Association of serum alkaline phosphatase levels with bone mineral density, osteoporosis prevalence, and mortality in US adults with osteoporosis: evidence from NHANES 2005-2018.

Abstract

The evidence regarding the association between serum T-ALP, BMD and osteoporosis prevalence in general population is incomplete, and limited evidence is available concerning its association with mortality among individuals with osteoporosis. The study investigated the association of serum T-ALP with BMD and osteoporosis prevalence in the general population, and examined its association with mortality in individuals with osteoporosis. All participants were adults from the NHANES (2005-2018), and mortality data were obtained from the National Death Index up to December 31, 2019. Firstly, the association of serum T-ALP with BMD and osteoporosis risk was assessed using linear regression model, subgroup analysis, analysis of covariance and weighted logistic regression model, respectively. Secondly, survival analysis including Kaplan-Meier curves, Cox proportional hazards models, and restricted cubic spline regression models were utilized to analyze the relationship between serum T-ALP levels and mortality risk. The study included 13,724 participants aged 18 to 85years, and 944 were diagnosed with osteoporosis, among whom 221 died during a median of 133months follow-up. Totally, elevated serum T-ALP was significantly associated with low BMD in femoral neck and lumbar spine, and the results exhibited consistency across diverse age, genders, races, and BMI subgroups. Moreover, for each 1 SD increase in T-ALP, there was a 0.5% increase in the prevalence of osteoporosis [OR (95%CI): 1.005 (1.005, 1.005), p < 0.001]. Among individuals with osteoporosis, for every 1 SD increase in T-ALP, the all-cause mortality increased by 0.4% [HR (95%CI):1.004 (1.002, 1.006), p < 0.001]. Meanwhile, comparing participants with highest serum T-ALP levels (> 79IU/L) to those with lowest levels (< 53IU/L) further raised the prevalence of osteoporosis [OR (95%CI):1.292 (1.021, 1.636), p = 0.033] and all-cause mortality [HR (95% CI):1.232 (1.041, 1.459), p = 0.015]. Based on a representative sample of US adults, elevated serum T-ALP levels were found to be significantly associated with both reduced BMD and an increased risk of osteoporosis across all participants, as well as with a higher all-cause mortality in individuals with osteoporosis.