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 174.4cm (s.d.=7.3) for men and 161.0cm (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% 01 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.