Lung function study and diffusion capacity in anorexia nervosa

In humans, malnutrition alters the respiratory system in different ways. It impairs the ventilatory drive, decreases respiratory muscle strength and reduces immune competence. In addition, typical emphysema-like changes were demonstrated in starved animals. The presence of emphysema has never been demonstrated in starved humans. Our objective was to investigate whether pulmonary emphysema occurs in anorexia nervosa by means of a pulmonary function study.

We examined 24 women aged between 14 and 38 years (nine smokers). We studied the lung function including lung volumes, ventilatory capacity, maximal respiratory pressures and transfer factor, as well as PaO2.

All respiratory tests were within normal limits with the exception of decreased maximal inspiratory (59% of predicted values) and expiratory pressures (35%), and increased residual volume (162%). Diffusion capacity (98.1 +/- 16.2%) and transfer coefficient (98.4 +/- 16.2%) were also normal. The diffusion coefficient was lower in current smokers than in those who had never smoked (P < 0.01), a difference similar to that calculated from existing reference values for transfer factor for smokers and nonsmokers.

In anorexia nervosa, pulmonary function tests are within normal limits with the exception of maximal pressures and residual volume. Diffusion capacity is not decreased. The present results within the limitations of the used method are not compatible with the hypothesis of starvation-induced pulmonary emphysema.