Introduction 1 3 3 4 5 6 3 7 8 5 9 10 14 15 3 7 8 14 16 17 18 4 19 20 2 18 The aim of the present study was to investigate, in a Dutch nursing home population, whether there is a difference in efficacy of different doses and intervals of oral vitamin D3 supplementation with the same total dose. A second aim was to assess the additional effect of calcium supplementation following vitamin D supplementation on serum PTH and markers of bone turnover. Subjects and methods Subjects Ten somatic and psychogeriatric nursing homes participated and 1,006 subjects were invited. Of these, 146 did not respond, 386 refused to participate and 136 did not meet inclusion criteria. Participants were 338 (76 male and 262 female) patients of 70 years or older with a mean age of 84 years (SD 6.2). Exclusion criteria were going outside in the sunshine more than once a week, the use of vitamin D or calcium supplementation, the use of more than one vitamin D-fortified food or drink per day, complete immobilisation and a very poor life expectancy. Poor cognition was not an exclusion criterion. This did not affect adherence. Nursing homes were enrolled in the study throughout the year. Participants living together in the same nursing home started the study during the same season. The dietary vitamin D intake was estimated at about 100 IU/day, based on fish and margarine consumption. In the Netherlands only margarine is fortified with vitamin D3 (3 IU/g) and the diet does not contain vitamin D2. Written informed consent was obtained from participants or their proxies. The protocol as well as the patient information letters were approved by the Ethical Review Board of the VU University medical centre. Randomisation Participants were randomised in blocks of six, to receive, during the study period of four and a half months, either oral vitamin D3 600 IU/day (one tablet) or placebo, 4200 IU/week (seven tablets once a week) or placebo or 18,000 IU/month (one powder once a month) or placebo. (Solvay Pharmaceuticals, Weesp, Netherlands). After four months, participants in every group were randomised again to receive during 14 days either calcium carbonate or placebo. The first 156 participants who were randomised received 800 mg calcium carbonate (320 mg Ca2+) or placebo, the subsequent 120 participants received 1,600 mg calcium carbonate (640 mg Ca2+) or placebo. The study medication was centrally distributed to ensure compliance. The study was completed by 269 patients. Measurements 2 21 22 During the study all falls and fractures were registered by the nursing staff on special forms and checked with the routine incident registration. At the end of each study period in a nursing home, every ward was asked to complete a questionnaire on the opinion of the nursing staff about the suitability of each distribution form, compliance, the risk of making mistakes, time investment and preferences. Random samples of the returned medication were counted in order to verify compliance. Adequate compliance was defined to exist when more than 80% of the study medication was ingested. Twice a quality check was made on the research medication by taking random samples for determining the vitamin D3 content of tablets and powders. Fasting blood samples were obtained at baseline, at two and four months. Serum 25(OH)D was measured by radioimmunoassay (Diasorin, Stillwater, MN) with an inter-assay coefficient of variation (CV) of 10% at 30 nmol/L. Serum PTH was measured by radioimmunoassay (Incstar, San Juan Capistrano, CA) with an inter-assay CV of 10% at 3.5 pmol/L. Serum carboxy-terminal collagen crosslinks or CTX, a marker for bone resorption, was measured by immuno-assay (CrossLaps, (Roche) with an interassay CV of 5%. \documentclass[12pt]{minimal}
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$$\end{document} Statistical analysis 0 2 2 3 0 P Results Baseline characteristics 1 P P P Table 1 0 0 2   Total D total D daily D weeky D monthly Pl D total b b ( = 338) ( = 166) ( = 55) ( = 54) ( = 57) ( = 172) ( = 68) ( = 71) % female 77.5 76.5 83.6 72.2 73.7 78.5 76.5 78.9 Variable Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Age (yr) 84.2 (6.2) 84.2 (6.5) 84.3 (6.3) 84.3 (6.4) 83.9 (6.9) 84.2 (5.9) 83.3 (6.2) 84.5 (6.8) 25(OH)D (nmol/L) 25.0 (10.9) 24.9 (10.1) 24.0 (8.6) 26.7 (12.6) 24.1 (8.8) 25.0 (11.7) 25.3 (10.6) 24.1 (9.6) Calcium corrected (mmol/L) 2.42 (0.10) 2.42 (0.09) 2.42 (0.09) 2.41 (0.08) 2.42 (0.10) 2.43 (0.10) 2.41 (0.08) 2.42 (0.10) Phosphate (mmol/L) 1.03 (0.14) 1.02 (0.14) 1.02 (0.13) 1.02 (0.16) 1.02 (0.13) 1.04 (0.14) 1.01 (0.14) 1.03 (0.13) CTX (ng/L) 592 (277) 571 (274) 594 (274) 626 (311) 496 (218) 613 (280) 552 (288) 565 (255) Albumin (g/L) 33.4 (3.3) 33.4 (3.3) 33.0 (3.5) 33.1 (3.4) 34.2 (2.8) 33.4 (3.2) 34.0 (3.2) 33.0 (3.4) Standing score (1–5) 3.3 (1.6) 3.3 (1.6) 3.5 (1.6) 3.1 (1.7) 3.5 (1.6) 3.3 (1.6) 3.2 (1.7) 3.5 (1.6) Walking score (1–5) 3.0 (1.4) 3.0 (1.4) 3.0 (1.4) 3.0 (1.6) 3.0 (1.3) 3.0 (1.4) 2.9 (1.4) 3.1 (1.4) Skewed variable Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) Median (IQR) b 750 (560–1035) 750 (594–1015) 725 (623–1039) 755 (550–1028) 788 (583–955) 750 (550–1053) 773 (614–1024) 730 (565–1003) PTH (pmol/L) 7.2 (5.1–10.5) 7.2 (5.2–10.4) 7.4 (5.2–10.4) 6.7 (5.3–9.9) 7.2 (5.1–10.5) 7.1 (5.1–11.1) 6.5 (5.2–9.4) 7.3 (5.1–10.9) AF (U/L) 85 (69–102) 86 (71–104) 82 (73–100) 90 (68–106) 87 (67–105) 85 (69–99) 89 (68–105) 82 (67–98) Creatinine (μmol/L) 93 (81–103) 92 (81–103) 87 (80–95) 96 (85–104) 94 (81–105) 93 (82–105) 91 (80–102) 92 (81–102) IQR = interquartile range a b Trial schedule 1 Fig. 1 Flow diagram of progress through the randomized clinical trial of vitamin D supplementation followed by the randomized clinical trial of calcium supplementation  Vitamin D intervention n n n n n n 0 1 2 n n P Calcium intervention n n n n Effectiveness of Vitamin D supplementation Nursing home and potential confounding variables at baseline were not included in the final models since the effect sizes were hardly influenced by adding these variables. Serum 25-hydroxyvitamin D 2 2 P P P P 3 Table 2 0 1 2   Mean (SD) or median (IQR) a b c P b a b c P b 0 1 2  0 2 0 2  0 2 0 2 Serum concentration 25(OH)D (nmol/L) Pl 25.2 (12.1) 24.3 (11.2) 25.5 (12.0) D/Pl 38.5 (35.7–41.3) 0.000     D daily 23.0 (8.3) 59.9 (16.5) 69.9 (17.8) Dd/Pld 47.2 (42.3–52.1) 0.000 Dd/Dw 6.6 (1.7–11.4) 0.009  D weekly 27.3 (12.7) 58.8 (12.8) 67.2 (14.0) Dw/Plw 40.7 (35.8–45.6) 0.000 Dw/Dm 11.2 (6.3–16.1) 0.000  D monthly 23.8 (8.0) 44.8 (14.1) 53.1 (15.9) Dm/Plm 27.6 (22.8–32.5) 0.000 Dm/Dd −17.8 (−22.7–−12.8) 0.000 Phosphate (mmol/L) Pl 1.04 (0.12) 1.05 (0.14) 1.01 (0.14) D/Pl 0.057 (0.025–0.088) 0.001     D daily 1.01 (0.14) 1.07 (0.12) 1.05 (0.11) Dd/Pld 0.088 (0.033–0.143) 0.002 Dd/Dw 0.022 (−0.033–0.076) 0.434  D weekly 1.03 (0.15) 1.06 (0.13) 1.04 (0.14) Dw/Plw 0.065 (0.01–0.12) 0.022 Dw/Dm −0.001 (−0.055–0.054) 0.981  D monthly 1.02 (0.13) 1.07 (0.16) 1.04 (0.12) Dm/Plm 0.017 (−0.037–0.072) 0.533 Dm/Dd −0.021 (−0.076–0.034) 0.454 Calcium corrected (mmol/L) Pl 2.42 (0.10) 2.40 (0.09) 2.42 (0.09) D/Pl 0.029 (0.008–0.05) 0.007     D daily 2.42 (0.10) 2.42 (0.10) 2.45 (0.10) Dd/Pld 0.036 (0–0.071) 0.050 Dd/Dw 0.006 (−0.03–0.042) 0.736  D weekly 2.41 (0.08) 2.41 (0.10) 2.43 (0.10) Dw/Plw 0.019 (−0.018–0.055) 0.307 Dw/Dm −0.001 (−0.036–0.035) 0.974  D monthly 2.42 (0.09) 2.42 (0.09) 2.44 (0.10) Dm/Plm 0.033 (−0.003–0.068) 0.072 Dm/Dd −0.005 (−0.041–0.03) 0.762 c Pl 7.2 (5.0–11.8) 7.8 (5.6–10.8) 7.5 (5.1–11.0) D/Pl 0.77 (0.7–0.85) 0.000     D daily 7.3 (5.0–10.3) 5.7 (4.3–7.4 5.1 (3.7–7.7) Dd/Pld 0.66 (0.56–0.78) 0.000 Dd/Dw 0.83 (0.7–0.99) 0.037  D weekly 6.5 (5.3–9.5) 6.5 (4.6–8.7) 5.9 (5.2–7.6) Dw/Plw 0.85 (0.72–1.01) 0.067 Dw/Dm 1.02 (0.86–1.22) 0.773  D monthly 7.2 (5.1–10.9) 6.6 (4.4–9.3) 5.6 (4.3–8.9) Dm/Plm 0.81 (0.68–0.96) 0.019 Dm/Dd 1.17 (0.99–1.39) 0.061 CTX (ng/L) Pl 598 (270) 612 (274) 624 (256) D/Pl −14 (−57–29) 0.491     D daily 578 (267) 574 (265) 579 (279) Dd/Pld −34 (−109–41) 0.341 Dd/Dw 1 (−73–75) 0.976  D weekly 606 (316) 599 (314) 595 (304) Dw/Plw −27 (−102–48) 0.445 Dw/Dm −36 (−111–39) 0.314  D monthly 490 (207) 528 (229) 523 (230) Dm/Plm 19 (−56–93) 0.589 Dm/Dd 35 (−40–110) 0.329 c Pl 84 (67–99) 82 (69–99) 82 (67–101) D/Pl 0.97 (0.92–1.03) 0.363     D daily 82 (72–99) 88 (69–101) 82 (67–97) Dd/Pld 0.96 (0.87–1.06) 0.412 Dd/Dw 0.96 (0.87–1.06) 0.394  D weekly 88 (66–107) 81 (64–105) 80 (69–104) Dw/Plw 1.03 (0.93–1.14) 0.553 Dw/Dm 1.1 (1–1.21) 0.057  D monthly 86 (67–103) 80 (64–96) 74 (63–100) Dm/Plm 0.94 (0.85–1.03) 0.180 Dm/Dd 0.95 (0.86–1.05) 0.270 a b c Fig. 2 Mean (± 1.96 × SD) serum 25(OH)D concentrations at baseline, 2 and 4 months during treatment with vitamin D daily, weekly, or monthly, or placebo  Table 3 Percentage of participants with 25(OH)D levels below a certain cut-off point at baseline and after vitamin D or placebo supplementation Group: Total Placebo Vitamin D total Vitamin D daily Vitamin D weekly Vitamin D monthly 25(OH)D < 25 nmol/L       Baseline (t0) 55.3 56.9 53.6 60.9 48.9 51.1 2 months (t1) 30.1 57.8 2.9 2.2 0.0 6.8 4 months (t2) 27.4 52.6 2.2 2.2 0.0 4.5 25(OH)D < 50 nmol/L       Baseline (t0) 97.5 96.4 98.6 100.0 95.7 100.0 2 months (t1) 65.4 94.8 36.5 26.1 19.1 65.9 4 months (t2) 58.0 97.1 19.0 10.9 10.6 36.4 25(OH)D < 75 nmol/L       Baseline (t0) 99.6 99.3 100.0 100.0 100.0 100.0 2 months (t1) 95.2 99.3 91.2 87.0 89.4 97.7 4 months (t2) 88.3 100.0 76.6 63.0 72.3 95.5 Secondary outcome measures: serum phosphate and corrected calcium 2 Serum parathyroid hormone and bone turnover markers 2 P P P Effectiveness of calcium supplementation P Fractures The number of falls and fractures did not differ between the intervention groups and the control groups, which was expected given the short study period of four and a half months. Compliance The compliance assessed within 96 random samples of the returned medication was good. In the daily administration group, all 33 participants were compliant–i.e., used at least 80% of the tablets–(median = 97.0; IQR 94.5–100). For weekly administration, 80% of the 35 participants were compliant–i.e., used at least 80% of the tablets (median = 98.5; IQR 84.0–100). For monthly administration, 93% of the 28 participants were compliant–i.e., used at least four out of five powders (median = 100; IQR 85.0–100). Survey nursing staff A survey among the nursing staffs of the participating nursing home wards showed a distinct preference (72%) for daily administration compared to weekly and monthly. Thirty-ning percent of the nursing staffs reported the impression that fewer mistakes were made using daily administration instead of weekly or monthly administration. Discussion 2 3 4 3 4 23 4 18 24 15 8 25 26 27 The median calcium intake in these Dutch nursing home residents (750 mg per day from dairy products, total estimated dietary intake 950–1,000 mg per day) was slightly lower than the guidelines recommend and relatively high compared to institutionalised elderly in other countries, probably due to a higher dairy intake. This was expected since every Dutch nursing home has its own dietician. Calcium supplementation combined with vitamin D in the last part of the study did not lead to a decrease of biochemical markers of bone turnover. An explanation might be that immobility is a cause of high bone turnover, which is not suppressed by calcium supplementation. The nursing staff’s preference for daily supplementation of vitamin D is probably due to the fact that it fits better in a regular distribution routine, is less time consuming and less susceptible for making mistakes. In conclusion, 98% of the participants had a baseline serum 25(OH)D lower than 50 nmol/L. Oral vitamin D3 supplementation, administered daily was more effective than weekly doses in nursing home residents, while monthly administration was the least effective, 35% still having a serum 25(OH)D < 50 nmol/l after 4 months treatment in this group. Calcium supplementation did not augment the effect of vitamin D supplementation.