Although osteoporosis is a progressive bone disease leading to increased risk of fracture, it has rarely been investigated on a large scale in older people with intellectual disabilities (ID). In this study, 768 persons with ID (aged ≥ 50 years) were measured with quantitative ultrasound to determine the prevalence of low bone quality. The association of low bone quality with patient characteristics, mobility, physical activity, body mass index (BMI), prior fractures, anticonvulsant drug use, intake of calcium, and vitamin D3 levels was also investigated. The prevalence of low bone quality was 43.9%. Low bone quality was positively associated with female gender, age, more severe level of ID, mobility impairment, and anticonvulsant drug use, and negatively with BMI. In clinical practice, people with ID who are at risk for low bone quality should periodically be screened for osteoporosis and be given advice about nutritional supplements and appropriate lifestyle.
Osteoporosis is a disease characterized by low bone mineral density (BMD), leading to an increase in fracture risk and, as a consequence, an increased risk of pain, deformity, loss of mobility, and independence. In the general population, osteoporosis is particularly common among older people. In the Netherlands, the prevalence of osteoporosis increases from 1.1% among men aged 45–64 years to 8.6% among men aged ≥ 75 years, and from 8.5% among women aged 45–64 years to 42.3% among women aged ≥ 75 years (Van der Linden, Westert, De Bakker, & Schellevis, 2004). In people with intellectual disabilities (ID), osteoporosis is also highly prevalent. Prevalence rates vary up to 78.5% depending on the population of interest (Center et al., 1998, Haveman et al., 2011, Jaffe and Timell, 2003, Jaffe et al., 2001 and Leslie et al., 2009Mergler et al., 2009, Srikanth et al., 2011 and Zylstra et al., 2008). For older people with ID, it is assumed that the prevalence of osteoporosis is even higher than in the general older population due to a combination of age-related and ID-related risk factors for this disease. Remarkably, osteoporosis has rarely been studied on a large scale in this specific population. Therefore, the present study investigates the prevalence of osteoporosis and its associated factors in older people with ID.
In the general population, a low vitamin D3 serum level, chronic malnutrition, and physical inactivity are associated with a low BMD, apart from the known risk factors in the ID population (Espallargues et al., 2001). The risk factors for the latter group have been examined in different populations. In adults with ID living in a residential facility, female sex, immobility, use of anticonvulsant drugs, and a more severe level of ID were found to be risk factors for low BMD (Jaffe, Timell, Elolia, & Thatcher, 2005). Leslie et al. (2009) confirmed immobility as an associated factor for osteoporosis in institutionalized adults with ID, together with a low body mass index (BMI) and prior fractures. In a study among 94 young adults with ID living in the community, Down syndrome (DS) was associated with low BMD (Center et al., 1998). However, information about risk factors in the heterogeneous group of older people with ID living inside or outside the institutions is currently lacking.
