Having children later in life and being overweight also appear to cut the risk of death as the result of a fracture.

Broken hips are a common symptom of osteoporosis, or brittle bone disease.

Most women who sustain a hip fracture survive, but sometimes death can occur as a result.

Age when having a first child could be a factor

Researchers in Norway sought to investigate the impact a woman's reproductive variables, such as age when her periods start, age when she first has a child and age at which the menopause started, on deaths from hip fractures.

Broken hip

They studied 63,000 women over a period of 29 years.

Of these, 465 died as a result of a hip fracture in the course of the study.

Many of the women included in the study would have broken their hip at some stage.

Those whose first period was separated from their menopause by less than 30 years were twice as likely to die from the fracture than those with 38 years or more between the two.

Those who had their first child when they were over the age of 35 also had a lower risk of a fatal hip fracture.

Risk factors

Few of the women had used hormone replacement therapy or smoked.

These are both factors that are known to affect the strength of bones.

The researchers, led by Dr Bjarne Jacobsen of the University of Tromso, said that women with more reproductive years are exposed to oestrogens for longer and this maintains bone strength.

They said: "Hip fracture is one of the most serious effects of osteoporosis in terms of mortality, disability, and economic costs."

However, they added that it might be possible to avoid fractures by having a first child later in life.

But they called for more research into the connection.