Longer femoral necks in the young: a predictor of further increases in hip fracture incidence?

AIMS

To determine whether femoral neck length, a risk factor for hip fracture, is likely to increase in the coming decades in normal elderly New Zealand women.

METHODS

Femoral neck length was measured from dual-energy x-ray absorptiometry scans of the proximal femur in white women aged 19-88 years (n = 211). Since this length remains constant throughout adult life, it is possible to predict future trends in this index in the elderly, from its measurement at the present time in younger adults.

RESULTS

Femoral neck length was inversely related to age (p = 0.018) such that a 3.7 mm (5.7%) difference occurred over the age-range of this sample.

CONCLUSIONS

Femoral neck length in elderly New Zealand women is likely to increase in the coming decades. As a result of the dependence of hip fracture risk on femoral neck length, future age-adjusted hip fracture incidence will increase by about 50% over the next 50 years unless significant public health initiatives are taken, either to increase bone density or to reduce fall frequency.