Efficacy, Safety, and Accuracy of Intra-articular Therapies for Hand Osteoarthritis: Current Evidence.

The lifetime risk of symptomatic hand osteoarthritis (OA) is 39.8%, with one in two women and one in four men developing the disease by age 85 years and no disease-modifying drug (DMOAD) available so far. Intra-articular (IA) therapy is one of the options commonly used for symptomatic alleviation of OA disease as it can circumvent systemic exposure and potential side effects of oral medications. The current narrative review focuses on the efficacy and safety profiles of the currently available IA agents in hand OA (thumb-base OA or interphalangeal OA) such as corticosteroids and hyaluronic acid (HA), as well as the efficacy and safety of IA investigational injectates in phase 2/3 clinical trials such as prolotherapy, platelet-rich plasma, stem cells, infliximab, interferon-? and botulinum toxin, based on the published randomized controlled trials on PubMed database. The limited published literature revealed the short-term symptomatic benefits of corticosteroids in interphalangeal OA while long-term data are lacking. Most of the short-term studies showed no significant difference between corticosteroids and hyaluronic acid in thumb-base OA, usually with a faster onset of pain relief in the corticosteroid group and a slower but greater (statistically insignificant) pain improvement in the HA group. The majority of studies in investigational agents were limited by small sample size, short-term follow-up, and presence of serious side effects. In addition, we reported higher accuracy rates of drug administrations under imaging guidance than landmark guidance (blind method), and then briefly describe challenges for the long-term efficacy and prospects of IA therapeutics.

Effectiveness of an Unsupervised Online Yoga Program on Pain and Function in People With Knee Osteoarthritis : A Randomized Clinical Trial.

BACKGROUND: Yoga is a mind-body exercise typically done in groups in person, but this delivery method can be inconvenient, inaccessible, and costly. Effective online programs may increase access to exercise for knee osteoarthritis. OBJECTIVE: To evaluate the effectiveness of an unsupervised 12-week online yoga program. DESIGN: Two-group superiority randomized trial. (Australian New Zealand Clinical Trials Registry: ACTRN12620000012976). SETTING: Community. PARTICIPANTS: 212 adults with symptomatic knee osteoarthritis. INTERVENTION: Both groups received online osteoarthritis information (control). The yoga group also received access to an unsupervised online yoga program delivered via prerecorded videos over 12 weeks (1 video per week, with each session to be performed 3 times per week), with optional continuation thereafter. MEASUREMENTS: Primary outcomes were changes in knee pain during walking (0 to 10 on a numerical rating scale) and physical function (0 to 68 on the Western Ontario and McMaster Universities Osteoarthritis Index) at 12 weeks (primary time point) and 24 weeks, analyzed using mixed-effects linear regression models. Secondary outcomes were self-reported overall knee pain, stiffness, depression, anxiety, stress, global change, quality of life, self-efficacy, fear of movement, and balance confidence. Adverse events were also collected. RESULTS: A total of 195 (92%) and 189 (89%) participants provided 12- and 24-week primary outcomes, respectively. Compared with control at 12 weeks, yoga improved function (between-group mean difference in change, -4.0 [95% CI, -6.8 to -1.3]) but not knee pain during walking (between-group mean difference in change, -0.6 [CI, -1.2 to 0.1]), with more yoga participants than control participants achieving the minimal clinically important difference (MCID) for both outcomes. At 12 weeks, knee stiffness, quality of life, and arthritis self-efficacy improved more with yoga than the control intervention. Benefits were not maintained at 24 weeks. Adverse events were minor. LIMITATION: Participants were unblinded. CONCLUSION: Compared with online education, an unsupervised online yoga program improved physical function but not knee pain at 12 weeks in people with knee osteoarthritis, although the improvement did not reach the MCID and was not sustained at 24 weeks. PRIMARY FUNDING SOURCE: National Health and Medical Research Council and Centres of Research Excellence.

Genetically predicted circulating concentrations of micronutrients and risk of colorectal cancer among individuals of European descent: a Mendelian randomization study.

BACKGROUND: The literature on associations of circulating concentrations of minerals and vitamins with risk of colorectal cancer is limited and inconsistent. Evidence from randomized controlled trials (RCTs) to support the efficacy of dietary modification or nutrient supplementation for colorectal cancer prevention is also limited. OBJECTIVES: To complement observational and RCT findings, we investigated associations of genetically predicted concentrations of 11 micronutrients (ß-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B-6, vitamin B-12, and zinc) with colorectal cancer risk using Mendelian randomization (MR). METHODS: Two-sample MR was conducted using 58,221 individuals with colorectal cancer and 67,694 controls from the Genetics and Epidemiology of Colorectal Cancer Consortium, Colorectal Cancer Transdisciplinary Study, and Colon Cancer Family Registry. Inverse variance-weighted MR analyses were performed with sensitivity analyses to assess the impact of potential violations of MR assumptions. RESULTS: Nominally significant associations were noted for genetically predicted iron concentration and higher risk of colon cancer [ORs per SD (ORSD): 1.08; 95% CI: 1.00, 1.17; P value = 0.05] and similarly for proximal colon cancer, and for vitamin B-12 concentration and higher risk of colorectal cancer (ORSD: 1.12; 95% CI: 1.03, 1.21; P value = 0.01) and similarly for colon cancer. A nominally significant association was also noted for genetically predicted selenium concentration and lower risk of colon cancer (ORSD: 0.98; 95% CI: 0.96, 1.00; P value = 0.05) and similarly for distal colon cancer. These associations were robust to sensitivity analyses. Nominally significant inverse associations were observed for zinc and risk of colorectal and distal colon cancers, but sensitivity analyses could not be performed. None of these findings survived correction for multiple testing. Genetically predicted concentrations of ß-carotene, calcium, copper, folate, magnesium, phosphorus, and vitamin B-6 were not associated with disease risk. CONCLUSIONS: These results suggest possible causal associations of circulating iron and vitamin B-12 (positively) and selenium (inversely) with risk of colon cancer.

Podiatry Intervention Versus Usual General Practitioner Care for Symptomatic Radiographic Osteoarthritis of the First Metatarsophalangeal Joint: A Randomized Clinical Feasibility Study.

OBJECTIVE: To determine the feasibility of a clinical trial comparing a podiatry intervention to usual general practitioner (GP) care for people with first metatarsophalangeal (MTP) joint osteoarthritis (OA). METHODS: A 2-arm, participant- and assessor-blinded, randomized feasibility study was conducted over 12 weeks. Participants were age >40 years and had pain and radiographic OA in the first MTP joint. Participants in the podiatry group had 3 visits and received foot orthoses, exercise, manual therapy, and advice. Participants in the GP group had 1 visit and received medication advice/prescription and the same advice as the podiatry group. Primary outcomes were measures of feasibility (recruitment, attendance, and retention rates; percentage of prescribed exercise sessions completed; orthoses wear hours/day; treatment fidelity). Secondary outcomes included self-reported pain, function, satisfaction, adherence, adverse events, and dropouts. RESULTS: A total of 236 people were screened, and 30 (13%) were included. All except 1 participant in the podiatry group attended the required clinical visits, and retention rates were 93% (podiatry group) and 80% (GP group). Participants completed 66% of the exercise sessions and wore orthoses for an average of 6.3 hours/day. Adherence to medication use was 5.3 on an 11-point numeric rating scale. Both treatment approaches improved pain and function by clinically important differences at 12 weeks. CONCLUSION: A clinical trial comparing a podiatry intervention to usual GP care for people with first MTP joint OA is feasible. Given the improvements in pain and function observed, a larger appropriately powered clinical trial is warranted to evaluate the superiority of one treatment approach over the other.

Core and adjunctive interventions for osteoarthritis: efficacy and models for implementation.

Osteoarthritis (OA) is a complex musculoskeletal disease and a leading cause of pain and disability worldwide. Hip and knee OA alone are major contributors to global disability, having notable effects on individual well-being, increasing the reliance of individuals on health-care services and contributing to a rise in the socioeconomic burden. Consistent, coordinated and tailored approaches are important for providing appropriate care to all people with OA, but despite the scale of the challenge many individuals are still not offered the safe, best-evidence treatments recommended for OA care. This Review discusses the core priority treatments for OA, including exercise and physical activity, weight-loss, education and support for self-management. Additional physical or psychological evidence-based adjunctive therapies and combined therapies that can be used to tailor individual programmes are also discussed. These options include cognitive behavioural therapy, heat therapy, walking aids and splints, manual therapies and transcutaneous electrical nerve stimulation. International examples of OA treatment options, models of care and resources available are also given. Many challenges still need to be addressed to advance the uptake of these conditions, including further discussion around the risks and costs involved with all treatments.

Pharmacokinetic assessment of constituents of Boswellia serrata, pine bark extracts, curcumin in combination including methylsulfonylmethane in healthy volunteers.

OBJECTIVES: Dietary supplements are increasingly used by people with osteoarthritis. Boswellia serrata extract, curcumin, pine bark extract and methylsulfonylmethane have been identified as having the largest effects for symptomatic relief in a systematic review. It is important to understand whether any pharmacokinetic interactions are among the major constituents of these supplements so as to provide information when considering the combination use of these supplements. The aim of this study was to investigate the pharmacokinetics of the constituents alone and in combination. METHODS: This study was a randomized, open-label, single-dose, four-treatment, four-period, crossover study with 1-week washout. The pharmacokinetics of the constituents of these supplements when dosed in combination with methylsulfonylmethane were compared to being administered alone. Plasma samples were obtained over 24 h from 16 healthy participants. Eight major constituents were analysed using a validated ultra-high-performance liquid chromatography-tandem mass spectrometry assay. KEY FINDINGS: The pharmacokinetics of each constituent was characterized, and there were no significant differences in the pharmacokinetic profiles of the constituents when administered as a combination, relative to the constituents when administered alone (P > 0.05). CONCLUSIONS: These data suggest that interactions between the major constituents of this supplement combination are unlikely and therefore could be investigated to manage patients with osteoarthritis without significant concerns for possible pharmacokinetic interactions.

Yoga for Osteoarthritis: a Systematic Review and Meta-analysis.

PURPOSE OF REVIEW: This study aims to systematically review and summarise the efficacy and safety of yoga for osteoarthritis. Medline (through PubMed), Scopus, and the Cochrane Library were searched through April 2018 for randomised controlled trials of yoga for osteoarthritis. Primary outcomes were pain intensity, function, and quality of life; secondary outcomes were mental health and safety. Risk of bias was assessed using the Cochrane tool and quality of evidence through GRADE. RECENT FINDINGS: Nine trials including 640 individuals with mainly lower extremity osteoarthritis aged 50-80 years were identified, with 80.3% female participants (median). Meta-analyses revealed very low-quality evidence for the effects of yoga on pain (vs. exercise: standardised mean difference (SMD) = - 1.07; 95%CI - 1.92, - 0.21; p = 0.01; vs. non-exercise: SMD = - 0.75; 95%CI - 1.18, - 0.31; p < 0.001), physical function (vs. exercise: SMD = 0.80; 95%CI 0.36; 1.24; p < 0.001; vs. non-exercise: SMD = 0.60; 95%CI 0.30, 0.98; p < 0.001), and stiffness (vs. exercise: SMD = - 0.92; 95%CI - 1.69, - 0.14; p = 0.008; vs. non-exercise: SMD = - 0.76; 95%CI - 1.26, - 0.26; p = 0.003) in individuals with knee osteoarthritis. Effects were not robust against potential methodological bias. No effects were found for quality of life, and depression, or for hand osteoarthritis. Safety was rarely reported. The findings of this meta-analysis indicate that yoga may be effective for improving pain, function, and stiffness in individuals with osteoarthritis of the knee, compared to exercise and non-exercise control groups. Due to the low methodological quality and potential risk of bias, only a weak recommendation can be made at this time for the use of yoga in adults with osteoarthritis of the knee.

Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: To investigate the efficacy and safety of dietary supplements for patients with osteoarthritis. DESIGN: An intervention systematic review with random effects meta-analysis and meta-regression. DATA SOURCES: MEDLINE, EMBASE, Cochrane Register of Controlled Trials, Allied and Complementary Medicine and Cumulative Index to Nursing and Allied Health Literature were searched from inception to April 2017. STUDY ELIGIBILITY CRITERIA: Randomised controlled trials comparing oral supplements with placebo for hand, hip or knee osteoarthritis. RESULTS: Of 20 supplements investigated in 69 eligible studies, 7 (collagen hydrolysate, passion fruit peel extract, Curcuma longa extract, Boswellia serrata extract, curcumin, pycnogenol and L-carnitine) demonstrated large (effect size >0.80) and clinically important effects for pain reduction at short term. Another six (undenatured type II collagen, avocado soybean unsaponifiables, methylsulfonylmethane, diacerein, glucosamine and chondroitin) revealed statistically significant improvements on pain, but were of unclear clinical importance. Only green-lipped mussel extract and undenatured type II collagen had clinically important effects on pain at medium term. No supplements were identified with clinically important effects on pain reduction at long term. Similar results were found for physical function. Chondroitin demonstrated statistically significant, but not clinically important structural improvement (effect size -0.30, -0.42 to -0.17). There were no differences between supplements and placebo for safety outcomes, except for diacerein. The Grading of Recommendations Assessment, Development and Evaluation suggested a wide range of quality evidence from very low to high. CONCLUSIONS: The overall analysis including all trials showed that supplements provided moderate and clinically meaningful treatment effects on pain and function in patients with hand, hip or knee osteoarthritis at short term, although the quality of evidence was very low. Some supplements with a limited number of studies and participants suggested large treatment effects, while widely used supplements such as glucosamine and chondroitin were either ineffective or showed small and arguably clinically unimportant treatment effects. Supplements had no clinically important effects on pain and function at medium-term and long-term follow-ups.

Caffeine Intake, Coffee Consumption, and Risk of Cutaneous Malignant Melanoma.

BACKGROUND: Caffeine has been shown to prevent ultraviolet radiation-induced carcinogenesis and to inhibit growth of melanoma cells in experimental studies. We evaluated the association among caffeine intake, coffee consumption, and melanoma risk among three large cohort studies. METHODS: The analysis used data from 89,220 women in the Nurses' Health Study II (1991-2009), 74,666 women in the Nurses' Health Study (1980-2008), and 39,424 men in the Health Professionals Follow-up Study (1986-2008). We used Cox proportional hazards models to estimate the hazard ratios (HR) with 95% confidence intervals (CIs) of melanoma associated with dietary intakes. RESULTS: We documented 2,254 melanoma cases over 4 million person-years of follow-up. After adjustment for other risk factors, higher total caffeine intake was associated with a lower risk of melanoma (≥393 mg/day vs. <60 mg/day: HR = 0.78, 95% CI = 0.64, 0.96; Ptrend = 0.048). The association was more apparent in women (≥393 mg/day vs. <60 mg/day: HR = 0.70, 95% CI = 0.58, 0.85; Ptrend = 0.001) than in men (HR = 0.94, 95% CI = 0.75, 1.2; Ptrend = 0.81), and more apparent for melanomas occurring on body sites with higher continuous sun exposure (head, neck, and extremities; ≥393 mg/day vs. <60 mg/day: HR = 0.71, 95% CI = 0.59, 0.86; Ptrend = 0.001) than for melanomas occurring on body sites with lower continuous sun exposure (trunk including shoulder, back, hip, abdomen, and chest; HR = 0.90, 95% CI = 0.70, 1.2; Ptrend = 0.60). This pattern of association was similar to that for caffeinated coffee consumption, whereas no association was found for decaffeinated coffee consumption and melanoma risk. CONCLUSIONS: Increasing caffeine intake and caffeinated coffee consumption is associated with decreased risk of cutaneous malignant melanomas.

DNA Methylation Variants at HIF3A Locus, B-Vitamin Intake, and Long-term Weight Change: Gene-Diet Interactions in Two U.S. Cohorts.

The first epigenome-wide association study of BMI identified DNA methylation at an HIF3A locus associated with BMI. We tested the hypothesis that DNA methylation variants are associated with BMI according to intake of B vitamins. In two large cohorts, we found significant interactions between the DNA methylation-associated HIF3A single nucleotide polymorphism (SNP) rs3826795 and intake of B vitamins on 10-year changes in BMI. The association between rs3826795 and BMI changes consistently increased across the tertiles of total vitamin B2 and B12 intake (all P for interaction <0.01). The differences in the BMI changes per increment of minor allele were -0.10 (SE 0.06), -0.01 (SE 0.06), and 0.12 (SE 0.07) within subgroups defined by increasing tertiles of total vitamin B2 intake and -0.10 (SE 0.06), -0.01 (SE 0.06), and 0.10 (SE 0.07) within subgroups defined by increasing tertiles of total vitamin B12 intake. In two independent cohorts, a DNA methylation variant in HIF3A was associated with BMI changes through interactions with total or supplemental vitamin B2, vitamin B12, and folate. These findings suggest a potential causal relation between DNA methylation and adiposity.

Efficacy of a physiotherapy rehabilitation program for individuals undergoing arthroscopic management of femoroacetabular impingement - the FAIR trial: a randomised controlled trial protocol.

BACKGROUND: Femoroacetabular impingement is a common cause of hip/groin symptoms and impaired functional performance in younger sporting populations and results from morphological abnormalities of the hip in which the proximal femur abuts against the acetabular rim. Many people with symptomatic femoroacetabular impingement undergo arthroscopic hip surgery to correct the bony abnormalities. While many case series over the past decade have reported favourable surgical outcomes, it is not known whether formal rehabilitation is needed as part of the management of patients undergoing this surgical procedure. This randomised controlled trial will investigate the efficacy of a progressive physiotherapist-supervised rehabilitation program (Takla-O'Donnell Protocol) in improving health-related quality of life, physical function and symptoms in individuals undergoing arthroscopic management of femoroacetabular impingement. METHODS/DESIGN: 100 people aged 16-35 years undergoing hip arthroscopy for symptomatic femoroacetabular impingement will be recruited from surgical practices in Melbourne, Australia and randomly allocated to either a physiotherapy or control group. Both groups will receive written information and one standardised post-operative physiotherapy visit whilst in hospital as per usual care. Those in the physiotherapy group will also receive seven individual 30-minute physiotherapy sessions, including one pre-operative visit (within 2 weeks of surgery) and six post-operative visits at fortnightly intervals (commencing two weeks after surgery). The physiotherapy intervention will incorporate education and advice, manual techniques and prescription of a progressive rehabilitation program including home, aquatic and gym exercises. The control group will not receive additional physiotherapy management. Measurements will be taken at baseline (2 weeks pre-operatively) and at 14 and 24 weeks post-surgery. Primary outcomes are the International Hip Outcome Tool and the sports subscale of the Hip Outcome Score at 14 weeks post-surgery. Secondary outcomes include the Copenhagen Hip and Groin Outcome Score, the activities of daily living subscale of the Hip Outcome Score, the Heidelberg Sports Activity Score, a modified Tegner Activity Scale and participant-perceived overall change. DISCUSSION: The findings from this randomised controlled trial will provide evidence for the efficacy of a specific physiotherapist-supervised rehabilitation program in improving outcomes following arthroscopic management of symptomatic femoroacetabular impingement. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry reference number: ACTRN12613000282785.

Emerging drugs for osteoarthritis.

INTRODUCTION: Osteoarthritis (OA), the most prevalent form of joint disease, affects as much as 13% of the world's population. In the USA, it is the leading cause of disability in people over age 65 and is characterized by progressive cartilage loss, bone remodeling, osteophyte formation and synovial inflammation with resultant joint pain and disability. There are no treatments marketed for structural disease modification; current treatments mainly target symptoms, with > 75% of patients reporting need for additional symptomatic treatment. AREAS COVERED: Drugs in later development (Phase II - III) for OA pain and joint structural degeneration are reviewed. Topics that are not covered in this article are procedural-based (e.g., arthrocentesis, physical therapy), behavioral-based (e.g., weight loss, pain coping techniques) or device-based (e.g., knee braces, surgical implants) treatments. EXPERT OPINION: More in-depth understanding of the pathophysiology of the disease, as well as elucidation of the link between clinical symptomatology and structural changes in the joint will likely lead to the development of novel target classes with promising efficacy in the future. Efficacy notwithstanding, there remain significant hurdles to overcome in clinical development of these therapeutics, inherent in the progression pattern of the disease as well as challenges with readouts for both pain and structure modification trials.

Intakes of vitamins A, C, and E and use of multiple vitamin supplements and risk of colon cancer: a pooled analysis of prospective cohort studies.

OBJECTIVE: To evaluate the associations between intakes of vitamins A, C, and E and risk of colon cancer. METHODS: Using the primary data from 13 cohort studies, we estimated study- and sex-specific relative risks (RR) with Cox proportional hazards models and subsequently pooled RRs using a random effects model. RESULTS: Among 676,141 men and women, 5,454 colon cancer cases were identified (7-20 years of follow-up across studies). Vitamin A, C, and E intakes from food only were not associated with colon cancer risk. For intakes from food and supplements (total), the pooled multivariate RRs (95% CI) were 0.88 (0.76-1.02, >4,000 vs. ≤ 1,000 µg/day) for vitamin A, 0.81 (0.71-0.92, >600 vs. ≤ 100 mg/day) for vitamin C, and 0.78 (0.66-0.92, > 200 vs. ≤ 6 mg/day) for vitamin E. Adjustment for total folate intake attenuated these associations, but the inverse associations with vitamins C and E remained significant. Multivitamin use was significantly inversely associated with colon cancer risk (RR = 0.88, 95% CI: 0.81-0.96). CONCLUSIONS: Modest inverse associations with vitamin C and E intakes may be due to high correlations with folate intake, which had a similar inverse association with colon cancer. An inverse association with multivitamin use, a major source of folate and other vitamins, deserves further study.

Transforming osteoarthritis care in an era of health care reform.

This article describes the dysfunctional delivery of existing conservative care practices in the treatment of osteoarthritis (OA) within the context of a dynamic environment of health reform. It is written from the patient perspective of one of the authors who is afflicted with OA and with the added clinical view of a rheumatologist. The authors envision benefits of more cost-effective care, a decrease in the impact of chronic illness on the financial viability of the United States, and an improvement in the quality of care provided to patients. These benefits can be achieved with tested innovations organized within the integrated delivery system described in this article.

A large prospective study of SEP15 genetic variation, interaction with plasma selenium levels, and prostate cancer risk and survival.

The role of selenium in prostate cancer (PCa) risk remains controversial, but many epidemiologic studies suggest an inverse association with more aggressive disease. A recently discovered selenoprotein, SEP15, which is highly expressed in the prostate, may play a role either independently or by modifying the effects of selenium. We genotyped four common single-nucleotide polymorphisms capturing common variation (frequency >5%; R(2) > 0.8) within SEP15, as well as rs5859 in the 3' untranslated region, previously reported to reduce the efficiency of selenium incorporation into SEP15. We examined the association of these single-nucleotide polymorphisms with PCa risk and PCa-specific mortality, as well as their interactions with plasma selenium levels, in the Physicians' Health Study. In this nested case-control study (1,286 cases and 1,267 controls), SEP15 polymorphisms were not significantly associated with PCa risk. However, among the cases, three variants were significantly associated with PCa-specific mortality [rs479341 hazard ratio (HR), 1.94; 95% confidence interval (95% CI), 1.15-3.25; rs1407131 HR, 2.85; 95% CI, 1.45-5.59; rs561104 HR, 1.54; 95% CI, 1.12-2.11] with a recessive model. Additionally, rs561104 significantly modified the association of plasma selenium with PCa survival (P(interaction) = 0.02); an inverse relationship of high levels of selenium with PCa mortality was apparent only among those without the increased risk genotype. This study provides evidence that SEP15 genetic variation may influence PCa mortality. Additionally, the association of selenium with PCa mortality was modified by a variant, suggesting the possibility that some men with PCa may benefit more from selenium than others, depending on their genotype.

Uracil misincorporation into DNA and folic acid supplementation.

BACKGROUND: Folate deficiency decreases thymidylate synthesis from deoxyuridylate, which results in an imbalance of deoxyribonucleotide that may lead to excessive uracil misincorporation (UrMis) into DNA during replication and repair. OBJECTIVE: We evaluated the relation between UrMis in different tissues and the effect of folate supplementation on UrMis. DESIGN: We analyzed UrMis concentrations in rectal mucosa (n = 92) and white blood cells (WBCs; n = 60) among individuals randomly assigned to receive supplementation with 1 mg folate/d or placebo, who were then evaluated for colorectal adenoma recurrence. RESULTS: As expected, total homocysteine was significantly lower among the study participants who received active folate treatment (Wilcoxon's P = 0.003) than among those in the placebo group. The median UrMis concentration in rectal mucosa and WBCs among individuals treated with folate was not significantly lower than that in those who received placebo (Wilcoxon's P = 0.17). UrMis concentrations in both rectal mucosa and WBCs did not correlate significantly with folate measured in plasma and red blood cells. UrMis in rectal mucosa was marginally associated with an increased risk of adenoma recurrence (odds ratio per SD: 1.43; 95% CI: 0.91, 2.25). CONCLUSIONS: UrMis measurements in WBCs are not a robust surrogate for UrMis measurements in the rectal mucosa (Spearman correlation coefficient = 0.23, P = 0.08). Furthermore, folate supplementation in an already replete population (half treated with folic acid supplements and all exposed to folic acid fortification of the food supply) was not significantly associated with reduced UrMis in rectal mucosa cells or WBCs. Large-scale studies are needed to evaluate whether excessive UrMis concentrations are an important risk factor for colorectal neoplasia. This trial was registered at clinicaltrials.gov as NCT00272324.