Predicting life span of type 2 diabetes patients through alkaline phosphatase and vitamin D: Results from NHANES 1999-2018

BACKGROUND AND AIMS: Disparities in serum biomarker levels related to mortality persist within the US diabetic population. We conducted a study to explore the impact of alkaline phosphatase (ALP) on all-cause mortality and cardiovascular disease (CVD) mortality in type 2 diabetes patients. METHODS: We analyzed a nationally representative sample of individuals aged 20 years and above from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States between 1999 and 2018. Baseline demographic information and biochemical markers, including blood glucose, γ-glutamyltranspeptidase, vitamin D and albumin, were collected. Participants were divided into four groups based on ALP levels and linked to the National Death Index to assess mortality. Follow-up continued until December 2019, and multiple mediation analyses were performed to assess the combined impact of different indicators on ALP differences in all-cause mortality and cardiovascular mortality risk. RESULTS: Our analysis included 6481 NHANES participants, categorized as follows: 1626 (21.9%) had ALP levels below 58 U/L, 1674 in the second quartile (58-72 U/L), 1569 in the third quartile (72-88.3 U/L), and 1612 in the fourth quartile (above 88.3U/L). Significantly higher all-cause mortality and cardiovascular mortality rates were observed among participants in the 4th ALP quartile compared to other levels. The all-cause mortality rate was 38.06 per 1000 person-years (95% CI 34.89-41.51), and the cardiovascular mortality rate was 10.67 (9.06-12.57). Mediation analysis indicated that Vitamin D and albumin played a mediating role in the association between all-cause mortality, cardiovascular mortality, and ALP levels, with mediation proportions ranging from 10.33% to 27.64%. CONCLUSIONS: Our study suggests that ALP levels have clinical value in predicting all-cause and CVD mortality risk in T2DM patients. The upregulation of Vitamin D and albumin might play a significant role in improving risk prediction and enable targeted interventions for reducing mortality risk in this population.