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Objectives: Medical cannabis is often used to alleviate common symptoms in patients with chronic conditions. With cannabis legalisation in Canada and easier access, it is important that rheumatologists understand its potential impact on their practice. Among patients attending rheumatology clinics in Ontario we assessed: the prevalence of medical cannabis use; symptoms treated; rheumatologists' perceptions., Methods: Eight rheumatology clinics recruited consecutive adult patients in a 3-part medical cannabis survey: the first completed by rheumatologists; the second by all patients; the third by medical cannabis users. Student's t-test and Chi-square test were used to compare medical cannabis users to never users., Results: 799 patients participated, 163 (20.4%) currently using medical cannabis or within <2 years and 636 never users; most had rheumatoid arthritis (37.8%) or osteoarthritis (34.0%). Compared to never users, current/past-users were younger; more likely to be taking opioids/anti-depressants, have psychiatric/gastrointestinal disorders, and have used recreational cannabis (p<0.05); had higher physician (2.9 vs. 2.1) and patient (6.0 vs. 4.2) global scores, and pain (6.2 vs. 4.7) (p<0.0001). Pain (95.5%), sleeping (82.3%) and anxiety (58.9%) were the most commonly treated symptoms; 78.2% of current/past-users reported medical cannabis was at least somewhat effective. Most rheumatologists reported being uncomfortable to authorise medical cannabis, primarily due to lack of evidence, knowledge, and product standardisation., Conclusions: Medical cannabis use among rheumatology patients in Ontario was two-fold higher than that reported for the general population of similar age. Use was associated with more severe disease, pain, and prior recreational use. Reported lack of research, knowledge, and product standardisation were barriers for rheumatologist use authorisation.

Objective: Reports of mortality risks among individuals with giant cell arteritis (GCA) have been mixed. Our aim was to evaluate all-cause mortality among individuals with GCA relative to the general population over time., Methods: We performed a population-based study in Ontario, Canada using health administrative data. We studied a cohort of 22,677 GCA patients ages ≥50 years that was identified using a validated case definition (with 81% positive predictive value, 100% specificity). General population comparators were residents ages ≥50 years without GCA. Deaths were ascertained from vital statistics. Annual crude, age- and sex-standardized, and age- and sex-specific all-cause mortality rates were determined for individuals with and without GCA between 2000 and 2018. Standardized mortality ratios (SMRs) were estimated., Results: Age- and sex-standardized mortality rates were significantly higher for GCA patients than comparators, and trending to increase over time with 50.0 deaths per 1,000 GCA patients in 2000 (95% confidence interval [95% CI] 34.0-71.1) and 57.6 deaths per 1,000 GCA patients in 2018 (95% CI 50.8-65.2), whereas mortality rates in the general population significantly declined over time. The annual SMRs for GCA patients generally increased over time, with the lowest SMR occurring in 2002 (1.22 [95% CI 1.03-1.40]) and the highest in 2018 (1.92 [95% CI 1.81-2.03]). GCA mortality rates were more elevated for male patients than female patients., Conclusion: Over a 19-year period, mortality rates were increased among GCA patients relative to the general population, and more premature deaths were occurring in younger age groups. The relative excess mortality for GCA patients did not improve over time., (© 2021 American College of Rheumatology.)

Objective: Systemic sclerosis (SSc) is a rare autoimmune disease. Pulmonary complications of SSc are some of the leading causes of morbidity and mortality. The objective of this study was to determine prevalence and survival estimates of SSc and SSc with interstitial lung disease (SSc-ILD) in the Canadian province of Ontario using administrative data over 10 years., Methods: Using International Classification of Diseases, 10th revision codes adapted for Canada (ICD-10-CA), adult patients diagnosed with SSc and SSc-ILD between April 1, 2008, and March 31, 2018, were identified from the National Ambulatory Care Reporting System and the Discharge Abstract Database administrative databases. SSc was identified first, and ILD was included if presence occurred after SSc diagnosis. Prevalence estimates were determined for both SSc and SSc-ILD. For survival rates, Kaplan-Meier survival curves were generated., Results: At the start of the 2017/18 fiscal year (final year of the cohort), there were 2114 prevalent SSc cases for a cumulative prevalence of 19.1 per 100,000 persons, as well as 257 prevalent cases of SSc-ILD that generated a prevalence of 2.3 cases per 100,000 persons. Mean ages were 57 and 58 years with 84% and 80% females for patients with SSc and SSc-ILD, respectively. One-, 5-, and 10-year survival rates were 85.0%, 64.5%, and 44.9% for the SSc group and 77.1%, 44.4%, and 22.0% for the SSc-ILD group, respectively., Conclusion: To our knowledge, this study provides the first population-based estimates of SSc and SSc-ILD in Canada for prevalence and survival. Results confirm that the prevalence estimates of SSc-ILD fall within the Canadian threshold for rare disease. It also demonstrates the poor survival in SSc, especially when ILD is also present., (© 2021 by the Journal of Rheumatology.)

Objective: To compare differences in clinical activity and remuneration between male and female rheumatologists and to evaluate associations between physician gender and practice sizes and patient volume, accounting for rheumatologists' age, and calendar year effects., Methods: We conducted a population-based study in Ontario, Canada, between 2000 to 2015 identifying all rheumatologists practicing as full-time equivalents (FTEs) or above and assessed differences in practice sizes (number of unique patients), practice volumes (number of patient visits), and remuneration (total fee-for-service billings) between male and female rheumatologists. Multivariable linear regression was used to evaluate the effects of gender on practice size and volume separately, accounting for age and year., Results: The number of rheumatologists practicing at ≥ 1 FTE increased from 89 to 120 from 2000 to 2015, with the percentage of females increasing from 27.0% to 41.7%. Males had larger practice sizes and practice volumes. Remuneration was consistently higher for males (median difference of CAD $46,000-102,000 annually). Our adjusted analyses estimated that in a given year, males saw a mean of 606 (95% CI 107-1105) more patients than females did, and had 1059 (95% CI 345-1773) more patient visits. Among males and females combined, there was a small but statistically significant reduction in mean annual number of patient visits, and middle-aged rheumatologists had greater practice sizes and volumes than their younger/older counterparts., Conclusion: On average, female rheumatologists saw fewer patients and had fewer patient visits annually relative to males, resulting in lower earnings. Increasing feminization necessitates workforce planning to ensure that populations' needs are met., (Copyright © 2021 by the Journal of Rheumatology.)

Objectives: RA patients are often not in remission due to patient global assessment of disease activity (PtGA) included in disease activity indices. The aim was to assess the lag of patient-reported outcomes (PROs) after remission measured by clinical disease activity index (CDAI) or swollen joint count (SJC28)., Methods: RA patients enrolled in the Ontario Best Practices Research Initiative registry not in low disease state at baseline with at ≥6 months of follow-up, were included. Low disease state was defined as CDAI ≤ 10, SJC28 ≤ 2, PtGA ≤ 2cm, pain score ≤ 2cm, or fatigue ≤ 2cm. Remission included CDAI ≤ 2.8, SJC28 ≤ 1, PtGA ≤ 1cm, pain score ≤ 1cm, or fatigue ≤ 1cm. Time to first low disease state/remission based on each definition was calculated overall and stratified by early vs established RA., Results: A total of 986 patients were included (age 57.4 (12.9), disease duration 8.3 (9.9) years, 80% women). The median (95% CI) time in months to CDAI ≤ 10 was 12.4 (11.4, 13.6), SJC28 ≤ 2 was 9 (8.2, 10), PtGA ≤ 2cm was 18.9 (16.1, 22), pain ≤ 2cm was 24.5 (19.4, 30.5), and fatigue ≤ 2cm was 30.4 (24.8, 31.7). For remission, the median (95% CI) time in months to CDAI ≤ 2.8 was 46.5 (42, 54.1), SJC28 ≤ 1 was 12.5 (11.4, 13.4), PtGA ≤ 1cm was 39.6 (34.6, 44.8), pain ≤ 1cm was 54.7 (43.6, 57.5) and fatigue ≤ 1cm was 42.6 (36.8, 48). Time to achieving low disease state and remission was generally significantly shorter in early RA compared with established RA with the exception of fatigue., Conclusion: Time to achieving low disease state or remission based on PROs was considerably longer compared with swollen joint count. Treating to a composite target in RA could lead to inappropriate changes in DMARDs., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Rheumatology workforces are increasingly challenged by too few physicians in face of the growing burden of rheumatic and musculoskeletal diseases (RMDs). Rheumatology is one of the most frequent non-surgical specialty referrals and has the longest wait times for subspecialists. We used a population-based approach to describe changes in the rheumatology workforce, patient volumes and geographic variation in the supply of and access to rheumatologists, in Ontario, Canada, between 2000 and 2019, and projected changes in supply by 2030. Over time, we observed greater feminization of the workforce and increasing age of workforce members. We identified a large regional variation in rheumatology supply. Fewer new patients are seen annually, which likely contributes to increasing wait times and reduced access to care. Strategies and policies to raise the critical mass and improve regional distribution of supply to effectively provide rheumatology care and support the healthcare delivery of patients with RMDs are needed., (Copyright © 2021 Longwoods Publishing.)

Objective: To estimate trends in the incidence and prevalence of GCA over time in Canada., Methods: We performed a population-based study of Ontario health administrative data using validated case definitions for GCA. Among Ontario residents ≥50 years of age we estimated the annual incidence and prevalence rates between 2000 and 2018. We performed sensitivity analyses using alternative validated case definitions to provide comparative estimates., Results: Between 2000 and 2018 there was a relatively stable incidence over time with 25 new cases per 100 000 people >50 years of age. Age-standardized incidence rates were significantly higher among females than males [31 cases (95% CI: 29, 34) vs 15 cases (95% CI: 13, 18) per 100 000 in 2000]. Trends in age-standardized incidence rates were stable among females but increased among males over time. Incidence rates were highest among those ≥70 years of age. Standardized prevalence rates increased from 125 (95% CI 121, 129) to 235 (95% CI 231, 239) cases per 100 000 from 2000 to 2018. The age-standardized rates among males rose from 76 (95% CI 72, 81) cases in 2000 to 156 (95% CI 151, 161) cases per 100 000 population in 2018. Between 2000 and 2018, the age-standardized rates among females similarly increased over time, from 167 (95% CI 161, 173) to 304 (95% CI 297, 310) cases per 100 000 population., Conclusion: The incidence and prevalence of GCA in Ontario is similar to that reported in the USA and northern Europe and considerably higher than that reported for southern Europe and non-European populations., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To quantify population-level and practice-level encounters with rheumatologists over time., Methods: We conducted a population-based study from 2000 to 2015 in Ontario, Canada, where all residents are covered by a single-payer healthcare system. Annual total number of unique patients seen by rheumatologists, the number of new patients seen, and total number of encounters with rheumatologists were identified., Results: From 2000 to 2015, the percentage of the population seen by rheumatologists was constant over time (2.7%). During this time, Ontario had a stable supply of rheumatologists (0.8 full-time equivalents/75,000). From 2000 to 2015, the number of annual rheumatology encounters increased from 561,452 to 786,061, but the adjusted encounter rates remained stable over time (at 62 encounters per 1000 population). New patient assessment rates declined over time from 10 new outpatient assessments per 1000 in 2000 to 6 per 1000 in 2015. The crude volume of new patients seen annually decreased and an increasing proportion of rheumatology encounters were with established patients. We observed a shift in patient case mix over time, with more assessments for systemic inflammatory conditions. Rheumatologists' practice volumes, practice sizes, and the annual number of days providing clinical care decreased over time., Conclusion: Over a 15-year period, the annual percentage of the population seen by a rheumatologist remained constant and the volume of new patients decreased, while followup patient encounters increased. Patient encounters per rheumatologist decreased over time. Our findings provide novel information for rheumatology workforce planning. Factors affecting clinical activity warrant further research.

Objectives: This meta-analysis investigated the frequency and type of ocular involvement in juvenile inflammatory arthritis (JIA) and other juvenile rheumatic diseases., Methods: Medline, Web of Science and Cochrane databases were searched from inception to September 2018 to identify publications related to juvenile arthritis and rheumatic diseases, which reported frequency of Uveitis in juvenile rheumatic conditions and contained at least 20 patients. The prevalence and type of eye complications were extracted, and random effects models estimated their frequency. Heterogeneity was evaluated using I 2 ., Results: In total, 7132 unique citations resulted in 59 articles included. Pooled frequency of uveitis was: 24% in oligoarticular JIA, 12% in polyarticular JIA, 1% in systemic JIA, 50% in pediatric Bechet's, 9% in juvenile psoriatic arthritis, 24% in juvenile spondyloarthropathy and 5% in juvenile systemic lupus erythematosus. The most common uveitis in JIA was anterior uveitis, which occurred in 14%; also described as iridocyclitis in 10% of patients. Publication bias was negligible for all conditions except those with few reported studies (juvenile SLE and systemic JIA). Uveitis in JIA was more common in Europe (14%), North America (11%) and the Middle East (12%) than East Asia (7%) and Oceania (3%)., Conclusions: Ocular involvement (mostly uveitis) in juvenile inflammatory arthritis and other pediatric rheumatic diseases varied between 3% and 50% depending on the underlying condition; and was highest in pediatric Bechet's. In JIA, the highest frequency of uveitis was in oligoarticular JIA; with anterior uveitis being the most frequent type of uveitis. There was variation geographically for uveitis in JIA., (Copyright © 2019 Société française de rhumatologie. Published by Elsevier Masson SAS. All rights reserved.)

Objective: We evaluated the associations between time-varying methotrexate (MTX) use and risk of cardiovascular events (CVE) in patients with rheumatoid arthritis (RA)., Methods: We studied an inception cohort of 23,994 patients with RA diagnosed after their 65th birthday. Multivariable Cox regression models were fit to evaluate the associations between time-varying MTX use, controlling for other risk factors, and time to CVE. Alternative models assessed the cumulative duration of MTX use over the (1) first year, (2) previous year (recent use), and (3) entire duration of followup. We also assessed whether the strength of the association varied over time., Results: Over 115,453 patient-years (PY), 3294 (13.7%) patients experienced a CVE (28.5 events per 1000 PY; 95% CI 27.6-29.5). In the multivariable analyses, the model assessing time-varying continuous use in the most recent year yielded the best fit. Increasing recent MTX use was associated with lower CVE risks (HR 0.79 for continuous use vs no use in past 12 months, 95% CI 0.70-0.88; p < 0.0001). Greater MTX use in the first year after cohort entry was also protective (HR 0.84, 95% CI 0.72-0.96; p = 0.0048), but this effect decreased with increasing followup. In contrast, longer MTX use during the entire followup was not clearly associated with CVE risk (HR 0.98, 95% CI 0.95-1.01; p = 0.1441)., Conclusion: We observed about a 20% decrease in CVE associated with recent continuous MTX use. Greater MTX use in the first year of cohort entry also appeared to be important in the association between MTX and CVE risk.

Objective: To determine the rate of low health literacy in the rheumatoid arthritis (RA) population in southwestern Ontario., Methods: For the study, 432 patients with RA were contacted, and 311 completed the assessment. The health literacy levels of the participants were estimated using 4 assessment tools administered in the following order: the Single Item Literacy Screener (SILS), the Medical Term Recognition Test (METER), the Rapid Estimate of Adult Literacy in Medicine (REALM), and the Shortened Test of Functional Health Literacy in Adults (STOFHLA)., Results: The rates of low literacy as estimated by STOFHLA, REALM, METER, and SILS were 14.5%, 14.8%, 14.1%, and 18.6%, respectively. All 4 assessment tools were statistically significantly correlated. STOFHLA, REALM, and METER were strongly correlated with each other (r = 0.59-0.79), while SILS only demonstrated moderate correlations with the other assessment tools (r = 0.33-0.45). Multiple linear regression and binary logistic regression analyses revealed that low levels of education and a lack of daily reading activity were common predictors of low health literacy. Using a non-English primary language at home was found to be a strong predictor of low health literacy in STOFHLA, REALM, and METER. Male sex was found to be a significant predictor of poor performance in REALM and METER, but not STOFHLA., Conclusion: Low health literacy is an important issue in the southwestern Ontario RA population. About 1 in 7 patients with RA may not have the necessary skills to become involved in making decisions regarding their personal health. Rheumatologists should be aware of the low health literacy levels of patients with RA and should consider identifying patients at risk of low health literacy.

Objective: To evaluate excess mortality over time, comparing rheumatoid arthritis (RA) patients with the general population., Methods: We computed all-cause mortality rates among Ontario residents age ≥15 years with RA versus without RA from 1996 to 2009. Age- and sex-standardized mortality rates were expressed as the number of deaths per 1,000 population. Excess mortality rates were calculated as the difference between death rates among RA patients and those in the general population. We estimated standardized mortality ratios (SMRs) and mortality rate ratios (MRRs) to assess relative excess mortality over time., Results: From 1996 to 2009, SMRs in RA ranged from 13.0 (95% confidence interval [95% CI] 12.2, 13.9) to 9.2 deaths per 1,000 RA patients (95% CI 8.4, 10.0); and for those without RA from 8.7 (95% CI 8.6, 8.7) to 6.0 deaths (95% CI 5.9, 6.0) per 1,000 general population. Over the study period, the excess mortality rate among RA patients was approximately 3 excess deaths per 1,000 population. Relative reductions in standardized mortality rates occurred over time for those with and without RA (-21.4% versus -13.4%). The SMRs for RA patients in 1996-1997, 2000-2001, 2004-2005, and 2008-2009 were 1.51 (95% CI 1.43, 1.59), 1.50 (95% CI 1.43, 1.57), 1.43 (95% CI 1.37, 1.50), and 1.41 (95% CI 1.35, 1.47), respectively. We did not find a significant change in the MRR by calendar time., Conclusion: Mortality for RA patients has decreased over time but remains elevated compared to the general population, with 40-50% more deaths among RA patients. The relative excess mortality over time (mortality gap) remains unchanged in our sample., (© 2015, American College of Rheumatology.)

Objective: The objective of this study was to determine predictors of 1-year remission in early RA (ERA) using baseline and 3-month data., Methods: The Canadian Early Arthritis Cohort (CATCH) patients were included if baseline, 3- and 12-month data were available. Regression analyses for four different definitions of remission at 12 months were done to determine baseline and 3-month predictors of remission., Results: Five hundred and sixty-two patients had complete data at 12 months (mean age 53.4 years, disease duration 6.2 years, 73% female). The factors at baseline associated with all four remission outcomes at 12 months were age, gender, income, education, tender joint count (TJC), patient global assessment (PtGA), HAQ and pain. Baseline ESR was associated with the 28-joint DAS (DAS28) remission only. At 3 months, all four remission definitions were associated with TJC, swollen joint count, physician global assessment (PGA), PtGA, HAQ, pain, ESR and CRP in univariate analyses. In the regression model, variables associated with Simple Disease Activity Index remission were PGA [odds ratio (OR) 0.77, P < 0.001), pain (OR 0.85, P = 0.004), age (OR 0.98, P = 0.006) and HAQ (OR 0.49, P = 0.011); Clinical Disease Activity Index remission was associated with PGA (OR 0.77, P < 0.001), pain (OR 0.85, P = 0.003), age (OR 0.98, P = 0.015) and CRP (OR 0.80, P = 0.031). DAS28 remission was predicted by ESR (OR 0.95, P < 0.001), PGA (OR 0.76, P < 0.001), age (OR 0.98, P = 0.001), HAQ (OR 0.57, P = 0.006) and male gender (OR 2.01, P = 0.005), whereas Boolean remission was associated with pain (OR 0.79, P = 0.009), age (OR 0.98, P = 0.016), PtGA (OR 0.83, P = 0.025) and PGA (OR 0.86, P = 0.038)., Conclusion: A low PGA at 3 months was consistently associated with 1-year remission in ERA.

Objective: Health administrative data can be a valuable tool for disease surveillance and research. Few studies have rigorously evaluated the accuracy of administrative databases for identifying rheumatoid arthritis (RA) patients. Our aim was to validate administrative data algorithms to identify RA patients in Ontario, Canada., Methods: We performed a retrospective review of a random sample of 450 patients from 18 rheumatology clinics. Using rheumatologist-reported diagnosis as the reference standard, we tested and validated different combinations of physician billing, hospitalization, and pharmacy data., Results: One hundred forty-nine rheumatology patients were classified as having RA and 301 were classified as not having RA based on our reference standard definition (study RA prevalence 33%). Overall, algorithms that included physician billings had excellent sensitivity (range 94-100%). Specificity and positive predictive value (PPV) were modest to excellent and increased when algorithms included multiple physician claims or specialist claims. The addition of RA medications did not significantly improve algorithm performance. The algorithm of "(1 hospitalization RA code ever) OR (3 physician RA diagnosis codes [claims] with ≥1 by a specialist in a 2-year period)" had a sensitivity of 97%, specificity of 85%, PPV of 76%, and negative predictive value of 98%. Most RA patients (84%) had an RA diagnosis code present in the administrative data within ±1 year of a rheumatologist's documented diagnosis date., Conclusion: We demonstrated that administrative data can be used to identify RA patients with a high degree of accuracy. RA diagnosis date and disease duration are fairly well estimated from administrative data in jurisdictions of universal health care insurance., (Copyright © 2013 by the American College of Rheumatology.)

Objective: We studied patients with systemic lupus erythematosus (SLE) in 1 clinical practice, and patients enrolled in the 1000 Canadian Faces of Lupus database, to determine the minimally important difference (MID) for pain, fatigue, sleep, Health Assessment Questionnaire-Disability Index (HAQ-DI), and Medical Outcomes Study Short Form-36 (SF-36) Physical Component Score (PCS) and SF-36 Mental Component Score (MCS) using a patient-reported overall health status anchor., Methods: Patients with SLE who had 2 consecutive clinic visits and completed a HAQ-DI and a pain, fatigue, and sleep visual analog scale (VAS) (0-100), and an overall health status question: "How would you describe your overall status since your last visit?": much better, better, the same, worse, or much worse were included. Those who self-rated as better or worse were considered the "minimally changed" subgroups. Patients with 2 consecutive annual visits in the 1000 Canadian Faces of Lupus database who completed the SF-36 and health transition question were eligible., Results: There were 202 patients in London, Ontario (94% women, mean age 50 yrs, mean disease duration 10 yrs). MID for better and worse on a VAS (0-100) were: pain (-15.8, 8.5), fatigue (-13.9, 9.1), and sleep problems (-8.6, 7.6). The MID for HAQ-DI (scale 0 to 3) was -0.08 (better) and 0.14 (worse). The MID for SF-36 was 2.1 (better) and -2.2 (worse) for the PCS and 2.4 (better) and -1.2 (worse) in the MCS., Conclusion: The MID in patients with SLE may be different bidirectionally depending on the measured outcome. The mean change observed for those reporting better than worse outcome in pain and fatigue was greater for better versus worst, in contrast to the HAQ, where the mean change was greater for worsening.

Objectives: Reactive arthritis (ReA) may occur from bacterial gastroenteritis. We studied the risk of arthritis after an outbreak of Escherichia coli O157:H7 and Campylobacter species within a regional drinking water supply to examine the relationship between the severity of acute diarrhoea and subsequent symptoms of arthritis., Methods: Participants with no known history of arthritis before the outbreak participated in a long-term follow-up study. Of the 2299 participants, 788 were asymptomatic during the outbreak, 1034 had moderate symptoms of acute gastroenteritis and 477 had severe symptoms that necessitated medical attention. The outcomes of interest were new arthritis by self-report and a new prescription of medication for arthritis during the follow-up period., Results: After a mean follow-up of 4.5 yrs after the outbreak, arthritis was reported in 15.7% of participants who had been asymptomatic during the outbreak, and in 17.6 and 21.6% of those who had moderate and severe symptoms of acute gastroenteritis, respectively (P-value for trend = 0.009). Compared with the asymptomatic participants, those with moderate and severe symptoms of gastroenteritis had an adjusted relative risk of arthritis of 1.19 [95% confidence interval (CI) 0.99-1.43] and 1.33 (95% CI 1.07-1.66), respectively. No association was observed between gastroenteritis and the subsequent risk of prescription medication for arthritis (P = 0.49)., Conclusions: Acute bacterial gastroenteritis necessitating medical attention was associated with a higher risk of arthritic symptoms, but not arthritic medications, up to 4 yrs afterwards. The nature and chronicity of these arthritic symptoms requires further study.

Objective: To estimate the prevalence of scleroderma (systemic sclerosis, SSc) in 3 cities, Windsor, Sarnia, and Woodstock, Ontario, within our referral area, which has a referral base population of 1 million., Methods: To compare the addresses and exposures of referrals with SSc, we performed a case control study using our patients with scleroderma and 2 age and sex matched controls from the same rheumatologist's practice., Results: Sixty-seven of 91 patients with SSc and 87 of 154 controls responded. The mean age of patients with SSc was 53.2 years versus 52.8 years in controls. There was no statistically significant increase in the number of SSc patients from Windsor (population 197,694): 14 patients (15.4%) with SSc versus 18 controls (11.6%) (p < 0.41); or Sarnia (population 72,738): 7 patients (7.7%) with SSc versus 7 controls (4.5%) (p < 0.31). However, there were 9 cases (9.9%) from Woodstock (population 32,086) versus one control (0.64%) (p < 0.0004). The point prevalence of scleroderma was at least 0.71/10,000 in Windsor, 0.96/10,000 in Sarnia, and 2.8/10,000 in Woodstock. There were no significant between-group differences in exposure to industrial toxins or chemicals including vinyl chloride, silica, and benzene, but exposure rates in both groups were low. Occupations and proportion of those who were work disabled were not different. Patients with SSc were not more likely to have smoked cigarettes (p < 0.43); however, they were more likely to drink at least 6 drinks of alcohol per week (p < 0.04) and had more dental fillings (p < 0.05). Patients with SSc knew on average 3.2 others with this disease, and controls knew only 0.25 others with scleroderma (p < 0.00001). Two patients with SSc knew someone with SSc in their workplace versus none of the controls., Conclusion: Our a priori expected higher prevalence of scleroderma in Windsor and Sarnia did not reach significance, but the cluster in Woodstock seems statistically validated, and the exact reason for this cluster remains unclear. It is unlikely that all patients with SSc in Woodstock were seen by us, so the prevalence of scleroderma is at least 2.8/10,000, which is a medium to high prevalence compared to other studies. Associations with alcohol and dental fillings require further study.