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In Reply: Dr Mortimer has pointed out an error that occurred in Table 7. The correct ADAS-Cog score for the control group should be geometric mean (SD) 6.4 (1.8) for completers and 10.6 (1.4) for dropouts. The results for participants in the intervention group are correct in Table 7. The data in Table 1 are correct, so that participants in the intervention and control groups had similar ADAS-Cog scores at baseline (P = .98).

Mortimer commented that the control group mean for the variable "all moderate-intensity–plus activities" was 40% higher than in the exercise group. He may have used the quotient of the difference of scores/baseline score to reach this conclusion ([177.2-126.4]/126.4). However, the variable "all moderate-intensity–plus activities" was log-transformed because it was not normally distributed. The log-transformed means for the exercise and control groups were 2.102 and 2.2485, respectively. Therefore, the difference between them was not 40%, but 7% . . . [Full Text of this Article]

Nicola T. Lautenschlager, MD
nicolatl@unimelb.edu.au
Academic Unit for Psychiatry of Old Age
St Vincent's Health
Department of Psychiatry
University of Melbourne
Melbourne, Australia

Jianguo Xiao, MD, PhD
Epidemiology Branch
Department of Health Western Australia
Perth, Australia

Osvaldo P. Almeida, MD, PhD
WA Centre for Health and Ageing
University of Western Australia
Perth

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