Effect of a wearable-based individualised multidomain lifestyle intervention on cognitive and physical function in older adults at risk of decline (INSPIOR): a single-centre, open-label, randomised controlled trial

Background Multidomain lifestyle programmes are the leading preventive approach to cognitive decline, but they rely on intensive face-to-face delivery that is hard to scale. We assessed whether an automated, wearable-based multidomain programme of activity, sleep, and optional nutrition prompts changed cognitive and physical function in at-risk older adults. Methods INSPIOR was a 6-month, single-centre, open-label, randomised controlled trial in Kashiwa, Japan. Adults aged 65–92 years with low body-mass index, pre-frailty, frailty, or sarcopenia-related decline were randomly assigned 1:1, in permuted blocks of four and without stratification, to the Fitbit-based intervention or an assessment-only control; allocation was not concealed and outcome assessors were not masked. Co-primary outcomes were the Montreal Cognitive Assessment (MoCA), Trail Making Test (TMT), and skeletal muscle mass index (SMI), with no pre-specified hierarchy or multiplicity adjustment; analyses used intention-to-treat analysis of covariance with multiple imputation. This trial was registered with UMIN-CTR, UMIN000052707, and ClinicalTrials.gov, NCT06135740. Findings Between Nov 8, 2023, and Jul 31, 2024, 355 participants were randomly assigned to the intervention group (n = 178) or control group (n = 177); all were analysed. Adjusted between-group differences were 0·58 MoCA points (95% CI 0·03–1·13; p=0·039; Holm-adjusted p=0·12), 0·16 s (−5·07 to 5·40; p=0·95) for TMT-A, 5·59 s (−3·88 to 15·05; p=0·25) for TMT-B, and −0·01 kg/m 2 (−0·09 to 0·07; p=0·88) for SMI. Mild skin irritation and dietary-recording stress occurred; no serious adverse event was intervention-related. Interpretation The intervention was associated with a small difference in a global cognitive screening score that did not survive multiplicity adjustment and is of uncertain clinical significance; the other two showed none. Larger, longer, masked trials are needed.