Leg length, skull circumference, and the incidence of dementia in Latin America and China: a 10/66 population-based cohort study
Date
2018-04-18Author
Prince, Martin J.
Acosta, Daisy
Guerra, Mariella
Huang, Yueqin
Jiménez- Velázquez, Ivonne Z.
Llibre Rodriguez, Juan J.
Salas, Aquiles
Sosa, Ana Luisa
Dewey, Michael E.
Guerchet, Maelenn M.
Liu, Zhaorui
Llibre Guerra, Jorge J.
Prina, A. Matthew
Metadata
Show full item recordAbstract
Adult leg length is influenced by nutrition in the first few years of life. Adult head circumference
is an indicator of brain growth. Cross-sectional studies indicate inverse associations
with dementia risk, but there have been few prospective studies.
Methods
Population-based cohort studies in urban sites in Cuba, Dominican Republic Puerto Rico
and Venezuela, and rural and urban sites in Peru, Mexico and China. Sociodemographic
and risk factor questionnaires were administered to all participants, and anthropometric
measures taken, with ascertainment of incident dementia, and mortality, three to five years
later.
Results
Of the original at risk cohort of 13,587 persons aged 65 years and over, 2,443 (18.0%) were
lost to follow-up; 10,540 persons with skull circumference assessments were followed up for
40,466 person years, and 10,400 with leg length assessments were followed up for 39,954
person years. There were 1,009 cases of incident dementia, and 1,605 dementia free
deaths. The fixed effect pooled meta-analysed adjusted subhazard ratio (ASHR) for leg
length (highest vs. lowest quarter) was 0.80 (95% CI, 0.66±0.97) and for skull circumference
was 1.02 (95% CI, 0.84±1.25), with no heterogeneity of effect between sites (I2 = 0%). Leg length measurements tended to be shorter at follow-up, particularly for those with baseline
cognitive impairment and dementia. However, leg length change was not associated with
dementia incidence (ASHR, per cm 1.006, 95% CI 0.992±1.020), and the effect of leg length
was little altered after adjusting for baseline frailty (ASHR 0.82, 95% CI 0.67±0.99). A priori
hypotheses regarding effect modification by gender or educational level were not supported.
However, the effect of skull circumference was modified by gender (M vs F ASHR 0.86,
95% CI 0.75±0.98), but in the opposite direction to that hypothesized with a greater protective
effect of larger skull dimensions in men.
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