Comparison of the Effect of Daily Vitamin D2 and Vitamin D3 Supplementation on Serum 25-Hydroxyvitamin D Concentration (Total 25(OH)D, 25(OH)D2, and 25(OH)D3) and Importance of Body Mass Index: A Systematic Review and Meta-Analysis.

BACKGROUND: Two previous meta-analyses showed smaller differences between vitamin D3 and vitamin D2 in raising serum 25-hydroxyvitamin D [25(OH)D] and a consistently high heterogeneity when only including daily dosing studies. OBJECTIVE: This study aimed to compare more frequently dosed vitamin D2 and vitamin D3 in improving total 25(OH)D and determine the concomitant effect of response modifiers on heterogeneity, and secondly, to compare the vitamin D2-associated change in 25(OH)D2 with the vitamin D3-associated change in 25(OH)D3. METHODS: PubMed, EMBASE, Cochrane, and the Web of Science Core collection were searched for randomized controlled trials of vitamin D2 compared with vitamin D3, daily or once/twice weekly dosed. After screening for eligibility, relevant data were extracted for meta-analyses to determine the standardized mean difference when different methods of 25(OH)D analyses were used. Otherwise, the weighted mean difference (WMD) was determined. RESULTS: Overall, the results based on 20 comparative studies showed vitamin D3 to be superior to vitamin D2 in raising total 25(OH)D concentrations, but vitamin D2 and vitamin D3 had a similar positive impact on their corresponding 25(OH)D hydroxylated forms. The WMD in change in total 25(OH)D based on 12 daily dosed vitamin D2-vitamin D3 comparisons, analyzed using liquid chromatography-tandem mass spectrometry, was 10.39 nmol/L (40%) lower for the vitamin D2 group compared with the vitamin D3 group (95% confidence interval: -14.62, -6.16; I2 = 64%; P < 00001). Body mass index (BMI) appeared to be the strongest response modifier, reducing heterogeneity to 0% in both subgroups. The vitamin D2- and vitamin D3-induced change in total 25(OH)D lost significance predominantly in subjects with a BMI >25 kg/m2 (P = 0.99). However, information on BMI was only available in 13/17 daily dosed comparisons. CONCLUSIONS: Vitamin D3 leads to a greater increase of 25(OH)D than vitamin D2, even if limited to daily dose studies, but vitamin D2 and vitamin D3 had similar positive impacts on their corresponding 25(OH)D hydroxylated forms. Next to baseline 25(OH)D concentration, BMI should be considered when comparing the effect of daily vitamin D2 and vitamin D3 supplementation on total 25(OH)D concentration. This study was registered in PROSPERO as CRD42021272674.

The Subjective Experience of Living with Parkinson's Disease: A Meta-Ethnography of Qualitative Literature.

BACKGROUND: A better understanding of the subjective experience of living with Parkinson's disease (PD) and the factors that influence this experience can be used to improve wellbeing of people with PD (PwP). OBJECTIVE: To gain more insight in the subjective experience of PD from the PwP's perspective, and the factors that contribute to this experience. METHODS: In this qualitative review, we performed a systematic search of qualitative studies discussing the subjective experience of PD and extracted reported themes (first order themes). Using a meta-ethnographic approach, we categorized the first order themes into second order themes, and created a third order construct: a holistic model of the subjective experience of living with PD. RESULTS: We included 20 studies with a total sample of 279 PwP. Data-extraction yielded 227 first order themes, which were categorized into the second order themes: 1) Awareness, 2) Disruption, 3) Adjustment, 4) The external environment, and 5) The changing self. With these themes, we developed the "model of dialectic change" which conceptualizes life with PD as a transformative journey, wherein PwP employ strategies to stabilize their changeable relationship with their external environment, while simultaneously redefining their self-concept. CONCLUSION: Our findings indicate that not only the symptoms of PD, but also the manner in which these cause disruptions in the PwP's interaction with their personal environment and self-concept, determine the subjective experience of PD andquality of life. Some PwP experience problems with adjusting, resulting in psychological distress. This calls for a holistic, multidisciplinary and participatory approach of PD.