The effect of anorexia nervosa on skin thickness, skin collagen and bone density.

The effects of anorexia nervosa on skin thickness, skin collagen content and bone density were investigated in a cross-sectional study of 36 women with anorexia nervosa with a 4-year median duration of amenorrhoea and compared with a group of 33 women of comparable age without anorexia and with normal periods. The median skin thickness, assessed radiologically, was significantly reduced (P less than 0.01) from 0.88 mm in the comparison group to 0.70 mm in the anorectic group and the median collagen content was significantly reduced from 209 micrograms/mm2 in the comparison group to 164 micrograms/mm2 in the anorectic group (P less than 0.05). The median bone density in the comparison group was 0.93 gHA/cm2 at the lumbar spine and 0.84 gHA/cm2 at the proximal femur. These values were greatly reduced in the women with anorexia nervosa to 0.77 gHA/cm2 and 0.65 gHA/cm2 respectively (P less than 0.01). Our findings confirm the loss of bone mass with anorexia and demonstrate the coexistent loss of skin thickness and skin collagen content. This association supports the hypothesis that a generalized loss of collagen is a major factor in the causation of osteoporosis following oestrogen deficiency.