Objective: To determine whether patients with dementia have reduced bone mass, altered vitamin D, or parathyroid hormone status.
Design: Survey.
Setting: University hospital outpatient department.
Participants: Twenty women with DSM-III-R mild dementia living in the community were compared with 40 cognitively normal community-dwelling women, matched for age, who had been recruited as part of studies in elderly twins.
Measurements: Bone density at the lumbar spine and neck of femur by dual-energy X-ray absorptiometry, intact serum PTH, and 25-hydroxyvitamin D levels.
Main results: There was no significant difference in bone density between the subjects with mild dementia and the age- and sex-matched controls. The intact PTH (mean +/- SD) in the demented subjects was 4.9 +/- 2.1 pmol/L compared with 2.9 +/- 1.7 pmol/L in the twin controls (P < .01). The mean 25-hydroxyvitamin D in the demented subjects was 61 +/- 33 nmol/L, whereas it was 90 +/- 38 nmol/L in the twin controls (P < .01).
Conclusions: We conclude that there were no significant differences in the bone density of community-dwelling women with mild dementia compared with normals. However, there were significant differences in parathyroid hormone and vitamin D levels between the two groups, suggesting that there is a high prevalence of subclinical hypovitaminosis D in demented women in the community.