Summer is just about over and I hope you found time away to be outside, exposed to sun with those who help your being. The last Menopause Matters addressed sunlight’s role in synthesizing vitamin D and its important role in bone health. Since then, I have attended a two-day UC San Francisco conference, (out of the sun) on bone remodeling and will spend the next few columns sharing new insights.
Why care about bone health and in particular, osteoporosis? Well, it depends on the age of the person you ask. Young women should care and know that peak bone strength (the strongest your bones will ever be) is typically reached by their late 30’s. By age 80, many women have lost, on average, 30% of their peak bone mass. This is why age matters. Variables including menstrual regularity, relative amount of exercise, intake of calcium and exposure to sunlight (Vit D), and the age of menopause play a role in bone strength over a women’s lifetime. The bone built earlier in a women’s life will pay dividends over her entire life.
Osteoporosis, typically diagnosed after a woman’s menstrual period has stopped for 12 months (menopause), is a silent skeletal disorder characterized by compromised bone strength and bone quality, both predisposing a woman to an increased risk of fracture. Bone strength is typically assessed with low dose x-ray called a DEXA scan. DEXA scan is a measure of bone quantity (bone mineral density = BMD) and is currently the best measure of risk for osteoporotic fracture. Investigational studies are underway looking at how to assess bone quality but none are currently used to assess risk.
Why care about osteoporosis? It’s more common than one would think. UCSF faculty reviewed the prevalence (just how common) of osteoporosis whose numbers shocked me. The National Osteoporosis Foundation (NOF) estimates that 9.9 million United States citizens have osteoporosis and 43 million have low bone density, both risk factors for fracture. Most cases of osteoporosis occur in postmenopausal women and the prevalence rises from 19% in women aged 65-74 to more than 50% in women 85 years and older. In the US, rates of osteoporosis and fracture vary with ethnicity. After adjusting for weight, BMD, and other covariates, whites and Hispanics had the largest risk for osteoporotic fracture, followed by Native Americans, and African Americans.
Osteoporotic fractures often do not make the headlines, consequently are under appreciated as to just how common relative to other diagnoses they occur. The annual incidence x 1000 US women of osteoporotic fractures is 1.5 million, compared to 513,000 heart attacks, 220,000 strokes, and 184,300 cases of breast cancer. In women 50 years and older, the lifetime risk of clinical fracture is 20% compared to risk of breast cancer of 15%. Age is an independent risk for hip fracture, in that there is greater than a 5-fold increase in fracture probability from age 50 to 80, independent of bone mineral density.
What happens when osteoporosis leads to a fracture? Consequences of fractures are also under appreciated as they are associated with increased morbidity and mortality. One year after hip fracture: 20% of patients will die, 30% will have permanent disability, 40% will be unable to walk independently, and 50% will no longer be able to live independently. Most importantly is that when you have had one fracture you are 4x more likely to have another vertebral fractures (associated with spine deformity & height loss, acute and chronic pain, diminished quality of life) and 2x more likely for another hip fracture. Not living independently ranks as one of the highest concerns shared by persons over age 65 and compromised bone health can play a major role in a person’s independence. That is why bone health matters!
Future columns will briefly touch on the broad categories of both preventative (fall prevention) and pharmacologic treatment options. I will put some of the fears of treatment into perspective with their very known significant benefits. For now, know that bone health matters and that regular moderate weight-bearing and strength-training exercise, moderate alcohol consumption, daily calcium 1200 mg and Vit. D 800-1000 units, assessing fall risk, and not smoking are lifestyle factors that can help you live long and independent.