RESUMO
BACKGROUND: The discovery of vitamin D is one of medicine's great achievements. Despite all the positive evidence emerging about the beneficial effect of vitamin D, we still find many are vitamin D deficient. The purposes of this study were to examine the association between serum 25-hydroxyvitamin D (25(OH)D) and glycosylated hemoglobin (HbA1c) levels, to test the hypothesis that lower 25(OH)D levels are associated with poorer glucose control in diabetes mellitus (DM) patients and to investigate the effect of vitamin D supplementation on HbA1c levels. METHODS: This was a prospective observational cohort study of all patients with type 1 and type 2 diabetes (above 12 years) who attended the outpatient clinics of a tertiary center in Riyadh. HbA1c and vitamin D levels were recorded prior to supplementation and after 9 months of supplementation with vitamin D. All patients were divided into four groups according to their vitamin D level and an association between 25(OH)D and HbA1c was tested. RESULTS: Results showed that 73.1% of the patients had 25(OH)D levels < 50 nmol/L. We observed lowering of HbA1c after vitamin D supplementation (from mean HbA1c of 10.55 to 7.70). We found HbA1c to be inversely related to serum vitamin D levels (r = -0.14 (P < 0.0000002) before supplementation and -0.16 (P < 0.000001) after supplementation with vitamin D). CONCLUSIONS: Advising patients with higher HbA1c to test their vitamin D level and correct any deficiency will result in better blood glucose control and benefit the patient's overall health.
RESUMO
CONTEXT: Diabetes in pregnancy (DIP) is either pregestational or gestational. AIMS: To determine the relationship between glycemic control and pregnancy outcomes in a cohort of DIP patients. SETTINGS AND DESIGN: In this 12-month retrospective study, a total of 325 Saudi women with DIP who attended the outpatient clinics at a tertiary center Riyadh, Saudi Arabia, were included. SUBJECTS AND METHODS: The patients were divided into two groups, those with glycated hemoglobin (HbA1c) ≤6.5% (48 mmol/mol) and those with glycated hemoglobin (HbA1c) above 6.5%. The two groups were compared for differences in maternal and fetal outcomes. STATISTICAL ANALYSIS USED: Independent Student's t-test and analysis of variance were performed for comparison of continuous variables and Chi-square test for frequencies. Odds ratio and 95% confidence intervals were calculated using logistic regression. RESULTS: Patients with higher HbA1c were older (P = 0.0077), had significantly higher blood pressure, proteinuria (P < 0.0001), and were multiparous (P = 0.0269). They had significantly shorter gestational periods (P = 0.0002), more preterm labor (P < 0.0001), more perineal tears (P = 0.0406), more miscarriages (P < 0.0001), and more operative deliveries (P < 0.0001). Their babies were significantly of greater weight, had more Neonatal Intensive Care Unit (NICU) admissions, hypoglycemia, and macrosomia. CONCLUSIONS: Poor glycemic control during pregnancy is associated with adverse maternal and fetal outcomes (shortened gestational period, greater risk of miscarriage, increased likelihood of operative delivery, hypoglycemia, macrosomia, and increased NICU admission). Especially at risk are those with preexisting diabetes, who would benefit from earlier diabetes consultation and tighter glycemic control before conception.