The vitamin D receptor gene variant and physical activity predicts fasting glucose levels in healthy young men

AIMS

Vitamin D can influence lipolysis and insulin secretion. A common genetic polymorphism of the vitamin D receptor (VDR), which has been found to be associated with bone mineral density, has been reported to be also associated with Type 2 diabetes mellitus (DM). To test the influence of the VDR polymorphism on fasting glucose in healthy young men before the onset of Type 2 DM, we studied a homogeneous population of aircrew members.

METHODS

A total of 1539 individuals were recruited during routine medical qualification for flying duty. Physical activity was assessed in all individuals and categorized into low physical activity (<or= 3 h per week) and high physical activity (> 3 h per week). The BsmI VDR polymorphism was analysed by polymerase chain reaction. On the day of blood testing the individuals were fasting for at least 8 h overnight. Serum glucose was measured within 60 min after sampling venous blood.

RESULTS

In young males with low physical activity (n = 752) gene carriers with the VDR genotype BB (n = 137) have significantly (P < 0.001) higher levels of fasting glucose (5.61 +/- 0.49 mmol/l) than gene carriers with the genotype Bb (n = 370; 5.44 +/- 0.44 mmol/l) or bb (n = 245; 5.38 +/- 0.44 mmol/l). Of BB gene carriers, 47% had fasting glucose levels > 5.55 mmol/l compared with 36% of Bb gene carriers and 34% of bb gene carriers (P = 0.018). This effect is absent in gene carriers with high physical activity (n = 787).

CONCLUSIONS

The VDR genotype is associated with altered fasting glucose levels in young men with low physical activity. If this association is confirmed in other populations it might be worthwhile studying the particular benefits of an exercise programme in dependents of the VDR genotype.

Vitamin D receptor gene polymorphism BsmI is not associated with the prevalence and severity of CAD in a large-scale angiographic cohort of 3441 patients

BACKGROUND

Recent studies found a relationship between Vitamin D and atherosclerosis. A common genetic polymorphism of the Vitamin D receptor (VDR) has been associated with coronary artery disease (CAD) in small study populations. To assess its influence on the prevalence and severity of CAD we studied a large-scale population.

METHODS

A total of 3441 consecutive patients were referred for diagnostic coronary angiography. The BsmI Vitamin D receptor polymorphism was analyzed by polymerase chain reaction. Angiography was used to define phenotypes with clear coronary arteries (n = 775), coronary sclerosis (diameter stenosis < 50%; n = 579), CAD (diameter stenosis > 50% in at least one vessel; n = 1524). Patients with CAD at a young age (females aged less than 65 years, males aged less than 55 years; n = 563) were specially defined as premature CAD. The risk profile of traditional cardiovascular risk factors was obtained for every patient.

RESULTS

The genotype frequencies of the VDR BsmI polymorphism did not differ between all four phenotypes (P = 0.756). The allele frequencies for the B allele were 0.43 vs. 0.44 vs. 0.42 vs. 0.45 in the four phenotypic groups (P = 0.827). All traditional cardiovascular risk factors (hypercholesterolaemia, smoking, hypertension, diabetes mellitus, severe obesity, male gender) were significantly (P < 0.001) associated with the angiographic phenotype.

CONCLUSIONS

The VDR gene variant BsmI was not associated with prevalence and severity of CAD in a large-scale cohort phenotyped by angiography.