Osteoporosis in Men

Dr Carol Fedler - BSc(Hons) MBBCh FCPath (SA) MMed (Chem Path)

PATHCHAT NO 7: OSTEOPOROSIS IN MEN

INTRODUCTION

Osteoporosis (OP) is a systemic condition of reduced bone mass and micro-architectural deterioration of bone tissue that results in decreased bone strength and increased risk of fracture, particularly of the hip, vertebrae, forearm and pelvis. It is associated with high morbidity and mortality in postmenopausal women and men. Osteoporosis in men has been less studied than in women, despite the fact that osteoporotic fractures in men are an increasing public health problem. In developed countries, 25-30% of hip fractures occur in men; in developing countries such as South Africa, men account for 50% of all hip fractures. Indeed, osteoporosis in men is an under-recognized problem, and goes untreated in the majority of men with fractures. More men than women die within the first year after a hip fracture, with the mortality rate in men being up to 37.5%. Vertebral fractures are also common in elderly men although the incidence rates, unlike in women, decline at older ages and the rates among men >65 years old are only half those among women. The majority of vertebral fractures (70-85%) are painless and are associated with height loss, difficulty with normal daily activities (hence reduced quality of life), respiratory dysfunction, increased risk of death, and subsequent hip and other fractures.

What causes bone loss in men?

Osteoporosis in men are predominantly due to secondary causes, hypogonadism being one of the most common causes. Longitudinal studies suggest that bone loss accelerates after 70 years of age, and rapid bone loss is more common with deficient testosterone or estrogen levels. Testosterone and estrogen have roles in maintaining bone mineral density (BMD), as they aid in bone formation, and help prevent bone resorption. Thus, estrogen levels, as in women, are also important for the male skeleton; (testosterone exerts indirect effects on bone through its aromatization to estrogen). Other common causes include medications (especially corticosteroids), excessive alcohol consumption, smoking, reduced dietary intake of calcium, vitamin D deficiency and family history (Table 1). Osteoporosis is classified as either primary or idiopathic when a secondary cause cannot be found (in up to 40% cases).

Diagnosis of Osteoporosis

Bone mineral densitometry using dual energy x-ray absorptiometry (DEXA) is the current gold standard for the diagnosis of osteoporosis. The WHO criterion for osteoporosis is a BMD or bone mineral content (BMC) that is 2.5 or more standard deviations (SD) below the normal mean for young adults i.e. normal peak bone mass (or T – score < -2.5). Low bone mass (osteopenia) is defined as BMD or BMC that is more than 1.0 but less than 2.5 SD below the mean for young adults (T-score between -1.0 and -2.5).

These assigned thresholds for the diagnosis of osteoporosis and osteopenia are based on total-hip bone mineral density in postmenopausal women, but they can be applied to other anatomical sites and to men. It need to be borne in mind that the average BMD in men who fracture is higher than in women, suggesting that other factors (bone micro-architecture or trauma) may contribute to the risk of fracture more in men than in women. The use of a sex –specific T score is presently controversial, but it is recognized that if female reference ranges were used in men, the prevalence of both osteoporosis and osteopenia would be reduced by two thirds. A single BMD measurement lacks sensitivity, and the majority of fractures occur in men whose BMD values do not fall within the osteoporosis range, which limits identification of those at risk. Fractures are better predicted by taking into account clinical risk factors that contribute to fracture risk independently of BMD. A WHO working group has identified the clinical risk factors that can be used to predict the risk of fracture independently of BMD in both sexes (Refer to reference no. 6 for further details).

Read the full article here.

Username:
Display Name (Full Name):
Email:

Login

Osteoporosis in Men