Neurofilament light chain is associated with olfactory dysfunction in US adults: findings from National Health and Nutrition Examination Survey. Rhinology BACKGROUND:Many individuals who have olfactory dysfunction are not aware of their impairment, which results in delayed detection of potentially hazardous situations. Simple and accurate methods for objectively assessing olfactory function are needed. In this study, we aim to investigate the utility of serum neurofilament light chain (NfL) levels as an indicator of olfactory dysfunction. METHODOLOGY:We analysed data on 1290 participants aged 40 years and older, who had valid data on olfaction and NfL level from the National Health and Nutrition Examination Survey 2013â€"2014. Multivariable modeling was used to investigate the relationship between olfactory dysfunction and NfL. RESULTS:Among 1290 participants, 174 participants had olfactory dysfunction based on the results of the NHANES Pocket Smell Test. In ordinal regression models, objective olfactory dysfunction was associated with NfL. After adjusting for age, sex, race/ethnicity, diabetes, smoking, olfaction-related medical history, Parkinson's disease and Alzheimer’s disease, the association remained significant. In logistic regression models, compared to participants with lower levels of NfL in the first tertile, those in the second and third tertiles had higher odds of objective olfactory dysfunction. There was no association between self-reported olfactory dysfunction and NfL tertiles. CONCLUSIONS:A strong association between objective olfactory dysfunction and serum NfL level was observed. NfL, independent of age, is a reliable marker indicating the development of olfactory dysfunction. The measurement of serum NfL level provides valuable support for assessment of olfactory dysfunction in clinical practice. 10.4193/Rhin24.001

Relationship between longer sleep and serum neurofilament light chain in american adults: evidence from the 2013-2014 US national health and nutrition examination survey. BMC public health BACKGROUND:Sleep disturbance is linked to neurodegenerative diseases and the related brain pathophysiology. Serum neurofilament light chain (NfL) is a reliable biomarker for neurological disorders. This study examined the association between sleep characteristics and serum NfL levels in American adults. METHODS:In this cross-sectional study, data from the 2013-2014 US National Health and Nutrition Examination Survey were utilized. Participants were categorized into short (≤ 6 h), normal (7-8 h), and long (≥ 9 h) sleep groups based on their self-reported sleep durations. Sleep duration, trouble sleeping, and diagnosed sleep disorders were queried, forming "sleep pattern (healthy, moderate, and poor)." The association between sleep characteristics and serum NfL levels was assessed using multivariate linear regression models. Stratification and sensitivity analyses were conducted to determine the stability of results. RESULTS:Overall, 1637 participants were included; among them, 48.2% were male and 51.8% were female (mean ± SD, age: 46.9 ± 15.5 years) and 38.8% reported sleeping for ≤ 6 h, 54.4% for 7-8 h, and 6.8% for ≥ 9 h. Participants with longer sleep duration, poor sleep pattern, diagnosed sleep disorders, or trouble sleeping exhibited higher serum NfL levels. A positive correlation was found between extended sleep and elevated serum NfL levels (Adjusted β = 4.82, 95%CI: 2.2, 7.44, P < 0.001), with no significant correlation observed in the short-sleep group or those with poor sleep pattern. Stratified and sensitivity analyses confirmed the robustness of the relationship between longer sleep and elevated serum NfL levels. CONCLUSIONS:A long sleep duration is associated with higher serum NfL levels than a normal sleep duration in American adults. 10.1186/s12889-024-20184-7

Dietary vitamin K intake is associated with decreased neurofilament light chain among middle-aged and older adults from the NHANES. Frontiers in nutrition Purpose:Neurofilament-light chain (NfL) is associated with neurodegenerative diseases, which are increasingly prevalent with aging. Vitamin K has been shown a neuroprotective effect. Therefore, we aimed to explore the potential relationship between dietary vitamin K intake and serum NfL. Methods:This study was conducted on the 2013-2014 cycles of the National Health and Nutrition Examination Survey, a multi-site population-based study of the US general population. Serum NfL level was measured using a highly sensitive immunoassay. Dietary vitamin K intake was estimated from two-day dietary recall interviews, and its relationship with NfL was determined using linear regression models. Results:The study included a total of 1,533 participants with a median age of 46 years, comprising 801 women (52.2%) and 732 men (47.8%). The median dietary intake of vitamin K was 81.6 μg/d, and the median serum NfL was 12 pg./mL. After adjusting for potential confounding factors in the full model, individuals with higher dietary vitamin K intake had lower serum NfL levels (Q4 vs. Q1,  = -4.92, 95%CI: -7.66, -2.19, 0.002). A non-linear negative dose-response association is found between dietary vitamin K intake and serum NfL levels ( for non-linearity = 0.008); this association reaches a plateau when the dietary vitamin K intake is higher than 200 μg/d. According to the results of stratified analysis, the relationship between dietary vitamin K intake and serum NfL levels was stronger in the population of middle-aged and older adults. Conclusion:The present study suggested a negative association between dietary vitamin K intake and serum NfL levels in the general US population, especially in middle-aged and older adults. This study might offer a novel nutritional idea for the primary prevention and mechanism exploration of neurodegenerative diseases. 10.3389/fnut.2024.1396707

Serum neurofilament light chain levels are associated with depression among US adults: a cross-sectional analysis among US adults, 2013-2014. BMC psychiatry BACKGROUND:Serum neurofilament light chain (sNfL) has been identified as a biomarker for neurologic diseases. However, sNfL remains unknown to be responsible for depression. AIMS:The aim of this research was to explore the relationship between sNfL levels and depression in US adults. METHODS:In this cross-sectional survey of the general population, we investigated representative data involving 10,175 participants from the 2013-2014 cycle of the National Health and Nutrition Examination Survey (NHANES). Depression was diagnosed using the Patient Health Questionnaire-9 (PHQ-9). The effect of related factors on depression was analyzed by conducting a univariate analysis. Stratified analysis was utilized to detect the stability and sensitivity of the relationship. After adjusting for race, education, marital status, smoking status, body mass index (BMI), sleep duration, income, and a history of hypertension, sedentary behavior and stroke, multivariable linear regression was performed to demonstrate the correlation between sNfL and depression. RESULTS:A total of 1301 individuals between the ages of 20 and 75 were involved in this investigation, of which 108 (8.3%) were diagnosed with depression. A significant positive correlation between sNfL and depression among adults in the US was observed by conducting univariable analyses. After adjusting for confounding factors, the multivariate analyses indicated that elevated sNfL levels might play a pivotal role in the development of depression (odds ratio (OR) = 3.0; 95% confidence interval (CI): (1.5, 6.1), P = 0.002). CONCLUSION:These results indicated that sNfL is closely linked to depression in a nationally representative individual. However, further studies are needed to confirm the biological mechanism as well as the clinical implications of sNfL and depression. 10.1186/s12888-024-05964-0