Radiographic hand osteoarthritis in two ethnic groups living in the same geographic area

Association between Race and Radiographic, Symptomatic, and Clinical Hand Osteoarthritis: A Propensity Score-Matched Study Using Osteoarthritis Initiative Data

OBJECTIVES

To determine the associations between race (black versus nonblack) and the presence of radiographic, symptomatic, and clinical hand osteoarthritis (OA).

METHODS

Using the Osteoarthritis Initiative cohort with available hand radiographs (n=4,699, black subjects n=849[18.1%], nonblack subjects n=3,850[81.9%]), propensity score-matching method was used to select black and nonblack subjects matched for known potential hand OA risk factors (age, gender, BMI, smoking status, cardiovascular disease, osteoporosis, excessive hand use, and knee OA). Posteroanterior radiographs of subjects' dominant hands were read by a musculoskeletal radiologist for this study in a blinded fashion. The modified KL grades (mKL, 0-4 scale) and the presence of erosive OA in the hand joints were recorded. Associations between race and hand OA severity criteria (mKL sum score), presence of radiographic OA (mKL≥2), erosive OA, symptomatic OA (radiographic OA with hand pain), and clinical OA (presence of Heberden's nodes) were studied using regression models. Odds ratios (ORs) and their 95% confidence interval (CI) are reported.

RESULTS

Black subjects had less severe hand OA (β:-1.93[95%CI:-2.53--1.34]), lower odds of radiographic (OR:0.79[95%CI:0.66-0.94]), erosive (OR:0.23[95%CI:0.11-0.47]), symptomatic (OR:0.63[95%CI:0.49-0.82]), and clinical (OR:0.49[95%CI:0.41-0.60]) hand OA.

CONCLUSIONS

In contrast to the well-established association between black race and knee or hip OA, odds of hand OA are lower in black versus nonblack subjects, which is not mediated by known hand OA risk factors. Future mechanistic works are warranted to determine the mediating protective factors for hand OA among the black subjects.

Climate is associated with prevalence and severity of radiographic hand osteoarthritis

The aim of this study was to evaluate whether geographic location and climatic factors are associated with prevalence and severity of radiographic hand osteoarthritis (OA) in several samples of the same ethnicity. The total sample included 2079 ethnic Russians (900 males and 1179 females), belonging to 7 samples from different geographic locations in the former USSR. Places of residence were characterized by latitude, longitude, altitude and climatic parameters (mean temperatures, humidity, and daylight duration of January and July). Radiographs of the left hand were obtained from each individual. Osteoarthritis (OA) was evaluated in 14 hand joints according to Kellgren and Lawrence's grading system. OA was characterized by the presence of at least one affected joint and its severity by the number of affected joints (NAJ). Statistical analysis included prevalence estimation, polynomial and logistic regressions, ANOVA and correlation analyses. Prevalence of hand OA and NAJ were significantly associated with latitude and altitude and with most climatic parameters (except the inter-seasonal temperature amplitude and the mean atmospheric pressure of January and July). The highest correlations of hand OA prevalence were found with altitude (r=0.29, p<0.001), annual precipitation (r=-0.26, p<0.001) and the mean temperatures of July (r=0.26, p<0.001). The highest correlations of NAJ were found with altitude (r=0.51, p<0.001), mean humidity in January (r=-0.44, p<0.001) and the mean day duration in January (r=0.0.37, p<0.001). The present study demonstrates that the differences in prevalence and severity of radiographic hand OA among Russian samples are most likely dependent on climatic conditions in the place of residence.