Effect of depot medroxyprogesterone acetate on bone density in a Scottish industrial city

To determine if long-term users of depot medroxyprogesterone acetate injectable contraception (DMPA) were more likely than their peers to have low bone density.

Cross-sectional observational study.

The Domiciliary Family Planning Service, Glasgow, Scotland.

Clients of the Domiciliary Service who had used DMPA for contraception for longer than 5 years (mean 12 years) were invited to participate and select their own control, a friend or relative who had never used this method of contraception.

Bone density measured at the hip and lumbar spine by dual X-ray absorptiometry (DXA).

DMPA users had a significantly lower bone density than controls, 12-13% less at both hip and lumbar spine. This difference remained even when controlling for parity, smoking, family history of kyphosis or hip fracture, and body mass index.

DMPA significantly decreases bone density in a group of long-term users with significant social deprivation. The long-term significance of this remains uncertain.