Abstract
This study aimed to investigate the association between the dietary index for gut microbiota (DI-GM) and the risk of osteoporosis in postmenopausal women aged 50 years and older in the United States. A total of 3520 postmenopausal women aged 50 years and older were selected from the National Health and Nutrition Examination Survey conducted from 2007 to 2018. Participants' DI-GM scores were obtained via a dietary questionnaire, and femoral bone mineral density was measured using dual-energy x-ray absorptiometry (DXA). Weighted logistic regression was used to analyze the association between DI-GM and osteoporosis risk. Subgroup analyses were performed to examine the association between DI-GM and osteoporosis risk in different subgroups. Participants were categorized into 4 groups based on DI-GM quartiles, with the lowest quartile (0-4) serving as the reference. After adjusting for covariates, compared with the reference group, participants in the second highest (DI-GM score of 6) and highest (DI-GM score ≥ 7) quartiles exhibited a 41% (OR: 0.59, 95% CI: 0.42-0.84) and 44% (OR: 0.56, 95% CI: 0.38-0.84), respectively, reduced risk of osteoporosis. Subgroup analysis revealed that this association was consistent across different age groups of postmenopausal women but was statistically significant only among White women. This study of postmenopausal women aged 50 and older in the United States demonstrated that those with higher DI-GM scores had a lower risk of osteoporosis compared to those with lower scores. This finding suggests that dietary intake increasing beneficial components of the gut microbiota may have a positive role in the prevention of postmenopausal osteoporosis.