J Bras Nefrol. 2012 Mar;34(1):58-63.
[Article in English, Portuguese]
Diniz HF, Romão MF, Elias RM, Romão Júnior JE.
Faculdade de Medicina, Universidade de São Paulo.
Vitamin D deficiency is common among patients with chronic kidney disease (CKD). A higher level of serum vitamin D is expected in residents of the tropics in relation to inhabitants of non-tropical regions, due to greater sun exposure and increased production of vitamin D.
To analyze serum levels of vitamin D, such as 25-hydroxyvitamin D - 25(OH)D, in Brazilian patients at the predialytic stage with CKD.
We studied 125 patients (aged 57.4 ± 16.2 years, 78 were white and 55.2%, male), with creatinine 2.67 ± 1.73 mg/dL and creatinine clearance 43.7 ± 34.5 mL/min. Body mass index was 27.4 ± 4.7 kg/m², and waist circumference was 95.0 ± 14.0 cm. Calcium was 9.3 ± 0.6 mg/dL, intact parathormone (iPTH) 212.6 ± 221.2 pg/mL and serum albumin 4.2 ± 0.6 g/dL. The mean 25(OH)D was 23.9 ± 10.7 ng/mL.
Out of the 125 patients, we found that 92 (72.6%) had suboptimal levels of 25(OH)D < 30 ng/mL, and 65 (52%) had vitamin D insufficiency (15-29 ng/mL); 27 (21.5%) had deficiency (5-14 ng/mL) and only one patient had severe vitamin D deficiency <5 ng/mL.
No differences were observed among the levels of 25 (H)D in stratified patients as to the CKD stage. Levels of 25(OH)D were higher among males (38.1 ± 20.6 versus 22.4 ± 9.7 ng/mL; p < 0.0001), and there was an inverse correlation between levels 25(OH)D and iPTH, proteinuria and abdominal circumference, and a positive correlation between 25(OH)D and calcium and serum albumin.
Multivariate analysis only showed inverse correlation between serum 25(OH)D and iPTH and abdominal circumference.
Even though the Brazilian population live in a tropical region, most patients had suboptimal levels of serum vitamin D, and this pattern may play a role in the development of hyperparathyroidism.
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Of Chronic Kidney Disease: 73% < 30 ng; 52% 15-29 ng; 27% 5-14 ng
No association of CKD stage and vitamin D level
- Overview Kidney and vitamin D which has the following summary March 2012
FACT: Kidney is one of the 2 ways that vitamin D is turned into something that body can use; active vitamin D = Calcitriol
FACT: When the Kidney has problems, there is less Calcitriol available in the body
FACT: When the Kidney has problems, there is increased death due to many factors - many of which are associated with lack of Calcitriol
FACT: There are many on-going intervention clinical trials trying to determine how much of what kind of vitamin D is needed to correct the problem
FACT: Vitamin D intervention has yet been proven to help health of people with kidney problems - with random controlled trials
FACT: Taking extra Vitamin D, in various forms, does not cause health problems - even for those with poor kidneys
Suggestion: Increase vitamin D getting into body now - and increase co-factors so that the vitamin D can be better used