Association between Caffeine Consumption and Depression in NHANES 2009-2010

Background and Purpose: Caffeine is ubiquitous in foods, supplements, and medications and has been hypothesized to be associated with several health-related outcomes, including mental health disorders such as anxiety. We explored a possible relationship between caffeine consumption and depression using data from the National Health and Nutrition Examination Survey (NHANES). Methods: Data from 1,342 adult NHANES participants were included. Statistical software for complex survey sample designs was used to perform two multivariable logistic regressions with a binary indicator of depression as the dependent variable: one using dietary caffeine consumption and one using the caffeine metabolite AAMU as the independent variable. Both analyses were adjusted for gender, race/ethnicity, smoking status, and use of anti-depressants. Results: We observed a descriptive, albeit non-significant (p = 0.12), pattern of increasing odds of depression with increasing levels of the AAMU caffeine metabolite. Conclusion: Our finding of a possible association between caffeine metabolite level and depression is compelling because it is independent of self-reported caffeine consumption. Prospective studies are warranted to further explore the temporal relationship

Association between Total Folate Intakes and Depression amongst Three Racial/Ethnic Groups

Background and Purpose: Low dietary folate intake has been associated with depression outcomes, but few studies have been reported on the association in diverse populations. Using data from the National Health and Nutrition Examination Survey (NHANES), we examined the relationship between depression and folate intake from diet and supplementation in non-Hispanic whites, Hispanics and African Americans. Methods: 3,687 adult respondents from the 2009-2010 NHANES cycle were included. Statistical methods for analyzing data from complex survey sample designs were used to assess differences by race/ethnicity in demographic, behavioral, dietary and depression variables and to assess the relationship between depression and folate, adjusting for confounding variables using multivariable logistic regression. Results: We observed significant (p < 0.01) differences by race/ethnicity for all demographic, behavioral, dietary and depression variables, except for physical activity. The relationship between dietary folate and depression significantly differed by race/ethnicity (p = 0.03), with an inverse and significant association in Hispanics only (OR= 0.25; 95% CI= 0.09 – 0.70.; p for trend = 0.02). Conclusion: These data suggest that a diet high in folate, such as from dark green leafy vegetables, may be associated with a reduced odds for depression, and specifically, Hispanics may benefit from nutrition education to potentially reduce depression in the population

Loops versus lines and the compression stiffening of cells

Both animal and plant tissue exhibit a nonlinear rheological phenomenon known as compression stiffening, or an increase in moduli with increasing uniaxial compressive strain. Does such a phenomenon exist in single cells, which are the building blocks of tissues? One expects an individual cell to compression soften since the semiflexible biopolymer-based cytoskeletal network maintains the mechanical integrity of the cell and in vitro semiflexible biopolymer networks typically compression soften. To the contrary, we find that mouse embryonic fibroblasts (mEFs) compression stiffen under uniaxial compression via atomic force microscopy (AFM) studies. To understand this finding, we uncover several potential mechanisms for compression stiffening. First, we study a single semiflexible polymer loop modeling the actomyosin cortex enclosing a viscous medium modeled as an incompressible fluid. Second, we study a two-dimensional semiflexible polymer/fiber network interspersed with area-conserving loops, which are a proxy for vesicles and fluid-based organelles. Third, we study two-dimensional fiber networks with angular-constraining crosslinks, i.e. semiflexible loops on the mesh scale. In the latter two cases, the loops act as geometric constraints on the fiber network to help stiffen it via increased angular interactions. We find that the single semiflexible polymer loop model agrees well with our AFM experiments until approximately 35% compressive strain. We also find for the fiber network with area-conserving loops model that the stress-strain curves are sensitive to the packing fraction and size distribution of the area-conserving loops, thereby creating a mechanical fingerprint across different cell types. Finally, we make comparisons between this model and experiments on fibrin networks interlaced with beads as well as discuss the tissue-scale implications of cellular compression stiffening.Comment: 19 pages, 17 figure

High fluoride and low calcium levels in drinking water is associated with low bone mass, reduced bone quality and fragility fractures in sheep

SUMMARY: Chronic environmental fluoride exposure under calcium stress causes fragility fractures due to osteoporosis and bone quality deterioration, at least in sheep. Proof of skeletal fluorosis, presenting without increased bone density, calls for a review of fracture incidence in areas with fluoridated groundwater, including an analysis of patients with low bone mass. INTRODUCTION: Understanding the skeletal effects of environmental fluoride exposure especially under calcium stress remains an unmet need of critical importance. Therefore, we studied the skeletal phenotype of sheep chronically exposed to highly fluoridated water in the Kalahari Desert, where livestock is known to present with fragility fractures. METHODS: Dorper ewes from two flocks in Namibia were studied. Chemical analyses of water, blood and urine were executed for both cohorts. Skeletal phenotyping comprised micro-computer tomography (μCT), histological, histomorphometric, biomechanical, quantitative backscattered electron imaging (qBEI) and energy-dispersive X-ray (EDX) analysis. Analysis was performed in direct comparison with undecalcified human iliac crest bone biopsies of patients with fluoride-induced osteopathy. RESULTS: The fluoride content of water, blood and urine was significantly elevated in the Kalahari group compared to the control. Surprisingly, a significant decrease in both cortical and trabecular bones was found in sheep chronically exposed to fluoride. Furthermore, osteoid parameters and the degree and heterogeneity of mineralization were increased. The latter findings are reminiscent of those found in osteoporotic patients with treatment-induced fluorosis. Mechanical testing revealed a significant decrease in the bending strength, concurrent with the clinical observation of fragility fractures in sheep within an area of environmental fluoride exposure. CONCLUSIONS: Our data suggest that fluoride exposure with concomitant calcium deficit (i) may aggravate bone loss via reductions in mineralized trabecular and cortical bone mass and (ii) can cause fragility fractures and (iii) that the prevalence of skeletal fluorosis especially due to groundwater exposure should be reviewed in many areas of the world as low bone mass alone does not exclude fluorosis

Retinal nerve fiber layer thickness predicts CSF amyloid/tau before cognitive decline

Background: Alzheimer's disease (AD) pathology precedes symptoms and its detection can identify at-risk individuals who may benefit from early treatment. Since the retinal nerve fiber layer (RNFL) is depleted in established AD, we tested whether its thickness can predict whether cognitively healthy (CH) individuals have a normal or pathological cerebrospinal fluid (CSF) A f42 (A) and tau (T) ratio. Methods: As part of an ongoing longitudinal study, we enrolled CH individuals, excluding those with cognitive impairment and significant ocular pathology. We classified the CH group into two sub-groups, normal (CH-NAT, n = 16) or pathological (CH-PAT, n = 27), using a logistic regression model from the CSF AT ratio that identified &gt;85% of patients with a clinically probable AD diagnosis. Spectral-domain optical coherence tomography (OCT) was acquired for RNFL, ganglion cell-inner plexiform layer (GC-IPL), and macular thickness. Group differences were tested using mixed model repeated measures and a classification model derived using multiple logistic regression. Results: Mean age (\ub1 standard deviation) in the CH-PAT group (n = 27; 75.2 \ub1 8.4 years) was similar (p = 0.50) to the CH-NAT group (n = 16; 74.1 \ub1 7.9 years). Mean RNFL (standard error) was thinner in the CH-PAT group by 9.8 (2.7) \u3bcm; p &lt; 0.001. RNFL thickness classified CH-NAT vs. CH-PAT with 87% sensitivity and 56.3% specificity. Conclusions: Our retinal data predict which individuals have CSF biomarkers of AD pathology before cognitive deficits are detectable with 87% sensitivity. Such results from easy-to-acquire, objective and non-invasive measurements of the RNFL merit further study of OCT technology to monitor or screen for early AD pathology