Tibial cartilage loss universal among older adults, exacerbated by age, higher BMI
Cartilage volume in the tibiofemoral joint decreases at a faster rate with increasing age and higher BMI in both men and women, especially in the medial compartment, according to findings published in Arthritis Research & Therapy.
“Osteoarthritis (OA) is the most common form of arthritis, characterized by gradual loss of articular cartilage,” Guoqi Cai, a PhD student at the Menzies Institute for Medical Research, University of Tasmania, in Australia, and colleagues wrote. “The prevalence of OA increases with age implying that the disease progresses with age.”
“However, current evidence concerning the role of age on the structural progression of OA is inconsistent,” they added. “Radiographic joint space width at the tibiofemoral joint has historically been considered a good measure of change in cartilage volume; however, radiograph-based studies have reported inconsistent findings with regard to joint space or cartilage loss with age.”
To examine the association of age, sex and BMI with the rate of change in tibial knee cartilage volume among older adults over the course of 10.7 years, Cai and colleagues studied data from the ongoing Tasmanian Older Adult Cohort. According to the researchers, this cohort began in 2002 and includes men and women aged 50 to 80 years, randomly selected from the electoral roll in southern Tasmania.
Baseline measurements were performed in 2002 on 1,099 participants, including assessments of tibial cartilage volume using a T1-weighted fat-suppressed 1.5T MRI. Follow-up data were collected at 2.7, 5 and 10.7 years. A total of 569 participants completed the 10.7-year follow-up. Cai and colleagues analyzed data on 481 participants who completed MRI assessments and had validated scans at baseline and the last follow-up. Among these participants, 49% had knee pain and 58% had radiographic arthritis.
According to the researchers, the average rate of cartilage volume loss of was 1.2% per year (range = 0.2% to 3.9%), with all participants losing cartilage volume during the study period. There was a significant association between age and tibial cartilage volume loss in the medial (rate = 0.023% per year; 95% CI, 0.01-0.036), lateral (0.013%; 95% CI, 0.003-0.023) and total tibia (0.018%; 95% CI, 0.009-0.026).
In addition, higher baseline BMI, as well as BMI increases over time, were associated with a greater tibial cartilage loss at the medial (baseline BMI 0.04% per year [95% CI, 0.022-0.058]; increases in BMI 0.055% per year [95% CI, 0.018-0.093]) but not the lateral compartment. Men lost more lateral tibial cartilage with increasing age (0.023% per year; 95% CI, 0.003-0.043; P=.024 for interaction), compared with women.
“The findings of this study reveal that tibial cartilage loss is universal in older adults and will become faster over time, particularly in those with higher BMI at baseline and increased BMI over time,” Cai and colleagues wrote. “The results of this study contrast to reports based on radiographic findings where less than 50% of the older population have progressive joint space narrowing over 4 to 14years.”
They added, “In contrast to the slow rate of change in radiographs, our findings suggest that cartilage loss at the knee is universal in this age group.” – by Jason Laday
Disclosure: The researchers report no relevant financial disclosures.