Bone Mineral Density after Weight Gain in 160 Patients with Anorexia Nervosa

Abstract

Low bone mineral density (BMD) is a frequent complication in anorexia nervosa (AN). There are controversial points of views regarding the restoration of bone mineralization after recovery in AN. We aimed to assess changes of BMD at 3 years in patients with AN and to explore the relationships between body composition, physical activity, and BMD. Patients with AN were included from 2009 to 2011 in a first visit (T0) with evaluation of weight, height, body mass index (BMI), body composition [fat mass (FM) and fat-free mass], and BMD. Those who had low BMD, either osteoporosis or osteopenia, were admitted in a second visit (T1) to carry out a new bone densitometry examination and body composition; they were also asked for their physical activity. At T0, our study involved 160 patients. Low BMD was observed in 53.6% of them and significant factors associated with demineralization were lower BMIs (16.5 ± 2.1 vs 17.3 ± 2.3 kg/m2, p = 0.01) and higher duration of AN (11.4 ± 10.5 vs 6.4 ± 6.5 years, p = 0.001). At 3 years follow-up (T1), 42 patients were involved and no significant changes in BMD were observed despite body weight increase (3.8 ± 6.1 kg). Interestingly, FM gain was a significant factor associated with BMD improvement at follow-up (8.0 ± 9.1 vs 3.0 ± 3.5 kg, p = 0.02). Our findings suggest that the restoration of normal bone values is not related to the increase of body weight, at least after 3 years. FM seems to play an important role in the pathophysiological mechanism of osteoporosis and osteopenia in AN.

Association between Body Mass Index and Bone Mineral Density in Patients Referred for Dual-Energy X-Ray Absorptiometry Scan in INMAS, Sylhet

“…In this study, more than half of the population exhibited low BMD either osteopenia or osteoporosis. This finding is in accordance with previous studies (6,7). Arround 61.2% and 26.3 % showed low BMD in lumbar spine and right femur respectively, indicating that low BMD was more prevalent in lumbar spine.…”

Body composition and resting energy expenditure in women with anorexia nervosa: Is hyperactivity a protecting factor?

“…Altogether, our results confirm previous indication on the protective effect of physical exercise in some patients with AN and suggests that that in recovery from AN, exercise (under strict supervision) may be beneficial 25 27 . In subjects with AN, positive effects of physical activity have been described on exercise capacity 28 , muscle strength 29 and restoration of lean body mass, but it remains unclear whether physical activity helps in maintaining bone mineral density 30 . Also, physical exercise increases circulating myokine levels, which have proved to provide beneficial metabolic effects on endothelial function 31 .…”

Bone mineral density at extremely low weight in patients with anorexia nervosa

“…On average, participants were older and more severe compared with previous studies on this subject. 8,[24][25][26] The prevalence of low BMD at lumbar spine was 51% with an average Z-score of −2.2 SD. Pre-existing research reports lower prevalence rates, ranging from 21% to 40% depending on population age and diagnostic criteria (T-scores vs Z-scores).…”