By Loretta Waldman
The importance of smell and taste is underappreciated, according to Valerie Duffy, Professor of Allied Health Sciences and InCHIP Principal Investigator. These senses enable us to detect pleasurable and unpleasant aromas as well as warning odors, such as the smell of natural gas. They also trigger specific memories and emotions, and drive what we like and choose to eat. These “forgotten” senses play significant roles in our lives, which is why Dr. Duffy was so excited about the addition of a chemosensory component to the National Health and Nutrition Examination Survey (NHANES) protocol.
NHANES is a survey research program conducted by CDC’s National Center for Health Statistics (NCHS), which assesses the health and nutritional status of adults and children in the United States and tracks changes over time. The very first NHANES protocol was conducted in 1971, and it has been administered annually since 1999. It is the primary way that researchers monitor the health of the U.S. population, including the prevalence of major diseases and risk factors for diseases.
The 2011-2014 NHANES was the first battery of assessments in which taste and smell assessments were included, and this change is due in large part to the efforts of Dr. Duffy and her team: former UConn graduate student Shristi Rawal, PhD at National Institute of Child Health and Human Development (NICHD), and Howard Hoffman, MA at National Institute on Deafness and other Communication Disorders (NIDCD). The addition of chemosensory assessments to the NHANES has created new opportunities for data collection and analysis, such as estimating the prevalence and risks of smell and taste alterations, and the associations between smell and taste perception and a wide range of measures of health and well-being.
Over the last year, Dr. Duffy and her team have published articles using the data from the NHANES survey, including a paper published in Reviews of Endocrine and Metabolic Disorders that provides an overview of the NHANES taste and smell protocol and reports on the first results from the 2012 NHANES olfactory exam findings, including the prevalence of olfactory dysfunction. The 2012 NHANES involved the collection of questionnaire and clinical measures from a nationally-representative sample of the non-institutionalized, civilian U.S. population. The sample for Duffy’s olfactory study consisted of 1281 adults, aged 40 years and over, who completed the 8-item odor identification test (Pocket Smell Test or PST) along with the Chemosensory Questionnaire (CSQ), which assesses perceived smell and taste problems. Olfactory dysfunction was found in 12.4% (55% males/45% females) of participants, including 4.2% of 40- to 49-year-olds, 12.7% of 60- to 69-year-olds, and 39.4% of those 80 years and older. Among adults aged 70 years and older, misidentification rates for warning odors were 20.3% for smoke and 31.3% for natural gas. “For the first time, we have evidence of smell impairment that is equal to vision and hearing,” stated Dr. Duffy. “When we have over 30% of people over 70 who can’t smell a natural gas warning odor, it’s a problem. This new knowledge supports the need for advances in public health, clinical care, and research to address smell impairment in health promotion and disease prevention efforts.”
The taste measure used in the NHANES survey was developed by Dr. Duffy after many years of collecting data in her lab at UConn. She recently published a paper in the journal Obesity, where she used that measure, among others, to model associations between taste and obesity among women with self-reported histories of risks factors for altered taste functioning: tonsillectomy, multiple ear infections, and head trauma. There is evidence from other studies that certain health conditions may lead to taste damage which in turn may alter food preferences and increase the risk for obesity. Dr. Duffy wanted to try to better understand this relationship, so she studied a sample of 407 women, 24% of whom had elevated waist circumferences, and 39% had overweight or obesity. Dr. Duffy and her colleagues, Dr. Rawal, Mr. Hoffman, and InCHIP researcher Tania Huedo-Medina, PhD (Allied Health Sciences) found that abdominal obesity was directly linked with a history of tonsillectomy and multiple ear infections and also directly linked with lower taste functioning. In addition, risk factors for taste alterations were significantly associated with lower taste functioning, with taste mediating the association between head trauma and reduced body fat. Dr. Duffy intends to confirm these findings with other population-based studies, including the National Health and Nutrition Examination Survey 2013-2014 taste data.