Dietary Fiber Intake in Relation to Knee Pain Trajectory

Dai Z, Lu N, Niu J, Felson DT, Zhang Y · Arthritis Care & Research (Hoboken)

Group-based trajectory modelling split the cohort into four eight-year pain courses — no pain (34.5%), mild (38.1%), moderate (21.2%), severe (6.2%) — rather than comparing means. Highest versus lowest quartile of total fibre: OR 0.76 (95% CI 0.61-0.93) for the moderate-pain course and 0.56 (95% CI 0.41-0.78) for the severe one, with the mild course unmoved. Cereal grain fibre followed total fibre on the severe course (OR 0.55, 95% CI 0.39-0.79) and not on the moderate one (OR 0.85, 95% CI 0.70-1.04, p trend 0.09), and fibre from fruit and vegetables or from nuts and legumes showed nothing in the full cohort. The authors anchor the benefit around the recommended 25 g/day.

Population

4,470 people (8,940 knees) aged 45-79 with or at risk of knee OA, followed annually for 8 years

Intervention

Higher baseline dietary total or grain fibre intake

Comparator

Lowest quartile

Limitations

Same cohort and same baseline questionnaire as the incidence paper, so this is a second analysis rather than independent support. Trajectory membership is model-assigned, and one food-frequency questionnaire stands for eight years of eating. Physical activity, NSAID use, education and baseline radiographic grade are in the primary model; body weight and depressive symptoms are deliberately left out of it, and adding them moves the severe-pain estimate to OR 0.71 (95% CI 0.50-0.995). Fibre intake also tracks overall diet quality.