Masters Degrees (Medical Physiology)

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Browsing Masters Degrees (Medical Physiology) by Author "Conradie, Maria Martha"

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    Abnormalities of bone and mineral metabolism in patients with eating disorders
    (Stellenbosch : Stellenbosch University, 2001) Conradie, Maria Martha; Hough, F. S.; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences. Division Medical Physiology.
    ENGLISH ABSTRACT: Osteopenia is a well documented complication of anorexia nervosa (AN). The pathogenesis of this bone loss is presently poorly defined in the literature. Pathogenetic mechanisms that have been implicated include certain nutritional factors, exercise abuse, hypogonadism, hypercortisolism and/or vitamin 0 deficiency. We studied, 59 Caucasian eating disorder patients aged 15-45yr. The eating disorder was classified by a single, qualified psychiatrist according to OSM IV R criteria as either anorexia nervosa (AN: n =25), bulimia nervosa (BN: n = 17) or eating disorder not otherwise specified (EONOS: n = 17). All patients were subjected to a detailed dietary and general history. We assessed the prevalence and severity (OEXA), the nature (osteocalcin, deoxypyridinoline) and site (vertebral versus hip) of osteopenla in these patients. he role of nutritional factors (energy intake, weight, height, BMI, plasma albumin, lipids), physical activity, hypercortisolemia (plasma and urinary free cortisol), vitamin 0 deficiency (plasma 250HD) and hypogonadism (amenorrhoea, E2, LH, FSH) in the pathogenesis of bone loss were also evaluated. Mild osteopenia (BMO decreased by more than 1SO below age-matched controls) was documented in 46% of the total study population, with more marked osteopenia (Z-Score < -2 SO) present in 15%. Both vertebral and hip osteopenia were documented. In the study population those patients with AN (Lumbar BMO (q/cm") = 0.869 ± 0.121) were most likely to develop osteoporosis, although a significant percentage of patients with BN (Lumbar BMO (q/crn") = 0.975 ± 0.16) and EONOS (Lumbar BMO (g/cm2) = 0.936 ± 0.10) were also osteopenic (29% and 35% respectively). Twenty four percent (24%) of the total patient population had a history of fragility fractures. These fractures were reported more commonly amongst patients with AN and EONOS (28% and29.4%). Fracture prevalence was however similar in patients with normal and low bone mass. Conventional risk factors were similar in patients with normal and low bone mass, except for a significantly longer duration of amenorrhoea (p = 0.009), a lower BMI (p = 0.0001) and greater alcohol consumption (p = 0.05) in the osteopenic patients. Nutritional parameters (S-albumin, protein, Ca, and P04 intakes), physical activity, as well as 25(OH) vitamin D levels were similar in AN and BN subjects, as well as in patients with a low versus normal BMD. Plasma and urine cortisol levels were also similar in these subgroups. With the exception of two patients with borderline osteopenia, significant bone loss was only documented in those patients with a past or current history of amenorrhoea. In the total patient population the duration of amenorrhoea was significantly (p<0.009) longer in patients with osteopenia versus those with a normal bone mass. A significant negative correlation between BMD (Z-Score) and duration of amenorrhoea was also documented in the total patient population (r = -0.4, P = 0.001) as well as in all three eating disorder groups (AN r - -0.4, P = 0.03; BN r = - 0.6, P = 0.008; EDNOS r = -0.6, P = 0.005). In the total patient population, those patients with amenorrhoea, had lower BMD and BMI values and lower estrogen levels compared to those with a normal menstrual cycle. We conclude that osteopenia commonly attends AN, as well as BN and EDNOS. Nutritional (with the exception of alcohol consumption) and mechanical factors as well as hypercortisolemia did not appear to contribute significantly to bone loss in this study population. Hypogonadism appeared to be the main cause of the bone loss observed in these patients.