Longitudinal changes in vitamin D and its metabolites in pregnant South Africans.

BACKGROUND: Vitamin D deficiency (VDD) has been associated with adverse maternal and foetal outcomes and is determined by measuring 25 hydroxyvitamin D (25(OH)D). The 25(OH)D is catabolized to 24, 25-(OH) 2D and the ratio of 25(OH) D to 24, 25-(OH)2D, the vitamin D metabolite ratio (VMR), is thought to be a superior marker of VDD, being elevated in such states. The aims of this study were to assess the longitudinal vitamin D status of pregnant women by measuring cholecalciferol, 25(OH)D, 24, 25-(OH)2D and VMR at two time points and also to determine any association of vitamin D and metabolites with gestational age at birth, birth length and weight. METHODS: We recruited 400 pregnant black African women in their first trimester (V1) and measured weights and heights. Ultrasound scans were performed for gestational age. Blood was drawn at V1 and at about 26 weeks (V2) of gestation for cholecalciferol, 25(OH)D, 24, 25-(OH)2D, VMR and parathyroid hormone (PTH). An OGTT was performed at V2 where fasting glucose, insulin and 30-minute glucose were measured. At birth, we measured birth weight, length and gestational age. Maternal insulin, PTH and vitamin D binding protein (VDBP) were measured by immunoassay. Maternal albumin was measured colorimetrically. Maternal cholecalciferol, 25(OH)D and 24, 25-(OH)2D, were measured by mass spectrometry and free and bioavailable vitamin D were calculated. Initial gestation was determined by ultrasound. We compared analytes by visit as well as by 25(OH)D status. Vitamin D deficiency (<30 nmol/L) was defined according to the National Academy of Medicine guidelines. Linear regression analysis was used to determine associations of vitamin D molecules with maternal blood pressure, fasting and 30-minute insulin and blood glucose and neonatal parameters. RESULTS: Results are presented for participants for whom we had complete data (n = 330-346 depending on variable). The prevalence of vitamin D deficiency (VDD) was 35.8 % at V1 and 32.4 % at V2. Levels of 25(OH)D did not change significantly between visits. Levels of 24, 25(OH)2D dropped from the first to the second visit (17.64 ± 12.64 to 9.39 ± 9.07 nmol/L; p < 0.0001) while VMR increased ((3.15 (1.31; 7.67) to 7.90 (2.44; 25.98); p < 0.0001). The proportion of women with the lowest cholecalciferol concentrations increased at V2 compared to the V1 (36.1-42.8 %; p = 0.02). In multivariable regression models 25(OH)D was negatively associated with 30-minute glucose concentrations (p = 0.038) whilst 24, 25-(OH)2D was positively associated with fasting insulin (p = 0.017) and HOM A-I R (p = 0.023). There was no correlation of 25(OH)D or metabolites with infant birth weight, birth length or gestational age. CONCLUSIONS: Maternal VDD is common in pregnant black South African women. Decreased VMR suggest that catabolism of 25(OH)D is reduced in pregnancy to maintain adequate free vitamin D levels.

Visceral adiposity is a predictor of parathyroid hormone levels in healthy adults.

PURPOSE: Parathyroid hormone (PTH) has been shown to correlate positively with fat mass, however there are no studies that have investigated whether this association is a result of, or is modified by, body fat distribution. The aim of this study was to investigate the association of PTH with several body composition indices, namely visceral (VAT) and subcutaneous adiposity (SCAT) as well as with lean mass and with serum leptin, which has been reported to increase PTH. METHODS: This was a cross-sectional study in which PTH was measured by chemiluminescent assay; body fat and lean mass by dual-energy X-ray absorptiometry (DXA) and abdominal fat by ultrasonography in 714 healthy adults aged 18-65 years. Serum leptin was measured by ELISA. RESULTS: In a multivariate linear regression model that included height, age, gender, ethnicity, serum 25 hydroxyvitamin D, leptin levels, calcium, magnesium and phosphate concentrations, glomerular filtration rate, smoking status, and calcium and vitamin D supplementation as independent variables and PTH as the dependent variable, VAT (ß = 0.094, p = 0.035) correlated significantly with PTH levels but SCAT (ß = -0.045, p = 0.386) and body fat mass (ß = 0.098, p = 0.126) did not. Leptin did not correlate with PTH (ß = 0.013, p = 0.832) in this regression model. CONCLUSIONS: Plasma PTH is significantly associated with VAT in healthy adults. In view of the association of PTH with increased cardiovascular mortality, it is important to investigate this association further.

Substance abuse and major trauma in Johannesburg : trauma

Introduction. The abuse of alcohol and drugs is a major public health problem and intoxication is one of the most important risk factors for violence and other causes of injury. The aim of the current study was to evaluate the prevalence of drug and alcohol use associated with injury in adult trauma patients in an inner city trauma unit in Johannesburg. Methods. A cohort of 105 adult trauma patients admitted to our university trauma unit and its allied medicolegal laboratory were studied in order to provide prospective data and enable us to correlate the prevalence and type of substance abuse with the demographics and injury patterns after major trauma. Results. Forty-five patients required resuscitation at the Johannesburg Hospital Trauma Unit (JHTU) and 60 patients were examined at the Johannesburg Medicolegal Laboratory (JMLL); giving a total of 105 patients. Blood alcohol concentration (BAC) was positive in 59of the patients. The average BAC in the trauma unit patients was 37 mmol/l (0.17 g/dl) ; more than three times the legal limit for driving. Of the patients 43.7were positive for urinary cannabis; women were statistically significantly more likely to have taken cannabis than men (p = 0.039). There was no difference in rates of exposure to cannabis or alcohol in patients who were the victims of interpersonal violence compared with the victims of accidents (p = 0.17). Only 3 patients had taken other drugs of abuse; 2 had taken Mandrax (methaqualone) and 1 amphetamine. Conclusion. Alcohol and cannabis are commonly misused by trauma patients in Johannesburg; the degree of misuse of other drugs appears to be low. Intoxication is a significant risk factor for violence and accidents and the resultant injuries are a massive burden on our society. Doctors have a responsibility to highlight the association between substance misuse and trauma and should also attempt to persuade individual trauma patients to reduce future alcohol consumption

A fatal case of pepper poisoning.

An 8 month old infant died as the result of administration of a traditional remedy, given orally as an infusion of a red powder. The symptoms on admission were coughing with diarrhoea and vomiting. Analysis of the powder using high-performance liquid chromatography (HPLC) confirmed the suspicion of capsaicin. Pepper preparations, which are used as traditional medicines, are highly toxic and their use on infants should be discouraged.