Frances Vaughn Wilder

Objective: To evaluate the association between vitamin C supplementation and the incidence and progression of radiographic knee osteoarthritis (OA).Design: Prospective cohort study.Setting: Clearwater Osteoarthritis Study (COS): (1988 to the present) a longitudinal study.Subjects: Male and female COS participants aged 40 years and above (n 1023). The study exposure was the participants’ self-reported history of vitamin C supplementation. The participants underwent biennial, sequential knee radiographs, which were assessed using the Kellgren–Lawrence ordinal scale to determine evidence of the study 2 outcomes: incident radiographic knee OA (RKOA) and progression of RKOA.Results: Individuals without baseline knee OA who self-reported vitamin C supplement usage were 11 % less likely to develop knee OA than were those individuals who self-reported no vitamin C supplement usage (risk ratio (RR) = 0·89, 95 % CI 0·85, 0·93). Among those participants with RKOA at baseline, vitamin C supplement usage did not demonstrate an association with RKOA progression (RR = 0·94, 95 % CI 0·79, 1·22).Conclusions: In the present prospective cohort study, we found no evidence to support a protective role of vitamin C in the progression of knee OA. However, after controlling for confounding variables, these data suggest that vitamin C supplementation may indeed be beneficial in preventing incident knee OA. Given the massive public health burden of OA, the use of a simple, widely available and inexpensive supplement to potentially reduce the impact of this disease merits further consideration.

Relative to other sites, the cervical spine has received little attention in the osteoarthritis (OA) literature. Using data from a longitudinal study, we provide age-specific progression rates of radiographic cervical spine OA, by gender. Data from cohort subjects (ages 40+) from the Clearwater Osteoarthritis Study were analyzed (N = 707). All study subjects’ demonstrated radiographic cervical spine OA at baseline (2+). Lateral cervical spine radiographs were taken biennially. The study outcome was radiographic disease progression. A grade increase of 1, or more, by the Lawrence and Kellgren ordinal scale was considered progression. Incidence rates were calculated as per 100 person-years of observation. We show that the progression rates for cervical spine OA increase with age. For all ages combined, men demonstrated higher rates of progression compared with women. However, among subjects in their forties and fifties, women were more likely to experience worsening of their disease when compared with men. Progression rates were similar for men and women in their sixties (8.2 and 8.0, respectively). Among subjects in their seventies, men demonstrated a significantly higher rate of progression compared with women (12.5 and 8.6, respectively). As the baby-boomer population continues to increase, cervical spine OA progression assessment can be a useful tool for health-care resource planning. Cervical spine OA research offers an abundance of opportunities. Instability as a precursor to the development of cervical spine OA warrants further research. Epidemiological studies addressing demographic differences (e.g., gender, age) in the incidence of cervical spine OA will contribute to the current knowledge base.

Many people with radiographic knee osteoarthritis (RKOA) do not present with pain. It is suspected that such persons tend toward lower body mass index (BMI). The purpose of the study was to explore the relationship between BMI and knee pain among persons with RKOA.

Background and Purpose. Little is known about predictors of dropout status in exercise studies for people with osteoarthritis. Losses to follow-up can pose serious threats to study validity. The purpose of this study was to assess the ability of arthritis medication usage the month prior to enrollment to predict dropout status among participants in an exercise study for people with osteoarthritis. Subjects and Methods. Men and women who participated in an exercise study for people with osteoarthritis (N=143) were followed. Participants who completed 24+ months of the exercise program were considered retained, whereas individuals who withdrew prior to 24 months were considered dropouts. Results. Of the 143 participants analyzed, 78 (55%) completed 24+ months of the exercise program and 65 (45%) dropped out. Among those who reported arthritis medication usage, 54% were lost to follow-up. The group reporting no usage of arthritis medication had a 20% dropout rate (odds ratio=3.5, 95% confidence interval=1.6–7.6). The final adjusted model controlling for baseline health status, body mass index, and the interaction between baseline health status and body mass index indicated that those individuals who reported arthritis medication usage were more than 4 times more likely to drop out than were those who reported no arthritis medication usage (odds ratio=4.5, 95% confidence interval=1.8–11.4). Discussion and Conclusion. The results showed that self-reported arthritis medication usage the month prior to study enrollment was associated with subsequent dropout status among this group of exercisers with osteoarthritis. Further identification of baseline characteristics predictive of participant dropout status may benefit future exercise studies. A priori knowledge of “at-risk” exercise study participants will afford the opportunity for the timely allocation of appropriate resources aimed at reducing losses to follow-up.

Objective. To evaluate the association between weather (barometric pressure, precipitation and temperature) and pain among individuals with osteoarthritis (OA) (n=154) at the following sites: neck, hand, shoulder, knee and foot.