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1.  A bespoke mobile application for the longitudinal assessment of depression and mood during pregnancy: protocol of a feasibility study 
BMJ Open  2017;7(5):e014469.
Depression is a common mental health disorder during pregnancy, with important consequences for mothers and their children. Despite this, it goes undiagnosed and untreated in many women attending antenatal care. Smartphones could help support the prompt identification of antenatal depression in this setting. In addition, these devices enable the implementation of ecological momentary assessment techniques, which could be used to assess how mood is experienced during pregnancy. With this study, we will assess the feasibility of using a bespoke mobile application (app) running on participants’ own handsets for the longitudinal (6 months) monitoring of antenatal mood and screening of depression.
Methods and analysis
We will use a randomised controlled study design to compare two types of assessment strategies: retrospective + momentary (consisting of the Edinburgh Postnatal Depression Scale plus five momentary and two contextual questions), and retrospective (consisting of the Edinburgh Postnatal Depression Scale only). We will assess the impact that these strategies have on participant adherence to a prespecified sampling protocol, dropout rates and timeliness of data completion. We will evaluate differences in acceptance of the technology through a short quantitative survey and open-ended questions. We will also assess the potential effect that momentary assessments could have on retrospective data. We will attempt to identify any patterns in app usage through the analysis of log data.
Ethics and dissemination
This study has been reviewed and approved by the National Research Ethics Service Committee South East Coast—Surrey on 15 April 2016 as a notice of substantial amendment to the original submission (9 July 2015) under the Research Ethics Committee (REC) reference 15/LO/0977. This study is being sponsored by Imperial College London under the reference number 15IC2687 and has been included in the UK Clinical Research Network Study Portfolio under the Central Portfolio Management System number 19280. The findings of this study will be disseminated through academic peer-reviewed publications, poster presentations and abstracts at academic and professional conferences, discussion with peers, and social media. The findings of this study will also inform the PhD theses of JSMB and KD.
PMCID: PMC5729976  PMID: 28554914
Depression & mood disorders < PSYCHIATRY; Ecological momentary assessment; mHealth; Antenatal care; Mobile apps
2.  Novel Genetic Variants for Cartilage Thickness and Hip Osteoarthritis 
PLoS Genetics  2016;12(10):e1006260.
Osteoarthritis is one of the most frequent and disabling diseases of the elderly. Only few genetic variants have been identified for osteoarthritis, which is partly due to large phenotype heterogeneity. To reduce heterogeneity, we here examined cartilage thickness, one of the structural components of joint health. We conducted a genome-wide association study of minimal joint space width (mJSW), a proxy for cartilage thickness, in a discovery set of 13,013 participants from five different cohorts and replication in 8,227 individuals from seven independent cohorts. We identified five genome-wide significant (GWS, P≤5·0×10−8) SNPs annotated to four distinct loci. In addition, we found two additional loci that were significantly replicated, but results of combined meta-analysis fell just below the genome wide significance threshold. The four novel associated genetic loci were located in/near TGFA (rs2862851), PIK3R1 (rs10471753), SLBP/FGFR3 (rs2236995), and TREH/DDX6 (rs496547), while the other two (DOT1L and SUPT3H/RUNX2) were previously identified. A systematic prioritization for underlying causal genes was performed using diverse lines of evidence. Exome sequencing data (n = 2,050 individuals) indicated that there were no rare exonic variants that could explain the identified associations. In addition, TGFA, FGFR3 and PIK3R1 were differentially expressed in OA cartilage lesions versus non-lesioned cartilage in the same individuals. In conclusion, we identified four novel loci (TGFA, PIK3R1, FGFR3 and TREH) and confirmed two loci known to be associated with cartilage thickness.The identified associations were not caused by rare exonic variants. This is the first report linking TGFA to human OA, which may serve as a new target for future therapies.
Author Summary
Osteoarthritis (OA) is the most common form of arthritis and a leading cause of chronic disability in the western society affecting millions of people. OA is a degenerative joint disease characterized by changes in all joint tissues, including cartilage, bone and synovium, causing chronic pain and loss of function. There are no effective therapeutic treatments available for OA and therefore finding novel biological pathways through genetic association studies can open up new treatment options. The number of known DNA variants associated with OA-risk is limited.
To identify new loci, we have performed a Genome Wide Association Study meta-analysis on cartilage thickness, one of the joint tissues affected in OA in a total sample of more than 20,000 individuals from twelve cohorts. This analysis revealed six variants associated with cartilage thickness, four of these being novel associations, including TGFA as the most prominent one. A systematic prioritization for underlying causal genes, using diverse lines of evidence, highlighted genes underlying the disease associations, including TGFA, RUNX2 and PIK3R1. Large scale exome sequencing data (n = 2,050 individuals) indicated that there were no rare exonic variants that could explain the identified associations. This is the first report linking TGFA to human OA, which may serve as a new target for future therapies
PMCID: PMC5049763  PMID: 27701424
3.  Genome-wide Association and Functional Studies Identify a Role for IGFBP3 in Hip Osteoarthritis 
Annals of the rheumatic diseases  2014;74(10):1861-1867.
To identify genetic associations with hip osteoarthritis (HOA), we performed a meta-analysis of genome-wide association studies (GWAS) of HOA.
The GWAS meta-analysis included approximately 2.5 million imputed HapMap single nucleotide polymorphisms (SNPs). HOA cases and controls defined radiographically and by total hip replacement were selected from the Osteoporotic Fractures in Men (MrOS) Study and the Study of Osteoporotic Fractures (SOF) (654 cases and 4697 controls, combined). Replication of genome-wide significant SNP associations (P-value ≤ 5x10−8) was examined in five studies (3243 cases and 6891 controls, combined). Functional studies were performed using in vitro models of chondrogenesis and osteogenesis.
The A allele of rs788748, located 65 kb upstream of the IGFBP3 gene, was associated with lower HOA odds at the genome-wide significance level in the discovery stage (OR = 0.71, P-value = 2x10−8). The association replicated in five studies (OR = 0.92, P-value = 0.020), but the joint analysis of discovery and replication results was not genome-wide significant (P-value = 1x10−6). In separate study populations, the rs788748 A allele was also associated with lower circulating IGFBP3 protein levels (P-value = 4x10−13), suggesting that this SNP or a variant in linkage disequilibrium (LD) could be an IGFBP3 regulatory variant. Results from functional studies were consistent with association results. Chondrocyte hypertrophy, a deleterious event in OA pathogenesis, was largely prevented upon IGFBP3 knockdown in chondrocytes. Furthermore, IGFBP3 overexpression induced cartilage catabolism and osteogenic differentiation.
Results from GWAS and functional studies provided suggestive links between IGFBP3 and HOA.
PMCID: PMC4449305  PMID: 24928840
Osteoarthritis of hip; genome-wide association study; functional study; chondrogenesis; IGFBP3
5.  Large-Scale Analysis of Association Between GDF5 and FRZB Variants and Osteoarthritis of the Hip, Knee, and Hand 
Arthritis and rheumatism  2009;60(6):1710-1721.
GDF5 and FRZB have been proposed as genetic loci conferring susceptibility to osteoarthritis (OA); however, the results of several studies investigating the association of OA with the rs143383 polymorphism of the GDF5 gene or the rs7775 and rs288326 polymorphisms of the FRZB gene have been conflicting or inconclusive. To examine these associations, we performed a large-scale meta-analysis of individual-level data.
Fourteen teams contributed data on polymorphisms and knee, hip, and hand OA. For rs143383, the total number of cases and controls, respectively, was 5,789 and 7,850 for hip OA, 5,085 and 8,135 for knee OA, and 4,040 and 4,792 for hand OA. For rs7775, the respective sample sizes were 4,352 and 10,843 for hip OA, 3,545 and 6,085 for knee OA, and 4,010 and 5,151 for hand OA, and for rs288326, they were 4,346 and 8,034 for hip OA, 3,595 and 6,106 for knee OA, and 3,982 and 5,152 for hand OA. For each individual study, sex-specific odds ratios (ORs) were calculated for each OA phenotype that had been investigated. The ORs for each phenotype were synthesized using both fixed-effects and random-effects models for allele-based effects, and also for haplotype effects for FRZB.
A significant random-effects summary OR for knee OA was demonstrated for rs143383 (1.15 [95% confidence interval 1.09–1.22]) (P = 9.4 × 10−7), with no significant between-study heterogeneity. Estimates of effect sizes for hip and hand OA were similar, but a large between-study heterogeneity was observed, and statistical significance was borderline (for OA of the hip [P = 0.016]) or absent (for OA of the hand [P = 0.19]). Analyses for FRZB polymorphisms and haplotypes did not reveal any statistically significant signals, except for a borderline association of rs288326 with hip OA (P = 0.019).
Evidence of an association between the GDF5 rs143383 polymorphism and OA is substantially strong, but the genetic effects are consistent across different populations only for knee OA. Findings of this collaborative analysis do not support the notion that FRZB rs7775 or rs288326 has any sizable genetic effect on OA phenotypes.
PMCID: PMC4412885  PMID: 19479880
7.  Garlic Revisited: Antimicrobial Activity of Allicin-Containing Garlic Extracts against Burkholderia cepacia Complex 
PLoS ONE  2014;9(12):e112726.
The antimicrobial activities of garlic and other plant alliums are primarily based on allicin, a thiosulphinate present in crushed garlic bulbs. We set out to determine if pure allicin and aqueous garlic extracts (AGE) exhibit antimicrobial properties against the Burkholderia cepacia complex (Bcc), the major bacterial phytopathogen for alliums and an intrinsically multiresistant and life-threatening human pathogen. We prepared an AGE from commercial garlic bulbs and used HPLC to quantify the amount of allicin therein using an aqueous allicin standard (AAS). Initially we determined the minimum inhibitory concentrations (MICs) of the AGE against 38 Bcc isolates; these MICs ranged from 0.5 to 3% (v/v). The antimicrobial activity of pure allicin (AAS) was confirmed by MIC and minimum bactericidal concentration (MBC) assays against a smaller panel of five Bcc isolates; these included three representative strains of the most clinically important species, B. cenocepacia. Time kill assays, in the presence of ten times MIC, showed that the bactericidal activity of AGE and AAS against B. cenocepacia C6433 correlated with the concentration of allicin. We also used protein mass spectrometry analysis to begin to investigate the possible molecular mechanisms of allicin with a recombinant form of a thiol-dependent peroxiredoxin (BCP, Prx) from B. cenocepacia. This revealed that AAS and AGE modifies an essential BCP catalytic cysteine residue and suggests a role for allicin as a general electrophilic reagent that targets protein thiols. To our knowledge, we report the first evidence that allicin and allicin-containing garlic extracts possess inhibitory and bactericidal activities against the Bcc. Present therapeutic options against these life-threatening pathogens are limited; thus, allicin-containing compounds merit investigation as adjuncts to existing antibiotics.
PMCID: PMC4249831  PMID: 25438250
8.  Synovial pathology detected on ultrasound correlates with the severity of radiographic knee osteoarthritis more than with symptoms 
Osteoarthritis and Cartilage  2014;22(10):1627-1633.
To [1] compare the frequency and severity of ultrasound (US) features in people with normal knees (controls), knee pain (KP), asymptomatic radiographic OA (ROA), and symptomatic OA (SROA), [2] examine relationships between US features, pain and radiographic severity, [3] explore the relationship between change in pain and US features over a 3-month period.
Community participants were recruited into a multiple group case–control study. All underwent assessment for pain, knee radiographs and US examination for effusion, synovial hypertrophy, popliteal cysts and power Doppler (PD) signal within the synovium. A 3-month follow-up was undertaken in over half of control and SROA participants.
243 participants were recruited (90 controls; 59 KP; 32 ROA; 62 SROA). Effusion and synovial hypertrophy were more common in ROA and SROA participants. Severity of effusion and synovial hypertrophy were greater in SROA compared to ROA (P < 0.05). Severity of US effusion and synovial hypertrophy were correlated with radiographic severity (r = 0.6 and r = 0.7, P < 0.01) but the relationship between pain severity and US features was weak (r = 0.3, P < 0.01). In SROA participants, pain severity did not change in tandem with a change in synovial hypertrophy over time.
US abnormalities are common in OA. Effusion and synovial hypertrophy were moderately correlated with radiographic severity but the relationship with pain is less strong. The degree to which these features reflect “active inflammation” is questionable and they may be better considered as part of the total organ pathology in OA. Further studies are warranted to confirm these findings.
PMCID: PMC4192137  PMID: 25278071
Ultrasound; Knee osteoarthritis; Inflammation; Pain; Synovitis
9.  The association between ANKH promoter polymorphism and chondrocalcinosis is independent of age and osteoarthritis: results of a case–control study 
Chondrocalcinosis (CC) most commonly results from calcium pyrophosphate crystal deposition (CPPD). The objective of this study is to examine the association between candidate single-nucleotide polymorphisms (SNPs) and radiographic CC.
SNPs in ankylosis human (ANKH), high ferritin (HFE), tissue non-specific alkaline phosphatase (TNAP), ecto-neucleotide pyrophosphatase 1 (ENPP1), and transferrin (TE) genes were genotyped in participants of the Genetics of Osteoarthritis and Lifestyle (GOAL) and Nottingham Osteoarthritis Case-Control studies. Adjusted genotype odds ratio (aORGENOTYPE), the OR for association between one additional minor allele and CC, was calculated and adjusted for age, gender, body mass index (BMI), and osteoarthritis (OA) by using binary logistic regression. Statistical significance was set at P ≤0.003 after Bonferroni correction for multiple tests.
The -4bpG > A polymorphism in the 5′ untranslated region (5′ UTR) of ANKH associated with CC after Bonferroni correction. This was independent of age, gender, OA, and BMI; aORGENOTYPE (95% confidence interval, or CI) was 1.39 (1.14-1.69) (P = 0.001). rs3045 and rs875525, two other SNPs in ANKH, associated with CC; aORGENOTYPE (95% CI) values were 1.31 (1.09-1.58) (P = 0.005) and 1.18 (1.03-1.35) (P = 0.015), respectively; however, this was non-significant after Bonferroni correction.
This study validates the association between a functional polymorphism in the 5′ UTR of ANKH and CC and shows for the first time that this is independent of age and OA – the two key risk factors for CC. It shows that other SNPs in ANKH may also associate with CC. This supports the role of extracellular inorganic pyrophosphate in the pathogenesis of CC. The findings of this hospital-based study require replication in a community-based population.
PMCID: PMC3978851  PMID: 24467728
10.  A Role for PACE4 in Osteoarthritis Pain: Evidence from Human Genetic Association and Null Mutant Phenotype 
Annals of the rheumatic diseases  2012;71(6):1042-1048.
To assess if genetic variation in the PACE4 gene, PCSK6, influences the risk for symptomatic knee OA.
Ten PCSK6 single nucleotide polymorphisms (SNP) were tested for association in a discovery cohort of radiographic knee OA (n= 156 asymptomatic and 600 symptomatic cases). Meta-analysis of the minor allele at rs900414 was performed in three additional independent cohorts (total n=674 asymptomatic and 2068 symptomatic). Pcsk6 knockout (KO) mice and wildtype C57BL/6 mice were compared in a battery of algesiometric assays, including hypersensitivity in response to intraplantar substance P; pain behaviours in response to intrathecal substance P; and pain behaviour in the abdominal constriction test.
In the discovery cohort of radiographic knee OA, an intronic SNP at rs900414 was significantly associated with symptomatic OA. Replication in three additional cohorts confirmed that the minor allele at rs900414 was consistently increased among asymptomatic compared to symptomatic radiographic knee OA cases in all four cohorts. A fixed-effects meta-analysis yielded an odds ratio =1.35 (95% CI 1.17, 1.56; p-value 4.3×10−5 and no significant between-study heterogeneity). Studies in mice revealed that Pcsk6 knockout (KO) mice were significantly protected against pain in a battery of algesiometric assays.
These results suggest that a variant in PCSK6 is strongly associated with protection against pain in knee OA, offering some insight as to why in the presence of the same structural damage, some individuals develop chronic pain and others are protected. Studies in Pcsk6 null mutant mice further implicate PACE4 in pain.
PMCID: PMC3603144  PMID: 22440827
Knee osteoarthritis; pain; PACE4; genetic association; SNP
11.  Gene-environment interaction between body mass index and transforming growth factor beta 1 (TGFβ1) gene in knee and hip osteoarthritis 
The objective was to investigate potential gene-environment interaction between body mass index (BMI) and each of eight TGFβ1 polymorphisms in knee and hip osteoarthritis (OA).
We conducted a case-control study of Caucasian men and women aged 45 to 86 years from Nottingham, United Kingdom (Genetics of OA and Lifestyle (GOAL) study). Cases had clinically severe symptoms and radiographic knee or hip OA; controls had no symptoms and no radiographic knee/hip OA. We used logistic regression to investigate the association of TGFβ1 polymorphisms and OA when stratifying by BMI. Knee and hip OA were analyzed separately with adjustment for potential confounders. Additive and multiplicative interactions were examined.
2,048 cases (1,042 knee OA, 1,006 hip OA) and 967 controls were studied. For hip OA, the highest risk was in overweight (BMI ≥25 kg/m2) individuals with the variant allele of single-nucleotide polymorphism (SNP) rs1800468 (odds ratio (OR) 2.21, 95% confidence interval (CI) 1.55, 3.15). Evaluation of gene-environment interaction indicated significant synergetic interaction (relative excess risk due to interaction (RERI) = 0.93, synergy index (SI) = 4.33) with an attributable proportion due to interaction (AP) of 42% (AP = 0.42; 95% CI 0.16, 0.68). Multiplicative interaction was also significant (OR for interaction (ORINT) = 2.27, P = 0.015). For knee OA, the highest risk was in overweight individuals with homozygous genotype 11 of SNP rs2278422 (OR = 6.95, P <0.001). In contrast, the variant allele indicated slightly lower risks (OR = 4.72, P <0.001), a significant antagonistic interaction (RERI = -2.66, SI = 0.59), AP = -0.56 (95%CI -0.94, -0.17) and a significant multiplicative interaction (ORINT = 0.47, P = 0.013).
TGFβ1 gene polymorphisms interact with being overweight to influence the risk of large joint OA.
PMCID: PMC4060375  PMID: 23597094
12.  Meta-analysis of genome-wide association studies confirms a susceptibility locus for knee osteoarthritis on chromosome 7q22 
Evangelou, Evangelos | Valdes, Ana M. | Kerkhof, Hanneke J.M | Styrkarsdottir, Unnur | Zhu, YanYan | Meulenbelt, Ingrid | Lories, Rik J. | Karassa, Fotini B. | Tylzanowski, Przemko | Bos, Steffan D. | Akune, Toru | Arden, Nigel K. | Carr, Andrew | Chapman, Kay | Cupples, L. Adrienne | Dai, Jin | Deloukas, Panos | Doherty, Michael | Doherty, Sally | Engstrom, Gunnar | Gonzalez, Antonio | Halldorsson, Bjarni V. | Hammond, Christina L. | Hart, Deborah J. | Helgadottir, Hafdis | Hofman, Albert | Ikegawa, Shiro | Ingvarsson, Thorvaldur | Jiang, Qing | Jonsson, Helgi | Kaprio, Jaakko | Kawaguchi, Hiroshi | Kisand, Kalle | Kloppenburg, Margreet | Kujala, Urho M. | Lohmander, L. Stefan | Loughlin, John | Luyten, Frank P. | Mabuchi, Akihiko | McCaskie, Andrew | Nakajima, Masahiro | Nilsson, Peter M. | Nishida, Nao | Ollier, William E.R. | Panoutsopoulou, Kalliope | van de Putte, Tom | Ralston, Stuart H. | Rivadeneira, Fernado | Saarela, Janna | Schulte-Merker, Stefan | Slagboom, P. Eline | Sudo, Akihiro | Tamm, Agu | Tamm, Ann | Thorleifsson, Gudmar | Thorsteinsdottir, Unnur | Tsezou, Aspasia | Wallis, Gillian A. | Wilkinson, J. Mark | Yoshimura, Noriko | Zeggini, Eleftheria | Zhai, Guangju | Zhang, Feng | Jonsdottir, Ingileif | Uitterlinden, Andre G. | Felson, David T | van Meurs, Joyce B. | Stefansson, Kari | Ioannidis, John P.A. | Spector, Timothy D.
Annals of the rheumatic diseases  2010;70(2):349-355.
Osteoarthritis (OA) is the most prevalent form of arthritis and accounts for substantial morbidity and disability, particularly in the elderly. It is characterized by changes in joint structure including degeneration of the articular cartilage and its etiology is multifactorial with a strong postulated genetic component. We performed a meta-analysis of four genome-wide association (GWA) studies of 2,371 knee OA cases and 35,909 controls in Caucasian populations. Replication of the top hits was attempted with data from additional ten replication datasets. With a cumulative sample size of 6,709 cases and 44,439 controls, we identified one genome-wide significant locus on chromosome 7q22 for knee OA (rs4730250, p-value=9.2×10−9), thereby confirming its role as a susceptibility locus for OA. The associated signal is located within a large (500kb) linkage disequilibrium (LD) block that contains six genes; PRKAR2B (protein kinase, cAMP-dependent, regulatory, type II, beta), HPB1 (HMG-box transcription factor 1), COG5 (component of oligomeric golgi complex 5), GPR22 (G protein-coupled receptor 22), DUS4L (dihydrouridine synthase 4-like), and BCAP29 (the B-cell receptor-associated protein 29). Gene expression analyses of the (six) genes in primary cells derived from different joint tissues confirmed expression of all the genes in the joint environment.
PMCID: PMC3615180  PMID: 21068099
13.  Chito-Oligosaccharide Inhibits the De-Methylation of a ‘CpG’ Island within the Leptin (LEP) Promoter during Adipogenesis of 3T3-L1 Cells 
PLoS ONE  2013;8(3):e60011.
Chito-oligosaccharide (COS) is a natural bioactive compound, which has been shown to suppress lipid metabolic genes and lipid accumulation in differentiating adipocytes. Leptin has been identified as a key regulator of energy homeostasis and is known to be under epigenetic regulation during adipogenesis. Hence, the first objective of this experiment was to compare leptin gene (LEP) expression and leptin secretion during the different stages of adipogenesis and to investigate the effect of COS on these processes. As COS inhibited LEP expression during adipogenesis, the second aim was to investigate the methylation dynamics of a ‘CpG’ island in the proximal region of the LEP promoter during adipogenesis and to determine the effect of COS on this process. Mouse 3T3-L1 cells were stimulated to differentiate in the absence or presence of COS and the levels of leptin mRNA and protein were evaluated on days 0, 2, 4 and 6 post-induction of differentiation (PID). The extent of de-methylation of six CpG sites was evaluated. LEP mRNA transcript and protein could not be detected on either day 0PID or 2PID. In contrast, both were detected on day 4PID (P<0.05) and 6PID (P<0.001) and both were inhibited by COS (P<0.001). Of the six CpG sites analyzed, CpG_52, CpG_62 and CpG_95 became 11.5, 5.0 and 5.0% de-methylated between day 2PID and 6PID, respectively. COS blocked this de-methylation event at CpG_52 (P<0.001), CpG_62 (P<0.01) and CpG_95 (P<0.01) on day 6PID. These data suggest that COS can have an epigenetic effect on differentiating adipocytes, a novel biological function of COS which has potential applications for the manipulation of leptin gene expression, adipogenesis, and conditions within the metabolic syndrome spectrum.
PMCID: PMC3609775  PMID: 23544120
14.  Chondrocalcinosis is common in the absence of knee involvement 
Arthritis Research & Therapy  2012;14(5):R205.
We aimed to describe the distribution of radiographic chondrocalcinosis (CC) and to examine whether metacarpophalangeal joint (MCPJ) calcification and CC at other joints occurs in the absence of knee involvement.
This was a cross-sectional study embedded in the Genetics of Osteoarthritis and Lifestyle study (GOAL). All participants (n = 3,170) had radiographs of the knees, hands, and pelvis. These were scored for radiographic changes of osteoarthritis (OA), for CC at knees, hips, symphysis pubis, and wrists, and for MCPJ calcification. The prevalence of MCPJ calcification and CC overall, at each joint, and in the presence or absence of knee involvement, was calculated.
The knee was the commonest site of CC, followed by wrists, hips, and symphysis pubis. CC was more likely to be bilateral at knees and wrists but unilateral at hips. MCPJ calcification was usually bilateral, and less common than CC at knees, hips, wrists, and symphysis pubis. Unlike that previously reported, CC commonly occurred without any knee involvement; 44.4% of wrist CC, 45.9% of hip CC, 45.5% of symphysis pubis CC, and 31.3% of MCPJ calcification occurred in patients without knee CC. Those with meniscal or hyaline articular cartilage CC had comparable ages (P = 0.21), and neither preferentially associated with fibrocartilage CC at distant joints.
CC visualized on a plain radiograph commonly occurs at other joints in the absence of radiographic knee CC. Therefore, knee radiographs alone are an insufficient screening test for CC. This has significant implications for clinical practice, for epidemiologic and genetic studies of CC, and for the definition of OA patients with coexistent crystal deposition.
PMCID: PMC3580517  PMID: 23036436
15.  A Genome-Wide Association Study identifies a locus on chromosome 7q22 to influence susceptibility for osteoarthritis 
Arthritis and Rheumatism  2010;62(2):499-510.
To identify genes involved in osteoarthritis (OA), the most prevalent form of joint disease, we performed a genome-wide association study (GWAS) in which we tested 500,510 Single Nucelotide Polymorphisms (SNPs) in 1341 OA cases and 3496 Dutch Caucasian controls. SNPs associated with at least two OA-phenotypes were analysed in 14,938 OA cases and approximately 39,000 controls. The C-allele of rs3815148 on chromosome 7q22 (MAF 23%, 172 kb upstream of the GPR22 gene) was consistently associated with a 1.14-fold increased risk (95%CI: 1.09–1.19) for knee- and/or hand-OA (p=8×10−8), and also with a 30% increased risk for knee-OA progression (95%CI: 1.03–1.64, p=0.03). This SNP is in almost complete linkage disequilibrium with rs3757713 (located 68 kb upstream of GPR22) which is associated with GPR22 expression levels in lymphoblast cell lines (p=4×10−12). GPR22 encodes an G-protein coupled receptor with unkown ligand (orphan receptor). Immunohistochemistry experiments showed absence of GPR22 in normal mouse articular cartilage or synovium. However, GPR22 positive chondrocytes were found in the upper layers of the articular cartilage of mouse knee joints that were challenged by in vivo papain treatment or in the presence of interleukin-1 driven inflammation. GRP22 positive chondrocyte-like cells were also found in osteophytes in instability-induced OA. In addition, GPR22 is also present in areas of the brain involved in locomotor function. Our findings reveal a novel common variant on chromosome 7q22 to influence susceptibility for prevalence and progression of OA.
PMCID: PMC3354739  PMID: 20112360
16.  Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium 
To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes.
Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. To investigate whether different OA definitions result in different association results, we created hip OA definitions used within the consortium in the Rotterdam Study-I and tested the association of hip OA with gender, age and BMI using one-way ANOVA. For radiographic OA, we standardized the hip, knee and hand ROA definitions and calculated prevalence's of ROA before and after standardization in 9 cohort studies. This procedure could only be performed in cohort studies and standardization of SOA definitions was not feasible at this moment.
In this consortium, all studies with symptomatic OA phenotypes (knee, hip and hand) used a different definition and/or assessment of OA status. For knee, hip and hand radiographic OA 5, 4 and 7 different definitions were used, respectively. Different hip OA definitions do lead to different association results. For example, we showed in the Rotterdam Study-I that hip OA defined as “at least definite JSN and one definite osteophyte” was not associated with gender (p=0.22), but defined as “at least one definite osteophyte” was significantly associated with gender (p=3×10−9). Therefore, a standardization process was undertaken for radiographic OA definitions. Before standardization a wide range of ROA prevalence's was observed in the 9 cohorts studied. After standardization the range in prevalence of knee and hip ROA was small. Standardization of SOA phenotypes was not possible due to the case-control design of the studies.
Phenotype definitions influence the prevalence of OA and association with clinical variables. ROA phenotypes within the TREAT-OA consortium were standardized to reduce heterogeneity and improve power in future genetics studies.
PMCID: PMC3236091  PMID: 21059398
17.  Large Scale Replication Study of the Association between HLA Class II/BTNL2 Variants and Osteoarthritis of the Knee in European-Descent Populations 
PLoS ONE  2011;6(8):e23371.
Osteoarthritis (OA) is the most common form of arthritis and a major cause of disability. This study evaluates the association in Caucasian populations of two single nucleotide polymorphisms (SNPs) mapping to the Human Leukocyte Antigen (HLA) region and deriving from a genome wide association scan (GWAS) of knee OA in Japanese populations. The frequencies for rs10947262 were compared in 36,408 controls and 5,749 knee OA cases from European-descent populations. rs7775228 was tested in 32,823 controls and 1,837 knee OA cases of European descent. The risk (major) allele at rs10947262 in Caucasian samples was not significantly associated with an odds ratio (OR)  = 1.07 (95%CI 0.94 -1.21; p = 0.28). For rs7775228 the meta-analysis resulted in OR = 0.94 (95%CI 0.81-1.09; p = 0.42) for the allele associated with risk in the Japanese GWAS. In Japanese individuals these two SNPs are in strong linkage disequilibrium (LD) (r2 = 0.86) with the HLA class II haplotype DRB1*1502 DQA1*0103 DQB1*0601 (frequency 8%). In Caucasian and Chinese samples, using imputed data, these SNPs appear not to be in LD with that haplotype (r2<0.07). The rs10947262 and rs7775228 variants are not associated with risk of knee OA in European descent populations and they do not appear tag the same HLA class II haplotype as they do in Japanese individuals.
PMCID: PMC3154440  PMID: 21853121
18.  Recovering from recurrent mental health problems: giving up and fighting to get better 
The purpose of this paper is to present selected findings of a grounded theory study which aims to explore individual processes and desired outcomes of recovery from recurrent health problems in order to build up a theoretical framework of recovering in an Irish context.
Volunteers include mental health service users or participants of peer support groups who have experienced recurrent mental health problems for two or more years, consider themselves in improvement, and are willing to participate in individual interviews. The current paper is based on the analysis of 15 audio recorded and transcribed interviews.
We identified two open codes of ‘giving up’ and ‘fighting to get better’. Giving up was associated with accepting a passive identity of a chronic ‘mental patient’ and a lack of intrinsic motivation to get better. Fighting had both positive (fighting for) and negative (fighting against) dimensions, as well as internal and external ones.
The ‘fight’ for recovery entailed substantial and sometimes risky effort. Starting such fight required strong self-sustained motivation. Service providers may need to discuss internal and external motivators of fighting for recovery with service users, with a view to including such motivators in the care plans.
PMCID: PMC2839479  PMID: 20074198
interviews; mental health services; mental illness; recovery; grounded theory
19.  Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study 
Annals of the Rheumatic Diseases  2010;70(5):864-867.
The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis.
The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent.
None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects.
Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.
PMCID: PMC3070286  PMID: 21177295
20.  Gender and self-reported mental health problems: predictors of help-seeking from a general practitioner 
British journal of health psychology  2009;15(Pt 1):213-228.
Findings have shown that many people do not seek help when experiencing psychological distress. The main aim of this paper was to examine the sociodemographic and health status factors that predict help seeking for self reported mental health problems for males and females from a general practitioner.
The analysis used data from the HRB National Psychological Wellbeing and Distress Survey – a telephone survey of the population aged 18 years and over.
Telephone numbers were selected on a random probability basis. An initial set of random clusters was selected from the Geodirectory. Using these sampling areas, random digit dialling was used to generate a random telephone sample. Data were weighted on key variables. Respondents who reported mental health problems in the previous year were included in the current study (382 / 2674).
The findings showed gender differences in the models of predictors between males and females with more factors influencing attendance at the GP for males than for females. While only social limitations and access to free healthcare predicted female attendance, a range of sociodemographic and psychological factors influenced male attendance.
Findings suggest that a ‘gender sensitive approach’ should be applied to mental health policies and mental health promotion and prevention programmes. Acknowledgement and awareness of the factors that influence help seeking will aid the design of gender specific promotion, prevention and treatment programmes at primary care level.
PMCID: PMC2845878  PMID: 19527564
21.  Development and validation of self-reported line drawings for assessment of knee malalignment and foot rotation: a cross-sectional comparative study 
For large scale epidemiological studies clinical assessments and radiographs can be impractical and expensive to apply to more than just a sample of the population examined. The study objectives were to develop and validate two novel instruments for self-reported knee malalignment and foot rotation suitable for use in questionnaire studies of knee pain and osteoarthritis.
Two sets of line drawings were developed using similar methodology. Each instrument consisted of an explanatory question followed by a set of drawings showing straight alignment, then two each at 7.5° angulation and 15° angulation in the varus/valgus (knee) and inward/outward (foot) directions. Forty one participants undertaking a community study completed the instruments on two occasions. Participants were assessed once by a blinded expert clinical observer with demonstrated excellent reproducibility. Validity was assessed by sensitivity, specificity and likelihood ratio (LR) using the observer as the reference standard. Reliability was assessed using weighted kappa (κ). Knee malalignment was measured on 400 knee radiographs. General linear model was used to assess for the presence of a linear increase in knee alignment angle (measured medially) from self-reported severe varus to mild varus, straight, mild valgus and severe valgus deformity.
Observer reproducibility (κ) was 0.89 and 0.81 for the knee malalignment and foot rotation instruments respectively. Self-reported participant reproducibility was also good for the knee (κ 0.73) and foot (κ 0.87) instruments. Validity was excellent for the knee malalignment instrument, with a sensitivity of 0.74 (95%CI 0.54, 0.93) and specificity of 0.97 (95%CI 0.94, 1.00). Similarly the foot rotation instrument was also found to have high sensitivity (0.92, 95%CI 0.83, 1.01) and specificity (0.96, 95%CI 0.93, 1.00). The knee alignment angle increased progressively from self reported severe varus to mild varus, straight, mild valgus and severe valgus knee malalignment (ptrend <0.001).
The two novel instruments appear to provide a valid and reliable assessment of self-reported knee malalignment and foot rotation, and may have a practical use in epidemiological studies.
PMCID: PMC2896354  PMID: 20565825
22.  Satisfied Carers of Persons With Enduring Mental Illness: Who and Why? 
This secondary mixed-methods analysis is based on the interview data collected for an exploratory study of the experiences and needs of carers of persons with enduring mental illness. The aims were to identify and describe socio-demographic and contextual factors associated with the satisfaction of carers with family support.
Content analysis and non-parametric tests were used for the exploration of qualitative and quantitative data collected from 38 carers.
The majority of the satisfied carers were male, and from a higher socio-economic group than other carers. The ill relatives of all satisfied participants resided outside of their family homes. Carer satisfaction was associated with such categories as: a caring service; supportive and unintrusive family relationships; being accepted as partners; supportive community; and suitable family services. All the identified categories were interrelated.
The identified categories and socio-demographic factors should be considered for inclusion in the planning and evaluation of family support services.
PMCID: PMC2885433  PMID: 19383669
mental illness; family carers; mixed methods; family support; satisfaction with services; socio-demographic factors
23.  Coping strategies and styles of family carers of persons with enduring mental Illness: a mixed methods analysis 
A qualitative exploratory study investigated the experiences and needs of family carers of persons with enduring mental illness in Ireland. The current mixed-methods secondary study used content analysis and statistical procedures in order to identify and explore the coping strategies emerging from the original interviews. The majority of family carers reported use of active behavioural coping strategies, sometimes combined with active cognitive or avoidance strategies. The percentage of cares reporting use of active cognitive strategies was the lowest among those whose ill relative lived in their home, and the highest among those whose relative lived independently. Participants with identified active cognitive strategies often reported that their relative was employed or in training. Participants who reported use of avoidance strategies were significantly younger than participants who did not report use of such strategies. The lowest percentage of avoidance strategies was among participants whose ill relative lived independently, whereas the highest was among carers whose relative lived in their home. The findings of this study highlight the importance of a contextual approach to studying coping styles and processes. Further research questions and methodological implications are discussed.
PMCID: PMC2846687  PMID: 18269419
24.  Genetic risk of knee osteoarthritis: a sibling study 
Annals of the Rheumatic Diseases  2004;63(9):1022-1027.
Objectives: To determine whether there is a genetic contribution to knee osteoarthritis (OA) as defined by structural change on plain radiographs.
Design: Sibling study. Comparison of knee OA prevalence in the community with knee OA prevalence among siblings of index cases with knee OA.
Subjects: 490 knee OA index cases listed for total knee replacement and 737 of their siblings aged >40 years, 1729 community subjects aged >40 years.
Main outcome measure: Odds ratio for radiographic knee OA in siblings v community participants.
Results: The age, sex, and knee pain adjusted odds ratios in siblings were 2.9 (95% confidence interval 2.3 to 3.7) for tibiofemoral OA and 1.7 (1.4 to 2.2) for patellofemoral OA. This difference remained after adjustment for important environmental risk factors. The heritability estimate for knee OA was 0.62.
Conclusions: Siblings are at increased risk of knee OA in comparison with the general population. This is likely to be due to genetic factors.
PMCID: PMC1755130  PMID: 15308512
25.  Relative risk of knee chondrocalcinosis in siblings of index cases with pyrophosphate arthropathy 
Annals of the Rheumatic Diseases  2004;63(8):969-973.
Objectives: To examine the genetic contribution to common, apparently sporadic, radiographic knee chondrocalcinosis (CC) and pyrophosphate arthropathy (PA).
Method: (1) Design: radiographic sibling study. Comparison of the prevalences of knee CC and PA in siblings of index cases with PA with those in the community. (2) Subjects: 80 index cases with PA listed for total knee replacement; 122 of their siblings aged ⩾40 years; and 1729 participants from community knee pain surveys who had undergone knee radiographs. (3) Main outcome measure: odds ratios of knee CC and PA in siblings versus community participants.
Results: The prevalence of knee CC was 13% (15/116) in the siblings and 6.9% (119/1727) in the community participants. The adjusted odds ratio (aOR) was 1.2, 95% confidence interval (CI) 0.6 to 2.3. The main risk factors for knee CC were age, knee pain, and knee OA. The prevalence of knee PA was 7% (9/122) in the siblings and 3.4% (59/1729) among the community participants (aOR = 1.1, 95% CI 0.4 to 2.7). The main risk factors for PA were age and knee pain. The age, sex, and knee pain standardised prevalence of PA in the Nottingham community aged ⩾40 was 2.40%.
Conclusion: The risk of knee CC and PA in siblings of index cases with PA is no higher than that in the general population. Although rare familial CC is recognised, this study suggests that no major genetic predisposition to CC occurs in common symptomatic knee OA.
PMCID: PMC1755084  PMID: 15249324

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