Using national representative data, we found the prevalence of and risk factors associated with low BMD differed by race and ethnicity. PurposeRace/ethnicity is an important determinant of osteoporosis risk. The study aims were to (1) estimate the racial and ethnic differences in the prevalence of low BMD, (2) identify factors associated with low BMD by race and ethnic group, and (3) evaluate if the association between sleep duration and low BMD is modified by age, sex, gender, and/or race/ethnicity. MethodsUsing data from the National Health and Nutrition Examination Survey (NHANES) database from 2005 to 2014, totally, 7992 participants aged >= 50 years were included as the primary cohort. Three race/ethnic groups were included: non-Hispanic Whites, Hispanics, and non-Hispanic Blacks. Low BMD was defined by femoral neck BMD T-scores less than -1, as measured by DXA scan. Univariate and multivariate analyses were performed to determine associations between participants' demographics, comorbidities, lifestyle characteristics, and prevalent low BMD. ResultsPrevalence of low BMD was 50.8% among non-Hispanic Whites, 23.7% among non-Hispanic Blacks, and 44.0% among Hispanics. After adjusting for confounders, advanced age, female gender, and fracture history were significantly associated with increased odds of low BMD in all three race/ethnic groups. Family history of osteoporosis, ever used glucocorticoids daily, and vitamin D deficiency or insufficiency were associated with increased odds of low BMD only among non-Hispanic Whites. Cardiovascular disease (CVD) history and diabetes were associated with low BMD only among non-Hispanic Blacks. Short sleep duration was not associated with low BMD in all ethnic groups, but was significantly associated with low BMD in older adults (>65 years) and females ConclusionsPrevalence of low BMD among three race/ethnic groups in the USA is determined, with race/ethnic disparities in several risk factors associated with low BMD identified. By contrast, advanced age, female gender, and fracture history are associated with increased odds of low BMD across all race/ethnic groups. The association between sleep duration and low BMD is modified by age and sex. Together, these findings may help clinicians and healthcare providers formulate better care for individual's bone health.