OBJECTIVES: To investigate whether the APOE 4
allele was associated with increased risk of hip
fracture in an older community-based sample and
whether such an increased risk was independent of
dementia and history of falling.
DESIGN:
Case-control study nested within a prospective
community study.
SETTING: The Monongahela
Valley Independent Elders Survey (MoVIES), an ongoing
prospective community study of older adults in
southwestern Pennsylvania.
PARTICIPANTS: A
total of 899 MoVIES participants (63.9% women; mean
age, 76.2 years, SD = 4.9 years), who provided both
information on hip fractures and blood samples for
genotyping.
MEASUREMENTS: Interview questions
regarding hip fractures and falls, polymerase chain
reaction to determine APOE genotype, and clinical
assessment using a standardized protocol to determine
the presence or absence of dementia.
RESULTS:
Twenty-five subjects reported having hip fractures in
the year preceding screening interviews. Subjects with
one or two APOE 4 alleles were twice as likely as
subjects without an APOE 4 allele to report hip
fractures (age-adjusted OR = 2.1, 95%
CI:
0.9-4.7). Based on multivariate analysis, subjects
with a history of falling were more likely to report
hip fractures (OR = 4.7, 95%
CI: 2.1-10.8).
After adjusting for history of falls and diagnosis of
dementia, subjects with an APOE 4 allele were still
twice as likely to report hip fractures (adjusted OR =
2.1, 95%
CI: 0.9 - 4.7).
CONCLUSIONS:
The APOE 4 allele appears to be a risk factor for hip
fracture, independent of the effect of dementia and
falling. Theoretically, this may be mediated by
alterations in vitamin K metabolism. Caution should be
used in interpreting these results, because the 95%
confidence intervals for the odds ratios include 1.