Quantitation of serum 25(OH)D2 and 25(OH)D3 concentrations by liquid chromatography tandem mass spectrometry in patients with diabetes mellitus

Yi-Ching Lin ^a,b,c,d, Hei-Hwa Lee ^a, Shing-Cheng Tseng ^e, Kun-Der Lin ^f, Li-Ping Tseng ^a, Jong-Feng Lee ^a, Yung-Hung Lee ^a, Bai-Hsiun Chen ^a,c,d,g,*

^a Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University,

Kaohsiung, Taiwan

^b Department of Laboratory Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University,

Kaohsiung, Taiwan

^c Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung,

Taiwan

^d Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

^e Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

^f Division of Endocrinology and Metabolism, Department of Internal Medicine, Kaohsiung Medical University

Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan

^g Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan

Vitamin D has been considered to regulate calcium and phosphorus homeostasis and to preserve skeletal integrity. Serum 25-hydroxyvitamin D (25(OH)D) is the best indicator of vitamin D levels. The association of serum 25(OH)D deficiency with increased risk of type 1 diabetes (T1DM) and type 2 diabetes (T2DM) is controversial. We investigated serum 25(OH)D2 and 25(OH)D3 levels in diabetes patients by using liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum 25(OH)D2 and 25(OH)D3 levels were measured with liquid chromatography tandem mass spectrometry in electrospray ionization positive mode. Chromatograms were separated using an ACE5 C18 column on a gradient of methanol. The total 25(OH)D levels were calculated as the sum of 25(OH)D3 and 25(OH)D2 levels. A total of 56 patients with T1DM and 41 patients with T2DM were enrolled in this study. There were 42 and 28 non-diabetic, age-matched volunteers who participated as the T1DM controls and the T2DM controls, respectively. The total 25(OH)D levels were lowest in the 21-40 age group. The levels of both 25(OH)D3 and the total 25(OH)D were significantly higher in the T1DM and T2DM groups than in the controls (p < 0.01 in T1DM and p < 0.05 in T2DM group, respectively). The 25(OH)D2 levels were only significantly higher in T1DM patients than in the controls. The percentages of vitamin D deficiency (total 25(OH)D less than 20 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 7.1%, 0%, 14.3% and 3.6%, respectively. The percentages of vitamin D insufficiency (total 25(OH)D less than 30 ng/mL) in the T1DM, T2DM, the T1DM controls and the T2DM controls were 26.8%, 7.3%, 54.8% and 17.9%, respectively. The percentages of vitamin D deficiency and insufficiency were significantly lower in the T1DM patients than in the T1DM controls (p < 0.01). In the present study, both type 1 and type 2 diabetes patients had higher serum 25(OH)D levels and lower percentages of vitamin D deficiency/insufficiency.

Keywords:

25-Hydroxyvitamin D3, 25-Hydroxyvitamin D2, Liquid chromatography tandem mass spectrometry, Type 1 diabetes mellitus, Type 2 diabetes mellitus