Height in relation to dementia death: individual participant meta-analysis of 18 UK prospective cohort studies

BACKGROUND: That risk factors measured in middle age may not fully explain future dementia risk implicates exposures acting earlier in life. Height may capture early-life illness, adversity, nutrition and psychosocial stress. AIMS: To investigate the little-explored association between height and dementia death. Method Individual participant meta-analysis using 18 prospective general population cohort studies with identical methodologies (1994-2008; n = 181 800). RESULTS: Mean follow-up of 9.8 years gave rise to 426 and 667 dementia deaths in men and women respectively. The mean heights were 174.4 cm (s.d. = 7.3) for men and 161.0 cm (s.d. = 6.8) for women. In analyses taking into account multiple covariates, increasing height was related to lower rates of death from dementia in a dose-response pattern (P ⩽ 0.01 for trend). There was evidence of a differential effect by gender (P = 0.016 for interaction). Thus, the association observed in men (hazard ratio per s.d. decrease in height 1.24, 95% CI 1.11-1.39) was markedly stronger than that apparent in women (HR = 1.13, 95% CI 1.03-1.24). CONCLUSIONS: Early-life circumstances, indexed by adult height, may influence later dementia risk.