Young cancer survivors have lower bone mineral density compared with healthy controls: a nationwide population-based study in Korea

Direct effects of cancer cells and various cancer treatments can cause bone loss in cancer survivors. The aim of this study was to assess the risk of bone loss in Korean cancer survivors, and the relationship between body composition and bone mineral density (BMD). We hypothesized that cancer survivors would have lower BMD than healthy people, and increased muscle mass has a protective effect on BMD. We measured BMD and body composition in 259 cancer survivors (99 men and 160 women). Subjects were selected from the Korean National Health and Nutrition Survey conducted from 2008 to 2011. Body composition and BMD were measured by dual-energy X-ray absorptiometry. We examined the linear trend of lumbar BMD according to tertiles of lean mass (LM) and fat mass (FM) by linear regression, adjusting for age, alcohol consumption, smoking, exercise, 25-hydroxyvitamin D, height, protein intake, and menopausal status. Cancer survivors under 50 years of age had lower lumbar BMD compared with healthy controls (0.93 ± 0.04 g/cm(2) vs. 1.02 ± 0.01 g/cm(2), p = 0.032 in males; 0.95 ± 0.02 g/cm(2) vs. 0.98 ± 0.01 g/cm(2), p = 0.015 in females). Lumbar BMD significantly increased from the lowest to highest tertiles of LM in male (p for trend < 0.001) and marginally significantly increased in female survivors (p for trend = 0.060). In this study of Korean cancer survivors, young survivors were at higher risk of having low lumbar BMD. Higher LM had beneficial effects on BMD in cancer survivors. To prevent osteoporosis and fractures, efforts to increase lean body mass, including bone, are needed for young cancer survivors.