RESUMO
OBJECTIVE: A decrease in bone mineral density (BMD) is frequently seen in patients with anorexia nervosa (AN). This study was designed to assess BMD of young Icelandic women with current or previous history of AN and identify predictors which might be targets for preventive measures. MATERIAL AND METHODS: The study was retrospective. Participants were women aged 18-40 years, with diagnosis of AN (F50.0, F50.1) attending the anorexia unit at Landspítali - The National University Hospital of Iceland - in 2001-2009, who had undergone measurement of BMD by dual-energy X-ray absorptiometry. A control group consisted of 58 healthy 30 years old women participating in a study of bone health in 2001-2003. RESULTS: At time of BMD measurement the median body mass index (BMI: kg/m2) in the AN group (n=40) was 17.4 (12.3-25.2) compared to 23.6 (18.1-43.7) in the control group (p<0,001). Lumbar spine and hip BMD were 15.3-17.5% lower in AN patients than in control subjects (p<0.001). In both groups there was a strong correlation between BMD and body weight (r=0.354-0.604, p<0.05) and lean mass (r=0.425-0.588, p<0.05). Among patients with AN a correlation was also seen between BMD and lowest weight during the illness (r=0.482-0.499, p<0.01). Among the 26 AN patients who had repeated BMD measurement, a significant decrease in BMD at femoral neck (-6.6%, p=0.030) was observed in those who lost weight between the measurements (n=9). Those who had BMI ≤17.5 between BMD measurements lost 5.5-7.1% of the BMD at the hip (p<0.05). CONCLUSION: Young women with AN have 15% lower bone mass than healthy young women. The relationship between BMD and body weight seems to be a continuum across disease states. Increased body weight may be the most important factor for recovery of bone mass in AN patients.