Osteoporosis is among the most common reasons older adults will break a bone.  However, it’s not just a problem of older adults, and you can start early to prevent your risk of getting osteoporosis in the first place.
What is osteoporosis?
I’ve in the past explained (as one of my university instructors did!) explained bones in the way of candy bars. However, I’ve since realized that these candy bars (or chocolate bars as we call them in Canada) are less readily available in the United States than they are in Canada. So, you’ll have to bear with me (and please, suggest American alternatives I can use for explanations!).
Vastly different in their composition, Aero bars and Crunchie bars work equally well for this comparison. For those unfamiliar, a Crunchie bar may be easier to visualize: a Three Musketeers size bar of sponge toffee, dipped in a layer of milk chocolate. An Aero bar is all chocolate, but the middle part has “bubbles”. Here are some visuals (Crunchie, top; Aero, bottom).
Image from the BMJ
Now, the BMJ article states that bone structure is really oversimplified by these examples , however, I really just wanted the picture.
The inside of parts of certain larger bones are made with what is called, literally, “spongy bone” (cancellous bone). This type of bone is not dense—instead it it looks like the above photos—full of small “bubbles” or holes, that allow the bone to be strong without weighing as much as they would if they were made entirely of cortical (compact) bone. However, this does make parts of the bone that is “spongy” more prone to breakage. For instance, the upper and lower rounded bits of bones, as well as our pelvic (hip) bones, are made of cancellous (spongy) bone.
As we age, we may begin to lose bone density. Loss of bone density makes these “holes” or “bubbles” in spongy bone larger. And, you guessed it, that makes the bone weaker. This is osteoporosis: osteo meaning bone, and poro- deriving form “porous”—full of small holes. Osteoporosis is sometimes referred to as “bone loss”. We are more prone to developing osteoporosis as we get older, but fortunately, there are ways to prevent osteoporosis, too.
How can osteoporosis be prevented or treated?
You may notice that middle-aged and older women in your life take a daily vitamin D and calcium supplement—risk of osteoporosis is highest in women older than 50 and men older than 70 (among other factors). Calcium, a mineral, and the D vitamins, are indicated to be good for bone health. Supplementation is recommended by the International Osteoporosis Foundation only if you cannot get enough calcium, specifically, from foods.  Calcium rich foods include dairy products, nuts, leafy greens (such as spinach), and some fortified foods like cereals. 
And, while it may seem counterintuitive, exercise is also a great preventative AND treatment measure for osteoporosis. One of my university instructors, who has a research focus in osteoporosis, drilled into our heads that exercise that puts force on the bones is actually good for helping them “remodel” to be stronger, and decreasing fracture risk—force is provided by gravity, impact of body weight and muscle pulling on the bones (which causes movement). Activities such as running (so long as a person does not already have osteoporosis), dancing, weights, and more, put force on the bones and can help in prevention of osteoporosis. Aerobics are also a great choice for people with osteoporosis.
A quarter of women and an eighth of men over 50 are diagnosed with osteoporosis. If you have osteoporosis, follow your doctors instructions, including any exercise, medicines, or dietary changes you are to be including in your lifestyle.  Following your care plan carefully can help to prevent fractures. You may feel safest exercising with another person, and we also recommend wearing a medical ID bracelet for osteoporosis, in the event a fracture or other injury occurs.