Independent and combined associations of dietary antioxidant intake with bone mineral density and risk of osteoporosis among elderly population in United States

The influence of dietary antioxidant intake on the occurrence and progression of osteoporosis may be significant. However, to date, evidence on the link between combined effect of dietary antioxidants on bone mineral density (BMD) level and risk of osteoporosis is limited. We aimed to assess the independent and combined association of dietary antioxidant intake with BMD level and risk of osteoporosis among elderly population in United States through analysis of data in the National Health and Nutrition Examination Survey. The dietary antioxidant intake was assessed based on six antioxidants, including vitamin A, vitamin C, vitamin E, zinc, selenium, and total carotenoid. A composite dietary antioxidant index (CDAI) was used to evaluate the combined exposure of dietary antioxidant intake. A total of 5618 participants were included. Higher dietary vitamin A, vitamin C, vitamin E, zinc, selenium, and total carotenoid, were positively associated with BMD level. Compared with participants in the first quartile, those in the higher quartile of vitamin E (Q4: OR 0.652; 95% CI 0.463–0.918), zinc (Q4: OR 0.581; 95% CI 0.408–0.826), and selenium (Q3: OR 0.673; 95% CI 0.503–0.899) were associated with decreased risk of overall osteoporosis. Furthermore, compared to those in the first quartile, participants in the highest quartile of CDAI were associated with increased total femur (β 0.019; 95% CI 0.007–0.032), femur neck (β 0.020; 95% CI 0.009–0.032), trochanter (β 0.012; 95% CI 0.001–0.023), and intertrochanter BMD level (β 0.022; 95% CI 0.007–0.037); participants in the highest quartile of CDAI were associated with decreased risk of overall osteoporosis (OR 0.536; 95% CI 0.376–0.763). Furthermore, the associations of CDAI with the BMD level and osteoporosis risk were more significant among female participants. Our study provides evidence that a combination of dietary antioxidants intake was associated increased BMD level and decreased osteoporosis risk.