AbstractBackgroundMotor (slowing of gait) and cognitive declines are common in older adults. We reported that older adults with both motor and cognitive decline (dual‐decliners) had a higher risk of progressing to dementia than individuals with either decline alone. Our aim in this study is to examine the role of sex in these cognitive and motor trajectories before dementia.MethodsData was used from the Gait and Brain Study, a prospective cohort study in community‐dwelling older adults free of dementia at baseline. Participant’s motor and cognitive trajectories were assessed twice a year for 5 years, using gait speed and the MoCA test, respectively. We ascertained incident dementia using DSM‐IV‐RT criteria. The risk to progress to dementia was evaluated with Cox regression models, stratifying by sex and adjusting by age and comorbidities.ResultsFrom 207 older adults, 37 individuals (18%) progressed to dementia, from which 43% were males and 57% were females. Among dual‐decliners, males had a higher risk for progressing to dementia when compared with females (Males HR: 3.90, 95%CI: 1.02‐14.87, p = 0.046; Females: HR: 2.41, 95%CI: 0.72‐ 8.12, p = 0.155). In addition, in males, the association becomes stronger after adjusting for comorbidities (HR: 4.36, 95%CI: 1.08‐17.66, p = 0.039), whereas in females, the risk for progressing to dementia lowers when adjusting for comorbidities (HR: 1.44, 95%CI: 0.38‐ 5.41, p = 0.590), suggesting that number of comorbidities might be driving the association with dementia in females. Male dual‐decliners showed a stronger association with progression to dementia (HR = 4) when compared with females (HR = 1) in both adjusted and unadjusted models.ConclusionOlder adults that present both motor and cognitive decline (dual‐decliners) have the highest risk to progress to dementia, particularly if they are men. Sex differences in motor and cognitive trajectories before dementia may increase accuracy of dementia risk prediction. Future studies are needed to understand mechanisms underlying our findings.