 years, smell impairment associated with lower BMI [β= -1.6; 95% CI: -3.2, -0.01)]. In adults < 65 years, smell impairment was associated with lower FPG [β= -7.9; 95% CI: -13.0, -2.6] and triglyceride levels [β= -27.0; 95% CI: -51.0, -3.7], but this was only significant among men. In older men (≥65 years), smell impairment was positively associated with higher total cholesterol [β= 12.8; 95% CI: 7.4, 18.1] and LDL [β= 18.1; 95% CI: 9.1, 27.2] ; among older women however, smell impairment was inversely associated with both total [β= -15.0; 95% CI: -25.0, -5.7] and LDL cholesterol [β =-12.0; 95% CI: -25.0, 1.2)], and positively associated with FPG [β= 15.6; 95% CI:1.5, 29.7]. No significant associations were observed with SBP or DBP.
In adults ≥40 years, smell impairment is associated with adiposity measures, and glucose and lipid levels, with differential associations by age and sex.
Funding Sources : Rutgers University, NJ