Estimates of the prevalence of rheumatic diseases in the population of Tecumseh, Michigan, 1959-60.

Abstract Over 90 per cent of the more than 9000 residents of Tecumseh, Michigan participated in a program of comprehensive health examinations in 1959–1960. Included in the examination were inquiries regarding rheumatic symptoms, physical examination of the spine and peripheral joints, and the latex fixation test for rheumatoid factor and serum uric acid measurement. Joint pain or aching, joint swelling, morning stiffness, and past arthritis or rheumatism were common complaints, occurring in one-eighth to one-third of the population age 6 yr and over. The age-sex specific prevalence rates for each of these historical items rose with increasing age. Male and female rates were quite similar during the first four decades of life, but thereafter female rates were somewhat higher. The prevalence of positive latex fixation tests for rheumatoid factor was essentially the same for male and female subjects, 3.4 per cent for males and 3.35 per cent for females. The rates rose progressively from approximately one per cent in the 6–16 yr age group to almost 14 per cent for males and 9.4 per cent for females in the oldest age groups. The latex fixation test performed poorly as a case detection tool, only one-third of those respondents with positive tests having any other evidence to suggest a diagnosis of rheumatoid arthritis. Relatively high rates of latex positively occurred in individuals with a history of jaundice or infectious hepatitis and in those with evidence of emphysema or right heart failure. None of the respondents with psoriasis or pregnancy at the time of examination had positive latex tests. The prevalence of latex positivity showed a rise with increasing systolic blood pressure in persons over 30 yr of age, but appeared to be unrelated to diastolic blood pressure, serum cholesterol or serum uric acid. Prevalence rates for “definite” rheumatoid arthritis, based on the diagnostic criteria proposed by the American Rheumatism Association, were 0.4 per cent for all subjects age 6 yr and over and 0.5 per cent for all subjects age 16 yr and over. Prevalence rates for “definite” plus “probable” rheumatoid arthritis were 1.3 per cent in the age group 6 yr and over and 1.7 per cent in the age group 16 yr and over. In all diagnostic categories prevalence rates for females exceeded those for males. In the age group 16 yr and over the female to male ratio was 2.3: 1 for “definite” disease and 2.4: 1 for total suspected cases of rheumatoid arthritis. The prevalence rates for rheumatoid arthritis rose with increasing age; rates for “definite” disease rose from 0.44 per cent in the fourth decade to 0.79 per cent in the eighth decade for males and from 1.69 per cent in the fifth decade to 2.47 per cent in the eighth decade for females. The over-all prevalence rates for suspected ankylosing spondylitis, not confirmed by X-ray examination of the spine or sacroiliac joints, were 0.4 per cent for males and 0.05 per cent for females age 6 yr and over. Prevalence rates for osteoarthritis, diagnosed on the basis of physical rather than radiological examination were 2.2 per cent for males and 5.0 per cent for females age 6 yr and over. Rates were highest in the older age groups, being 20.3 per cent for males and 40.8 per cent for females in the age group 60 yr and over. The prevalence of Heberden's nodes was greater in female than in male respondents and demonstrated a similar rise with increasing age. The prevalence of “probable” gout, based on available clinical information was 0.5 per cent for male and 0.3 per cent for female subjects age 4 yr and over having serum uric acid determinations. The highest rates were observed in subjects in the age range 40–59 yr. The prevalence rates for a history of rheumatic fever and / or chorea were similar for male and female subjects age 6 yr and over, 0.8 per cent in the case of rheumatic fever and 0.1 per cent in the case of chorea. A history of chorea was not obtained among respondents under age 20. Physical evidence of rheumatic heart disease was recorded in all age groups and was slightly more prevalent in females, 0.6 per cent as compared to 0.4 per cent in males. Comparisons of the results of this investigation with those of other population studies have been made although the interpretation of any differences or similarities is inherently limited by methodological problems and observer variation.