Effect of dietary sources of calcium and protein on hip fractures and falls in older adults in residential care: cluster randomised controlled trial

Abstract

Objective: To assess the antifracture efficacy and safety of a nutritional intervention in institutionalised older adults replete in vitamin D but with mean intakes of 600 mg/day calcium and <1 g/kg body weight protein/day.

Design: Two year cluster randomised controlled trial.

Setting: 60 accredited residential aged care facilities in Australia housing predominantly ambulant residents.

Participants: 7195 permanent residents (4920 (68%) female; mean age 86.0 (SD 8.2) years).

Intervention: Facilities were stratified by location and organisation, with 30 facilities randomised to provide residents with additional milk, yoghurt, and cheese that contained 562 (166) mg/day calcium and 12 (6) g/day protein achieving a total intake of 1142 (353) mg calcium/day and 69 (15) g/day protein (1.1 g/kg body weight). The 30 control facilities maintained their usual menus, with residents consuming 700 (247) mg/day calcium and 58 (14) g/day protein (0.9 g/kg body weight).

Main outcome measures: Group differences in incidence of fractures, falls, and all cause mortality.

Results: Data from 27 intervention facilities and 29 control facilities were analysed. A total of 324 fractures (135 hip fractures), 4302 falls, and 1974 deaths were observed. The intervention was associated with risk reductions of 33% for all fractures (121 v 203; hazard ratio 0.67, 95% confidence interval 0.48 to 0.93; P=0.02), 46% for hip fractures (42 v 93; 0.54, 0.35 to 0.83; P=0.005), and 11% for falls (1879 v 2423; 0.89, 0.78 to 0.98; P=0.04). The risk reduction for hip fractures and falls achieved significance at five months (P=0.02) and three months (P=0.004), respectively. Mortality was unchanged (900 v 1074; hazard ratio 1.01, 0.43 to 3.08).

Conclusions: Improving calcium and protein intakes by using dairy foods is a readily accessible intervention that reduces the risk of falls and fractures commonly occurring in aged care residents.

Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12613000228785.

Fig 1

Flowchart for participating aged care facilities. Of 108 eligible facilities, 48 were excluded, leaving 60 randomised to intervention or control. Three intervention facilities and one control facility did not start study, leaving 27 intervention and 29 control facilities participating, of which two intervention facilities closed during study period. Median number of residents in intervention and control groups were 111 (interquartile range 75-147) and 125 (88-163), respectively; P=0.42 by Wilcoxon’s rank test

Fig 2

Mean (SD) daily dietary intake of dairy servings, energy, calcium, and protein at baseline (regular menu) and during two year study period in intervention group compared with controls. *P<0.05 denotes significant difference between groups at corresponding time point

Fig 3

Cumulative probability of event over 24 months for all fractures, hip fractures, falls, and mortality in intervention group and controls. Numbers of participants in two groups at risk for each event are shown below panels