Walking pace, handgrip strength, age, APOE genotypes, and new-onset dementia: the UK Biobank prospective cohort study

BACKGROUND: The independent and additive associations of walking pace and grip strength on dementia risk and the potential modifying effects of age, APOE phenotypes, and other dementia risk factors on the walking pace and dementia relationships demand further clarification. We aimed to investigate the independent and additive relationships of walking pace and handgrip strength on the risk of new-onset dementia and examine the potentially modifying effects of age, APOE phenotypes, lifestyle factors, and family history of dementia in the relationships. METHODS: A total of 495,700 participants from the UK Biobank, who were free of dementia at baseline, were included in this study. Walking pace was self-defined as slow, average, or brisk. Handgrip strength was assessed by dynamometer and was divided into sex-specific quartiles. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. Other dementia risk factors, including education, physical activity, hypertension, depression, diabetes, and family history of dementia, were also collected. The primary outcome was new-onset all-cause dementia. RESULTS: Over a median follow-up duration of 12.0 years, 3986 (0.8%) participants developed new-onset all-cause dementia. Compared with those with slow walking pace, participants with average (HR, 0.61; 95%CI: 0.55–0.68) or brisk (HR, 0.59; 95%CI: 0.52–0.67) walking pace had a significantly lower risk of new-onset all-cause dementia. Moreover, compared with those with both slow walking pace and lower handgrip strength (the first quartile), the lowest risk of new-onset all-cause dementia was observed in participants with both average or brisk walking pace and higher handgrip strength (the 2–4 quartiles) (HR, 0.45; 95%CI: 0.40–0.52). Notably, the negative relationship between walking pace and the risk of new-onset all-cause dementia was significantly reduced as APOE ε4 dosage increased (APOE ε4 dosages = 0 or 1: brisk vs. slow: HR, 0.55; 95%CI: 0.48–0.63; vs. APOE ε4 dosages = 2: brisk vs. slow: HR, 1.14; 95%CI: 0.77–1.68; P for interaction = 0.001) or age increased (< 58 [median]: brisk vs. slow: HR, 0.27; 95%CI: 0.18–0.41; vs. ≥ 58 years: brisk vs. slow: HR, 0.55; 95%CI: 0.48–0.63; P for interaction = 0.007). CONCLUSIONS: Walking pace was inversely associated with new-onset dementia in the general population, especially in younger participants and those with lower APOE ε4 dosage. Participants with both faster walking pace and higher handgrip strength had the lowest risk of dementia, suggesting that maintaining both high handgrip strength and fast walking pace may be a more comprehensive strategy for preventing dementia risk. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13195-022-01158-6.