Meta-analysis of erosive hand osteoarthritis identifies four common variants that associate with relatively large effect

OBJECTIVES

Erosive hand osteoarthritis (EHOA) is a severe subset of hand osteoarthritis (OA). It is unclear if EHOA is genetically different from other forms of OA. Sequence variants at ten loci have been associated with hand OA but none with EHOA.

METHODS

We performed meta-analysis of EHOA in 1484 cases and 550 680 controls, from 5 populations. To identify causal genes, we performed eQTL and plasma pQTL analyses, and developed one zebrafish mutant. We analysed associations of variants with other traits and estimated shared genetics between EHOA and other traits.

RESULTS

Four common sequence variants associated with EHOA, all with relatively high effect. Rs17013495 (SPP1/MEPE, OR=1.40, p=8.4×10^-14) and rs11243284 (6p24.3, OR=1.35, p=4.2×10^-11) have not been associated with OA, whereas rs11631127 (ALDH1A2, OR=1.46, p=7.1×10^-18), and rs1800801 (MGP, OR=1.37, p=3.6×10^-13) have previously been associated with hand OA. The association of rs1800801 (MGP) was consistent with a recessive mode of inheritance in contrast to its additive association with hand OA (OR homozygotes vs non-carriers=2.01, 95% CI 1.71 to 2.37). All four variants associated nominally with finger OA, although with substantially lower effect. We found shared genetic components between EHOA and other OA measures, grip strength, urate levels and gout, but not rheumatoid arthritis. We identified ALDH1A2, MGP and BMP6 as causal genes for EHOA, with loss-of-function Bmp6 zebrafish mutants displaying EHOA-like phenotypes.

CONCLUSIONS

We report on significant genetic associations with EHOA. The results support the view of EHOA as a form of severe hand OA and partly separate it from OA in larger joints.

Do associations with hand OA vary by knee osteoarthritis phenotype? Cross-sectional data from the Multicenter Osteoarthritis Study

Objective

Osteoarthritis (OA) is highly heterogeneous and has both biomechanical and systemic components that may not have the same etiology. We therefore aimed to identify specific knee OA phenotypes that may be more strongly associated with hand OA to refine the criteria used to define multi-joint OA.

Design

We assessed data from the Multicenter Osteoarthritis Study (MOST). We ascertained hand OA from bilateral hand photographs; scores for each joint row were summed to yield an aggregate hand OA score. Knee OA was ascertained from bilateral posteroanterior knee radiographs read for Kellgren-Lawrence grade and individual radiographic features. We tested associations between hand and knee OA with phenotypes including symptomatic OA, hyper- and atrophic knee OA, and one excluding post-traumatic OA. Associations between hand and knee OA were assessed with logistic regression, adjusted for age.

Results

We studied 2493 participants with hand and knee OA measures. Median age was 63 years with 57% women. 55% had an aggregate hand OA score ≥2; frequency of knee OA phenotypes ranged from 8% to 34%. The age-adjusted odds ratio (OR) was 1.14 (95% confidence interval (CI) ​= ​1.04-1.26) for knee OA per standard deviation of the hand OA aggregate score. Hand OA associations with symptomatic knee OA and knee OA excluding post-traumatic knee OA were OR ​= ​1.16 (95% CI ​= ​1.03-1.31) and OR ​= ​1.21 (95% CI ​= ​1.08-1.35), respectively. No other knee OA phenotype reached statistical significance.

Conclusions

Age-adjusted associations between hand and knee OA were modest and were largely similar across knee OA phenotypes.

Holes in the tundra: Invasive earthworms alter soil structure and moisture in tundra soils

Human introductions have resulted in earthworms establishing in the Arctic, species known to cause cascading ecosystem change. However, few quantitative outdoor experiments have been performed that describe how these soil modifying earthworms are reshaping structures in tundra soils. In this study, we used three-dimensional (3-D) X-ray images of soil cores (approximately 10 cm diameter, 20 cm height, N = 48) to assess how earthworms (Aporrectodea sp. and Lumbricus sp.) affect soil structure and macropore networks in an outdoor mesocosm experiment that lasted four summers. Effects were assessed in both shrub-dominated (heath) and herb-dominated (meadow) tundra. Earthworms almost doubled the macroporosity in meadow soils and tripled macroporosity in heath. Interestingly, the fractal dimension of macropores decreased in response to earthworm burrowing in both systems, indicating that the presence of earthworms reduced the geometric complexity in comparison to other pore-generating processes active in the tundra. Observed effects on soil structure occurred along with a dramatically reduced soil moisture content, which was observed the first winter after earthworm introduction in the meadow. Our findings suggest that predictions of future changes in vegetation and soil carbon pools in the Arctic should include major impacts on soil properties that earthworms induce.

Multiomics analysis of rheumatoid arthritis yields sequence variants that have large effects on risk of the seropositive subset

OBJECTIVES

To find causal genes for rheumatoid arthritis (RA) and its seropositive (RF and/or ACPA positive) and seronegative subsets.

METHODS

We performed a genome-wide association study (GWAS) of 31 313 RA cases (68% seropositive) and ~1 million controls from Northwestern Europe. We searched for causal genes outside the HLA-locus through effect on coding, mRNA expression in several tissues and/or levels of plasma proteins (SomaScan) and did network analysis (Qiagen).

RESULTS

We found 25 sequence variants for RA overall, 33 for seropositive and 2 for seronegative RA, altogether 37 sequence variants at 34 non-HLA loci, of which 15 are novel. Genomic, transcriptomic and proteomic analysis of these yielded 25 causal genes in seropositive RA and additional two overall. Most encode proteins in the network of interferon-alpha/beta and IL-12/23 that signal through the JAK/STAT-pathway. Highlighting those with largest effect on seropositive RA, a rare missense variant in STAT4 (rs140675301-A) that is independent of reported non-coding STAT4-variants, increases the risk of seropositive RA 2.27-fold (p=2.1×10^-9), more than the rs2476601-A missense variant in PTPN22 (OR=1.59, p=1.3×10^-160). STAT4 rs140675301-A replaces hydrophilic glutamic acid with hydrophobic valine (Glu128Val) in a conserved, surface-exposed loop. A stop-mutation (rs76428106-C) in FLT3 increases seropositive RA risk (OR=1.35, p=6.6×10^-11). Independent missense variants in TYK2 (rs34536443-C, rs12720356-C, rs35018800-A, latter two novel) associate with decreased risk of seropositive RA (ORs=0.63-0.87, p=10^-9-10^-27) and decreased plasma levels of interferon-alpha/beta receptor 1 that signals through TYK2/JAK1/STAT4.

CONCLUSION

Sequence variants pointing to causal genes in the JAK/STAT pathway have largest effect on seropositive RA, while associations with seronegative RA remain scarce.

The sequences of 150,119 genomes in the UK Biobank

Detailed knowledge of how diversity in the sequence of the human genome affects phenotypic diversity depends on a comprehensive and reliable characterization of both sequences and phenotypic variation. Over the past decade, insights into this relationship have been obtained from whole-exome sequencing or whole-genome sequencing of large cohorts with rich phenotypic data^1,2. Here we describe the analysis of whole-genome sequencing of 150,119 individuals from the UK Biobank³. This constitutes a set of high-quality variants, including 585,040,410 single-nucleotide polymorphisms, representing 7.0% of all possible human single-nucleotide polymorphisms, and 58,707,036 indels. This large set of variants allows us to characterize selection based on sequence variation within a population through a depletion rank score of windows along the genome. Depletion rank analysis shows that coding exons represent a small fraction of regions in the genome subject to strong sequence conservation. We define three cohorts within the UK Biobank: a large British Irish cohort, a smaller African cohort and a South Asian cohort. A haplotype reference panel is provided that allows reliable imputation of most variants carried by three or more sequenced individuals. We identified 895,055 structural variants and 2,536,688 microsatellites, groups of variants typically excluded from large-scale whole-genome sequencing studies. Using this formidable new resource, we provide several examples of trait associations for rare variants with large effects not found previously through studies based on whole-exome sequencing and/or imputation.

Development of radiographic classification criteria for hand osteoarthritis: a methodological report (Phase 2)

OBJECTIVES

In Phase 1 of developing new hand osteoarthritis (OA) classification criteria, features associated with hand OA were identified in a population with hand complaints. Radiographic findings could better discriminate patients with hand OA and controls than clinical examination findings. The objective of Phase 2 was to achieve consensus on the features and their weights to be included in three radiographic criteria sets of overall hand OA, interphalangeal OA and thumb base OA.

METHODS

Multidisciplinary, international expert panels were convened. Patient vignettes were used to identify important features consistent with hand OA. A consensus-based decision analysis approach implemented using 1000minds software was applied to identify the most important features and their relative importance influencing the likelihood of symptoms being due to hand OA. Analyses were repeated for interphalangeal and thumb base OA. The reliability and validity of the proposed criteria sets were tested.

RESULTS

The experts agreed that the criteria sets should be applied in a population with pain, aching or stiffness in hand joint(s) not explained by another disease or acute injury. In this setting, five additional criteria were considered important: age, morning stiffness, radiographic osteophytes, radiographic joint space narrowing and concordance between symptoms and radiographic findings. The reliability and validity were very good.

CONCLUSION

Radiographic features were considered critical when determining whether a patient had symptoms due to hand OA. The consensus-based decision analysis approach in Phase 2 complemented the data-driven results from Phase 1, which will form the basis of the final classification criteria sets.

Deciphering osteoarthritis genetics across 826,690 individuals from 9 populations

Osteoarthritis affects over 300 million people worldwide. Here, we conduct a genome-wide association study meta-analysis across 826,690 individuals (177,517 with osteoarthritis) and identify 100 independently associated risk variants across 11 osteoarthritis phenotypes, 52 of which have not been associated with the disease before. We report thumb and spine osteoarthritis risk variants and identify differences in genetic effects between weight-bearing and non-weight-bearing joints. We identify sex-specific and early age-at-onset osteoarthritis risk loci. We integrate functional genomics data from primary patient tissues (including articular cartilage, subchondral bone, and osteophytic cartilage) and identify high-confidence effector genes. We provide evidence for genetic correlation with phenotypes related to pain, the main disease symptom, and identify likely causal genes linked to neuronal processes. Our results provide insights into key molecular players in disease processes and highlight attractive drug targets to accelerate translation.

The CRTAC1 protein in plasma associates with osteoarthritis and predicts progression to joint replacements: a large-scale proteomics scan in Iceland

Objective

Biomarkers for diagnosis and progression of osteoarthritis (OA) are lacking. This study was undertaken to identify circulating biomarkers for OA that could predict disease occurrence and/or progression to joint replacement.

Methods

Using the SomaScan platform, we measured 4,792 proteins in plasma from 37,278 individuals, of whom 12,178 individuals had OA and 2,524 had undergone joint replacement. We performed a case–control study for identification of potential protein biomarkers for hip, knee, and/or hand OA, and a prospective study for identification of biomarkers for joint replacement.

Results

Among the large panel of plasma proteins assessed, cartilage acidic protein 1 (CRTAC1) was the most strongly associated with both OA diagnosis (odds ratio 1.46 [95% confidence interval 1.41–1.52] for knee OA, odds ratio 1.36 [95% confidence interval 1.29–1.43] for hip OA, and odds ratio 1.33 [95% confidence interval 1.26–1.40] for hand OA) and progression to joint replacement (hazard ratio 1.40 [95% confidence interval 1.30–1.51] for knee replacement and hazard ratio 1.31 [95% confidence interval 1.19–1.45] for hip replacement). Patients with OA who were in the highest quintile of risk of joint replacement, based on known risk factors (i.e., age, sex, and body mass index) and plasma CRTAC1 level, were 16 times more likely to undergo knee replacement within 5 years of plasma sample collection than those in the lowest quintile, and 6.5 times more likely to undergo hip replacement. CRTAC1 was not associated with other types of inflammatory arthritis. A specific protein profile was identified in those patients who had undergone joint replacement prior to plasma sample collection.

Conclusion

Through a hypothesis‐free approach, we identified CRTAC1 in plasma as a novel promising candidate biomarker for OA that is both associated with occurrence of OA and predictive of progression to joint replacement. This biomarker might also be useful in the selection of suitable patients for clinical trial enrollment.

Diffuse idiopathic skeletal hyperostosis in elderly Icelanders and its association with the metabolic syndrome: the AGES-Reykjavik Study

Objective: To describe the prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in a large population-based study of elderly Icelanders, with particular reference to weight-related factors and the metabolic syndrome.Method: The study population comprised 5321 participants aged 68-96 years (2276 males, mean ± sd age 76 ± 5 , and 3045 females, age 77 ± 6) from the AGES-Reykjavik Study. DISH diagnosis was based on computed tomography (CT) scans, and interpreted strictly by the Resnick criteria and additional suggestions for CT interpretation by Oudkerk et al. Radiology readings were taken by a radiology resident and sample readings by two experienced radiologists.Results: A diagnosis of DISH was made in 13.7% of males and 2.8% of females. There was no association with age, but a strong association was seen with the metabolic syndrome [odds ratio (OR) 2.12, 95% confidence interval (CI) 1.69-2.64, p = 3.9 × 10^-11]. Among the components of the metabolic syndrome, the association with DISH was significant for the insulin resistance criterion (OR 1.66, 95% CI 1.32-2.01, p < 0.001) and the body mass index (BMI) criterion (OR 2.16, 95% CI 1.70-2.74, p < 0.001). Other weight-related variables (midlife BMI, weight, and abdominal circumference) showed similar associations.Conclusions: This study, which to our knowledge is the largest published study on the prevalence of DISH, shows an association with the metabolic syndrome, particularly with the insulin resistance and BMI criteria. This is analogous with previous reports linking DISH with metabolic causes. In this age category, we did not observe any increase in prevalence with age.

Development of classification criteria for hand osteoarthritis: comparative analyses of persons with and without hand osteoarthritis

OBJECTIVES

Further knowledge about typical hand osteoarthritis (OA) characteristics is needed for the development of new classification criteria for hand OA.

METHODS

In a cross-sectional multi-centre international study, a convenience sample of patients from primary and secondary/tertiary care with a physician-based hand OA diagnosis (n = 128) were compared with controls with hand complaints due to inflammatory or non-inflammatory conditions (n = 70). We examined whether self-reported, clinical, radiographic and laboratory findings were associated with hand OA using logistic regression analyses. Discrimination between groups was assessed by calculating the area under receiver operating curves (AUC).

RESULTS

Strong associations with hand OA were observed for radiographic osteophytes (OR = 1.62, 95% CI 1.40 to 1.88) and joint space narrowing (JSN) (OR = 1.57, 95% CI 1.36 to 1.82) in the distal interphalangeal (DIP) joints with excellent discrimination (AUC = 0.82 for both). For osteophytes and JSN, we found acceptable discrimination between groups in the proximal interphalangeal joints (AUC = 0.77 and 0.78, respectively), but poorer discrimination in the first carpometacarpal joints (AUC = 0.67 and 0.63, respectively). Painful DIP joints were associated with hand OA, but were less able to discriminate between groups (AUC = 0.67). Age and family history of OA were positively associated with hand OA, whereas negative associations were found for pain, stiffness and soft tissue swelling in metacarpophalangeal joints, pain and marginal erosions in wrists, longer morning stiffness, inflammatory biomarkers and autoantibodies.

CONCLUSIONS

Differences in symptoms, clinical findings, radiographic changes and laboratory tests were found in patients with hand OA versus controls. Radiographic OA features, especially in DIP joints, were best suited to discriminate between groups.

Quantitative 3D imaging parameters improve prediction of hip osteoarthritis outcome

Osteoarthritis is an increasingly important health problem for which the main treatment remains joint replacement. Therapy developments have been hampered by a lack of biomarkers that can reliably predict disease, while 2D radiographs interpreted by human observers are still the gold standard for clinical trial imaging assessment. We propose a 3D approach using computed tomography—a fast, readily available clinical technique—that can be applied in the assessment of osteoarthritis using a new quantitative 3D analysis technique called joint space mapping (JSM). We demonstrate the application of JSM at the hip in 263 healthy older adults from the AGES-Reykjavík cohort, examining relationships between 3D joint space width, 3D joint shape, and future joint replacement. Using JSM, statistical shape modelling, and statistical parametric mapping, we show an 18% improvement in prediction of joint replacement using 3D metrics combined with radiographic Kellgren & Lawrence grade (AUC 0.86) over the existing 2D FDA-approved gold standard of minimum 2D joint space width (AUC 0.73). We also show that assessment of joint asymmetry can reveal significant differences between individuals destined for joint replacement versus controls at regions of the joint that are not captured by radiographs. This technique is immediately implementable with standard imaging technologies.

Longitudinal validity of using digital hand photographs for assessing hand osteoarthritis progression over 7 years in community-dwelling older adults with hand pain

Background

To determine the longitudinal construct validity of assessing hand OA progression on digital photographs over 7 years compared with progression determined from radiographs, clinical features and change in symptoms.

Methods

Participants were community-dwelling older adults (≥50 years) in North Staffordshire, UK. Standardized digital hand photographs were taken at baseline and 7 years, and hand joints graded for OA severity using an established photographic atlas. Radiographic hand OA was assessed using the Kellgren and Lawrence grading system. Hand examination determined the presence of nodes, bony enlargement and deformity. Symptoms were reported in self-complete questionnaires. Radiographic and clinical progression and change in symptoms were compared to photographic progression. Differences were examined using analysis of covariance and Chi-Square tests.

Results

Of 253 individuals (61% women, mean age 63 years) the proportion with photographic progression at the joint and joint group-level was higher in individuals with radiographic or clinical progression compared to those without, although differences were not statistically significant. At the person-level, those with moderate photographic progression over 7 years had significantly higher summed radiographic and clinical scores (adjusted for baseline scores) compared to those with no or mild photographic progression. Similar findings were observed for change in symptoms, although differences were small and not statistically significant.

Conclusion

Assessing hand OA on photographs shows modest longitudinal construct validity over 7 years compared with change in radiographic and clinical hand OA at the person-level. Using photographs to assess overall long-term change in a person with hand OA may be a reasonable alternative when hand examinations and radiographs are not feasible.

Target genes, variants, tissues and transcriptional pathways influencing human serum urate levels

Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.

Hyperuricemia is associated with intermittent hand joint pain in a cross sectional study of elderly females: The AGES-Reykjavik Study

Background

The debate whether "asymptomatic hyperuricemia" should be treated is still ongoing. The objective of this cross-sectional study was to analyze whether hyperuricema in the elderly is associated with joint pain.

Methods and findings

Participants in the population-based AGES-Reykjavik Study (males 2195, females 2975, mean age 76(6)) answered standardized questions about joint pain. In addition they recorded intermittent hand joint pain by marking a diagram of the hand. In males, no association was found between hyperuricemia and pain. Females however, showed a positive association between hyperuricemia and joint pain at many sites. After adjustment for age, BMI and hand osteoarthritis however, only intermittent hand joint pain (OR 1.30(1.07–1.58), p = 0.008) and intermittent pain in ≥10 hand joints (OR 1.75(1.32–2.31), p<0.001) remained significant. The best model for describing the relationship between serum uric acid levels (SUA) and intermittent hand joint pain in ≥10 joints was non-linear with a cut-off at 372 μmol/L. The attributable surplus number of symptomatic females with SUA ≥372 μmol/L was approximately 2.0% of the study population for those reporting pain in ≥10 hand joints. Next after having severe hand osteoarthritis, SUA ≥372 was an independent predictive factor of intermittent pain in ≥10 hand joints. Intermittent hand joint pain was also an independent risk factor for worse general health description.

Conclusion

Results from this population based study indicate that hyperuricemia in elderly females may be a rather frequent cause of intermittent hand joint pain, often in many joints. The most likely explanation relates to low-grade urate crystal induced inflammation. Our data do not allow for assessment of the severity of symptoms or whether they merit specific treatment, but intermittent hand joint pain was an independent predictor of worse general health. These findings may be an important contribution to the debate on whether hyperuricemia should be treated.

GWAS of bone size yields twelve loci that also affect height, BMD, osteoarthritis or fractures

Bone area is one measure of bone size that is easily derived from dual-energy X-ray absorptiometry (DXA) scans. In a GWA study of DXA bone area of the hip and lumbar spine (N ≥ 28,954), we find thirteen independent association signals at twelve loci that replicate in samples of European and East Asian descent (N = 13,608 - 21,277). Eight DXA area loci associate with osteoarthritis, including rs143384 in GDF5 and a missense variant in COL11A1 (rs3753841). The strongest DXA area association is with rs11614913[T] in the microRNA MIR196A2 gene that associates with lumbar spine area (P = 2.3 × 10-42, β = -0.090) and confers risk of hip fracture (P = 1.0 × 10-8, OR = 1.11). We demonstrate that the risk allele is less efficient in repressing miR-196a-5p target genes. We also show that the DXA area measure contributes to the risk of hip fracture independent of bone density.

Hand and knee osteoarthritis are associated with reduced diameters in retinal vessels: the AGES-Reykjavik study

To investigate the association between osteoarthritis (OA) and microvascular pathology, we examined the relationship between retinal microvascular caliber and osteoarthritis of the hand and knee in an elderly population. The AGES-Reykjavik is a population-based, multidisciplinary longitudinal cohort study of aging. Retinal vessel caliber, hand osteoarthritis and total knee joint replacements due to OA were examined in 4757 individuals (mean age 76 ± 5 years; 57% female). Incident knee joint replacements during 5-year follow-up (n = 2961, mean age 75 ± 5 years; 58% female) were also assessed. Logistic regression analysis, adjusting for age, sex, and body mass index, showed an association between narrow arteriolar caliber and hand OA, as well as knee replacement. After adjustment for other covariates, including statin therapy, this association was significant for both hand OA in men and women [OR 1.10(1.03-1.17), p < 0.01] (per unit standard deviation decrease in CRAE) and TKR prevalence [OR 1.15 (1.01-1.32), p = 0.04], especially for men [OR 1.22 (1.00-1.51) p = 0.04] and also for incident TKRs in men [OR 1.50 (1.07-2.10), p = 0.04]. Narrow venular caliber was associated with hand OA in women [OR 1.10 (1.01-1.21), p = 0.03]. Retinal arterial narrowing in hand and knee OA is present in males as well as females. Venular narrowing in hand OA in women was an unexpected finding and is in contrast with the venular widening usually observed in cardiovascular diseases.

2018 update of the EULAR recommendations for the management of hand osteoarthritis

Since publication of the European League Against Rheumatism (EULAR) recommendations for management of hand osteoarthritis (OA) in 2007 new evidence has emerged. The aim was to update these recommendations. EULAR standardised operating procedures were followed. A systematic literature review was performed, collecting the evidence regarding all non-pharmacological, pharmacological and surgical treatment options for hand OA published to date. Based on the evidence and expert opinion from an international task force of 19 physicians, healthcare professionals and patients from 10 European countries formulated overarching principles and recommendations. Level of evidence, grade of recommendation and level of agreement were allocated to each statement. Five overarching principles and 10 recommendations were agreed on. The overarching principles cover treatment goals, information provision, individualisation of treatment, shared decision-making and the need to consider multidisciplinary and multimodal (non-pharmacological, pharmacological, surgical) treatment approaches. Recommendations 1-3 cover different non-pharmacological treatment options (education, assistive devices, exercises and orthoses). Recommendations 4-8 describe the role of different pharmacological treatments, including topical treatments (preferred over systemic treatments, topical non-steroidal anti-inflammatory drugs (NSAIDs) being first-line choice), oral analgesics (particularly NSAIDs to be considered for symptom relief for a limited duration), chondroitin sulfate (for symptom relief), intra-articular glucocorticoids (generally not recommended, consider for painful interphalangeal OA) and conventional/biological disease-modifying antirheumatic drugs (discouraged). Considerations for surgery are described in recommendation 9. The last recommendation relates to follow-up. The presented EULAR recommendations provide up-to-date guidance on the management of hand OA, based on expert opinion and research evidence.

Genome-wide analyses using UK Biobank data provide insights into the genetic architecture of osteoarthritis

Osteoarthritis is a common complex disease imposing a large public-health burden. Here, we performed a genome-wide association study for osteoarthritis, using data across 16.5 million variants from the UK Biobank resource. After performing replication and meta-analysis in up to 30,727 cases and 297,191 controls, we identified nine new osteoarthritis loci, in all of which the most likely causal variant was noncoding. For three loci, we detected association with biologically relevant radiographic endophenotypes, and in five signals we identified genes that were differentially expressed in degraded compared with intact articular cartilage from patients with osteoarthritis. We established causal effects on osteoarthritis for higher body mass index but not for triglyceride levels or genetic predisposition to type 2 diabetes.

Evaluation of shared genetic aetiology between osteoarthritis and bone mineral density identifies SMAD3 as a novel osteoarthritis risk locus

Osteoarthritis (OA) is a common complex disease with high public health burden and no curative therapy. High bone mineral density (BMD) is associated with an increased risk of developing OA, suggesting a shared underlying biology. Here, we performed the first systematic overlap analysis of OA and BMD on a genome wide scale. We used summary statistics from the GEFOS consortium for lumbar spine (n = 31,800) and femoral neck (n = 32,961) BMD, and from the arcOGEN consortium for three OA phenotypes (hip, n_cases=3,498; knee, n_cases=3,266; hip and/or knee, n_cases=7,410; n_controls=11,009). Performing LD score regression we found a significant genetic correlation between the combined OA phenotype (hip and/or knee) and lumbar spine BMD (r_g=0.18, P = 2.23 × 10⁻²), which may be driven by the presence of spinal osteophytes. We identified 143 variants with evidence for cross-phenotype association which we took forward for replication in independent large-scale OA datasets, and subsequent meta-analysis with arcOGEN for a total sample size of up to 23,425 cases and 236,814 controls. We found robustly replicating evidence for association with OA at rs12901071 (OR 1.08 95% CI 1.05–1.11, P_meta=3.12 × 10⁻¹⁰), an intronic variant in the SMAD3 gene, which is known to play a role in bone remodeling and cartilage maintenance. We were able to confirm expression of SMAD3 in intact and degraded cartilage of the knee and hip. Our findings provide the first systematic evaluation of pleiotropy between OA and BMD, highlight genes with biological relevance to both traits, and establish a robust new OA genetic risk locus at SMAD3.

Age related prevalence of hand osteoarthritis diagnosed by photography (HOASCORE)

Background

Hand photography has been used in a number of studies to determine the presence and severity of hand osteoarthritis (HOA). The aim of this study was to present age and gender specific prevalences of HOA diagnosed by this method.

Methods

Six thousand three hundred forty three photographs (from 3676 females and 2667 males aged 40–96) were scored for hand osteoarthritis by a 0–3 grade (0 = no evidence of OA, 1 = possible OA, 2 = definite OA and 3 = severe OA) for each of the three main sites, distal interphalangeal joints (DIP), proximal interphalangeal joints (PIP) and thumb base (CMC1). An aggregate score of 0–9 was thus obtained (HOASCORE) to reflect the severity of HOA in each case.

Results

DIP joints were most commonly affected, followed by the thumb base and the PIP joints. Having definite DIP joint OA starts at a younger age compared with the other two sites, and there is a marked female preponderance in the age groups from 55 to 69, but after 70 the gender differences are less marked and the prevalence is fairly stable. PIP joint prevalence also indicates a female preponderance from 60 to 79. Thumb base OA has a more marked female preponderance and a rising prevalence thoughout life. The prevalence of individuals with no evidence of photographic OA (HOASCORE = 0) drops from 88% to 57% between the age categories 40–49 and 50–54 and decreased to 33% in the 70–74 age group with a slower decline after that age.

DIP and PIP prevalence were strongly associated with each other with an OR of 16.6(12.8–21.5),p < 0.001 of having definite OA at the other site. This was less marked for the thumb base with an OR of 2.2(1.8–2.7, p < 0.001), and 2.7(2.0–3.5, p < 0.001) of having definite DIP or PIP HOA respectively.

Conclusions

The prevalence of hand OA in DIP, PIP and thumb base joints obtained by the photographic HOASCORE method is higher in women and increases after the age of fifty. These results are in line with those obtained by clinical examination and radiography. The advantage of the method lies in easy applicability and low cost.

Electronic supplementary material

The online version of this article (10.1186/s12891-017-1870-0) contains supplementary material, which is available to authorized users.

Determinants of outcome of vocational rehabilitation

BACKGROUND

Information regarding the determinants of successful vocational rehabilitation (VR) is scarce.

OBJECTIVE

Investigate whether sex, duration, quality of life and financial circumstances influence the success of VR.

METHODS

The study group consisted of 519 participants (293 women, 56%), who finished VR in the period 2000-2014. The group was divided into the following subgroups: dropouts, unsuccessful and successful VR. Data were collected by questionnaire.

RESULTS

Income had the most impact on whether the outcome was successful. Having supplemental income when entering the VR program increased the likelihood of a successful conclusion, odds ratio (OR) 5.60 (95% CI; 2.43-13.59) (p < 0.001), being on sick leave OR 5.02 (95% CI 1.93-13.79) (p < 0.001) or rehabilitation pension OR 1.93 (95% CI 1.07-3.52) (p < 0.03). The participants in the successful sub-group were older (p < 0.06) and stayed in rehabilitation longer (p < 0.001), compared to those who were unsuccessful. However, the effect on OR was limited: 1.03 (95% CI 1.01-1.06) and 1.04 (95% CI 1.02-1.07), respectively.

CONCLUSIONS

For this sample, supplemental income appears to be the most important factor for a successful rehabilitation outcome. Checking financial status at the beginning of the rehabilitation process could minimize financial strain and increase the likelihood of success.

Physiological changes associated with routine nursing procedures in critically ill are common: an observational pilot study

BACKGROUND

Nursing procedures that are routinely performed in the intensive care unit (ICU) are assumed to have minimal side effects. However, these procedures may sometimes cause physiological changes that negatively affect the patient. We hypothesized that physiological changes associated with routine nursing procedures in the ICU are common.

METHODS

A clinical observational study of 16 critically ill patients in a nine-bed mixed university hospital ICU. All nursing procedures were observed, and physiological data were collected and subsequently analyzed. Minor physiological changes were defined as minimal changes in respiratory or circulatory variables, and major physiological changes were marked as hyper/hypotension, bradycardia/tachycardia, bradypnea/tachypnea, ventilatory distress, and peripheral blood oxygen desaturation.

RESULTS

In the 16 patients, 668 procedures generated 158 major and 692 minor physiological changes during 187 observational hours. The most common procedure was patient position change, which also generated the majority of the physiological changes. The most common major physiological changes were blood oxygen desaturation, ventilatory distress, and hypotension, and the most common minor changes were arterial pressure alteration, coughing, and increase in respiratory rate.

CONCLUSION

In this pilot study, we examined physiological changes in connection with all regular routine nursing procedures in the ICU. We found that physiological changes were common and sometimes severe.

Long-Term Hormone Replacement Therapy Is Associated with Low Coronary Artery Calcium Levels in a Cohort of Older Women: The Age, Gene/Environment Susceptibility-Reykjavik Study

OBJECTIVES

To assess the relationship between hormone replacement therapy (HRT) and coronary artery calcium (CAC).

DESIGN

Cross-sectional.

SETTING

Established population-based cohort in Reykjavik, Iceland.

PARTICIPANTS

Women (mean age 76 ± 5) who had completed questionnaires on HRT use (N = 2,867).

MEASUREMENTS

Coronary artery calcium assessed using computed tomography was the outcome variable and was compared between women with history of HRT and those who had never used HRT and analyzed according to age, length of use, and time after menopause that HRT was initiated.

RESULTS

Eight hundred seventy-two (30.4%) participants had used HRT, and 312 (10.9%) were current users. After adjustment for age, other late-life variables, and a propensity score based on midlife data for HRT use as observed in late life, there were significant negative associations between CAC and history and length of HRT use. This association was evident in all age categories. When HRT had been used for longer than 15 years, median CAC level was less than 50% of that observed in never users. The lowest CAC was observed in those who started HRT within 5 years after menopause. The prevalence of coronary events was comparable in both groups.

CONCLUSION

A strong association was found between long-term HRT use and low CAC. The negative association between duration of HRT and CAC was evident in all age groups of older women.

Activation of Complement Following Total Hip Replacement

The aim of this study was to investigate whether complement activation, via the classical and alternative pathways, occurs following a cemented total hip replacement (THR) surgery due to osteoarthritis. Blood samples were collected systematically from 12 patients - six male and six women, with a median age of 75 (range: 59-90 years) - preoperatively, 6 h post-operatively and on the first, second and third post-operative day. Total function of classical (CH50) and alternative pathways (AH50) was evaluated, along with the determination of serum concentrations of the complement proteins C3, C4, C3d, the soluble terminal complement complex (sTCC) sC5b-9, as well as C-reactive protein (CRP) and albumin. Measurements of CRP and albumin levels elucidated a marked inflammatory response following the operation. The CH50, AH50 and C3 and C4 levels were significantly lower 6 h after the surgery compared with the preoperative levels, but elevated above the preoperative levels during the following 3 days. The complement activation product C3d levels increased continually during the whole observation period, from 13.5 AU/ml (range: 8-19 AU/ml) preoperative to 20 AU/ml (range: 12-34 AU/ml) on the third post-operative day. Furthermore, we observed an increase in the sC5b-9 levels between the preoperative and the third post-operative day. These results demonstrate a significant activation of the complement system following cemented THR. Further studies are needed to elucidate the time frame and the pathogenic role of this observed complement activation.

Incidence and prevalence of total joint replacements due to osteoarthritis in the elderly: risk factors and factors associated with late life prevalence in the AGES-Reykjavik Study

Background

Total joint replacements (TJRs) should be considered as one of few definite endpoints in osteoarthritis research. We analyzed factors associated with late-life prevalence and risk factors for incidence of TJRs due to osteoarthritis in a population based cohort.

Methods

After exclusion of inflammatory arthritis and fractures as causes of TJR, 5170 participants in the AGES-Reykjavik Study (mean age (SD) 76.4(6), 58 % females) were included for osteoarthritis studies. Three thousand one hundred thirty-three of them had a follow-up visit 5 years later.

Results

The prevalence of having at least one joint replacement operation due to OA was 13.6 % and the yearly incidence was 1.4 %/year during the five-year follow-up. Factors positively associated with late life prevalence of TJR included BMI, hand OA severity, female gender, finger length ratio and spine BMD. Risk factors for TJRs in the incidence group were symptoms at initial visit, prior TJR in the contralateral joint and BMI. Much stronger associations were seen for TKR than for THR with discriminatory analysis showing an AUC 0.71 for late life prevalence and 0.84 for the incidence.

Conclusions

This study illustrates the importance of the different information expressed by late life prevalence vs. incidence on the factors associated with severe osteoarthritis of the knee and hip. The observation that prior TJR is a risk factor for subsequent TJR in the contralateral joint has not been described previously. The high power predictions for TKR suggest that a predictive model may be feasible, particularly if it can be extended by the addition of further predictive variables, perhaps through genetic, biomarker or imaging data.

Reliability of Assessing Hand Osteoarthritis on Digital Photographs and Associations With Radiographic and Clinical Findings

OBJECTIVE

To investigate the reliability and construct validity of an atlas for grading hand osteoarthritis (OA) on photographs in a separate younger community-dwelling population than the development cohort.

METHODS

Participants were community-dwelling adults (ages ≥50 years) in North Staffordshire, UK with hand pain or hand problems in the last year who attended a research clinic. High-quality photographs were taken in a standardized position. A photographic atlas was used to score hand joints (second and third distal interphalangeal [DIP], second and third proximal interphalangeal [PIP], and first carpometacarpal [CMC] joints) and joint groups (DIP, PIP, and CMC joints) for OA on a 0-3 scale. Hand radiographs were graded for OA using the Kellgren/Lawrence (K/L) grading system. Clinical features (nodes, bony enlargement, and deformity) were determined by physical examination. Associations of photographic hand OA grades with radiographic OA and clinical features were determined to assess construct validity.

RESULTS

In total, 558 participants (mean age 64 years, 62% women) were included in the analyses. Reliability for scoring OA on the photographs was good (mean intrarater intraclass correlation coefficient [ICC] 0.77 and mean interrater ICC 0.71). At the joint level, photographic hand OA grade was positively associated with radiographic OA grade (Spearman's ρ = 0.19-0.57, P < 0.001) and the number of clinical features (Spearman's ρ = 0.36-0.59, P < 0.001). At the person level, individuals with higher global photographic OA scores had higher summed K/L scores and higher percentages meeting the American College of Rheumatology clinical hand OA criteria.

CONCLUSION

This photographic scoring system was reliable and a good indicator of hand OA in a separate younger community-dwelling population than the development cohort. This method of data collection offers researchers a feasible alternative to physical examination and radiography.

Sex-specific predictors of hearing-aid use in older persons: The age, gene/environment susceptibility - Reykjavik study

OBJECTIVE

We estimate the prevalence of hearing-aid use in Iceland and identify sex-specific factors associated with use.

DESIGN

Population-based cohort study.

STUDY SAMPLE

A total of 5172 age, gene/environment susceptibility - Reykjavik study (AGES-RS) participants, aged 67 to 96 years (mean age 76.5 years), who completed air-conduction and pure-tone audiometry.

RESULTS

Hearing-aid use was reported by 23.0% of men and 15.9% of women in the cohort, although among participants with at least moderate hearing loss in the better ear (pure-tone average [PTA] of thresholds at 0.5, 1, 2, and 4 kHz ≥ 35 dB hearing level [HL]) it was 49.9% and did not differ by sex. Self-reported hearing loss was the strongest predictor of hearing-aid use in men [OR: 2.68 (95% CI: 1.77, 4.08)] and women [OR: 3.07 (95% CI: 1.94, 4.86)], followed by hearing loss severity based on audiometry. Having diabetes or osteoarthritis were significant positive predictors of use in men, whereas greater physical activity and unimpaired cognitive status were important in women.

CONCLUSIONS

Hearing-aid use was comparable in Icelandic men and women with moderate or greater hearing loss. Self-recognition of hearing loss was the factor most predictive of hearing-aid use; other influential factors differed for men and women.

A meta-analysis of genome-wide association studies identifies novel variants associated with osteoarthritis of the hip

OBJECTIVES

Osteoarthritis (OA) is the most common form of arthritis with a clear genetic component. To identify novel loci associated with hip OA we performed a meta-analysis of genome-wide association studies (GWAS) on European subjects.

METHODS

We performed a two-stage meta-analysis on more than 78,000 participants. In stage 1, we synthesised data from eight GWAS whereas data from 10 centres were used for 'in silico' or 'de novo' replication. Besides the main analysis, a stratified by sex analysis was performed to detect possible sex-specific signals. Meta-analysis was performed using inverse-variance fixed effects models. A random effects approach was also used.

RESULTS

We accumulated 11,277 cases of radiographic and symptomatic hip OA. We prioritised eight single nucleotide polymorphism (SNPs) for follow-up in the discovery stage (4349 OA cases); five from the combined analysis, two male specific and one female specific. One locus, at 20q13, represented by rs6094710 (minor allele frequency (MAF) 4%) near the NCOA3 (nuclear receptor coactivator 3) gene, reached genome-wide significance level with p=7.9×10(-9) and OR=1.28 (95% CI 1.18 to 1.39) in the combined analysis of discovery (p=5.6×10(-8)) and follow-up studies (p=7.3×10(-4)). We showed that this gene is expressed in articular cartilage and its expression was significantly reduced in OA-affected cartilage. Moreover, two loci remained suggestive associated; rs5009270 at 7q31 (MAF 30%, p=9.9×10(-7), OR=1.10) and rs3757837 at 7p13 (MAF 6%, p=2.2×10(-6), OR=1.27 in male specific analysis).

CONCLUSIONS

Novel genetic loci for hip OA were found in this meta-analysis of GWAS.

Abstract P2-04-02: Overdiagnosis in mammography screening in two randomised trials in Malmö, Sweden – An age specific analysis

OBJECTIVES: The aim of the current study was to estimate age-specific overdiagnosis due to mammography screening in the two randomized trials in Malmö, Sweden: The Malmö Mammographic Screening Trial I and II (MMST I and MMST II).

SETTING: Women living in Malmö were randomized in a 1:1 proportion to a screening group or a control group. The MMST I included 42,283 women born between 1908 and 1932 and the MMST II included 17,793 women born between 1933 and 1945. Women in the study group were invited from 1976 until 1990 when the control group was invited. The age at randomization was 45-70 years in MMST I and 43-48 years in MMST II.

METHODS: Data from the two trials were merged and overdiagnosis was estimated using age specific incidence rates excluding the first years of screening. The age specific relative breast cancer incidence rate for the screening group versus the control group was estimated and adjusted for lead time. Only the first breast cancer diagnosis was considered and results for invasive cancer and carcinoma in situ combined as well as for invasive cancer were calculated.

RESULTS: The number of breast cancer cases, including carcinoma in situ, for the period 1976-1989 was 867 and 676 for the study group and the control group, respectively. The rate ratio for overdiagnosis in age 43-78 years adjusted for lead time was 1.04 (95% CI, 0.93-1.16). No overdiagnosis from subsequent screening was found for women below the age of 60. In women aged 60-69 and 70-78 years overdiagnosis was estimated at 1.13 (0.95-1.33) and 1.15 (0.85-1.54), respectively. The corresponding results for invasive cancer only was lower and no overdiagnosis was seen except for the age group 60-69 years where the rate ratio was 1.10 (0.92-1.32). For age 43-78 the result was 0.96 (0.85-1.08).

CONCLUSIONS

For the total material overdiagnosis from subsequent screening, including carcinoma in situ, was 4%. This is somewhat lower than an earlier evaluation of MMST I where age were higher and another method was used. For women below the age of 60 no overdiagnosis was seen and indicated that the possible problem with overdiagnosis concern women 60+. However none of the results were statistically significant at the 5% level.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-04-02.

How to define responders in osteoarthritis

BACKGROUND

Osteoarthritis is a clinical syndrome of failure of the joint accompanied by varying degrees of joint pain, functional limitation, and reduced quality of life due to deterioration of articular cartilage and involvement of other joint structures.

SCOPE

Regulatory agencies require relevant clinical benefit on symptoms and structure modification for registration of a new therapy as a disease-modifying osteoarthritis drug (DMOAD). An international Working Group of the European Society on Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and International Osteoporosis Foundation was convened to explore the current burden of osteoarthritis, review current regulatory guidelines for the conduct of clinical trials, and examine the concept of responder analyses for improving drug evaluation in osteoarthritis.

FINDINGS

The ESCEO considers that the major challenges in DMOAD development are the absence of a precise definition of the disease, particularly in the early stages, and the lack of consensus on how to detect structural changes and link them to clinically meaningful endpoints. Responder criteria should help identify progression of disease and be clinically meaningful. The ideal criterion should be sensitive to change over time and should predict disease progression and outcomes such as joint replacement.

CONCLUSION

The ESCEO considers that, for knee osteoarthritis, clinical trial data indicate that radiographic joint space narrowing >0.5 mm over 2 or 3 years might be a reliable surrogate measure for total joint replacement. On-going research using techniques such as magnetic resonance imaging and biochemical markers may allow the identification of these patients earlier in the disease process.

Type 3 finger length pattern is associated with total knee replacements due to osteoarthritis but not with hip replacements or hand osteoarthritis in the elderly: the AGES-Reykjavik study

Background

Recent case–control studies have shown an association between type 3 finger length pattern (longer ring finger than index finger) and knee osteoarthritis. This large cross-sectional study tests the hypothesis that the type 3 pattern is associated with total joint replacements due to osteoarthritis in a large population based study.

Methods

Finger length ratios were assessed visually on 5170 hand photographs (2975 females, 2195 males, mean age 76). In this population-based multidisciplinary study of aging in Reykjavik, Iceland, the prevalence of osteoarthritis associated total knee replacements was 223(4.3%) and total hip replacements 316(6.1%). We then performed a binary logistic regression analysis for total knee replacements and total hip replacements, including finger length patterns, osteoarthritis at other sites and other variables with possible association to osteoarthritis such as age, BMI and bone mineral density of the spine.

Results

The prevalence of the type 3 pattern was 50% (43% in females, 58% in males). The regression analysis revealed an odds ratio for total knee replacements of 1.65 (1.24-2.2) p = 0.0007, in the type 3 finger pattern group, similar in both genders. This association was independent of the associations we have previously reported between total knee replacements and BMI and the presence of hand osteoarthritis. No association was seen between finger length patterns and total hip replacements.

Conclusion

Finger length patterns read from digital photographs in this large study confirm previous radiographic observations with significant associations between the type 3 pattern and total knee replacements but not total hip replacements in both genders in this elderly group.

Clinical examination, spondylolysis and adolescent athletes

Symptomatic spondylolysis is a stress reaction caused by microtrauma during physical exercise, an imaging diagnostic subgroup of Adolescent Low Back Pain (ALBP), found in adolescent athletes. Early diagnosis increases the possibility of healing. Thus, it is important to divide ALBP into subgroups. The aim of this study was to evaluate clinical tests that can distinguish symptomatic spondylolysis from other forms of ALBP in order to facilitate early referral for diagnostic imaging. The investigation subjects were a prospective case series with a control group, 25 subjects with ALBP and 13 subjects that had no history of LBP. The 2 groups were examined using the same clinical protocol. MRI of the whole lumbar spine was performed in both the case and control groups and CT investigations of the L4 and L5 vertebrae were performed in the case group. Significant differences between the 2 groups were found in 8 of our clinical tests. No clinical test, alone or in combination, could distinguish between spondylolysis and other forms of ALBP. As 88% of the subjects in the case group had MRI findings and almost 50% had spondylolysis, MRI should be performed at an early age in young athletes with ALBP.

Metabolic risk factors and skin cancer in the Metabolic Syndrome and Cancer Project (Me-Can)

BACKGROUND

Little is known about the associations of metabolic aberrations with malignant melanoma (MM) and nonmelanoma skin cancer (NMSC).

OBJECTIVES

To assess the associations between metabolic factors (both individually and combined) and the risk of skin cancer in the large prospective Metabolic Syndrome and Cancer Project (Me-Can).

METHODS

During a mean follow-up of 12 years of the Me-Can cohort, 1728 (41% women) incident MM, 230 (23% women) fatal MM and 1145 (33% women) NMSC were identified. Most NMSC cases (76%) were squamous cell carcinoma (SCC) (873, 33% women). Hazard ratios (HRs) were estimated by Cox proportional hazards regression for quintiles and standardized z-scores (with a mean of 0 and SD of 1) of body mass index (BMI), blood pressure, glucose, cholesterol, triglycerides and for a combined metabolic syndrome score. Risk estimates were corrected for random error in the measurements.

RESULTS

Blood pressure per unit increase of z-score was associated with an increased risk of incident MM cases in men and women [HR 1·17, 95% confidence interval (CI) 1·04-1·31 and HR 1·18, 95% CI 1·03-1·36, respectively] and fatal MM cases among women (HR 2·39, 95% CI 1·58-3·64). In men, all quintiles for BMI above the reference were associated with a higher risk of incident MM. In women, SCC NMSC risk increased across quintiles for glucose levels (P-trend 0·02) and there was a trend with triglyceride concentration (P-trend 0·09).

CONCLUSION

These findings suggest that mechanisms linked to blood pressure may be involved in the pathogenesis of MM. SCC NMSC in women could be related to glucose and lipid metabolism.

The use of digital photographs for the diagnosis of hand osteoarthritis: the AGES-Reykjavik study

Background

The objective of the study was to standardize a method using digital photographs to diagnose and grade hand osteoarthritis (HOA), to compare it with radiographs and clinical examination with regard to prevalence and relation to symptoms, and finally to construct a simple shortened version suitable for use in very large studies, where a global estimate may be preferable.

Methods

High quality photographs with standard distance and hand positioning were analysed for the presence of HOA and subsequently compared with standard radiographs and clinical examination in 381 random participants in the AGES-Reykjavik Study, a large population study. The mean age of the participants was 76 years.

Results

Using the photographic method, the most commonly affected joints were the second DIP joints followed by the third DIP joints and second and third PIP joints. Both interobserver (ICC = 0.83) and intraobserver reading agreements (ICC = 0.89) were acceptable. On comparison with radiography and clinical examination, aggregate scores were significantly correlated (R_s 0.35-0.69), more so in females (R_s 0.53-0.72) than males. Hand pain in males showed very little association with HOA findings by the three methods but all methods showed a comparable moderate association with hand pain in females. The performance of photography in predicting pain on most days for at least a month in females was comparable to that of radiography and clinical examination (AUC 0.63 p = 0.004). Analysis of intermittent pain yielded similar results for in the DIP and PIP joints (OR 3.2-3.3, p < 0.01), but for the CMC1 joints, both radiography (OR 9.0, p < 0.0001), and clinical examination (OR 9.8, p < 0.0001), had higher predictive odds ratios for pain than photography (OR 3.6, p < 0.0001)., A shortened, rapidly performed form of reading photographs also showed a high degree of correlation with the other methods (R_s 0.56-0.82).

Conclusion

High quality hand photographs can be used to diagnose and grade hand osteoarthritis. The method has the advantage of being inexpensive and easy to perform. By using a slightly simplified method of reading, it appears to be highly suitable for use in large studies.

Altered activity of the serratus anterior during unilateral arm elevation in patients with cervical disorders

Altered activity in the axioscapular muscles is considered to be an important feature in patients with neck pain. The activity of the serratus anterior (SA) and trapezius muscles during arm elevation has not been investigated in these patients. The objectives of this study was to investigate whether there is a pattern of altered activity in the SA and trapezius in patients with insidious onset neck pain (IONP) (n=22) and whiplash associated disorders (WAD) (n=27). An asymptomatic group was selected for baseline measurements (n=23). Surface electromyography was used to measure the onset of muscle activation and duration of muscle activity of the SA as well as the upper, middle, and lower trapezius during unilateral arm elevation in the three subject groups. Both arms were tested. With no interaction, the main effect for the onset of muscle activation and duration of muscle activity for serratus anterior was statistically significant among the groups. Post hoc comparison revealed a significantly delayed onset of muscle activation and less duration of muscle activity in the IONP group, and in the WAD group compared to the asymptomatic group. There were no group main effects or interaction effects for upper, middle and lower trapezius. This finding may have implications for scapular stability in these patients because the altered activity in the SA may reflect inconsistent or poorly coordinated muscle activation that may reduce the quality of neuromuscular performance and induce an increased load on the cervical and the thoracic spine.

Large scale replication study of the association between HLA class II/BTNL2 variants and osteoarthritis of the knee in European-descent populations

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) (r(2) = 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 (r(2)<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.

The presence of total knee or hip replacements due to osteoarthritis enhances the positive association between hand osteoarthritis and atherosclerosis in women: the AGES-Reykjavik study

OBJECTIVE

This study examines the relationship between total knee replacements (TKR), total hip replacements (THR) or replacements of either joint (total joint replacement; TJR) due to osteoarthritis and atherosclerosis in a large population-based study.

METHODS

The participants were 2195 men and 2975 women, mean age 76 ± 6 years. The osteoarthritis data were analysed in relation to measures of atherosclerosis, including carotid artery intima media thickness and plaque severity (ultrasound), coronary and aortic calcifications (CT), cerebral white matter lesions (MRI) and a history of previous cardiac and cerebral events.

RESULTS

The prevalence of TKR was 223 (4.3%) and THR 316 (6.1%). The presence of TJR in women was associated with a non-significant trend towards increased carotid plaque severity, coronary calcifications and periventricular white matter hyperintensities (PVH) but not with a history of cardiac or cerebral events. No associations were seen in men. When TJR were grouped according to the presence or absence of hand osteoarthritis (HOA) there was a highly significant association in the order -TJR/-HOA < +TJR/-HOA < -TJR/+HOA < +TJR/+HOA, for carotid plaque severity, coronary calcifications and PVH.

CONCLUSION

The presence of TJR did not show a significant independent association with atherosclerosis but enhanced the strength of the positive association between HOA and subclinical atherosclerosis in women.

Recommendations for standardization and phenotype definitions in genetic studies of osteoarthritis: the TREAT-OA consortium

OBJECTIVE

To address the need for standardization of osteoarthritis (OA) phenotypes by examining the effect of heterogeneity among symptomatic (SOA) and radiographic osteoarthritis (ROA) phenotypes.

METHODS

Descriptions of OA phenotypes of the 28 studies involved in the TREAT-OA consortium were collected. We investigated whether different OA definitions result in different association results by creating various hip OA definitions in one large population based cohort (the Rotterdam Study I (RSI)) and testing those for association with gender, age and body mass index using one-way ANOVA. For ROA, we standardized the hip-, knee- and hand ROA definitions and calculated prevalence's of ROA before and after standardization in nine cohort studies. This procedure could only be performed in cohort studies and standardization of SOA definitions was not feasible at this moment.

RESULTS

In this consortium, all studies with SOA phenotypes (knee, hip and hand) used a different definition and/or assessment of OA status. For knee-, hip- and hand ROA five, four and seven different definitions were used, respectively. Different hip ROA definitions do lead to different association results. For example, we showed in the RSI that hip OA defined as "at least definite joint space narrowing (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 ROA definitions. Before standardization a wide range of ROA prevalence's was observed in the nine cohorts studied. After standardization the range in prevalence of knee- and hip ROA was small.

CONCLUSION

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.

Hand Osteoarthritis Severity is Associated with Total Knee Joint Replacements Independently of BMI. The Ages-Reykjavik Study

OBJECTIVE

To identify factors associated with having total knee replacement due to osteoarthritis in the AGES-Reykjavik Study, a large population based study of elderly Icelanders.

METHODS

Information about total knee and hip joint replacements (TKR,THR) and hand OA (HOA) severity was available in 2195 males and 2975 females, mean age 76±6 years. The prevalence of TKR was 223 (4.3%) and THR 316 (6.1%). We performed a backwards binary logistic regression analysis of possible OA associated variables including age, gender, abdominal circumference, BMI, hs-CRP, cholesterol, statin use, bone mineral density of the spine, education and smoking history as well as HOA severity and the presence of THR.

RESULTS

Only three factors showed significant associations with TKR; BMI (p=3.5x10(-17)), HOA severity (p=2.9x10(-8)) and THR (p=0.0002). The highest quintile of BMI was associated with a fivefold risk of TKR compared with the lowest (8% vs 1.6%), and severe HOA had a 2.4 fold risk compared with those with no HOA (8% vs 3.3%). There was no statistical interaction between BMI and HOA. Thus, individuals with BMI<23.5 with no evidence of HOA had a prevalence of TKR of 1.1%, while those with BMI>30.3 and severe HOA had a prevalence of 13.4%.

CONCLUSIONS

Hand and hip osteoarthritis in conjunction with BMI are strongly associated with the prevalence of TKR due to osteoarthritis. Together, BMI and HOA severity seem to contribute to the majority of the total TKR prevalence. While BMI has long been recognized as the major risk factor for TKR, the influence of osteoarthritis at other sites may have been underestimated.

Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study

Objectives

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.

Methods

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.

Results

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.

Conclusions

Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.