Bones, balance and ageing: The surprising links between bone health and brain function
On her 86th birthday in December, Jane Fonda declared herself the happiest she’d ever been. The actor reportedly put her younger cast mates to shame on the set of her recent movie, Book Club: The Next Chapter; rising at dawn and clocking up thousands of steps around the streets of Rome before her day began.
Fonda and many of her fellow seniors – including the baby boomer bubble now in their mid-70s – are living longer and healthier lives than any generation before them. That longevity seems set to continue for the following generations; people in their 50s and 60s can now reasonably expect to see their 90s. Older people are more active and generally healthier than ever before.
But while we’re out there biking the trails and walking the tracks, there can be changes going on inside the body that might put paid to that extended health span. Diseases of the bones and brain can stealthily start decades ahead of when they finally show up externally. Scientists are learning more, not only about new ways to treat these issues, but also about what individuals can do to lower their risk and potentially prevent them.
The fact that we’re living longer is one reason bone health is becoming more of a focus for innovative research. Unless we’ve broken bones, it’s likely we’ve devoted little time to thinking about their health. Yet bone density is linked to longevity – and having poor bone density is linked to early death.
Early in Ian Reid’s career as an endocrinologist, he started to realise that bones needed more attention.
“The epidemic of heart disease was beginning to get under control,” says Reid, a distinguished professor at the University of Auckland. “One of the problems cardiologists caused for us by not letting us die of a heart attack at three score years and 10 was that we lived to four score years and more, which was long enough for our skeletons to fall apart and start letting us down.”
The progressive increase in life expectancy over the years has seen osteoporosis go from what Reid describes as “a sort of a niche thing” to being recognised as “a very major public health problem”.
He says more than half of older Pākehā women will have a fracture at some point between menopause and when they die. Fracture rates are about half this in Māori and Pacific women who tend to have higher bone density, by about 10%. For men, one in five will have an osteoporotic fracture in their lifetime.
Hip fractures – more common in those over 70 – are particularly worrying; global estimates show that up to a third of older adults who have suffered hip fractures will die within a year. The rates go up for those with dementia or who live in a nursing home.
Long before we get to the point of fracture, there are things going on in our bodies that might lead to that moment. There’s hormonal change, for a start. Osteoporosis and its precursor, osteopenia, affect women more severely than men, and more rapidly; women lose bone at 2-3% per year over five to 10 years during perimenopause and postmenopause. After that, the bone loss in both sexes is about 0.5-1% a year.