Associations between head circumference, leg length and dementia in a Korean population.

BACKGROUND: Adult leg length is influenced by nutritional intake in childhood. Shorter leg length has been found to be associated with adverse health outcomes in late life, including dementia. Smaller head circumference has also been found to be associated with dementia. The independence of these two potential markers of risk for dementia has not been investigated.
METHODS: Community residents aged 65 or over (n = 916) within a defined geographic area of South Korea were screened clinically for dementia and dementia subtypes. Data on anthropometric measures (head circumference and leg length), demographics (age, gender), apolipoprotein E, and early life environment (birth order, number of siblings, parental occupation, area of residence, education) were gathered. Reproductive history was also ascertained in women.
RESULTS: Both smaller head circumference and shorter leg length were associated with increased age, rural residence in childhood and lower education. After adjustment for these factors, they were both independently associated with Alzheimer's disease but only in women.
CONCLUSIONS: Smaller head size and shorter limb length were associated with lower early-life socio-economic status. Both factors were apparently independent markers of risk for dementia which may indicate risk factors occurring in childhood affecting both brain and skeletal development. Associations were principally present in women. Reasons for gender differences in associations require clarification but, for this population and age group, may include preferential treatment of male children.