Seeking Health

World Osteoporosis Day, 20 October, might not be as exciting as Christmas Day, or even Pancake Day, but it's important nonetheless. An alarming number of people in New Zealand suffer from osteoporosis, a condition which can lead to serious and sometimes disabling fractures.

Many osteoporotic fractures are preventable – essentially it’s “the disease we don’t have to have”. Like the major epidemics of the past, targeted health interventions now could drastically curb the incidence of osteoporosis, fractures and morbidity, which in New Zealand currently stands at one hip fracture every two hours.

This year about 80,000 New Zealanders will break bones because of osteoporosis, and about three quarters will be women. That is a fracture every 6 minutes, and if nothing is done, this will increase to 120,000 people by 2020, with a fracture every 41/2 minutes.

Too Young to Have to Worry?

Most fractures are seen later in life, but the foundations of bone health are laid down in childhood, adolescence and young adulthood, and so osteoporosis is sometimes referred to as a paediatric disease. If preventative action is taken early on, the health burden and financial burden of osteoporosis for New Zealanders can be significantly reduced in the future.

What is Osteoporosis?

Bone is living, growing tissue made mostly of an organic matrix (protein collagen), bone cells and bone minerals. Bone cells consist of osteoblasts (bone forming cells) and osteoclasts (bone resorption cells). The bones that form the skeleton of the human body undergo a continuous process of modelling during childhood and adolescence. The mechanical competence of the skeleton is maintained by the process of remodelling where osteoclasts remove old bone, which is replaced by new bone formation by osteoblasts. Formation of new bones on one site, and removal of old bone at another site on the same bone, allows for bone growth and repair. During the first three decades of life there is bone growth, with relative balance occurring (under normal circumstances) between 20-40 years of age.

Peak bone mass, the point at which bones have their maximum strength, is attained at the third decade of life. With higher peak bone mass, the impact of subsequent bone loss is lessened, and therefore the risk of fracture is reduced. Bone mineral density (BMD) is often used as a surrogate measure of bone strength. Bone loss starts to occur when there is increased bone resorption that is not followed by equivalent bone formation. This bone loss gives rise to porous bones, or osteoporosis. Bone loss is often gradual and without warning signs until the disease is advanced. For this reason, osteoporosis has become known as “the silent thief”.

Osteoporosis is generally viewed as resulting from a combination of age-related, hormonal, dietary, lifestyle and genetic factors, all of which can lead to reduced bone mass. Much can be done to optimise bone mass early in life and slow/prevent bone loss later on in life.

As with other diet and lifestyle related diseases, forewarned is forearmed. Early detection can prompt people to make changes that will provide them with better long term outcomes for their bone health and mobility into old age. However, due to scientific advances in our understanding of bone health in recent decades, much of the popular wisdom regarding osteoporosis prevention is outdated and counterproductive.

For the latest in education for prevention of osteoporosis, visit OsteoHealth NZ.

Article written by Cath King based on information from “The Burden of Osteoporosis in New Zealand: 2007-2020” University of Auckland