Low serum 25(OH) D levels are associated with higher prevalence of peripheral arterial disease (PAD). It has been proposed that this inverse relationship is nonlinear in that the association diminishes with rising 25(OH) D levels. To test this hypothesis, we examined the relationship between 25(OH) D and PAD as measured by AnkleBrachial index (ABI) in healthy adult US population.
We analyzed data from the continuous National Health and Nutrition Examination Survey for years 20012004. ABI was treated as a continuous variable and the minimum of the two reported ABI values was chosen for each individual. To examine the nonlinear relationship between 25(OH) D and ABI, we introduced a spline, with a single knot at the median serum levels (21 ng/mL) of 25(OH) D. The effect of 25(OH) D was calculated for every 10 ng/mL increase below and above spline. Regression models were adjusted for age, sex, race, body mass index, blood pressure, serum glucose, creactive protein, smoking, total cholesterol, and renal function.
Of the 4979 individuals, 48% were females and 58% were Caucasians. The mean (SD) age, 25(OH) D, creactive protein, and ABI was 60.4(13.22) years, 22.1(8.68) ng/mL, 0.46(0.81) mg/dL and 1.07(0.15), respectively. In both unadjusted and adjusted linear regression models without a spline, we found that 25(OH) D was associated with a significant increase in ABI (0.018, 95% CI: 0.013 to 0.023 and 0.018, 95% CI: 0.012 to 0.024, respectively) for each 10 ng/mL increase in serum 25(OH) D. In the unadjusted linear regression model with spline, any change in ABI with rising serum 25(OH) D was much larger before 21 ng/mL (0.04, 95% CI: 0.03 to 0.05) than after 21 ng/mL (0.01, 95% CI: 0.003 to 0.013), for each 10 ng/mL increase in serum 25(OH) D. In adjusted analysis, the association between ABI and 25(OH) D remained statistically significant before 21 ng/mL (0.04, 95% CI: 0.02 to 0.05 ) but not after 21 ng/mL (0.008, 95% CI: 0.0008 to 0.017) for each 10 ng/mL increase in 25(OH) D.
ABI increases as serum 25(OH) D levels increases, however, the change is nonlinear and it appears to plateau after 21 ng/mL of 25(OH) D in healthy adults. It is likely that the benefit of 25(OH) D supplementation for the prevention of PAD may only be seen in individuals with 25(OH) D levels below 21 ng/mL.
To cite this abstract:Amer M, Qayyum R. Relationship Between 25Hydroxyvitamin D and Peripheral Arterial Disease As Measured by Anklebrachial Index. Abstract published at Hospital Medicine 2012, April 1-4, San Diego, Calif. Abstract 97624. Journal of Hospital Medicine. 2012; 7 (suppl 2). https://www.shmabstracts.com/abstract/relationship-between-25hydroxyvitamin-d-and-peripheral-arterial-disease-as-measured-by-anklebrachial-index/. Accessed March 20, 2019.