Hearing loss is a major public problem with a heritability of up to 70%. Catechol-O-methyltransfe... more Hearing loss is a major public problem with a heritability of up to 70%. Catechol-O-methyltransferase (COMT) encodes an enzyme that is highly expressed in sensory hair cells of the inner ear. The association between COMT and hearing loss has not been reported previously in nationally representative population-based studies. A regression linear model was used to estimate associations between the allele/genotype of COMT and self-reported hearing loss based on 13,403 individuals from Wave IV of the Add Health study, a nationally representative sample of multiethnic U.S. young adults. The inverse variance-weighted effect magnitude was estimated using a genetic meta-analysis model. The “A” allele frequency of rs6480 (a missense variant in COMT) was 0.44. The prevalence of hearing loss was 7.9% for individuals with the “A” allele and 6.5% for those with the “G” allele. The “A” allele was significantly associated with increased hearing loss (p = 0.01). The prevalence of hearing loss was 6....
Objectives To assess the associations between smell function and adiposity and cardiometabolic me... more 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, 3527 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 ra...
NSCL1 is a basic helix-loop-helix transcription factor involved in the development of the nervous... more NSCL1 is a basic helix-loop-helix transcription factor involved in the development of the nervous system. To elucidate its role in neurogenesis, we cloned chick NSCL1 (cNSCL1) and examined its expression pattern and the effect of its misexpression on brain development. cNSCL1 was predominantly expressed during active neurogenesis. Double-labeling experiments showed that proliferating neuroblasts in the ventricular zone lacked cNSCL1 expression and cells expressing cNSCL1 were located just outside the ventricular zone. Retroviral misexpression of cNSCL1 in chick embryos produced a brain with abnormal structure. While the forebrain of the embryonic day-12 (E12) brain appeared normal, the tectum was enlarged. The enlargement was likely due to an increase in cell proliferation, since more radioactivity was detected in this region of the brain after [3H]thymidine labeling at E9. The cerebellum, on the other hand, was reduced in size. Fewer cells were labeled with BrdU in the external granule layer (a secondary germinal layer required for cerebellum development) in experimental embryos than in the controls, suggesting that misexpression of cNSCL1 might interfere with cell proliferation in the external granular layer. Our data indicate that regulated expression of cNSCL1 is required for normal brain development. They also imply that cNSCL1 might be involved in preventing some postmitotic cells from reentering the cell cycle during neurogenesis. Dev Dyn 1999;215:238-247.
Objectives To identify associations of self-reported olfactory dysfunction (OD) with attributes o... more Objectives To identify associations of self-reported olfactory dysfunction (OD) with attributes of diet quality in a nationally-representative sample of US adults. Methods In this cross-sectional study, we utilized self-reported taste and smell, and dietary data collected from participants 40 years and older (n = 6356) in the NHANES 2011–2014. In the home-interview, a taste and smell questionnaire asked about smell-related problems, treatments and related conditions. Dietary information was collected by trained dietary interviewers using an in-person 24-h dietary recall interview and an automated multi-pass method. Self-reported OD was based on 3 questions, and defined as affirmative response to either a smell problem in the last 12 months, worse ability to smell since age 25, or smelling phantom odors. Diet quality was assessed using the Healthy Eating Index 2015 (HEI-2015) and its adequacy and moderation components (higher scores indicating higher diet quality). Other qualitative ...
Precise identification of drinking and smoking patterns during pregnancy is crucial to better und... more Precise identification of drinking and smoking patterns during pregnancy is crucial to better understand the risk to the fetus. The purpose of this manuscript is to describe the methodological approach used to define prenatal drinking and smoking trajectories from a large prospective pregnancy cohort, and to describe maternal characteristics associated with different exposure patterns. In the Safe Passage Study, detailed information regarding quantity, frequency, and timing of exposure was self-reported up to four times during pregnancy and at 1 month post-delivery. Exposure trajectories were developed using data from 11,692 pregnancies (9912 women) where pregnancy outcome was known. Women were from three diverse populations: white (23%) and American Indian (17%) in the Northern Plains, US, and mixed ancestry (59%) in South Africa (other/not specified [1%]). Group-based trajectory modeling was used to identify 5 unique drinking trajectories (1 none/minimal, 2 quitting groups, 2 cont...
To study the prevalence and usefulness of audiometric notches in the diagnosis of noise-induced h... more To study the prevalence and usefulness of audiometric notches in the diagnosis of noise-induced hearing loss (NIHL). Audiograms and data on noise exposure from 23,297 men and 26,477 women, aged 20 to 101 years, from the Nord-Trøndelag Hearing Loss Study, 1996-1998. The prevalence of four types of audiometric notches (Coles, Hoffman, Wilson) and 4 kHz notch were computed in relation to occupational noise exposure, age, sex, and report of recurrent ear infections. The prevalence of notches in the 3 to 6 kHz range (Wilson, Hoffman, and Coles) ranged from 50% to 60% in subjects without occupational noise exposure, and 60% to 70% in the most occupationally noise-exposed men. The differences were statistically significant only for bilateral notches. For 4 kHz notches, the prevalence varied from 25% in occupationally nonexposed to 35% in the most occupationally exposed men, and the differences were statistically significant for both bilateral and unilateral notches. For women, the prevalen...
Reviews in Endocrine and Metabolic Disorders, 2016
The U.S. NHANES included chemosensory assessments in the 2011-2014 protocol. We provide an overvi... more The U.S. NHANES included chemosensory assessments in the 2011-2014 protocol. We provide an overview of this protocol and 2012 olfactory exam findings. Of the 1818 NHANES participants aged ≥40 years, 1281 (70.5 %) completed the exam; non-participation mostly was due to time constraints. Health technicians administered an 8-item, forced-choice, odor identification task scored as normosmic (6-8 odors identified correctly) versus olfactory dysfunction, including hyposmic (4-5 correct) and anosmic/severe hyposmic (0-3 correct). Interviewers recorded self-reported smell alterations (during past year, since age 25, phantosmia), histories of sinonasal problems, xerostomia, dental extractions, head or facial trauma, and chemosensory-related treatment and changes in quality of life. Olfactory dysfunction was found in 12.4 % (13.3 million adults; 55 % males/45 % females) including 3.2 % anosmic/severe hyposmic (3.4 million; 74 % males/26 % females). Selected age-specific prevalences were 4.2 % (40-49 years), 12.7 % (60-69 years), and 39.4 % (80+ years). Among adults ≥70 years, misidentification rates for warning odors were 20.3 % for smoke and 31.3 % for natural gas. The highest sensitivity (correctly identifying dysfunction) and specificity (correctly identifying normosmia) of self-reported olfactory alteration was among anosmics/severe hyposmics (54.4 % and 78.1 %, respectively). In age- and sex-adjusted logistic regression analysis, risk factors of olfactory dysfunction were racial/ethnic minority, income-to-poverty ratio ≤ 1.1, education <high school, and heavy drinking. Moderate-to-vigorous physical activity reduced risk of impairment. Olfactory dysfunction is prevalent, particularly among older adults. Inexpensive, brief odor identification tests coupled with questions (smell problems past year, since age 25, phantosmia) could screen for marked dysfunction. Healthcare providers should be prepared to offer education on non-olfactory avoidance of hazardous events.
To investigate whether and how the basic helix-loop-helix (bHLH) gene cNSCL2 is involved in retin... more To investigate whether and how the basic helix-loop-helix (bHLH) gene cNSCL2 is involved in retinal development. cNSCL2, the chick homologue of human NSCL2, was isolated and sequenced. In situ hybridization was used to examine its spatial and temporal expression pattern in the retina. Replication-competent retrovirus RCAS was used to drive cNSCL2 misexpression in the developing chick retina, and the effect of the misexpression was analyzed. Expression of cNSCL2 in the retina was restricted. Its mRNA was detected in amacrine and horizontal cells, but not in photoreceptor, bipolar, or ganglion cells. Retroviral-driven misexpression of cNSCL2 in the developing chick retina resulted in missing photoreceptor cells and gross deficits in the outer nuclear layer (ONL). These deficits were probably not because of decreased photoreceptor production, in that the ONL appeared normal in early developmental stages. TUNEL+ cells were detected in the ONL, indicating that photoreceptor cells underwe...
Background: The 2008 National Health Interview Survey (NHIS) Balance and Dizziness Supplement is ... more Background: The 2008 National Health Interview Survey (NHIS) Balance and Dizziness Supplement is the first household survey of United States civilian, non-institutionalized adults (ages 18+) to include extensive coverage of disturbances in balance and vestibular function. Objective: To investigate associations between dizziness/imbalance and chronic health conditions with falling risk during the past year. Methods: Respondents (N=21,781) were asked about dizziness/imbalance (DI) symptoms, use of balance aids, physical and psychological problems, health care utilization and outcomes. Characteristics of frequent fallers (FF) who reported falling at least once a month were compared to those falling less (FL) often and those that did not fall (NF). Results: Annual DI symptom prevalence was 14.8% (33.4 million adults); higher for women, 18.3%, than men, 11.1%. DI was associated with ages 65+ (OR=2.03, CI=1.802.29), females (OR=1.79, CI=1.621.96), non-Hispanic whites (OR=1.43, CI=1.281.61...
Hearing loss is a major public problem with a heritability of up to 70%. Catechol-O-methyltransfe... more Hearing loss is a major public problem with a heritability of up to 70%. Catechol-O-methyltransferase (COMT) encodes an enzyme that is highly expressed in sensory hair cells of the inner ear. The association between COMT and hearing loss has not been reported previously in nationally representative population-based studies. A regression linear model was used to estimate associations between the allele/genotype of COMT and self-reported hearing loss based on 13,403 individuals from Wave IV of the Add Health study, a nationally representative sample of multiethnic U.S. young adults. The inverse variance-weighted effect magnitude was estimated using a genetic meta-analysis model. The “A” allele frequency of rs6480 (a missense variant in COMT) was 0.44. The prevalence of hearing loss was 7.9% for individuals with the “A” allele and 6.5% for those with the “G” allele. The “A” allele was significantly associated with increased hearing loss (p = 0.01). The prevalence of hearing loss was 6....
Objectives To assess the associations between smell function and adiposity and cardiometabolic me... more 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, 3527 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 ra...
NSCL1 is a basic helix-loop-helix transcription factor involved in the development of the nervous... more NSCL1 is a basic helix-loop-helix transcription factor involved in the development of the nervous system. To elucidate its role in neurogenesis, we cloned chick NSCL1 (cNSCL1) and examined its expression pattern and the effect of its misexpression on brain development. cNSCL1 was predominantly expressed during active neurogenesis. Double-labeling experiments showed that proliferating neuroblasts in the ventricular zone lacked cNSCL1 expression and cells expressing cNSCL1 were located just outside the ventricular zone. Retroviral misexpression of cNSCL1 in chick embryos produced a brain with abnormal structure. While the forebrain of the embryonic day-12 (E12) brain appeared normal, the tectum was enlarged. The enlargement was likely due to an increase in cell proliferation, since more radioactivity was detected in this region of the brain after [3H]thymidine labeling at E9. The cerebellum, on the other hand, was reduced in size. Fewer cells were labeled with BrdU in the external granule layer (a secondary germinal layer required for cerebellum development) in experimental embryos than in the controls, suggesting that misexpression of cNSCL1 might interfere with cell proliferation in the external granular layer. Our data indicate that regulated expression of cNSCL1 is required for normal brain development. They also imply that cNSCL1 might be involved in preventing some postmitotic cells from reentering the cell cycle during neurogenesis. Dev Dyn 1999;215:238-247.
Objectives To identify associations of self-reported olfactory dysfunction (OD) with attributes o... more Objectives To identify associations of self-reported olfactory dysfunction (OD) with attributes of diet quality in a nationally-representative sample of US adults. Methods In this cross-sectional study, we utilized self-reported taste and smell, and dietary data collected from participants 40 years and older (n = 6356) in the NHANES 2011–2014. In the home-interview, a taste and smell questionnaire asked about smell-related problems, treatments and related conditions. Dietary information was collected by trained dietary interviewers using an in-person 24-h dietary recall interview and an automated multi-pass method. Self-reported OD was based on 3 questions, and defined as affirmative response to either a smell problem in the last 12 months, worse ability to smell since age 25, or smelling phantom odors. Diet quality was assessed using the Healthy Eating Index 2015 (HEI-2015) and its adequacy and moderation components (higher scores indicating higher diet quality). Other qualitative ...
Precise identification of drinking and smoking patterns during pregnancy is crucial to better und... more Precise identification of drinking and smoking patterns during pregnancy is crucial to better understand the risk to the fetus. The purpose of this manuscript is to describe the methodological approach used to define prenatal drinking and smoking trajectories from a large prospective pregnancy cohort, and to describe maternal characteristics associated with different exposure patterns. In the Safe Passage Study, detailed information regarding quantity, frequency, and timing of exposure was self-reported up to four times during pregnancy and at 1 month post-delivery. Exposure trajectories were developed using data from 11,692 pregnancies (9912 women) where pregnancy outcome was known. Women were from three diverse populations: white (23%) and American Indian (17%) in the Northern Plains, US, and mixed ancestry (59%) in South Africa (other/not specified [1%]). Group-based trajectory modeling was used to identify 5 unique drinking trajectories (1 none/minimal, 2 quitting groups, 2 cont...
To study the prevalence and usefulness of audiometric notches in the diagnosis of noise-induced h... more To study the prevalence and usefulness of audiometric notches in the diagnosis of noise-induced hearing loss (NIHL). Audiograms and data on noise exposure from 23,297 men and 26,477 women, aged 20 to 101 years, from the Nord-Trøndelag Hearing Loss Study, 1996-1998. The prevalence of four types of audiometric notches (Coles, Hoffman, Wilson) and 4 kHz notch were computed in relation to occupational noise exposure, age, sex, and report of recurrent ear infections. The prevalence of notches in the 3 to 6 kHz range (Wilson, Hoffman, and Coles) ranged from 50% to 60% in subjects without occupational noise exposure, and 60% to 70% in the most occupationally noise-exposed men. The differences were statistically significant only for bilateral notches. For 4 kHz notches, the prevalence varied from 25% in occupationally nonexposed to 35% in the most occupationally exposed men, and the differences were statistically significant for both bilateral and unilateral notches. For women, the prevalen...
Reviews in Endocrine and Metabolic Disorders, 2016
The U.S. NHANES included chemosensory assessments in the 2011-2014 protocol. We provide an overvi... more The U.S. NHANES included chemosensory assessments in the 2011-2014 protocol. We provide an overview of this protocol and 2012 olfactory exam findings. Of the 1818 NHANES participants aged ≥40 years, 1281 (70.5 %) completed the exam; non-participation mostly was due to time constraints. Health technicians administered an 8-item, forced-choice, odor identification task scored as normosmic (6-8 odors identified correctly) versus olfactory dysfunction, including hyposmic (4-5 correct) and anosmic/severe hyposmic (0-3 correct). Interviewers recorded self-reported smell alterations (during past year, since age 25, phantosmia), histories of sinonasal problems, xerostomia, dental extractions, head or facial trauma, and chemosensory-related treatment and changes in quality of life. Olfactory dysfunction was found in 12.4 % (13.3 million adults; 55 % males/45 % females) including 3.2 % anosmic/severe hyposmic (3.4 million; 74 % males/26 % females). Selected age-specific prevalences were 4.2 % (40-49 years), 12.7 % (60-69 years), and 39.4 % (80+ years). Among adults ≥70 years, misidentification rates for warning odors were 20.3 % for smoke and 31.3 % for natural gas. The highest sensitivity (correctly identifying dysfunction) and specificity (correctly identifying normosmia) of self-reported olfactory alteration was among anosmics/severe hyposmics (54.4 % and 78.1 %, respectively). In age- and sex-adjusted logistic regression analysis, risk factors of olfactory dysfunction were racial/ethnic minority, income-to-poverty ratio ≤ 1.1, education <high school, and heavy drinking. Moderate-to-vigorous physical activity reduced risk of impairment. Olfactory dysfunction is prevalent, particularly among older adults. Inexpensive, brief odor identification tests coupled with questions (smell problems past year, since age 25, phantosmia) could screen for marked dysfunction. Healthcare providers should be prepared to offer education on non-olfactory avoidance of hazardous events.
To investigate whether and how the basic helix-loop-helix (bHLH) gene cNSCL2 is involved in retin... more To investigate whether and how the basic helix-loop-helix (bHLH) gene cNSCL2 is involved in retinal development. cNSCL2, the chick homologue of human NSCL2, was isolated and sequenced. In situ hybridization was used to examine its spatial and temporal expression pattern in the retina. Replication-competent retrovirus RCAS was used to drive cNSCL2 misexpression in the developing chick retina, and the effect of the misexpression was analyzed. Expression of cNSCL2 in the retina was restricted. Its mRNA was detected in amacrine and horizontal cells, but not in photoreceptor, bipolar, or ganglion cells. Retroviral-driven misexpression of cNSCL2 in the developing chick retina resulted in missing photoreceptor cells and gross deficits in the outer nuclear layer (ONL). These deficits were probably not because of decreased photoreceptor production, in that the ONL appeared normal in early developmental stages. TUNEL+ cells were detected in the ONL, indicating that photoreceptor cells underwe...
Background: The 2008 National Health Interview Survey (NHIS) Balance and Dizziness Supplement is ... more Background: The 2008 National Health Interview Survey (NHIS) Balance and Dizziness Supplement is the first household survey of United States civilian, non-institutionalized adults (ages 18+) to include extensive coverage of disturbances in balance and vestibular function. Objective: To investigate associations between dizziness/imbalance and chronic health conditions with falling risk during the past year. Methods: Respondents (N=21,781) were asked about dizziness/imbalance (DI) symptoms, use of balance aids, physical and psychological problems, health care utilization and outcomes. Characteristics of frequent fallers (FF) who reported falling at least once a month were compared to those falling less (FL) often and those that did not fall (NF). Results: Annual DI symptom prevalence was 14.8% (33.4 million adults); higher for women, 18.3%, than men, 11.1%. DI was associated with ages 65+ (OR=2.03, CI=1.802.29), females (OR=1.79, CI=1.621.96), non-Hispanic whites (OR=1.43, CI=1.281.61...
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Papers by Chuan-Ming Li