CONCLUSION Our meta- analysis highlights that hypovitaminosis D is associated with orthostatic hypotension , independent of potential confounders .
OBJECTIVES Orthostatic hypotension is a common condition among older adults and is associated with a range of deleterious outcomes .
Recently , interest has developed in hypovitaminosis D ( defined as low 25 hydroxiyvitamin D levels ) as a potential risk factor for orthostatic hypotension .
We conducted a systematic review and meta- analysis examining the association of orthostatic hypotension between study participants with and without hypovitaminosis D , including the adjustment of potential confounders ( age , sex , BMI , renal function , comorbidities , seasonality , use of antihypertensive medications , and supplementation with cholecalciferol ) .
Association between circulating 25-hydroxyvitamin D and incident type 2 diabetes: a mendelian randomisation study
Summary Background Low circulating concentrations of 25-hydroxyvitamin D ( 25[OH]D ) , a marker of vitamin D status , are associated with an increased risk of type 2 diabetes  , but whether this association is causal remains unclear . We aim ed to estimate the unconfounded , causal association between 25(OH)D concentration and risk of type 2 diabetes using a mendelian r and omisation approach . Methods Using several data sources from population s of European descent , including type 2 diabetes cases and non-cases , we did a mendelian r and omisation analysis using single nucleotide polymorphisms ( SNPs ) within or near four genes related to 25(OH)D synthesis and metabolism : DHCR7 ( related to vitamin D synthesis ) , CYP2R1 ( hepatic 25-hydroxylation ) , DBP ( also known as GC ; transport ) , and CYP24A1 ( catabolism ) . We assessed each SNP for an association  with circulating 25(OH)D concentration ( 5449 non-cases ; two studies ) , risk of type 2 diabetes ( 28 144 cases , 76 344 non-cases ; five studies ) , and glycaemic traits ( concentrations of fasting glucose , 2-h glucose , fasting insulin , and HbA1c  ; 46 368 non-cases ; study consortium ) . We combined these associations in a likelihood-based mendelian r and omisation analysis to estimate the causal association of 25(OH)D concentration with type 2 diabetes and the glycaemic traits , and compared them with that from a meta- analysis of data from observational studies ( 8492 cases , 89 698 non-cases ; 22 studies ) that assessed the association between 25(OH)D concentration and type 2 diabetes . Findings All four SNPs were associated with 25(OH)D concentrations ( p<10−6 ) . The mendelian r and omisation-derived unconfounded odds ratio for type 2 diabetes was 1·01 ( 95 % CI 0·75–1·36 ; p=0·94 ) per 25·0 nmol/L ( 1 SD ) lower 25(OH)D concentration . The corresponding ( potentially confounded ) relative risk from the meta- analysis of data from observational studies was 1·21 ( 1·16–1·27 ; p=7·3 × 10−19 ) . The mendelian r and omisation-derived estimates for glycaemic traits were not significant ( p>0·25 ) . Interpretation The association between 25(OH)D concentration and type 2 diabetes is unlikely to be causal . Efforts to increase 25(OH)D concentrations might not reduce the risk of type 2 diabetes as would be expected on the basis of observational evidence . These findings warrant further investigations to identify causal factors that might increase 25(OH)D concentration and also reduce the risk of type 2 diabetes . Funding UK Medical Research Council Epidemiology Unit and European Union Sixth Framework Programme
CONCLUSION Our meta- analysis highlights that hypovitaminosis D is associated with orthostatic hypotension , independent of potential confounders .
OBJECTIVES Orthostatic hypotension is a common condition among older adults and is associated with a range of deleterious outcomes .
Recently , interest has developed in hypovitaminosis D ( defined as low 25 hydroxiyvitamin D levels ) as a potential risk factor for orthostatic hypotension .
We conducted a systematic review and meta- analysis examining the association of orthostatic hypotension between study participants with and without hypovitaminosis D , including the adjustment of potential confounders ( age , sex , BMI , renal function , comorbidities , seasonality , use of antihypertensive medications , and supplementation with cholecalciferol ) .