Volume 91, Issue 6, June (2004), pp. 959-969 © The Author 2004
doi:10.1079/BJN20041151

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Lipoprotein metabolism in patients with anorexia nervosa: a case–control study investigating the mechanisms leading to hypercholesterolaemia

T. Weinbrenner¹, M. Züger⁴, G. E. Jacoby⁴, S. Herpertz⁵, R. Liedtke², T. Sudhop¹, I. Gouni-Berthold³, M. Axelson⁶ and H. K. Berthold^1
1Department of Clinical Pharmacology,
²Clinic and Policlinic for Psychosomatic Medicine and Psychotherapy, and
³Medical Policlinic, University of Bonn, 53105 , Bonn, Germany
⁴Clinic Am Korso, 32545 Bad Oeynhausen, Germany
⁵Clinic for Psychotherapy and Psychosomatic Medicine, University of Essen, 45147 , Essen, Germany
⁶Department of Clinical Chemistry, Karolinska Hospital, 17176 , Stockholm, Sweden

 (Received 1 April 2003–Revised 8 December 2003–Accepted 13 February 2004)

Hypercholesterolaemia is a common finding in patients with anorexia nervosa (AN). To investigate the type, frequency and pathophysiological mechanisms of changes in lipoprotein metabolism in AN we performed a cross-sectional study in fifty-eight female patients (mean age 24·2 years, BMI 15·3 (sd 1·5) kg/m²) and fifty-eight healthy age-matched controls (CO; BMI 22·2 (sd 1·7) kg/m²). Total cholesterol and LDL-cholesterol were higher in AN (5·5 (sd 1·3) v. 5·0 (sd 0·8) mmol/l, P=0·023; 3·6 (sd 1·1) v. 3·2 (sd 0·7) mmol/l, P=0·025 respectively). LDL particles were significantly more enriched in cholesterol and triacylglycerol in AN. In multiple regression analysis with LDL-cholesterol as the dependent and BMI, total body fat ( %), lathosterol:cholesterol ratio (endogenous cholesterol synthesis), 7α-hydroxy-4-cholesten-3-one (bile acid synthesis), non-esterified glycerol, free triiodothyronine and free thyroxine as independent variables, BMI was the only significant predictor in CO (R² 0·36, overall P=0·001). In AN the variability of LDL-cholesterol was significantly predicted by total body fat, free thyroxine, BMI, free triiodothyronine and non-esterified glycerol (R² 0·55, overall P<0·001). Subgroup analysis between restricting (AN-R) and binge-eating–purging patients (AN-B) indicated that in AN-R changes in lipoproteins, BMI and total body fat were more pronounced. AN-R patients had lower bile acid synthesis than AN-B (P=0·02). We conclude that elevated cholesterol concentrations in AN are generally due to an increase in LDL-cholesterol, which is mostly determined by the severe loss of body fat and the resulting changes in thyroid hormones, increased lipolysis and decreased endogenous cholesterol synthesis with resulting decrease in LDL removal. The clinical subtype of AN plays a major role in the mechanisms leading to hypercholesterolaemia.

Keywords:
Anorexia nervosa, Lipoprotein metabolism, Hypercholesterolaemia

Abbreviations:
AN, anorexia nervosa, AN-B, binge eating–purging type of anorexia nervosa, AN-R, restricting type of anorexia nervosa, Chol, cholesterol, CO, healthy control subjects, TBF, total body fat, T3, triiodothyronine, T4, thyroxine, TG, triacylglycerol, 7α-HCO, 7α-hydroxy-4-cholesten-3-one