Abstract 121: Relationship of Vitamin D Level with Cardiovascular Fitness: Does Demography Matter?
Authors: Panchal Hemang B , Desai Saurabh , Shah Tejaskumar , Patel Rakeshkumar , Ramu Vijay 
Published: July 2021

Background:
Recent studies have suggested association of vitamin D with cardiovascular events. The relationship of vitamin D deficiency with cardiovascular fitness level (CVF) has not been studied in current literatures. Demographic variation of this association is also unclear. The primary objective of our study was to assess the relationship of vitamin D level to CVF and evaluate the demographic variation of this association in young adults. The secondary objective of this study was to assess the relationship of vitamin D level with the other cardiovascular risk factors.

Methods:
We evaluated 5388 adults from National Health and Nutrition Examination Survey 2001-2004. The associations of serum 25-hydroxy vitamin D level with CVF and cardiovascular risk factors such as systolic/diastolic blood pressure (SBP/DBP), low density lipoprotein (LDL), high density lipoprotein (HDL), and glycohemoglobin (HbA1c) levels in young adults aged 20-49 years were evaluated. Adults with vitamin D deficiency (≤30 mg/dL) and normal vitamin D level (>30 mg/dL) were compared. The CVF was assessed with peak oxygen uptake on treadmill test (VO2 max <20 percentile= low CVF, VO2 max ≥60 percentile= high CVF). Chi square analysis and odds ratio were calculated to assess the association of vitamin D deficiency with CVF. Pearson correlation was measured for the secondary analysis of association of vitamin D level with cardiovascular risk factors. The alpha error ≤0.05 was used as a level of significance.

Results:
Total of 85.4% (n=4603/5388) young adults had vitamin D deficiency. Vitamin D level was positively associated with CVF (p<0.001). In comparison to normal vitamin D level, vitamin D deficiency was significantly associated with low CVF (Odds ratio 2.01, confidence interval 1.64-2.46, p<0.001). In contrast to normal vitamin D level, vitamin D deficiency was significantly associated with low CVF in subgroups of males (p<0.01), females (p<0.01), age group of 20-29 years (p<0.01) and age group of 30-49 years (p<0.01). In contrast to normal vitamin D level, vitamin D deficiency was significantly associated with low CVF only in Caucasians (p=0.001). This association was not significant in Mexican-Hispanics (p=0.35), other Hispanics (p=0.095), African Americans (p=0.061) and other races (p=0.206). In comparison to normal vitamin D level, vitamin D deficiency was significantly associated with low CVF among normal BMI (p<0.001), overweight BMI (p<0.001) and obese adults (p=0.019) but not in underweight BMI adults (p=0.48). Vitamin D level was inversely associated with SBP (p<0.001), and HbA1c (p<0.001) and positively associated with HDL (p<0.001). There was no significant association found between vitamin D level and DBP (p=0.66) or LDL (p=0.79).

Conclusions:
The results of our study demonstrate that vitamin D deficiency may decrease CVF in Caucasian young adults. Surprisingly it may not affect CVF in other races and underweight adults. Vitamin D deficiency is also associated with increase in cardiovascular risk factors such as low HDL, high SBP and HbA1c. The large population based clinical trials are needed for evaluation of this relationship and long-term consequences on cardiovascular outcomes.