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Abnormalities of bone and mineral metabolism in patients with eating disorders

Thesis (MScMedSc) -- Stellenbosch University, 2001. / 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. / AFRIKAANSE OPSOMMING: Osteopenie is In welbekende komplikasie van anorexia nervosa (AN). Die
patogenese van hierdie beenverlies is swak in die huidige literatuur omskryf en
nutrisiele faktore, 'n vita mien 0 gebrek, oormatige oefening, hiperkortisolemie en
hipogonadisme word onder andere qeimpliseer.
Vir die doel van die studie is In totaal van 59 Kaukasier eetsteurnis pasiente
patients volledig ondersoek. Die tipe eetsteurnis is deur In enkel gekwalifiseerde
psigiater volgens die DSM IV R kriteria geklassifiseer as anorexia nervosa (AN: n
=25) of bulimia nervosa (BN: n = 17) of eetsteurnis nie anders gespesifiseer
(EDNOS: n = 17). Elke pasient is ook aan In gedetailleerde dieet en algemene
risikofaktor vraelys vir osteoporose onderwerp. Die voorkoms en graad (DEXA),
die aard (osteokalsien, deoksipiridinolien) asook die tipe (werwelkolom/heup)
osteopenie is ondersoek. Die rol van nutrisiele faktore (totale kalorie-inmame,
gewig ,Iente LMI, plasma albumien, lipiede) en vitamien 0 gebrek, oefening,
hiperkortisolemie (plasma en urinere kortisol) en hipogonadisme (amenoree,
plasma E2, LH,FSH) in die patogenese van die beenverlies is ook evalueer.
Matige osteopenie (BMD meer as 1 SO onder die van ouderdomskontrole) is in
46% van die totale pasientpopulasie gedokumenteer, met erge osteopenie
(Z-Telling < -2) in 15%. Aantasting van beide werwelkolom en heup is
aangetoon. In hierdie studiepopulasie kom osteopenie meer algemeen voor in
die AN (Lumbaal BMD (g/cm2) = 0.869 ± 0.121) groep (64%) in vergelyking met
BN (Lumbaal BMD (g/cm2) = 0.975 ± 0.16) (29%) en (EDNOS) (Lumbaal BMD
(g/cm2) = 0.936 ± 0.10) (32%). Vier-en-twintig persent van die totale
pasientpopulasie het In geskiedenis van frakture gehad. Frakture het meer
algemeen in AN en EDNOS pasiente voorgekom (28% en 29%).
Pasiente met 'n lae beenmassa was gekenmerk deur In betekenisvolle laer LMI
(p = 0.0001), hoer alkolholverbruik (p = 0.05) en langer duurte van amenoree(p = 0.009). Nutrisiele parameters (s-albumien, protetene, Ca, P04 inname)
oefening, asook 25(OH) vitamien 0 vlakke was soortgelyk in AN en BN pasiente.
Hierdie parameters het ook nie verskil tussen pasiente met osteopenie en die
met In normale BMD nie. Plasma en urinere vry kortisolvlakke was ook
soortgelyk in hierdie twee groepe.
Betekenisvolle beenverlies (met die uitsondering van twee pasiente met grenslyn
osteopenie) het slegs voorgekom in pasiete met 'n huidige of In vorige
geskiedenis van amenoree. In die totale pasientpopulasie was die duurte van
amenoree (p< 0.009) betekenisvollanger in die pasiente met osteopenie. In
Betekenisvolle negatiewe korrelasie tussen BMD (Z-Telling) en die duurte van
amenoree in die toale pasient populasie (r = -0.4; P = 0.001) asook in al drie
eetsteurnis groepe (AN: r = -0.4; P = 0.03; BN: r = -0.06; P = 0.008; EDNOS: r = -
0.6, P = 0.005) is aangetoon. In die groep as 'n geheel, het die amenoree
pasiente In laer LMI, E2vlakke en BMD gehad in vergelyking met die pasiente
met normale menses.
Opsommend dus, kom osteopenie algemeen in pasiente met AN, asook BN en
EDNOS voor. In Betekenisvolle bydrae van nutrisiele (met die uitsondering van
alkoholinname) en meganiese faktore asook hiperkortisolemie tot been verlies,
kon nie in hierdie tudie populasie gedemonstreer word nie. Hipogonadisme is as
die hoofoorsaak van osteopenie in die pasiente qefdentifiseer.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52058
Date January 2001
CreatorsConradie, Maria Martha
ContributorsHough, F.S., Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences. Division Medical Physiology.
PublisherStellenbosch : Stellenbosch University
Source SetsSouth African National ETD Portal
Languageen_ZA
Detected LanguageUnknown
TypeThesis
Format80 leaves : ill.
RightsStellenbosch University

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