Interaction between diet and sunlight exposure on vitamin D status in women living in southern England: Multilevel modelling analysis of the D-FINES study

The relative contribution of UVB sunlight exposure and dietary vitamin D intake to 25-hydroxyvitamin D (25(OH)D) remains to be fully determined. The aim of this study was to examine these factors in combination using a repeated measures multilevel modelling approach. The D-FINES study investigated 373 Surrey Caucasian and Asian women in four seasons of the year for 25(0H)D, dietary vitamin D and UVB exposure. To capitalise on the clustered nature of the repeated seasonal measurements within individuals, multilevel modelling was undertaken using MLwiN v.2.1software. Thus seasonal data (dietary vitamin D (DietaryVitD), UV exposure (UVdosi), vitamin D status (VitDstatus)) were included at level one (ij) and individual level data (ethnicity, menopausal status (0=Caucasian, 1=Asian; 0=Premenopausal, 1=Postmenopausal)) at level two (j). Using a random intercept model, the following equation was constructed, which was significantly different from an intercept only model (Log likelihood test- Chi square X2= 2216.51, df=5, p<0.001): 25(OH)Dij= 0j-0.130(0.283)DietaryVitDij + 1.199(0.201)UVdosiij -27.559(2.637) Ethnicity_j: -6.082(2.051)Menopause_1j – 0.020(0.008)UVdosi2ij+ e ij0j=56.650(1.825) + u0j This model showed no effect of diet on 25(OH)D, but did show a significant interaction between Standard Erythema Dose (SED)UV and 25(OH)D. Being of Caucasian ethnicity was associated with a 27.6 nmol/l higher 25(OH)D than Asian ethnicity, and being of premenopausal status was associated with a 6.1 nmol/l higher 25(OH)D than postmenopausal status. Total body fat mass and seasonal dietary calcium had initially been included in the model but were removed as they were not significant parameters. Dietary vitamin D was retained, even though not a significant parameter as it was of high theoretical and practical importance. The implications of this model are that UV exposure has an effect on vitamin D status but dietary vitamin D does not. Ethnicity has a greater influence than menopausal status. This work is funded by the FSA (Project No. NO5064). This work was funded by the UK Foods Standards Agency (NO5064). The views expressed are those of the authors alone. Disclosure o

Economic evaluation of a randomized controlled trial of ultrasound therapy for hard-to-heal venous leg ulcers

Abstract Background A pragmatic, multicentre randomized controlled trial (VenUS III) was conducted to determine whether low-dose ultrasound therapy increased the healing rate of hard-to-heal leg ulcers. This study was a cost-effectiveness analysis of the trial data. Methods Cost-effectiveness and cost–utility analyses were conducted alongside the VenUS III trial, in which patients were randomly allocated to either ultrasound treatment administered weekly for 12 weeks along with standard care, or standard care alone. The time horizon was 12 months and based on the UK National Health Service (NHS) perspective. Results The base-case analysis showed that ultrasound therapy added to standard care was likely to be more costly and provide no extra benefit over standard care alone. Individuals who received ultrasound treatment plus standard care took a mean of 14·7 (95 per cent confidence interval − 32·7 to 56·8) days longer to heal, had 0·009 (−0·042 to 0·024) fewer quality-adjusted life years and had higher treatment costs by £197·88 (−35·19 to 420·32). Based on these point estimates, ultrasound therapy plus standard care for leg ulcers was dominated by standard care alone. The analysis of uncertainty showed that this treatment strategy is unlikely to be cost-effective. Conclusion Ultrasound treatment was not cost-effective for hard-to-heal leg ulcers and should not be recommended for adoption in the NHS. Registration number: ISRCTN21175670 (http://www.controlled-trials.com) and N0484162339 (National Research Register). </jats:sec