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Anorexia Nervosa and Emphysema

We thank Drs. Stanescu and Pieters for their interest in our article (1). We agree that the Warsaw Ghetto studies and case reports should be interpreted with caution. However, the Warsaw Ghetto studies have inspired many animal model studies and investigations in humans. The animal studies have demonstrated a relationship between starvation and the development of an "emphysema-like" condition. Replication of these studies in humans is difficult because tissue samples are not available for pathologic analysis.

We also agree that the pulmonary function tests alone do not show significant differences between groups. In our study we only found evidence of a reduction in lung mass in patients with a very low body mass index (BMI). This suggests why average values were not abnormal and the correlation between BMI and lung mass for all subjects was not greater. It has been shown that in anorexia nervosa there is a reduction in maximal inspiratory and expiratory pressure that is presumably due to a concomitant decrease in diaphragmatic muscle mass without a change in lung structure (2). We chose to present the maximal inspiratory and expiratory values as absolute values because we did not have control values to compare against, although they were both within the normal range (100 ± 23% and 88 ± 39%, respectively). We chose to present the diffusing capacity as percent predicted, corrected for both hemoglobin and alveolar volume, to allow comparison to normal and to the control group. Thurlbeck concludes in his paper that the diffusing capacity has the best correlation with emphysema observed at necropsy, but suggests that a combination of functional tests must be used to infer the presence of emphysema (3).

Finally, these observations have led us to the main aim of the study, which was to attempt to measure the structure of the lung in subjects with anorexia nervosa. We disagree that CT studies have not been validated, as there have been numerous careful investigations (4–6) that have demonstrated a correlation between quantitative pathology and the structure of the lung measured using CT.

There is still much work that needs to be done to clarify a relationship between malnutrition and emphysema. However, we stand by the conclusion of our paper that there is a correlation between BMI and diffusing capacity and CT measurements of lung structure. A causal mechanism and the potential reversibility of lung pathology await elucidation. Importantly, the CT scan does provide us with a tool to help answer these questions longitudinally.

Harvey O. Coxson^a, John R. Mayo^a and C. Laird Birmingham^b

^a James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Vancouver General Hospital, Vancouver, British Columbia, Canada
^b University of British Columbia, St. Paul's Hospital, Vancouver, British Columbia, Canada

FOOTNOTES

Conflict of Interest Statement: H.O.C. received $2,500 in 2002 and £1,500 in 2003 for serving on an advisory board for GlaxoSmithKline (GSK) and in addition is the coinvestigator on two multicenter studies sponsored by GSK and has received travel expenses to attend meetings related to the project, and a percentage of salary between 2003 and 2006 ($15,000/year) derives from contract funds provided to a colleague, Peter D. Pare, by GSK for the development of validated methods to measure emphysema and airway disease using computed tomography; C.L.B. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript; J.R.M. does not have a financial relationship with a commercial entity that has an interest in the subject of this manuscript.

REFERENCES

1. Coxson HO, Chan IHT, Mayo JR, Hlynsky J, Nakano Y, Birmingham CL. Early emphysema in patients with anorexia nervosa. Am J Respir Crit Care Med 2004;170:748–752.
2. Murciano D, Rigaud D, Pingleton S, Armengaud MH, Melchior JC, Aubier M. Diaphragmatic function in severely malnourished patients with anorexia nervosa: effects of renutrition. Am J Respir Crit Care Med 1994;150:1569–1574.
3. Thurlbeck WM, Henderson JA, Fraser RG, Bates DV. Chronic obstructive lung disease: a comparison between clinical, roentgenologic, functional and morphologic criteria in chronic bronchitis, emphysema, asthma and bronchiectasis. Medicine 1970;49:81–145.
4. Müller NL, Staples CA, Miller RR, Abboud RT. "Density mask": an objective method to quantitate emphysema using computed tomography. Chest 1988;94:782–787.
5. Gould GA, MacNee W, McLean A, Warren PM, Redpath A, Best JJ, Lamb D. CT measurements of lung density in life can quantitate distal airspace enlargement—an essential defining feature of human emphysema. Am Rev Respir Dis 1988;137:380–392.
6. Gevenois PA, de Maertelaer V, De Vuyst P, Zanen J, Yernault JC. Comparison of computed density and macroscopic morphometry in pulmonary emphysema. Am J Respir Crit Care Med 1995;152:653–657.

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