Spine fractures represent a significant public health concern, particularly among aging populations. They are among the most common osteoporotic fractures and are associated with substantial morbidity, mortality, and healthcare costs. Trends in the prevalence of spine fractures have not been well described in subgroups of demographic characteristics, and understanding trends in the prevalence of spine fractures and risk factors for spine fractures is critical to planning public health approaches to prevent and manage the disease in US adults. In this study, we evaluated the time trends in the prevalence of spine fractures and their associated risk factors in the US adult population from 1999 to 2018. The survey study comprised a series of cross-sectional analyses using nationally representative data from 10 cycles of the National Health and Nutrition Examination Survey (NHANES) spanning from 1999 to 2000 to 2017-2018. All study samples were weighted to represent the civilian resident US population. Spine fractures were defined by self-reporting of spine fracture diagnosis by a physician that they had spine fractures. Trends in the prevalence of spine fractures in subgroups of demographic characteristics for spine fractures were estimated using logistic regression analysis. The age-standardized prevalence (95% CI) of spine fractures increased from 2.54% (1.94-3.14%) in the 1999-2002 cycles to 5.04% (3.62-6.46%) in the 2015-2018 cycles (p < 0.05 for trend). The prevalence of spine fractures among Americans aged 50 and above was 3.24%, which was similar between those under 65 and those aged 65 and above (< 65 3.20% vs. aged >= 65 3.31%, p = 0.74). However, the prevalence of spine fractures in males is higher than that in females (males 3.81% vs. females 2.76%, p = 0.005). Univariate analysis showed that age, sex, race (mainly non-Hispanic white), marital status, osteoporosis, smoking, alcohol consumption, hypertension, and diabetes were risk factors for spine fractures. In multivariate analysis, sex (male), race (mainly non-Hispanic white), osteoporosis, smoking, and hypertension were independently associated with spine fractures. Based on NHANES surveys of US adults from 1999 to 2000 to 2017-2018, the prevalence of spine fractures showed an overall increasing trend, with variations across sociodemographic subgroups. In addition, age, sex, race (mainly non-Hispanic white), osteoporosis, smoking, alcohol consumption, hypertension, and diabetes may be closely linked to the occurrence of spine fractures.