RESUMO
End-stage renal disease (ESRD) patients are vulnerable to vitamin D deficiency due to impaired renal hydroxylation, low dietary intake and inadequate sun exposure. Vitamin D plays a role in innate and adaptive immunity and its seasonal variation has been linked to mortality. ESRD is associated with inadequate removal of pro-inflammatory cytokines regulating acute phase protein (APP) synthesis. Our aim was to look for associations between lifestyle factors, diet, and vitamin D seasonal variation and their relationship with selected APPs and calcium-phosphate metabolism. The study included 59 ESRD patients treated with maintenance hemodialysis. A 24-hour dietary recall was conducted in the post-summer (November 2018, PS) and post-winter (February/March 2019, PW) period, and blood was collected for the measurements of serum total vitamin D, α1-acid glycoprotein (AGP), C-reactive protein (CRP), albumin, prealbumin (PRE), parathormone, calcium and phosphate. A self-constructed questionnaire gathered information on vitamin D supplementation, sun exposure and physical activity. Higher caloric intake was observed PW compared PS. Less than 15% of participants met the dietary recommendations for energy, protein, fiber, vitamin D and magnesium intake. Vitamin D supplementation was associated with higher serum vitamin D regardless of season. AGP, PRE, albumin, and vitamin D presented seasonal changes (higher values PS). In patients with serum vitamin D below 25 ng/mL, vitamin D seasonal change correlated with CRP and prealbumin change. Phosphate and Ca × P correlated positively with AGP. A low vitamin D serum level could impact the inflammatory process; however, more studies are needed to confirm the relationship.
RESUMO
BACKGROUND: Vitamin D is a major regulator of mineral bone metabolism. The lower vitamin D levels in patients with acute myocardial infarction (AMI) and the seasonal variation of vitamin D levels are proposed. AIM: The evaluation of the seasonal relationship of 25(OH)D levels in patients with AMI and analysis of confounding factors (gender or diabetes mellitus) affecting the levels of vitamin D in AMI patients. METHODS: Fifty-nine consecutive patients with mean age 58 ± 9.4 years were admitted to the Department of Invasive Cardiology. Subjects had diagnosed uncomplicated myocardial infarction. Blood samples for analysis were collected on patient admission to the cardiac unit after heparin treatment. Samples for routine laboratory tests were immediately processed. For 25(OH)D, the 25-hydroxycholecalciferol test, which measures total vitamin D levels in serum (DRG Instruments GmbH, Marburg, Germany), was applied. RESULTS: Median serum 25(OH)D concentration in AMI patients was below the recommended optimal values 7.1 (2.3-13.3) ng/mL. Fifty-three (89.8%) patients had vitamin D deficiency (VDD) below 20 ng/mL, six (10.2%) patients had suboptimal 25(OH)D levels (between 20 ng/mL and 30 ng/mL), and no one had the recommended reference range. The seasonal effect of 25(OH)D variations among AMI patients was observed with the lowest levels in the beginning of the year (January-March) and the highest levels at the end of the year (September-December) (p = 0.007). Patients with normoglycaemia had significantly higher (9.2 [2.3-16.8] ng/mL) vitamin D levels compared to patients with impaired glucose tolerance (2.3 [2.3-3.9] ng/mL) or diabetes mellitus (8.5 [2.5-13.3] ng/mL) (p = 0.01). CONCLUSIONS: A high prevalence of VDD in AMI patients has been confirmed. Supplementation of vitamin D in AMI patients with hyperglycaemia can bring greater benefits.