A protocol for the prospective study of urinary cadmium with risk of fracture, bone loss, and muscle loss

Cadmium (Cd) is a heavy metal and natural element found in soil and crops with increasing concentrations linked to phosphate fertilizers and sewage sludge applied to crop lands. A large fraction of older US men and woman have documented Cd exposure. Cd exposure has proven health concerns such as risk of lung cancer from inhalation and impaired renal function; however, growing evidence suggests it also influences bone and muscle health. Given that low levels of Cd could affect bone and muscle, we have designed prospective studies using the two largest and most detailed US studies of bone health in older men and women: the Osteoporotic Fractures in Men Study and the Study of Osteoporotic Fractures. We are investigating the association of urinary cadmium (U-Cd), as a surrogate for long-term Cd exposure, with bone and muscle health. Building off suggestive evidence from mechanistic and cross-sectional studies, this will be the first well-powered prospective study of incident fracture outcomes, bone loss, and muscle loss in relation to U-Cd, an established biomarker of long-term Cd exposure. The following is a proposed protocol for the intended study; if successful, the proposed studies could be influential in directing future US policy to decrease Cd exposure in the US population similar to recent policies adopted by the European Union to limit Cd in fertilizers.

Association of Subjective and Objective Measures of Sleep With Gut Microbiota Composition and Diversity in Older Men: The Osteoporotic Fractures in Men Study

BACKGROUND

Growing evidence suggests bidirectional links between gut microbiota and sleep quality as shared contributors to health. Little is known about the relationship between microbiota and sleep among older persons.

METHODS

We used 16S rRNA sequencing to characterize stool microbiota among men (n = 606, mean [standard deviation] age = 83.9 [3.8]) enrolled in the Osteoporotic Fractures in Men (MrOS) study from 2014 to 2016. Sleep was assessed concurrently by a questionnaire (Pittsburgh Sleep Quality index [PSQI]), and activity monitor to examine timing (acrophase) and regularity of patterns (F-statistic). Alpha diversity was measured using Faith's phylogenetic diversity (PD). Beta diversity was calculated with robust Aitchison distance with matrix completion (RPCA) and phylogenetic-RPCA (PRPCA). Their association with sleep variables was tested with partial distance-based redundancy analysis (dbRDA). Predictive-ratio biomarkers associated with sleep measurements were identified with CoDaCoRe.

RESULTS

In unadjusted analyses, men with poor sleep (PSQI >5) tended to have lower alpha diversity compared to men with normal sleep (Faith's PD, beta = -0.15; 95% confidence interval [CI]: -0.30 to 0.01, p = .06). Sleep regularity was significantly associated with RPCA and PRPCA, even after adjusting for site, batch, age, ethnicity, body mass index, diabetes, antidepressant and sleep medication use, and health behaviors (RPCA/PRPCA dbRDA; p = .033/.002). In taxonomic analysis, ratios of 7:6 bacteria for better regularity (p = .0004) and 4:7 for worse self-reported sleep (p = .005) were differentially abundant: some butyrate-producing bacteria were associated with better sleep characteristics.

CONCLUSIONS

Subjective and objective indicators of sleep quality suggest that older men with better sleep patterns are more likely to harbor butyrate-producing bacteria associated with better health.

THE ASSOCIATION BETWEEN OBJECTIVE MEASURES OF INTERMITTENT SEDENTARY BREAKS WITH RECURRENT FALL RISK IN OLDER MEN

BACKGROUND

We assessed the relationship between objectively measured sedentary bout frequency with recurrent falls (2+ falls/year).

METHODS

The sample included 2,918 men aged 79.0±5.1 years attending the Osteoporotic Fractures in Men Study (MrOS) Year 7 (2007-2009) visit. Sedentary bout frequencies were defined as the average daily number of transitions out of 5+ minutes sedentary (<1.5 METS). Falls were self-reported from mailed questionnaires. Generalized Estimating Equations estimated the odds of recurrent falls.

RESULTS

Over four follow-up years, 1,025 (35.1%) men had recurrent falls. Compared to men with <13.6 transitions from sedentary (Quartile (Q)1), the odds of recurrent falls among men with 13.6-<17.0 transitions (Q2), 17.0-<20.4 transitions (Q3), and 20.4-<34.6 transitions (Q4) were 0.82 (95%CI: 0.66-1.01), 0.79 (95%CI: 0.64, 0.99), and 1.01 (95%CI: 0.81, 1.27), respectively, after adjustment.

CONCLUSIONS

A U-shaped association may exist between sedentary bout frequency and recurrent falls risk. The least and most active men are at higher risk.

Associations of Dietary Patterns With the Gut Microbiota in Older, Community-Dwelling Men

We investigated associations of dietary patterns with composition and diversity of the gut bacterial microbiota in 517 community-dwelling older men (mean age 84.3 y) who were participants in the Osteoporotic Fractures in Men (MrOS) study. Eligible participants provided a stool sample and completed a food frequency questionnaire at the MrOS Visit 4 in 2014-2016. Dietary patterns were derived by factor analysis. 16S rRNA target gene sequencing was performed. Linear regression and PERMANOVA considered variation in alpha and beta-diversity by dietary pattern, and metagenomeSeq assessed taxonomic variation by dietary pattern. In multivariable-adjusted models, greater adherence to the Western pattern was positively associated certain taxa, including Alistipes, Desulfovibrio, Dorea, Eubacterium, and Ruminococcus, while greater adherence to the prudent pattern was positively associated with certain taxa, including Faecalibacterium, Lachnospira, and Paraprevotella. Dietary patterns were not associated with measures of alpha diversity; beta diversity measures were significantly associated with both Western and prudent patterns.

Comparing Analytical Methods for Gut Microbiome and Aging: Gut Microbiota and Body Weight in the MrOS

Gut microbiome datasets comprise microbial taxa relative abundances that necessarily sum to 1; analysis ignoring this feature may produce misleading results. We assessed 163 genera from the first batch of Microbiome Ancillary Study (n=530) stool samples and examined associations between microbiota and body weight. We compared conventional Bayesian linear regression (BLR) and network analysis to their compositional counterparts, adjusting for past weight and other covariates. Conventional BLR identified Roseburia and Dialister (positive association) and Coprococcus-1 (negative association) after multiple comparisons adjustment(P<.0125). No conventional network module was associated with weight. Using compositional BLR, men with higher Coprococcus-2 and Acidaminococcus had higher weight, whereas men with higher Coprococcus-1 and Ruminococcus-1 had lower weight (P<.05), but findings were non-significant after multiple comparisons adjustment. Two compositional network modules with respective hub taxa Blautia and Faecalibacterium were associated with weight(P<.01). Findings depended on analytical workflow; compositional analysis is advocated to appropriately handle the sum-to-1 constraint.

Vitamin D Metabolites and the Gut Microbiome in Older Men

We examined the bidirectional impact of vitamin D on the composition and diversity of the gut microbiome in 567 MrOS men. Vitamin D metabolites were measured using LC-MSMS and stool sub-operational taxonomic units defined from 16S ribosomal RNA sequencing data using Deblur and Greengenes 13.8. Men’s mean serum level of 25(OH)D was in the sufficient range. Faith’s Phylogenetic Diversity and non-redundant covariate analyses revealed that 1,25(OH)2D explained 5% of variance in α-diversity; the other non-redundant covariates of site, race, recent antibiotic and antidepressant use explained another 6%. In β-diversity analyses using unweighted UniFrac, 1,25(OH)2D was the strongest factor assessed, explaining 2%. Random forest plot analyses identified 12 taxa, 6 in the phylum Firmicutes, positively associated with either 1,25(OH)2D and/or [1,25(OH)2D/25(OH)D] activation ratio. Higher levels of the active 1,25(OH)2D, but not 25(OH)D, were associated with butyrate producing bacteria. Men with favorable vitamin D activation profiles also had greater gut microbial diversity.

MON-098 FSH and Body Composition in Older Adults

Background: Common changes with menopause and aging include an increase in visceral adiposity and loss of lean body mass. Declines in sex steroid hormones contribute to these body composition changes, but emerging evidence also implicates increased pituitary production of follicle stimulating hormone (FSH). Blocking FSH action with an FSH-β subunit antibody reduced adiposity and increased lean body mass in ovariectomized female mice, and both male and female intact mice (Liu Nature 2017). Some, but not all, clinical observational studies have demonstrated positive associations between FSH and measures of adiposity (Zaidi Endocrinology 2018). Objective: To investigate the associations between endogenous FSH levels and measures of body composition in older adults from the AGES-Reykjavik cohort, independent of sex steroid hormones. Methods/Results: Participants were recruited from the AGES-R study, excluding those using sex steroid hormone agonists or antagonists. FSH (ELISA), total estradiol and total testosterone (GC/MS) were measured from fasting serum. Total body fat (kg), total body lean mass (kg), and appendicular lean mass (kg) were measured with total body DXA. Appendicular lean mass index (ALMI) was calculated as appendicular lean mass/height² (kg/m²). Visceral adipose tissue (VAT) area (cm²) and subcutaneous adipose tissue (SAT) area (cm²) were measured with abdominal CT. Linear regression analyses of FSH in association with body composition parameters were performed, stratified by gender, both unadjusted and adjusted for age, visit window, BMI, total estradiol and total testosterone levels. Among the 245 men, the mean age was 82.4 (SD 4.0) years, mean BMI was 26.7 (SD 3.6) kg/m² and mean FSH 19.0 (SD 16.9) IU/L . Among the 238 women, the mean age was 80.6 (SD 4.0) years, mean BMI 27.4 (SD 4.1) kg/m² and mean FSH 71.6 (SD 23.2) IU/L. In models adjusted for age, visit window, BMI, estradiol and testosterone, there were no significant associations between FSH and any measure of body composition in men. In adjusted models in women, each SD increase in FSH was associated with a 2.67% greater SAT area (p=0.03) but no significant difference in VAT area or total body fat. Conversely, each SD increase in FSH was associated with a1.62% lower total body lean mass (p=0.005) in women, but no significant difference in ALMI. Conclusion: Consistent with preclinical models, we found higher FSH to be associated with greater subcutaneous adiposity and lower lean body mass in older women. We found no associations between FSH and measures of body composition in older men. Further research is needed to determine whether FSH-directed therapy may be an effective means of combatting the body composition changes associated with menopause.

The Efficacy and Safety of Vertebral Augmentation: A Second ASBMR Task Force Report

Vertebral augmentation is among the current standards of care to reduce pain in patients with vertebral fractures (VF), yet a lack of consensus regarding efficacy and safety of percutaneous vertebroplasty and kyphoplasty raises questions on what basis clinicians should choose one therapy over another. Given the lack of consensus in the field, the American Society for Bone and Mineral Research (ASBMR) leadership charged this Task Force to address key questions on the efficacy and safety of vertebral augmentation and other nonpharmacological approaches for the treatment of pain after VF. This report details the findings and recommendations of this Task Force. For patients with acutely painful VF, percutaneous vertebroplasty provides no demonstrable clinically significant benefit over placebo. Results did not differ according to duration of pain. There is also insufficient evidence to support kyphoplasty over nonsurgical management, percutaneous vertebroplasty, vertebral body stenting, or KIVA®. There is limited evidence to determine the risk of incident VF or serious adverse effects (AE) related to either percutaneous vertebroplasty or kyphoplasty. No recommendation can be made about harms, but they cannot be excluded. For patients with painful VF, it is unclear whether spinal bracing improves physical function, disability, or quality of life. Exercise may improve mobility and may reduce pain and fear of falling but does not reduce falls or fractures in individuals with VF. General and intervention-specific research recommendations stress the need to reduce study bias and address methodological flaws in study design and data collection. This includes the need for larger sample sizes, inclusion of a placebo control, more data on serious AE, and more research on nonpharmacologic interventions. Routine use of vertebral augmentation is not supported by current evidence. When it is offered, patients should be fully informed about the evidence. Anti-osteoporotic medications reduce the risk of subsequent vertebral fractures by 40-70%. © 2018 American Society for Bone and Mineral Research.

Effect of Combination Folic Acid, Vitamin B6 , and Vitamin B12 Supplementation on Fracture Risk in Women: A Randomized, Controlled Trial

Epidemiologic studies have demonstrated an association of elevated plasma homocysteine levels with greater bone resorption and fracture risk. Vitamins B₁₂ , B₆ , and folic acid are cofactors in homocysteine metabolism, and supplementation with B vitamins is effective in lowering homocysteine levels in humans. However, randomized trials of supplemental B vitamins for reduction of fracture risk have been limited. Therefore, we performed an ancillary study to the Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS), a large randomized trial of women with preexisting cardiovascular disease or three or more coronary risk factors, to test whether a daily B vitamin intervention including folic acid (2.5 mg/day), vitamin B₆ (50 mg/day), and vitamin B₁₂ (1 mg/day) reduces nonspine fracture risk over 7.3 years of treatment and follow-up. Among 4810 women, we confirmed 349 nonspine fracture cases by centralized review of medical records. In a substudy of 300 women (150 in treatment group and 150 controls) with paired plasma samples at randomization and follow-up (7.3 years later), we measured two bone turnover markers, including C-terminal cross-linking telopeptide of type I collagen (CTX) and intact type I procollagen N-propeptide (P1NP). In Cox proportional hazards models based on intention-to-treat, we found no significant effects of B vitamin supplementation on nonspine fracture risk (relative hazard = 1.08; 95% confidence interval, 0.88 to 1.34). In a nested case-cohort analysis, there were no significant effects of B vitamins on fracture risk among women with elevated plasma homocysteine levels, or low levels of vitamins B₁₂ or B₆ , or folate at baseline. Furthermore, treatment with B vitamins had no effect on change in markers of bone turnover. We found no evidence that daily supplementation with B vitamins reduces fracture risk or rates of bone metabolism in middle-aged and older women at high risk of cardiovascular disease. © 2017 American Society for Bone and Mineral Research.

Association of serum fibroblast growth factor 23 (FGF23) and incident fractures in older men: the Osteoporotic Fractures in Men (MrOS) study

Normal mineral metabolism is critical for skeletal integrity, and recently serum fibroblast growth factor 23 (FGF23) levels were found to be directly related to overall fracture risk in elderly Swedish men. To confirm this association, we performed a prospective case-cohort study to understand the relation of FGF23 and fracture risk in older white men enrolled in the Osteoporotic Fractures in Men (MrOS) study. In the cohort of 5994 men attending the baseline MrOS examination, we evaluated a subgroup of 387 men with incident nonvertebral fracture including 73 hip fractures and a sample of 1385 men randomly selected from the cohort with baseline mineral and calcium hormone measurements. FGF23 was measured in baseline serum samples by ELISA (Millipore, Billerica, MA, USA). Modified Cox proportional hazards models that account for case-cohort study design were used to estimate the relative hazards (RH) of fracture in men across quartiles of FGF23. Subjects were also stratified by renal function, and RH per strata was estimated in men with the highest quartile of FGF23 compared with quartiles 3, 2, and 1. Overall, there was no difference in risk of nonspine or hip fracture by baseline FGF23. However, associations differed by strata of eGFRCrCy . Among men with eGFRCrCys <60 mL/min/1.73 m2 (n = 73/313 nonspine fractures), the RH in the highest quartile of FGF23 compared with the rest was 2.02 (95% confidence interval [CI] 1.07-3.79), but in men with eGFRCrCy , >60 mL/min/1.73 m2 (304/1370 fractures) the RH was 0.91 (95% CI 0.66-1.25) after adjustment for age, clinic site, body mass index, race, total hip bone mineral density, vitamin D, parathyroid hormone, alcohol use, physical activity, fracture history, and serum phosphorus. Serum FGF23 levels are not associated with incident fractures in elderly men overall. However, higher levels of serum FGF23 are associated with fracture risk in those with poor renal function.

Do the effects of APOE-ε4 on cognitive function and decline depend upon vitamin status? MacArthur Studies of Successful Aging

OBJECTIVES

To investigate whether gene nutrient interactions influence the risk of cognitive dysfunction among older persons.

DESIGN

We performed a cross-sectional and longitudinal study of 499 adults aged 70-79 years from the Mac Arthur Study of Successful Aging to determine the effect of apolipoprotein E (APOE) in conjunction with plasma levels of homocysteine and of the related B vitamins on multiple domains of cognitive function and cognitive decline.

RESULTS

The APOE-ε4 allele, high homocysteine, low folate, and low vitamin B6 levels were each associated with worse baseline cognitive function, and all but B6 and B12 were associated with seven year cognitive decline. There was no interaction between APOE-ε4, and homocysteine, folate, B6, or B12 in predicting baseline cognitive function (p-values: 0.12-0.94) or longitudinal decline (p-values: 0.52-0.91). Of five cognitive subtests, there was a significant interaction between the ε4 allele, low B6, and decline in correct naming response items (p=0.04).

CONCLUSION

B vitamin status does not influence the risk of overall cognitive dysfunction in ε4 allele affected older adults.

Methylenetetrahydrofolate reductase C677T polymorphism and cognitive function in older women

Homocysteine may play a causal role in cognitive decline. The authors analyzed the 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T genotype, a correlate of plasma homocysteine levels, among 6,653 participants in the Study of Osteoporotic Fractures, a community-based, prospective cohort study of older women in four US states. During the years 1986-1998, the authors assessed whether the distribution of MTHFR C677T genotypes was independent of potential confounders and whether persons with the TT genotype had lower baseline performance or showed greater longitudinal declines on standard cognitive tests. Although ethnicity was associated with MTHFR genotype distribution within the entire cohort (p < 0.001), all measured confounders appeared independent of MTHFR genotype within the largest ethnically homogenous subgroup, persons of Northern and/or Central European ancestry (n = 5,668) (Kolmogorov-Smirnov p = 0.97). In this subgroup, the TT genotype was associated with lower scores on the Digit Symbol Substitution Test (p = 0.034) and the Trails B test (p = 0.020) and with a small excess annual decline on a modified version of the Mini-Mental State Examination (p = 0.035). Although the strength of the observed associations was modest, these results lend some support to the theory that an elevated homocysteine level contributes to cognitive decline.

Lymphomatosis Cerebri Presenting as Rapidly Progressive Dementia

BACKGROUND

As the population ages, the incidence of dementing illness is increasing. Accurate and timely diagnosis provides the best hope for instituting appropriate treatment and educating the patient and family members as to prognosis based upon likely etiology in a given patient.

REVIEW SUMMARY

We present a case of an elderly patient referred to our tertiary-care center for further evaluation of a rapidly progressive dementia, whose definitive diagnosis was delayed by nonspecific MRI findings, presence of 14-3-3 protein in the CSF, and nonspecific cutaneous lesions. At brain biopsy, he was thought to have a diffusely infiltrating lymphoma, with distinctive immunohistochemical features.

CONCLUSION

This case is notable in that it presents a patient with progressive dementia whose diagnosis of primary central nervous system lymphoma (PCNSL) was delayed because of the lymphoma's atypical diffusely infiltrating nature. Awareness of this unique presentation may hasten the time between clinical presentation, diagnosis, and subsequent treatment.