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. 2010 Jul 29;341:c3691. doi: 10.1136/bmj.c3691

Table 1.

 Characteristics of 15 studies eligible for inclusion in meta-analysis

Studies No in calcium group/No in control group Daily dose and supplement type Trial duration (years) Primary end point Baseline mean age (years) % female
Patient level data on cardiovascular outcomes:
 Reid 199321 22 68/67 1 g lactogluconate-carbonate 4 Bone mineral density 58 100
 Baron 199925 464/466 1.2 g carbonate 4 Colorectal adenoma 61 28
 Grant 200528 2617/2675 1 g carbonate 4* Low trauma fracture 77 85
 Reid 200615 16 732/739 1 g citrate 5 Clinical fracture 74 100
 Reid 200833 216/107 0.6 g or 1.2 g citrate 2 Spine bone mineral density 56 0
Subtotal/average† 4097/4054 — 4.1 — 73 78
Trial level data on cardiovascular outcomes‡:
 Dawson-Hughes 199019 238/123 0.5 g carbonate or citrate 2 Spine bone mineral density 58 100
 Riggs 199824 119/117 1.6 g citrate 4 Bone mineral density 66 100
 Bonithon-Kopp 200027 204/212 2 g lactogluconate-carbonate 3 Colorectal adenoma 59 37
 Prince 200629 730/730 1.2 g carbonate 5 Osteoporotic fracture 75 100
 Bonnick 200730 282/281 1 g carbonate 2 Spine bone mineral density 66 100
 Lappe 200731 32 446/288 1.4 g citrate or 1.5 g carbonate 4 Fracture incidence 67 100
Subtotal/average† 2019/1751 — 3.8 — 68 93
Total/average† 6116/5805 4.0 72 83
No data on cardiovascular outcomes:
 Smith 198918§ 84/85 1.5 g carbonate 4 Arm bone mineral density 51 100
 Elders 199120 198/97 1g or 2g lactogluconate-carbonate or citrate 2 Spine bone mineral density NA 100
 Recker 199623 95/102 1.2 g carbonate 4 Vertebral fracture 74 100
 Peacock 200026 126/135 0.75 g citrate 4 Hip bone mineral density 76 72
Subtotal/average† 503/419 — 4.0 — 69 88

NA=not available.

*All participants were followed for two years with a median follow-up of 45 months.

†Weighted by person years of follow-up.

‡Complete trial level data were available for two studies.29 31 Partially complete data were available for four studies19 24 27 30 (see table 2 for details).

§No original records remained but lead author recalled no heart attacks in either treatment group.