Women with 'Constitutional Thinness' Have Bone Problems
New phenotype has bone density similar to anorexics but no hormonal or nutritional causalities
MONDAY, Nov. 19 (HealthDay News) -- Young adult women who fit the diagnostic criteria for constitutional thinness have a bone mineral density similar to that of young women with anorexia nervosa and significantly lower than that of normal weight women, researchers report in the December issue of the Journal of Clinical Endocrinology & Metabolism.
Bogdan Galusca, of CHU Saint Etienne, France, and colleagues assessed 25 women diagnosed as constitutionally thin, 44 women diagnosed as anorexic and 28 normal-weight controls, all 18 to 30 years old. Constitutionally thin subjects fit the World Health Organization classification of "severe underweight" with a body mass index between 12 and 16.5 kg/m2. They menstruated without hormone therapy.
A high prevalence of women in the constitutionally thin group had low bone mass (44 percent) characterized by normal bone turnover, high OPG/RANKL ratio, small bone size, and selective bone structural impairment, primarily in weight-bearing skeletal regions. Women in the constitutionally thin group had higher percentages of fat mass than women in the anorexic group but similar bone mineral mass.
"The low bone mass and overall bone size reduction in constitutional thinness associated with normal hormonal parameters led us to hypothesize a genetic causality," the authors write."