Cross-sectional associations of dietary and circulating magnesium with skeletal muscle mass in the EPIC-Norfolk cohort

Background: Maintenance of skeletal muscle in older age is critical to reducing frailty and the risk of falls and fractures. Nutrition has established importance for muscle health in general, but less research has looked at associations of dietary intake of specific micronutrients on skeletal muscle mass in older adults. Aims: This study aimed to investigate the influence of dietary and circulating magnesium on skeletal muscle mass in a UK population of 14,340 middle to older-aged men and women participating in the EPIC-Norfolk cohort study. Methods: Dietary nutrient intakes were estimated from 7-day food diaries and fat-free mass (FFM) by bioelectrical impedance analysis. Multivariable regression was used to investigate associations of FFM-based indices of muscle mass with quintiles of dietary magnesium intake or serum magnesium concentration groups. All analyses were stratified by sex, and regression models were adjusted for relevant covariates. Results: Significant positive trends in FFM measures were evident across magnesium dietary intake quintiles for both sexes (all p < 0.001; n = 6350 men; n = 7990 women) and both <60 and ≥ 60 year olds, with all-age quintile 5 versus quintile 1 maximal differences of 4.6% in men and 6.3% in women; highly relevant compared to the estimated 1% decline per year after 40 years of age. These observations were not reflected in serum magnesium analyses, where no consistent trends were found across the skeletal muscle mass indices tested. Conclusion: Further investigation will be required to improve our understanding of the relationship between serum magnesium concentration and skeletal muscle mass. However, this study has demonstrated strong associations between dietary magnesium intake and indices of skeletal muscle mass in a UK population of middle to older-aged adults, highlighting the likely importance of dietary magnesium for optimal muscle health in this population

Cross-sectional associations of dietary and circulating magnesium with skeletal muscle mass in the EPIC-Norfolk cohort.

BACKGROUND: Maintenance of skeletal muscle in older age is critical to reducing frailty and the risk of falls and fractures. Nutrition has established importance for muscle health in general, but less research has looked at associations of dietary intake of specific micronutrients on skeletal muscle mass in older adults. AIMS: This study aimed to investigate the influence of dietary and circulating magnesium on skeletal muscle mass in a UK population of 14,340 middle to older-aged men and women participating in the EPIC-Norfolk cohort study. METHODS: Dietary nutrient intakes were estimated from 7-day food diaries and fat-free mass (FFM) by bioelectrical impedance analysis. Multivariable regression was used to investigate associations of FFM-based indices of muscle mass with quintiles of dietary magnesium intake or serum magnesium concentration groups. All analyses were stratified by sex, and regression models were adjusted for relevant covariates. RESULTS: Significant positive trends in FFM measures were evident across magnesium dietary intake quintiles for both sexes (all p < 0.001; n = 6350 men; n = 7990 women) and both <60 and ≥ 60 year olds, with all-age quintile 5 versus quintile 1 maximal differences of 4.6% in men and 6.3% in women; highly relevant compared to the estimated 1% decline per year after 40 years of age. These observations were not reflected in serum magnesium analyses, where no consistent trends were found across the skeletal muscle mass indices tested. CONCLUSION: Further investigation will be required to improve our understanding of the relationship between serum magnesium concentration and skeletal muscle mass. However, this study has demonstrated strong associations between dietary magnesium intake and indices of skeletal muscle mass in a UK population of middle to older-aged adults, highlighting the likely importance of dietary magnesium for optimal muscle health in this population

Fracture Incidence and the Relevance of Dietary and Lifestyle Factors Differ in the United Kingdom and Hong Kong: An International Comparison of Longitudinal Cohort Study Data.

Geographic variation in fracture risk may be due to divergent profiles of dietary, lifestyle, and other risk factors between populations. We investigated differences in fracture rates between two older-population cohorts: the European Prospective Investigation into Cancer and Nutrition (EPIC) Norfolk cohort (n = 7732) in the United Kingdom (UK), and the Mr and Ms Os cohort (n = 3956) in Hong Kong (HK). Data were collected by questionnaires, laboratory assessments, and hospital records. Incidence of hip, spine, and wrist fractures in the two cohorts was calculated and multivariable regression was used to explore variables important to fracture risk. Total hip, spine, and wrist fracture incidence was higher in the UK vs HK for women (13.70 vs 8.76 per 1000 person-years; p < 0.001), but not men (5.95 vs 5.37 per 1000 person-years; p = 0.337), and the proportions of different fractures also varied between cohorts (p < 0.001). Hip fracture was the most common UK fracture (accounting for 56.8% fractures in men and 52.6% in women), while wrist fracture was most common in HK (42.9% in men and 57.9% in women). The major contributor to total fracture risk in multivariable regression models of both cohorts and sexes, was age; with BMI also an important contributor to fracture risk HK men and UK women. The distribution of factors relevant to fracture risk, and the rates of different fractures, varied significantly between UK and HK cohorts. However, the importance of each factor in contributing to fracture risk was similar between the cohorts. The differences in fracture rates suggest targeted approaches may be required when developing interventions and public health recommendations to reduce the burden of osteoporosis in these two countries

PCB-containing wood floor finish is a likely source of elevated PCBs in residents' blood, household air and dust: a case study of exposure

© 2008 Rudel et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Serum and follicular fluid organochlorine concentrations among women undergoing assisted reproduction technologies

<p>Abstract</p> <p>Background</p> <p>Exposure to persistent organic pollutants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides, is widespread among the general population. There is evidence of adverse effects on reproduction and early pregnancy in relation to organochlorine exposure but human studies remain limited. The increased use of assisted reproductive technologies (ART) presents unique opportunities for the assessment of environmental influences on early pregnancy outcomes not otherwise observable in humans, but studies need to be designed to maximize the efficiency of the exposure data collected while minimizing exposure measurement error.</p> <p>Methods</p> <p>The present study was conducted to assess the correlation between concentrations of organochlorines in serum and follicular fluid samples collected from a subset of women undergoing ART in a large study that took place between 1994 and 2003, as well as the temporal reliability of serum organochlorine concentrations among women undergoing multiple ART cycles in the study. PCB congeners (118, 138, 153, and 180), 1,1,1-trichloro-2,2-bis(<it>p</it>-chlorophenyl)ethane (p,p'-DDT), the DDT metabolite p,p'-DDE, hexachlorobenzene (HCB), oxychlordane, trans-nonachlor and mirex were measured in 72 follicular fluid samples and 265 serum samples collected from 110 women.</p> <p>Results</p> <p>Organochlorine concentrations in paired serum and follicular fluid samples were correlated, with Pearson and Spearman coefficients ranging from 0.60 to 0.92. Serum organochlorine concentrations were two- to three-fold greater than in follicular fluid, and a significant inverse trend was observed in the distribution of follicular fluid:serum ratios with increasing molecular weight of the compound (p-value for trend < 0.0001). Serum organochlorine concentrations were highly reliable over the course of several months, with intraclass correlation coefficients ranging from 0.86 to 0.98. Finally, there was evidence for a declining trend in organochlorine concentrations between samples collected between years 1994–1998 and those collected in 1999–2003.</p> <p>Conclusion</p> <p>Our results support the use of a single serum sample to adequately represent a more biologically relevant dose (concentrations in follicular fluid), as well as exposure levels over time, in epidemiological studies of ART outcomes in relation to organochlorine exposure.</p

Social inequalities in self-rated health by age: Cross-sectional study of 22 457 middle-aged men and women

<p>Abstract</p> <p>Background</p> <p>We investigate the association between occupational social class and self-rated health (SRH) at different ages in men and women.</p> <p>Methods</p> <p>Cross sectional population study of 22 457 men and women aged 39–79 years living in the general community in Norfolk, United Kingdom, recruited using general practice age-sex registers in 1993–1997. The relationship between self-rated health and social class was examined using logistic regression, with a poor or moderate rating as the outcome.</p> <p>Results</p> <p>The prevalence of poor or moderate (lower) self-rated health increased with increasing age in both men and women. There was a strong social class gradient: in manual classes, men and women under 50 years of age had a prevalence of lower self-rated health similar to that seen in men and women in non-manual social classes over 70 years old. Even after adjustment for age, educational status, and lifestyle factors (body mass index (BMI), smoking, physical activity and alcohol consumption) there was still strong evidence of a social gradient in self-rated health, with unskilled men and women approximately twice as likely to report lower self-rated health as professionals (OR_men= 2.44 (95%CI 1.69, 3.50); OR_women= 1.97 (95%CI 1.45, 2.68).</p> <p>Conclusion</p> <p>There was a strong gradient of decreased SRH with age in both men and women. We found a strong cross-sectional association between SRH and social class, which was independent of education and major health related behaviors. The social class differential in SRH was similar with age. Prospective studies to confirm this association should explore social and emotional as well as physical pathways to inequalities in self reported health.</p

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Water relations of evergreen and drought-deciduous trees along a seasonally dry tropical forest chronosequence

Seasonally dry tropical forests (SDTF) are characterized by pronounced seasonality in rainfall, and as a result trees in these forests must endure seasonal variation in soil water availability. Furthermore, SDTF on the northern Yucatan Peninsula, Mexico, have a legacy of disturbances, thereby creating a patchy mosaic of different seral stages undergoing secondary succession. We examined the water status of six canopy tree species, representing contrasting leaf phenology (evergreen vs. drought-deciduous) at three seral stages along a fire chronosequence in order to better understand strategies that trees use to overcome seasonal water limitations. The early-seral forest was characterized by high soil water evaporation and low soil moisture, and consequently early-seral trees exhibited lower midday bulk leaf water potentials (ΨL) relative to late-seral trees (−1.01 ± 0.14 and −0.54 ± 0.07 MPa, respectively). Although ΨL did not differ between evergreen and drought-deciduous trees, results from stable isotope analyses indicated different strategies to overcome seasonal water limitations. Differences were especially pronounced in the early-seral stage where evergreen trees had significantly lower xylem water δ18O values relative to drought-deciduous trees (−2.6 ± 0.5 and 0.3 ± 0.6‰, respectively), indicating evergreen species used deeper sources of water. In contrast, drought-deciduous trees showed greater enrichment of foliar 18O (∆18Ol) and 13C, suggesting lower stomatal conductance and greater water-use efficiency. Thus, the rapid development of deep roots appears to be an important strategy enabling evergreen species to overcome seasonal water limitation, whereas, in addition to losing a portion of their leaves, drought-deciduous trees minimize water loss from remaining leaves during the dry season

Transglutaminase 6: a protein associated with central nervous system development and motor function.

Transglutaminases (TG) form a family of enzymes that catalyse various post-translational modifications of glutamine residues in proteins and peptides including intra- and intermolecular isopeptide bond formation, esterification and deamidation. We have characterized a novel member of the mammalian TG family, TG6, which is expressed in a human carcinoma cell line with neuronal characteristics and in mouse brain. Besides full-length protein, alternative splicing results in a short variant lacking the second β-barrel domain in man and a variant with truncated β-sandwich domain in mouse. Biochemical data show that TG6 is allosterically regulated by Ca(2+) and guanine nucleotides. Molecular modelling indicates that TG6 could have Ca(2+) and GDP-binding sites related to those of TG3 and TG2, respectively. Localization of mRNA and protein in the mouse identified abundant expression of TG6 in the central nervous system. Analysis of its temporal and spatial pattern of induction in mouse development indicates an association with neurogenesis. Neuronal expression of TG6 was confirmed by double-labelling of mouse forebrain cells with cell type-specific markers. Induction of differentiation in mouse Neuro 2a cells with NGF or dibutyryl cAMP is associated with an upregulation of TG6 expression. Familial ataxia has recently been linked to mutations in the TGM6 gene. Autoantibodies to TG6 were identified in immune-mediated ataxia in patients with gluten sensitivity. These findings suggest a critical role for TG6 in cortical and cerebellar neurons