Potassium and AnorexiaChristina Ferraiuolo

HLSC 415

Thesis Question

What is the association between potassium

levels in the body and Anorexia Nervosa?

Ice Breaker

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

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)

Potassium Sources

All meats and fish Soy products Fruits: cantaloupe, banana, kiwi,

avocado Vegetables: broccoli, sweet potato, and

tomatoes Milk and yogurt Nuts (Zieve,2010)

Hypokalemia and Hyperkalemia

Too little potassium in the body is called Hypokalemia

Too much potassium in the body is called Hyperkalemia (Zieve,2009)

Anorexia

An eating disorder Body Dimorphic Obsession with weight and food Starvation Exercise excessively Abuse laxatives and diuretics

DSM IV TR Diagnostic Criteria for Anorexia

Intense fear of gaining weight

Distorted self image

Absence of menstrual cycle

Refusal to maintain body weight at healthy range (Dryden-Edwards, 2010)

Anorexia complications

Death Anemia Bone loss Kidney Problems Brain damage Heart failure or abnormal heart rhythm Electrolyte abnormalities (Dryden-Edwards, 2010)

Anorexia and Hypokalemia

Potassium is an electrolyte

Found in food sources

Anorexia patients lose potassium though weight regulation

Fatal electrical alterations of the heart

Thesis Question

What is the association between potassium

levels in the body and Anorexia Nervosa?

Effect of Weight-Regulating Practices on Potassium Level in Patients with

Anorexia or Bulimia Nervosa

Imbierowicz,K., Curkovic, I., Braks, K., Gesier, F., Liedtke, R., & Ernst Jacoby, G. (2004). Effects of weight-regulating practices on

potassium levels in patients with anorexia or bulimia nervosa. European Eating Disorders Review, 12(5), 300-306. doi: 10.1002/erv.591.

Purpose

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

Research Design

Descriptive Epidemiological› Cross sectional survey

Examining causal factors associated with different anorexia and bulimic groups with Hypokalemia

Retrospective study

Methods

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

Identification of Statistics

Descriptive Inferential Correlation tests

Descriptive Statistics

Standard Deviation Mean Range Median

Inferential Statistics

Mann-Whitney U test Kruskal-Wallis test Analysis of Variance test (ANOVA) Post-hoc test (Scheffe’)

Correlation tests

Pearson’s two-tailed testing Spearman’s correlation testing Multiple linear regression Stepwise Linear Regression (R2)

› Standardized regression coefficient Coefficient of determination

Interpretation of Results

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)

Results continued

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

Weaknesses of the Study

Number of participants Internal Validity

› Recall bias› Selection bias› Confounding variables

Strengths of the Study

Organization External Validity

› Results represent an entire population

Conclusion

Hypokalemia more common in binging and purging anorexics

Potassium losses through stool, urine and vomit

Possibly other factors associated with potassium loss not tested

Thesis Question

What is the association between potassium

levels in the body and Anorexia Nervosa?

Effects of Anorexia Nervosa on Clinical, Hematological, Biochemical, and Bone Density Parameters in Community-Dwelling Adolescent

Girls

Mirsa, M., Aggarwal, A., Miller, K., Almazan, C., Worley, M., Soyka, L., et al. (2004). Effects of anorexia nervosa on clinical, hematological, biochemical, and bone density parameters in community-dwelling adolescent girls.

Pediatrics, 114(6), 1574-1583. doi:10.1542/peds.2004-0540.

Purpose

To determine the medical effects of anorexia on a young population in terms of normal body function

Research Design

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

Methods Referred by treatment programs in

Boston, MA Prospective data collection at baseline

visit Three month or more community

dwelling Biochemical

› Potassium levels Anthropometric

› BMI

Identification of Statistics

Descriptive statistics Inferential statistics

Descriptive Statistics

Mean Standard Deviation

Inferential Statistics

T-test Univariate regression analysis

› Correlation between variables Stepwise regression analysis

› Significant predictors

Interpretation of Results

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

Weaknesses of the Study

Weakness in planning No hypothesis stated Limited external validity

Strengths of the Study

Comparability to the control and observed group

Diverse referrals decrease selection bias

Limited external validity› Caucasian Adolescent female specific

Conclusion

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

Thesis Question

What is the association between potassium

levels in the body and Anorexia Nervosa?

Overall Conclusion

Potassium levels are influenced by Anorexia

Both suggested potential cardiac risk Differences in studies

› Set potassium level as Hypokalemic› Population studied

Did I answer my question?

Yes!

Both saw changes in extracellular potassium in the Anorexic populations

Future Direction

More research in diverse groups

Identify relationship of purging and potassium levels

Identify other variables not accounted for

Measuring total potassium vs. only plasma

Questions?