Objective
To provide a single source for the best available estimates of the national prevalence of arthritis in general and of selected musculoskeletal disorders (osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, the spondylarthropathies, systemic lupus erythematosus, scleroderma, polymyalgia rheumatica/giant cell arteritis, gout, fibromyalgia, and low back pain).

Methods
The National Arthritis Data Workgroup reviewed data from available surveys, such as the National Health and Nutrition Examination Survey series. For overall national estimates, we used surveys based on representative samples. Because data based on national population samples are unavailable for most specific musculoskeletal conditions, we derived data from various smaller survey samples from defined populations. Prevalence estimates from these surveys were linked to 1990 US Bureau of the Census population data to calculate national estimates. We also estimated the expected frequency of arthritis in the year 2020.

Results
Current national estimates are provided, with important caveats regarding their interpretation, for self-reported arthritis and selected conditions. An estimated 15% (40 million) of Americans had some form or arthritis in 1995. By the year 2020, an estimated 18.2% (59.4 million) will be affected.

Conclusion
Given the limitations of the data on which they are based, this report provides the best available prevalence estimates for arthritis and other rheumatic conditions overall, and for selected musculoskeletal disorders, in the US population.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1529-0131%28199805%2941%3A5%3C778%3A%3AAID-ART4%3E3.0.CO%3B2-V

Estimates of the prevalence of arthritis and selected musculoskeletal disorders in the United States

Osteoarthritis is the most common form of arthritis, affecting millions of people in the United States. It is a complex disease whose etiology bridges biomechanics and biochemistry. Evidence is growing for the role of systemic factors (such as genetics, dietary intake, estrogen use, and bone density) and of local biomechanical factors (such as muscle weakness, obesity, and joint laxity). These risk factors are particularly important in weightbearing joints, and modifying them may present opportunities for prevention of osteoarthritis-related pain and disability. Major advances in management to reduce pain and disability are yielding a panoply of available treatments ranging from nutriceuticals to chondrocyte transplantation, new oral anti-inflammatory medications, and health education. This article is part 1 of a two-part summary of a National Institutes of Health conference. The conference brought together experts on osteoarthritis from diverse backgrounds and provided a multidisciplinary and comprehensive summary of recent advances in the prevention of osteoarthritis onset, progression, and disability. Part 1 focuses on a new understanding of what osteoarthritis is and on risk factors that predispose to disease occurrence. It concludes with a discussion of the impact of osteoarthritis on disability. Ann Intern Med. 2000;133:635-646. www.annals.org For author affiliations and current addresses, see end of text.

/pdf/osteoarthritis-new-insights-part-1-the-disease-and-its-risk-2p0wtgll5h.pdf

Osteoarthritis: New Insights Part 1: The Disease and Its Risk Factors

To investigate the prevalence of osteoarthritis (OA) of the knee in elderly subjects, we studied the Framingham Heart Study cohort, a population-based group. During the eighteenth biennial examination, we evaluated the cohort members for OA of the knee by use of medical history, physical examination, and anteroposterior (standing) radiograph of the knees. Radiographs were obtained on 1,424 of the 1,805 subjects (79%). Their ages ranged from 63-94 years (mean 73). Radiographs were read by a radiologist who specializes in bone and joint radiology, and were graded 0-4 according to the scale described by Kellgren and Lawrence. OA was defined as grade 2 changes (definite osteophytes), or higher, in either knee. Radiographic evidence of OA increased with age, from 27% in subjects younger than age 70, to 44% in subjects age 80 or older. There was a slightly higher prevalence of radiographic changes of OA in women than in men (34% versus 31%); however, there was a significantly higher proportion of women with symptomatic disease (11% of all women versus 7% of all men; P = 0.003). The age-associated increase in OA was almost entirely the result of the marked age-associated increase in the incidence of OA in the women studied. This study extends current knowledge about OA of the knee to include elderly subjects, and shows that the prevalence of knee OA increases with age throughout the elderly years.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780300811

The prevalence of knee osteoarthritis in the elderly. The Framingham Osteoarthritis Study.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/1529-0131%28199808%2941%3A8%3C1343%3A%3AAID-ART3%3E3.0.CO%3B2-9

An update on the epidemiology of knee and hip osteoarthritis with a view to prevention

Study objective To determine whether obesity preceded knee osteoarthritis and was thus a possible cause. Design Cohort study with weight and other important variables measured in 1948 to 1951 (mean age of subjects, 37 years) and knee arthritis evaluated in 1983 to 1985 (mean age of subjects, 73 years). Setting Population-based participants; a subset (n = 1420) of the Framingham Heart Study cohort. Methods For those subjects in the Framingham Study having knee radiographs taken as part of the 18th biennial examination (1983 to 1985), we examined Metropolitan Relative Weight, a measure of weight adjusted for height at the onset of the study (1948 to 1951). Relative risks were computed as the cumulative incidence rate of radiographic knee osteoarthritis in the heaviest weight groups at examination 1 divided by the cumulative rate in the lightest 60% weight groups at examination 1. Relative risks were adjusted for age, physical activity level, and uric acid level. Results In 1983 to 1985, 468 subjects (33%) had radiographic knee osteoarthritis. For men, the risk of knee osteoarthritis was increased in those in the heaviest quintile of weight at examination 1 compared with those in the lightest three quintiles (age-adjusted relative risk, 1.51; 95% confidence interval [CI], 1.14 to 1.98); risk was not increased for those in the second heaviest quintile (relative risk, 1.0). The association between weight and knee osteoarthritis was stronger in women than in men; for women in the most overweight quintile at examination 1, relative risk was 2.07 (95% CI, 1.67 to 2.55), and for those in the second heaviest group, relative risk was 1.44 (95% CI, 1.11 to 1.86). This link between obesity and subsequent osteoarthritis persisted after controlling for serum uric acid level and physical activity level, and was strongest for persons with severest radiographic disease. Obesity at examination 1 was associated with the risk of developing both symptomatic and asymptomatic osteoarthritis. Conclusions These results and other corroborative cross-sectional data show that obesity or as yet unknown factors associated with obesity cause knee osteoarthritis.

Obesity and knee osteoarthritis. The Framingham Study.

https://ard.bmj.com/content/annrheumdis/25/1/1.full.pdf

F. Bier

Papers

Osteo-arthrosis. Prevalence in the population and relationship between symptoms and x-ray changes.