Higher consumption of ultra-processed foods and increased likelihood of central nervous system demyelination in a case-control study of Australian adults

Using 2003-2006 Ausimmune Study data, the authors compared 267 incident FCD cases with 508 matched controls, classifying the 28 UPF items in a 101-item FFQ under NOVA category four and applying full propensity score matching for age, sex, region, education, smoking, BMI, physical activity, infectious mononucleosis history, dietary misreporting, and total energy intake. Higher UPF consumption was associated with increased FCD likelihood (adjusted OR=1.08; 95% CI 1.00,1.15; p=0.039), interpreted as an 8% increase per one energy-adjusted serving/day. Cases had higher smoking and infectious mononucleosis history than controls. Limitations included the FFQ not being designed for UPF assessment, potential UPF misclassification when items were grouped with non-UPFs, possible residual confounding inherent to observational designs, and a predominantly Caucasian sample limiting generalisability. The authors suggested that displacement of healthier eating patterns and UPF-related gut dysbiosis or chemical exposures are plausible mechanisms, while emphasising that the findings are associational and that nutrition awareness may benefit those at high risk of FCD.