Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 340

Bone loss, nutrition, and healthy ageing

Оглавление

Bone loss commences around age 40 and then averages between 0.5 and 1% per year in men. Women have accelerated bone loss around menopause ranging from about 2% per year. Bone mineral density (BMD) loss of 2.5 SD below the mean for younger adults is considered osteoporosis by WHO criteria.14 Osteoporosis is a multifactorial disease characterized as ‘a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fractures’. Both environmental and genetic factors play an important role in the risk, prevention, and progression of osteoporosis. The prevalence of osteoporosis varies widely by geographic and enthno‐racial strata. For instance, the NHANES III study15 showed that low BMD is most common among elderly non‐Hispanic white women (21% osteoporosis) and Mexican American women (20% osteoporosis) and lower in non‐Hispanic black women (18%). In Europe, it is estimated that 179,000 men and 611,000 women suffer a hip fracture every year, and these numbers are expected to double in the next 40 years.16,17

Although a low percentage of variance in the bone mass is attributable to nutritional factors (<20%), it can still have a significant impact. The benefits of supplementing populations at risk for osteoporosis with vitamin D and calcium are well established in studies with endpoints such as effects on BMD, bone turnover, and a reduced risk of fractures without side effects. The vitamin D requirement may be higher in regions where calcium intake is low. Vitamin D also has a beneficial effect on the risk of falling, explained by improved muscle function. Evidence for associations between optimal protein intake and bone mass is diverse, with positive, negative, and no associations all having been found. Other dietary factors such as vitamin K, vitamin A, caffeine, fluoride, phosphorus, strontium, and zinc are also under investigation and hotly debated for promotion of bone health.18

Pathy's Principles and Practice of Geriatric Medicine

Подняться наверх