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Updated: Apr 4, 2026
Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
Varying relationship between 25-hydroxy-vitamin D, high density lipoprotein cholesterol, and serum
Vivek G Patwardhan1, Anuradha V Khadilkar1, Shashi A Chiplonkar1
1Growth and Endocrine Unit, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, India.
Background:
Cholesterol and cholecalciferol are synthesized from a common substrate 7-dehydrocholesterol. 7-dehydrocholesterol is converted to cholesterol by 7-dehydrocholesterol reductase enzyme (DHCR7) and to cholecalciferol by ultraviolet B radiation from sunlight.
Objective:
To examine the effect of sunlight exposure and serum DHCR7 levels on cholecalciferol and cholesterol levels and studying any interrelationship.
Methods:
In a cross-sectional observational study, 307 apparently healthy men (aged 40-60 years) were assessed for sunlight exposure, lipid levels, serum DHCR7, 25 hydroxyvitamin D (25(OH)D), body composition, and dietary milk calcium intake.
Results:
Vitamin D deficiency (25(OH)D <20 ng/mL, 1 ng/mL = 2.496 nmols/L) was found in 56% of subjects. Serum 25(OH)D concentrations increased significantly with increasing duration of sunlight exposure (P < .05). At lower sunlight exposure (<1 h/d), serum 25(OH)D levels were positively associated with high-density lipoprotein cholesterol (HDL-C) levels (P < .05) but at moderate sunlight exposure (1-2 h/d), there was no significant association. However, with higher sunlight exposure (>2 h/d), serum 25(OH)D concentrations were significantly negatively associated with HDL-C (P < .05). At moderate and higher sunlight exposure, an inverse significant relationship was observed between 25(OH)D and serum DHCR7 (P < .05); however, at lower sunlight exposure, no significant relationship was seen.
Conclusions:
25(OH)D seems to show a varying relationship with HDL-C and serum DHCR7 at different durations of sunlight exposure.
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