Association between ultra-processed food and osteoporosis: a cross-sectional study based on the NHANES database

Nutritional characteristics and additives in ultra-processed foods (UPF) are directly related to bone health. Physical activity as a modifiable lifestyle intervention also plays a possible role in bone mineral density (BMD), but effect of physical activity on association between UPF and osteoporosis is not fully understood. Herein, this study aims to explore the association of UPF with osteoporosis, and assess the potential mediating effects of some related factors on this pathway. Data of adults were extracted from the National Health and Nutrition Examination Survey (NHANES) database in this cross-sectional study. Associations of unprocessed/minimally processed food (MPF), processed culinary ingredient (PCI), processed foods (PF) and UPF with femur neck BMD, total femur BMD and osteoporosis were investigated using linear regression and weighted univariate and multivariate logistic regression analyses respectively. Subgroup analyses of age, gender, physical activity, poverty income ratio (PIR), hypertension, diabetes mellitus (DM), cardiovascular disease (CVD), and dyslipidemia were performed. The potential mediating and interaction effects of physical activity and related factors on association of UPF with osteoporosis were also assessed. The evaluation indexes were β, odds ratios (ORs) and 95% confidence intervals (CIs). Among 10,678 eligible persons, 454 had osteoporosis. After adjusting for covariates, elevated UPF intake was associated with decreased demur neck and total femur BMD (β=-0.003). A higher UPF intake level (> 57.51%) was linked to higher odds of osteoporosis (OR = 1.789). These relationships were also significant in different subgroups. Physical activity had a potential mediating effect on the association between UPF and osteoporosis (OR = 0.47, mediating proportion = 21.54%). UPF intake levels were associated with BMD and osteoporosis. Physical activity had an interaction effect with UPF, and had a potential mediating effect on relationship between UPF and osteoporosis.