Download Potassium and anorexia - Christina Ferraiuolo

What is the association
between potassium
levels in the body and
Anorexia Nervosa?
Take two
What kind of micronutrient is potassium?
What relationship would it have with the
heart?
Do you think there is a connection
between anorexia and potassium?

Potassium is a micronutrient and an
electrolyte
Infant RDI 0.4 g/day
 Children RDI 3-4 g/day
 Adult RDI 4.7 g/day
 Breastfeeding RDI 5.1 g/day

(Zieve,2009)
All meats and fish
 Soy products
 Fruits: cantaloupe, banana, kiwi,
avocado
 Vegetables: broccoli, sweet potato, and
tomatoes
 Milk and yogurt


Nuts (Zieve,2010)

Too little potassium in the body is called
Hypokalemia

Too much potassium in the body is
called Hyperkalemia (Zieve,2009)
An eating disorder
 Body Dimorphic
 Obsession with weight and food
 Starvation
 Exercise excessively
 Abuse laxatives and diuretics


Intense fear of gaining weight

Distorted self image

Absence of menstrual cycle

Refusal to maintain body weight at
healthy range (Dryden-Edwards, 2010)
Death
 Anemia
 Bone loss
 Kidney Problems
 Brain damage
 Heart failure or abnormal heart rhythm
 Electrolyte abnormalities (Dryden-Edwards, 2010)


Potassium is an electrolyte

Found in food sources

Anorexia patients lose potassium though
weight regulation

Fatal electrical alterations of the heart
What is the association
between potassium
levels in the body and
Anorexia Nervosa?

To define several diagnostic and
symptomatic groups and test them
separately for their potassium levels
Anorexia with vomiting
 Anorexia with vomiting and laxative
abuse
 Anorexia without vomiting


Descriptive Epidemiological
› Cross sectional survey

Examining causal factors associated with
different anorexia and bulimic groups
with Hypokalemia

Retrospective study

397 patients with preexisting eating disorder

Klinik am Korso in Bad Oeynhausen, Germany

Subgroups based on complete
symptomatology

Similarities in BMI, age, disease duration

Hypokalemic: < 3.4 mmol/l plasma potassium
Descriptive
 Inferential
 Correlation tests

Standard Deviation
 Mean
 Range
 Median

Mann-Whitney U test
 Kruskal-Wallis test
 Analysis of Variance test (ANOVA)
 Post-hoc test (Scheffe’)

Pearson’s two-tailed testing
 Spearman’s correlation testing
 Multiple linear regression
 Stepwise Linear Regression (R2)

› Standardized regression coefficient

Coefficient of determination
Hypokalemia in purging anorexic (p =
0.001)
 Hypokalemia in non-purging anorexic
(p=0.82)
 Higher frequency (p = 0.001)
 Severity (p = 0.001)
 Differences between anorexic subgroups
(p = 0.001)


Potassium levels and BMI (r) 0.27
(p=0.001)

Vomiting frequency, laxative abuse and
potassium levels (r) -0.38 (p = 0.005)

Mean potassium 2.8 mmol/l
Table 2. Potassium levels and hypokalemia proportion in the subgroups
Number of participants
 Internal Validity

› Recall bias
› Selection bias
› Confounding variables
Organization
 External Validity

› Results represent an entire population

Hypokalemia more common in binging
and purging anorexics

Potassium losses through stool, urine and
vomit

Possibly other factors associated with
potassium loss not tested
What is the association
between potassium
levels in the body and
Anorexia Nervosa?

To determine the medical effects of
anorexia on a young population in terms
of normal body function

Descriptive Epidemiological study
› Cross sectional
› Prospective

Community dwelling adolescent girls
› Anorexia with outpatient care vs. healthy
adolescents

118 adolescent girls
› 60 with DSM IV diagnosed anorexia
› 58 healthy- no past history of eating disorder
Referred by treatment programs in
Boston, MA
 Prospective data collection at baseline
visit
 Three month or more community dwelling
 Biochemical

› Potassium levels

Anthropometric
› BMI
Descriptive statistics
 Inferential statistics

Mean
 Standard Deviation

T-test
 Univariate regression analysis

› Correlation between variables

Stepwise regression analysis
› Significant predictors

Mean serum potassium levels higher in
anorexic
› AN: 3.8 +/- 0.3 mmol/l
› Healthy: 3.6 +/- 0.2 mmol/l

no subject Hypokalemic
› Serum potassium< 3.0 mmol/l

Two subjects with history of purging
behavior
Weakness in planning
 No hypothesis stated
 Limited external validity

Comparability to the control and
observed group
 Diverse referrals decrease selection bias
 Limited external validity

› Caucasian Adolescent female specific
Normal serum potassium levels
 Higher in anorexic

› Due to dehydration
Total potassium levels may still be low
 Not at risk even with low BMI
 Still at risk for cardiac abnormalities
 No purging behaviors observed

What is the association
between potassium
levels in the body and
Anorexia Nervosa?
Potassium levels are influenced by
Anorexia
 Both suggested potential cardiac risk
 Differences in studies

› Set potassium level as Hypokalemic
› Population studied

Yes!

Both saw changes in extracellular
potassium in the Anorexic populations

More research in diverse groups

Identify relationship of purging and
potassium levels

Identify other variables not accounted for

Measuring total potassium vs. only plasma