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Dem bones, dem bones
Where would we be without our bones? Just a sack of skin puddled on the floor, that’s what. So it’s important to look after them — especially if you’re living with HIV. Studies suggest people with HIV have significantly lower bone mineral density (BMD) than their negative peers. But having some knowledge of the causes of decreased BMD — plus an idea of some of the steps you can take to minimise damage — can help you maintain healthy bones.
First up, Bones 101. Bone is living tissue that — much like the kidneys —has remarkable regenerative qualities. The two key components of bone are collagen and mineral. Collagen allows our bones their malleability, while the mineral elements harden the collagen so that the bones are strong and able to withstand physical stress. Peak bone mass is reached at around the age of 30, after that, our bone density is on the decline.
Low BMD is of particular concern as it can lead to osteoporosis — the most common bone condition in Australia. There are two types of osteoporosis: primary — one that occurs in both men and women at any age (but usually follows menopause in women and presents later in life in men); and secondary — occurring in people who take medications and/or have a disease that can cause decreased bone density (such as HIV and some of the drugs to treat it).
Dubbed the “silent disease”, osteoporosis is rarely accompanied by any symptoms. Indeed, many people are unaware they have the condition until they suffer a bone fracture. While the greatest risk of fracture occurs in the wrist, hip or spine, any bone in the body is more likely to fracture in someone who has osteoporosis.
BMD tests (a DXA scan) are the only way to detect osteoporosis. Scans are advised for all HIV-positive menopausal women, and for HIV-positive men aged 50 years or older. The risk of developing low BMD and osteoporosis increases with the length of time someone has been living with HIV. As age is a major factor of developing osteoporosis, older people living with HIV are particularly at risk of developing the condition. As well as osteoporosis, there are a number of other bone disorders associated with HIV including osteomalacia (softening of the bones), osteopenia (a weakening of the bones) and osteonecrosis (death of blood tissue due to reduced blood supply).
There are two categories of risk factors for low BMD: controllable and uncontrollable. Those factors out of your control include the ageing process, gender, being menopausal, being thin or small, race, and genetics. Factors within your control include insufficient levels of calcium and vitamin D; low intake of fruit and veg; too much protein, sodium and caffeine; lack of exercise; too much alcohol; and smoking. As mentioned, also in play for a positive person are some antiretroviral treatments. Early tenofovir-based anti-HIV drugs, and some protease inhibitors, have long been associated with bone loss, for example, though why is not fully understood.
Then there is the HIV itself. Studies comparing the incidence rates of fractures among people with HIV and their negative peers have found fracture rates to be significantly higher among the positive population. The reasons for this are not entirely clear, although there are a number of theories as to why: HIV can increase certain proteins in the body that have been found to accelerate bone loss; it’s thought that a positive person’s heightened T-cell activity may have an adverse effect on the bones; some researchers have also speculated that HIV’s ability to infect cells in the bone marrow may be to blame for bone loss. Another HIV-related risk factor is hepatitis C coinfection. Observational studies have found that hep C is a very strong additional risk factor for fractures in people living with HIV.
So how best to minimise the risk of developing low BMD? Controlling body weight, quitting smoking and moderating alcohol consumption, are all important steps to take for people at high risk of low BMD. As is soaking up the sunshine. Regular bone screenings for HIV-positive people aged 50-plus is also recommended. And both weight-bearing exercises and resistance exercises are helpful in maintaining and increasing bone density and strength. (Weight-bearing exercises include any activity that forces your muscles and bones to work against gravity such as running, jogging, walking, and stair climbing; while resistant exercises include weight lifting.)
And finally, rich sources of calcium (cheese, yogurt, seafood, dried fruit, leafy greens and tofu), vitamin D (fatty fish, orange juice, soy milk, cheese and egg yolks) and phosphorus (poultry, fish, nuts, beans and dairy products) are all dietary steps you can take to ensure dem bones stay strong and healthy for longer.
For more tips head to Healthy Bones Australia