Leg length, cognitive impairment and cognitive decline in an African-Caribbean population

Shorter leg length is associated with an adverse environment in early childhood and has been found to be associated with a variety of disorders occurring in mid- to late-life, including dementia in a Korean population. In a community population of African-Caribbean elders, in whom leg length had been measured, we sought to compare associations with cognitive impairment at baseline and cognitive decline over a three-year follow-up period.

Of 290 African-Caribbean residents in south London recruited at baseline, 216 (74%) were re-interviewed after a three-year period and 203 had sufficient data for this analysis. Cognitive impairment was derived as a binary category from a battery of cognitive tests administered at baseline and cognitive decline was derived from change in performance on a subset of these tests. Leg length (iliac crest to lateral malleolus) was also measured.

Shorter leg length was associated with female sex, lower occupational social class and reported hypertension and diabetes. Shorter leg length (lowest quartile) was significantly associated with cognitive impairment but there were no apparent associations with cognitive decline. The association with cognitive impairment was independent of age, sex and education. Social class appeared to be an important mediating factor.

Shorter leg length may be a marker of early life stressors which result in reduced cognitive reserve. Interestingly this association was mediated more strongly by social class (previous occupational status) than by education in this population.