Joint-specific prevalence and radiographic pattern of hand osteoarthritis in Korean

A Functional Polymorphism Downstream of Vitamin A Regulator Gene CYP26B1 Is Associated with Hand Osteoarthritis

While genetic analyses have revealed ~100 risk loci associated with osteoarthritis (OA), only eight have been linked to hand OA. Besides, these studies were performed in predominantly European and Caucasian ancestries. Here, we conducted a genome-wide association study in the Han Chinese population to identify genetic variations associated with the disease. We recruited a total of 1136 individuals (n = 420 hand OA-affected; n = 716 unaffected control subjects) of Han Chinese ancestry. We carried out genotyping using Axiom Asia Precisi on Medicine Research Array, and we employed the RegulomeDB database and RoadMap DNase I Hypersensitivity Sites annotations to further narrow down our potential candidate variants. Genetic variants identified were tested in the Geisinger's hand OA cohort selected from the Geisinger MyCode community health initiative (MyCode^®). We also performed a luciferase reporter assay to confirm the potential impact of top candidate single-nucleotide polymorphisms (SNPs) on hand OA. We identified six associated SNPs (p-value = 6.76 × 10^-7-7.31 × 10^-6) clustered at 2p13.2 downstream of the CYP26B1 gene. The strongest association signal identified was rs883313 (p-value = 6.76 × 10^-7, odds ratio (OR) = 1.76), followed by rs12713768 (p-value = 1.36 × 10^-6, OR = 1.74), near or within the enhancer region closest to the CYP26B1 gene. Our findings showed that the major risk-conferring CC haplotype of SNPs rs12713768 and rs10208040 [strong linkage disequilibrium (LD); D' = 1, r² = 0.651] drives 18.9% of enhancer expression activity. Our findings highlight that the SNP rs12713768 is associated with susceptibility to and severity of hand OA in the Han Chinese population and that the suggested retinoic acid signaling pathway may play an important role in its pathogenesis.

Comparison of Prevalence of Osteoarthritis in the Hand: A Multicenter Retrospective Cohort Study

Introduction Several studies have previously been undertaken to investigate the prevalence of radiologic hand osteoarthritis (OA) in Caucasian, Japanese, Chinese, and Arabic populations. To date, there has been no direct international comparison study on the prevalence of radiologic hand OA between a Western and a Southeast Asian population. We hypothesize that there is difference in the pattern of joint involvement among individuals of both populations.

Materials and Methods Consecutive hand radiographs from individuals aged 60 years and above were reviewed. Radiographic evidence of osteoarthritis in the various joints in the hands was graded using Kellgren–Lawrence (K-L) score. Chi-square test, Fisher’s exact test, or Student’s t-test was used as appropriate. Multiple logistic regression analysis was performed to evaluate the associations and relationships of radiographic hand OA between joints.

Results A total of 194 patients exhibited radiographic OA. Singaporean patients were more likely to have radiographic OA of the thumb interphalangeal joint (IPJ) (65.1%) compared with the thumb carpometacarpal joint (CMCJ; 40.2%); British patients were more likely to have CMCJ (43.3%) OA than thumb IPJ (21.0%). The difference was statistically significant (p = 0.00026). In the Singapore population, it was more likely that a patient had concurrent OA of both thumb and finger joints, whereas in the British population, this was apparent in only the above-80-year-old group. The most commonly affected joint was the left thumb IPJ (joint specific prevalence of 35%) in the Singapore population, and the right index finger distal interphalangeal joint (DIPJ; joint specific prevalence of 41.5%) in the British population.

Conclusion Our study, the first study to compare between Singaporean and British populations, showed statistically significant difference in the prevalence of OA in the hands. These findings suggest ethnic and cultural factors play a part in such a distribution trend.

Investigations of Potential Phenotypes of Foot Osteoarthritis: Cross-Sectional Analysis From the Clinical Assessment Study of the Foot

OBJECTIVE

To investigate the existence of distinct foot osteoarthritis (OA) phenotypes based on pattern of joint involvement and comparative symptom and risk profiles.

METHODS

Participants ages ≥50 years reporting foot pain in the previous year were drawn from a population-based cohort. Radiographs were scored for OA in the first metatarsophalangeal (MTP) joint, first and second cuneometatarsal, navicular first cuneiform, and talonavicular joints according to a published atlas. Chi-square tests established clustering, and odds ratios (ORs) examined symmetry and pairwise associations of radiographic OA in the feet. Distinct underlying classes of foot OA were investigated by latent class analysis (LCA) and their association with symptoms and risk factors was assessed.

RESULTS

In 533 participants (mean age 64.9 years, 55.9% female) radiographic OA clustered across both feet (P < 0.001) and was highly symmetrical (adjusted OR 3.0, 95% confidence interval 2.1, 4.2). LCA identified 3 distinct classes of foot OA: no or minimal foot OA (64%), isolated first MTP joint OA (22%), and polyarticular foot OA (15%). After adjustment for age and sex, polyarticular foot OA was associated with nodal OA, increased body mass index, and more pain and functional limitation compared to the other classes.

CONCLUSION

Patterning of radiographic foot OA has provided insight into the existence of 2 forms of foot OA: isolated first MTP joint OA and polyarticular foot OA. The symptom and risk factor profiles in individuals with polyarticular foot OA indicate a possible distinctive phenotype of foot OA, but further research is needed to explore the characteristics of isolated first MTP joint and polyarticular foot OA.

Carpal tunnel syndrome and radiographically evident basal joint arthritis of the thumb in elderly Koreans

BACKGROUND

Previous studies have suggested a high prevalence of carpal tunnel syndrome in patients seeking treatment for basal joint arthritis of the thumb. The purpose of this study was to compare the prevalence of carpal tunnel syndrome between individuals with and those without radiographic evidence of basal joint arthritis of the thumb in the general elderly Korean population, and to determine if there is a correlation between the severity of carpal tunnel syndrome shown by electrophysiological studies and the severity of basal joint arthritis as seen on radiographs.

METHODS

We evaluated hand radiographs and nerve conduction studies of 192 men and 176 women (more than sixty-five years of age) who participated in the Korean Longitudinal Study on Health and Aging. The basal joint of the thumb was assigned a grade for osteoarthritis of 0 to 4 on radiographs with use of the Kellgren and Lawrence criteria. The diagnosis of carpal tunnel syndrome was based on the combination of a positive response to survey questions and a positive nerve conduction study. Motor distal latency and motor conduction velocity were measured to assess the electrophysiological severity of carpal tunnel syndrome.

RESULTS

The prevalence of carpal tunnel syndrome was 16.7% in the group with basal joint arthritis and 10.9% in the group without basal joint arthritis, a difference that was not significant (p = 0.249). Neither motor distal latency nor motor conduction velocity was significantly correlated with the severity of the basal joint arthritis in the entire group of 368 study subjects (p = 0.154 and p = 0.662, respectively) or in those with carpal tunnel syndrome (p = 0.603 and p = 0.998, respectively).

CONCLUSIONS

This study of Koreans who were more than sixty-five years of age showed that the prevalence of carpal tunnel syndrome is similar in patients with and those without radiographic findings of basal joint arthritis of the thumb. We found no correlation between the electrophysiological severity of carpal tunnel syndrome and the severity of basal joint arthritis.

Feasibility study of semi-automated measurements of finger joint space widths

The purpose of this study is to evaluate technical feasibility based on image capturing conditions (film-focus distance (FFD), film sensitivity, film brand, exposure level and tube voltage) that potentially alter radiographs and consequently may influence the semi-automated measurement of joint space distance (JSD) by computer-aided joint space analysis (CAJSA) in rheumatoid arthritis and osteoarthritis. The radiographs of a left hand (deceased man) were acquired under systematically changing image capturing conditions (exposure level: 4-8 mAs; FFD: 90-130 cm; film sensitivity: 200/400 and tube voltage: 40-52 kV with different image modalities: conventional radiographs, original digital radiographs, digital print-outs). All JSD-measurements were performed with the CAJSA-technology (Radiogrammetry Kit, Version 1.3.6; Sectra; Sweden) at the metacarpal-phalangeal articulation. JSD-analysis was not influenced by changes of FFD, exposure level, film sensitivity or film brand. JSD showed significant variation caused by tube voltage (conventional: CV = 1.913% for Agfa and CV = 2.448% for Kodak; digital: CV = 0.741% for Philips print-outs and CV = 0.620% with original digital images versus CV = 2.185% for Siemens print-outs and 0.951% with original digital images). Computer-aided joint space analysis for JSD-measurements is unaffected by the following image capturing parameters: film-focus distance, film sensitivity, film brand and exposure level. An influence of tube voltage was detected in a lesser extent for original digital images compared to the printed digital as well as conventional versions. Consequently, a standardized tube voltage is essential for accurate reproductions of CAJSA-measurements in rheumatoid arthritis and osteoarthritis.