The effects of vitamin C supplementation on incident and progressive knee osteoarthritis: a longitudinal study.

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.

Radiographic cervical spine osteoarthritis progression rates: a longitudinal assessment.

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.

Job-related osteoarthritis of the knee, foot, hand, and cervical spine.

OBJECTIVES: To assess the influence of occupational exposures on risk of site-specific radiographic osteoarthritis (OA) of the knee, hand, foot, and cervical spine. METHODS: Using a cross-sectional design, data collected from men and women aged 40 years and older participating in the Clearwater Osteoarthritis Study were analyzed (n = 3436). Subjects' occupational exposures were queried using the study intake form, including stair climbing, standing on a rigid surface, squatting, and jolting. Physical examinations including radiographs of the knee, hand, foot, and cervical spine were conducted. The Kellgren and Lawrence ordinal scale was used to determine evidence of radiographic OA. RESULTS: Both the unadjusted and adjusted odds ratios (ORs) for men and women indicated that age and body mass index were associated with OA. There were no other significant odds ratios for the cervical spine. Among men, there were significant associations with knee OA for stair climbing and jolting of the legs and with foot OA with stair climbing. Among women, there was a significant association between standing on a rigid surface and knee OA. For hand OA in women, there was a significant association for jolting of the hands. CONCLUSIONS: Although the association with stair climbing was found in other investigations for knee OA, it was also associated with foot OA in this study. In addition, the jolting feature was seen in only one other study for men (knees) and novel for women (hands).

Exercise and hand osteoarthritis symptomatology: a controlled crossover trial.

STUDY DESIGN: Randomized Clinical Trial. INTRODUCTION: Hand exercises have been recommended as treatment for hand osteoarthritis (OA) but research evidence is sparse. PURPOSE OF THE STUDY: To investigate effects of daily 16-week home-based hand exercise among persons with hand OA. METHODS: Forty-six older adults completed a crossover trial with washout between exercise and sham treatments. The AUSCAN physical function sub-scale served as the primary outcome measure. Other outcomes included pain and stiffness sub-scales, dexterity, and grip & pinch strengths. RESULTS: Changes in AUSCAN sub-scales did not differ between exercise and sham treatments. No changes in dexterity were seen. Grip and pinch measures modestly improved after exercise but not sham. CONCLUSIONS: It is possible that our exercise protocol may have been too ambitious for this age group. Future research will further the understanding of the role of hand exercise in hand OA symptomatology. LEVEL OF EVIDENCE: 2b.