Some caution on this study.
There were significant baseline differences between the placebo and curcumin groups.
No differences between the treatment and placebo groups were observed in terms of the demographic and medical history variables evaluated (Table 1). Nevertheless, the placebo group performed significantly better at baseline in the digit symbol task (t=2·98, P<0·01), the MoCA (t=2·10, P<0·05) and cognitive composite (non-computerised) scores (t=2·40, P<0·05)...
The time×treatment variable was significant for the MoCA score (time×treatment; F=3·85, P<0·05; Table 3 and Fig. 2); however, it is important to note that the time variable itself was not significant (F=1·64, P=0·20). Mean MoCA scores improved by 0·64 points in the curcumin group and by 0·09 points in the placebo group from baseline to 12 months (Table 3 and Fig. 2). To assess whether the significant interaction observed in the repeated-measures analysis was driven by the decreased performance of the placebo group at the 6-month follow-up (a result not consistent with the 12-month follow-up assessment; Table 3 and Fig. 2), the analysis was re-run excluding the 6-month MoCA scores for both treatment groups. Using baseline and 12-month MoCA performance only, no significant interaction between time and treatment groups was observed (F=1·36, P=0·25; Table 3). No other differences in cognitive test performance were observed across the treatment groups.
It looks like the higher performance of the placebo group than curcumin at baseline led to a time x treatment interaction that really does not mean what we want it to mean from a therapeutic perspective.