16. Epidemiology of Osteoporosis

A young healthy adult can hardly imagine that he/she will ever suffer from osteoporosis. Moreover, when an older individual sustains a fracture or notices a gradual decrease in height, the first reaction is: “This cannot be true, this can’t be happening to me. Why should I have osteoporosis? I never had a single problem with my bones in all my life!” And that is just the problem! Osteoporosis slowly but surely nibbles away at the bones, possibly unnoticed for years, until finally it is exposed by the occurrence of a fracture almost without cause! Osteoporosis: a silent thief! And so the vicious cycle begins, and the patient is suddenly confronted by many psychological, social and possibly financial problems, which at times may appear overwhelming: starting from the fracture itself, leading to pain, possibly deformities, anger, anxiety, frustration, depression, loss of self-esteem, decreased mobility and finally even social isolation. One of the most appropriate and effective sources of help is the local osteoporosis support group, where patients can learn from other patients who have had a similar experience how best to cope with their new challenges. Unfortunately, many people who are at risk are unaware of it, and have not yet adopted preventive measures or received treatment. Some estimates suggest that less than 30 % of women with osteopenia/osteoporosis are correctly diagnosed, and less than 15 % of those diagnosed receive treatment for prevention in cases of ; or for therapy in established osteoporosis. The situation is even worse for men, because it has only recently been recognised that osteoporosis has no gender discrimination – it only attacks men later than women, that is, at the time of the andropause when the levels of male hormones start to decrease and androgen deficiency occurs, from about 50 to 60 years of age onwards. It has now been calculated that men >50 years have a 13 % lifetime risk for fractures! Regrettably, some doctors still regard osteoporosis as a “normal” aspect of ageing, a process whereby organisms gradually “lose the capacity to deal with life’s stresses effectively”. These changes may affect the structure of individual cells and their constituents such as mitochondria, as well as changes in the cytokines and other factors the cells produce. However, many of these mechanisms can be favourably influenced by outside interventions! The purpose of the following sections is to unmask the bone robbers and to provide guidelines for early prevention, correct diagnosis and successful treatment of osteoporosis. Today many in the medical profession and in health-care authorities have come to the realisation that osteoporosis can affect everybody from newborn babies to the oldest old and, significantly, that both sexes are equally prone and vulnerable, and under similar conditions, the difference is mainly a temporal one! An estimated 44 million people suffer from osteoporosis in the USA alone; 1.5 million fragility fractures were occurring each year and equally high percentages of the populations in many other countries in the Americas, in Europe and in Asia. Moreover, it has been estimated that the numbers of people with osteoporosis in the USA will increase to 61 million by the year 2020. Other calculations claim that there are already over 200 million osteoporotic people in the world today: one in three women and one in eight men! Fracture of a bone is the most significant consequence of osteoporosis. For comparison, while every eighth woman suffers from breast cancer, every third woman sustains a fracture due to osteoporosis. Although osteoporosis can attack any bone in the body, the typical sites of osteoporotic fractures are the hip, the spine and the wrist. 70 % of the fractures that occur annually in the USA in patients aged more than 45 years are attributable to osteoporosis. From the age of 50 years onwards, a woman has the following risk for a fracture: Vertebral 32 % Lower arm 16 % Hip 15 % Furthermore, a hip fracture poses an increased risk of mortality (Fig.16.1a, b) related to possible co-morbidities such as rheumatism, chronic cardiovascular disease, stroke, chronic lung disorders, as well as the complications secondary to surgical treatment of the fracture itself. Fig. 16.1 (a) Risk of mortality following clinical fractures (Modified from Cauley et al. 2000). (b) Risk of mortality in the pre- and post-fracture situation × Nearly 50 % of the patients with hip fractures never fully recover the mobility and the independence they previously had, and an additional 25 % require a long-term nursing facility or home care. Mortality after a hip fracture is estimated to range from 12 to 35 % which is higher than that expected in the general population. The highest mortality typically occurs within the first 6 months after a fracture, but some studies have shown a sustained effect over a longer period. It has been estimated that the respective figures for men are worse than these given for women. Monetary costs associated with osteoporotic fractures are tremendous: about 40 million US dollars daily in the USA. The total cost for medical and hospital expenses, possibly nursing home care, and lost productivity reached 17 billion US dollars in 2005 (Fig. 16.2a, b)! Hip fractures alone account for about 60 % of these costs, and fractures at other sites about 40 %. Fig. 16.2 (a) Fracture distribution by type in the USA, 2005. (b) Cost distribution by type in the USA, 2005 (Modified from Burge et al. 2007) × Global demographic changes are expected to increase the incidence of hip fractures nearly fourfold by the year 2050. Each year, osteoporotic fractures affect more women than heart attacks, strokes and breast cancer combined. Indeed, the economic costs of osteoporosis are as significant as those of chronic obstructive pulmonary disease, myocardial infarction, strokes and breast cancer. Another highly significant aspect of osteoporosis is the fact that numerous disorders in most medical disciplines have deleterious effects on the bones, primarily involving osteoporosis. Examples of some such conditions are infections and inflammatory disorders, e.g. AIDS and inflammatory bowel disease, cardiovascular disorders, diabetes mellitus and the metabolic syndrome and neurologic conditions such as Parkinson’s disease and epilepsy. Cancers of the breast, prostate, lung and colon, congenital disorders such as osteogenesis imperfecta and interdisciplinary causes such as effects of drugs – a notable example are the glucocorticoids – and last but not least transplantations of cells and of organs all may be associated, directly or indirectly, with decrease in bone mass and bone density. In this context, it should also be stressed that metabolic conditions that cause intrinsic biochemical alterations and thereby also damage the bones have initiated the concept and the classification of metabolic bone diseases. Included under this heading are rickets (osteomalacia), renal osteodystrophy, hyperparathyroidism and osteoporosis.

Medicine Matters Rheumatology

16. Epidemiology of Osteoporosis

Abstract