Physical fitness, bone mineral density and associations with physical activity in females with longstanding eating disorders and non-clinical controls.

AIM: To examine (i) aerobic fitness, muscular strength, and bone mineral density (BMD) in female inpatients with longstanding eating disorders and non-clinical controls, and (ii) associated and explanatory factors for BMD among the inpatients.

METHODS

Adult females with DSM-IV anorexia nervosa (AN), bulimia nervosa (BN) or eating disorders not otherwise specified (EDNOS) (n=59, mean(SD) age 30.1(8.5) yrs and ED duration 14.3 yrs) and non-clinical age-matched controls (n=53, mean(SD) age 31.3(8.3) yrs) accepted participation in this cross-sectional study. Measurements included accelerometer assessed and self reported amount of different types of physical activities, VO2max on treadmill, 1RM in leg and chest press, and BMD in lumbar spine (L2-L4), femur neck and total body analyzed by DXA.

RESULTS

Muscular strength and BMD were lower in patients with AN, not in patients with BN or EDNOS, compared to controls. Aerobic fitness did not differ between patients and controls. BMD in the patients was positively associated with body weight, muscular strength and self reported high impact PA (min.w-1), not self reported general weight-bearing PA (min.w-1) or accelerometer assessed PA (counts.min). History of AN (28%) and muscular strength (9%) contributed significantly to explain the variance in total body BMD.

CONCLUSION

Muscular strength and only high impact PA are associated with BMD in patients with longstanding ED. An implication of this is the need for more specific guidelines regarding types of PA recommended for this patient population. Special considerations should be made for severely malnourished patients, and for patients with osteoporosis.