This paper provides the first data on the incidence of RA based on a prospective population-based register. All new cases of inflammatory polyarthritis in the Norwich Health Authority are notified by general practitioners to the Norfolk Arthritis Register. The patients are then clinically evaluated by metrologists and blood taken for RF estimation. Cases of RA were defined as all those notified with an onset of symptoms in 1990; who presented by 31 December 1991; and who satisfied the 1987 ARA criteria for RA at the time of presentation. Two hundred and ten patients were notified in the defined time-frame, of whom 104 were classified as having RA. The annual incidence rate was 36/100,000 for women and 14/100,000 for men. RA was rare in men aged under 45 yr. The incidence in men rose steeply with age. The incidence in women rose up to age 45 yr, plateaued to age 75 yr, and fell in the very elderly.

Objective. To determine the degree and causes of any excess mortality observed during the early years of inflammatory polyarthritis (IP).Methods. Between 1990 and 1994, a total of 1,236 patients were registered with the Norfolk Arthritis Register, a primary care-based inception cohort. All patients were tracked on the National Health Service Central Register for notification of death. The vital status of each patient was determined as of December 31, 1999. Causes of death were coded according to the International Classification of Diseases, Ninth Revision. Expected death rates were calculated using annual death rates for the Norfolk population. Standardized mortality ratios (SMRs) were calculated for all IP patients and for the subgroups of patients who did and did not satisfy the American College of Rheumatology (ACR) 1987 criteria for rheumatoid arthritis (RA) at baseline, as well as for the subgroups who were and were not rheumatoid factor (RF) positive at baseline.Results. By December 31, 1999, 160 patients (13%; 79 women and 81 men) had died. The median duration of followup in the entire cohort was 6.9 years. Mortality rates were not significantly increased in the entire group of patients with IP or in the subgroup who met the ACR 1987 criteria for RA at baseline. In contrast, RF-positive patients had an increased rate of death from all causes (SMR in men 1.51, in women 1.41). Cardiovascular disease was the most common cause of death. The majority of the excess mortality in the RF-positive patients could be attributed to cardiovascular causes (SMR in men 1.34, in women 2.02).Conclusion. Excess mortality in the early years of IP is confined to patients who are seropositive for RF. While excess cardiovascular mortality has been described in patients with established RA, this is the first report of premature death from heart disease in the early years of IP.

Objective. To examine a range of demographic, social, and clinical risk factors for the development of rheumatoid arthritis (RA).Methods. Population-based case-control study in Norfolk, England, involving adult patients, ages 18-70, with an inflammatory polyarthritis of < 12 months' duration who were recruited from the Norfolk Arthritis Register. Controls, matched for sex and date of birth, were selected from the primary care register of the Nomich Health Authority. Both cases and controls completed identical self-administered questionnaires. Matched analysis of the 165 case-control sets was conducted for the whole group and for the subset in which the cases satisfied the 1987 American College of Rheumatology criteria for RA.Results. The controls were of higher socioeconomic status than the cases. This was probably due to response bias. Having a body mass index 1 3 0 was associated with an adjusted odds ratio (OR) of 3.74 for developing RA (95% confidence interval [95% CI] 1.14-12.27). RA was also associated with a history of blood transfusion (OR 4.83, 95% CI 1.29-18.07). Even after correcting for social class, a history of having ever Supported by the Arthritis and Rheumatism Council, UK.