Biochemical markers of nutrition and bone mineral density in the elderly

Protein depletion is detrimental in bone health, but the association between bone mineral density (BMD) and serum albumin is controversial. We recently showed a positive association between femur BMD and total lymphocyte count (TLC), a validated marker of protein nutrition status, in hip-fractured women.

To investigate the association between femur BMD and both serum albumin and TLC in hip-fractured men and women.

286 of 315 hip-fractured patients (243 women and 43 men) consecutively admitted to a rehabilitation hospital were studied. BMD was measured by DXA in the unfractured femur. The correlation between BMD and both TLC and serum albumin was studied by Pearson's coefficient and Bonferroni adjustment.

In women a positive correlation was observed between, TLC but not albumin, and BMD measured in the total femur (r = 0.26; p < 0.01), femur neck (r = 0.21, p < 0.01), trochanter (r = 0.22, p < 0.01), intertrochanteric area (r = 0.25, p < 0.01) and Ward's triangle (r = 0.17, p < 0.05). Conversely in men a positive correlation was found between albumin, but not TLC, and BMD measured in the total femur (r = 0.50, p < 0.01), femur neck (r = 0.52, p < 0.01), intertrochanteric area (r = 0.52, p < 0.01) and Ward's triangle (r = 0.49, p < 0.01). Linear multiple regression showed that the associations were independent of age, weight, height, body mass index, erythrocyte sedimentation rate, time between surgery and blood sample collection and type of hip fracture.

Our results support the role of protein nutrition in bone health, at least in elderly frail patients. TLC and serum albumin were suitable markers, however sex-related differences in their usefulness were observed.