Osteoporosis and HIV

Abstract

Osteoporosis poses a significant public health issue, causing significant morbidity and mortality. It is a disease of bone that leads to an increased fracture risk through a reduction in the bone mineral density (BMD), disruption of bone microarchitecture, and alteration of the amount and variety of non-collagenous proteins in bone. The treatment aims of this condition are to prevent fractures and maintain the quality of life of the aging adult. Approximately three million people in the UK have osteoporosis, and every year more than 230,000 fractures occur because of it. One in two women and one in five men over the age of 50 will have a fracture mainly as a result of the condition, and therefore, osteoporotic fractures are of great importance to patient and clinician. As the HIV-infected population continues to live longer, due to the advent of highly active anti-retroviral therapy (HAART), osteopenia and osteoporosis are becoming more common metabolic complications in the aging adult with HIV [1]. Certain lifestyle and hormonal factors, which increase the risk of disordered bone metabolism, are prevalent in HIV-infected patients. These include physical inactivity, suboptimal intake of calcium and Vitamin D, cigarette smoking, alcohol and opiate use, depression, and low testosterone levels. HAART itself may be associated with decreased BMD [2–5]. Although prevalence estimates of low BMD vary considerably, most studies indicate an increased risk in HIVinfected individuals. In a meta-analysis by Brown et al. [2], 20 cross-sectional studies were reviewed and it was demonstrated that 67 % of 884 HIV patients had reduced BMD and 15 % fulfilled the diagnostic criteria for osteoporosis. Similar findings were noted by Cazanave et al. [3] in a cross-sectional survey of 492 HIV patients within the Aquitaine cohort, which involved analysis of BMD of total body, lumbar spine, and femoral neck regions. Cazanave et al. reported osteopenia in 55 % of men and 51 % of women, along with osteoporosis in 34 and 8 %, respectively. Variations between sexes are being explained by age differences and cigarette use. More recent publications by Mallon [4] and Calmy et al. [5] report similar correlations between low BMD and HIV positive status among Irish and Australian patients, respectively. Low BMD among patients with HIV infection is usually multifactorial, since weight loss, malnutrition, malabsorption (leading to vitamin D deficiency), and hypogonadism may be present. HIV infection itself may cause chronic T cell activation and increased production of proinflammatory cytokines that enhance osteoclast activity [6]. Traditional risk factors for bone loss such as female gender, low body mass index (BMI), physical inactivity, steroid use, advanced age, duration of menopause, smoking, and injection drug use may act in concert with HIV-associated risk factors. In addition, the importance of the status of reproductive function was highlighted by a study of 84 normal-weight, HIV-infected women, which reported reduced bone density among women with oligomenorrhea or elevated follicle-stimulating hormone (FSH) levels compared to women with normal menses. Studies have been conducted to determine the effects of HAART and individual anti-retroviral agents or medication classes on bone loss in HIV-infected patients. In a metaanalysis of ten studies comparing HAART-naive (n = 202) with HAART-treated (n = 824) patients, there was a 2.5M. B. O’Connor (&) Department of Rheumatology, South Infirmary Victoria University Hospital, Old Blackrock Road, Cork, Ireland e-mail: mortimeroconnor@gmail.com