medwireNews: An analysis of two US cohorts suggests that higher dietary fiber intake is associated with lower risk for symptomatic osteoarthritis (OA).
“Such results support the current recommended daily fibre for older Americans,” say Zhaoli Dai (Boston University School of Medicine, Massachusetts, USA) and study co-authors.
In an analysis of data from the Osteoarthritis Initiative – a 48-month study of 4051 participants with a mean age of 61.2 years at baseline – the team found that participants in the highest quartile for fiber intake (median 20.6 g per day) had a significantly lower risk for symptomatic OA than those in the lowest quartile (median 8.6 g per day) after adjustment for factors including age, gender, energy intake, and other dietary factors (odds ratio [OR]=0.70).
Participants in the highest quartile for total fiber intake were also significantly less likely to experience knee pain worsening than those in the lowest quartile (OR=0.81), which was attributable to cereal fiber intake rather than fiber from fruits and vegetables or nuts and legumes.
Similarly, the authors identified a significant inverse association between fiber intake and symptomatic OA risk over an average 9.5 years of follow-up among 971 participants of the Framingham Offspring cohort, with an OR of 0.39 for participants in the highest versus lowest quartile for total fiber intake in a model adjusting for diet quality.
And after further adjustment for body mass index (BMI), there was an “attenuated but significant” inverse association between total fiber intake and the risk for symptomatic OA or knee pain worsening.
“These data demonstrate a consistent protective association between total fibre intake and symptom-related knee OA in two study populations with careful adjustment for potential confounders,” write Dai and colleagues in the Annals of the Rheumatic Diseases.
However, there was no significant association between fiber intake and incident radiographic OA (ROA) in either cohort. Although this relationship “was unclear,” the researchers note that “we cannot rule out the possibility that fibre may reduce the risk of ROA by lowering BMI which may not be detectable because of a bias due to depletion of susceptibility to knee ROA.”
The team cautions that fiber consumption was self-reported in the two cohort studies, and such data “are prone to biases,” potentially resulting in misclassification of fiber consumption.
And they conclude: “Ultimately randomised trials are needed to prove causation, but observational and other studies are needed first to provide empirical evidence.”
By Claire Barnard
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