1 LTJonathan Leshin, Ph.D . Antimicrobials Division Office of Pesticide Programs U.S. Environmental Protection Agency 

# EP A Science Assessment of Gardner et al. (1988)

# Study Information  

## Conducted at the Department of Medicine, Medical College, Richmond VA  

## Study Objective – Determine a tolerable upper limit for iodine consumption  

## Subjects – 30 Males, euthyroid , no history of thyroid disease or use of medications known to affect thyroid function or previous reactions to iodine, age 22-40  

## Self control study 2

# Test Substance

 

### Sodium Iodide dissolved in water (500, 1500 or 4500 μg/ml per day), co-administered with 1 mg/ml of ascorbic acid.  

### Administered as two 0.5 ml solutions twice daily  

### Study lasted 14 days  

### The subjects were randomly sorted into groups dosed with either 500, 1500 or 4500 μg/ml  

### Subjects maintained their normal diets 

##  Some diets may be higher in iodine than others but assumed average was 300 μg/day 3

# Study Method  

## All subjects had initial evaluations for the study  

## After an eight hour fast, baseline levels of T4

## , T3

## , T3

## -charcoal uptake, and thyroid stimulating hormone (TSH) were measured  

## Stimulated TSH was measured after stimulation by thyrotropin releasing hormone (TRH) every 15 minutes for an hour  

## On day 15, the protocol was repeated

4

# Endpoints  

# Serum T4 

###  

# Serum T3 

###  

# T3

# -charcoal uptake  

# TSH  

# Stimulated TSH 5

# Results - 1

**Iodide dose**  **Serum T** **4**

**(μg/dl) T** **3 charcoal** 

**uptake ratio**  **FTI Serum**  **T 3**  **( ng**  **/dl) 500**  **μg/ml (n= 10) Day 1**  9.2  0.5 1.06  0.04 9.8  0.8 153  8 **Day 15** 9.2  0.4 1.09  0.04 10.0  0.6 158  7 **p -** **value** NS NS NS NS **1500 μg/ml (n= 10)**  **Day 1** 8.6  0.4 1.02  0.04 8. 7  0.5 162  11 **Day 15** 7. 5  0.9* 1.00  0.05 7. 5  0.4* 161  7 **p -** **value** 0.005 NS 0.005 NS

**4500 μg/ml (n= 10)**  **Day 1** 8.9  0.6 1.12  0.09 9.9  0.6 151  9 **Day 15** 8.2  0. 7* 1.11  0.04 9.0  0.6* 155  6 **p -** **value** 0.02 NS 0.005 NS 

## Ta**ble 1:** Serum thyroid hormone concentrations before and after iodide administration Pa ired Student’

s t-test p value Mean  SEM NS = Not significant Day 15 compared with Day 1



### 6

# Results - 2
**Iodide dose**  **TSH (μU/ml) min after TRH Maximum**  **TSH increment**  0 15 30 45 60

**500 μg/day**  **(n= 10) Day 1**  3.0  0.3 9. 7  1.4 12.0  1.8 11.0  1. 7 9. 7  1.8 9.0  1.6 **Day 15** 3.3  0.5 11.1  1.5 15.2  4.8 13. 7  2.3 12.8  2.3 12.5  2.2 **p -** **value** NS 0.05 0.02 0.02 0.002 0.03 **1500 μg/day**  **(n= 10) Day 1**  2.5  0.3 9.6  1.5 11.6  1.8 10. 7  1. 7 8. 7  1.5 9.4  1. 7 **Day 15** 3. 7  0.5 14.2  2.2 16.3  2.2 14.6  1.9 12.5  1.9 12.8  2.0 **p -** **value** 0.04 0.004 0.002 0.01 0.002 0.005 **4500 μg/day**  **(n= 10) Day 1**  2.1  0.4 8.8  1.1 9.5  1.1 8.9  1.0 7. 8  0.9 7. 5  1.0 **Day 15** 3. 7  0.6 12. 7  1.8 15.5  2.0 14.0  1.4 12.0  1.6 12.2  1.6 **p -** **value** 0.008 0.003 0.001 0.001 0.001 0.001 

### Ta**ble 2:** Ef

fect of iodide on basal and TRH stim ulated serum

TSH concentration Pa ired Student’

s t-test p value Mean  SEM. NS = Not significant Day 15 compared with Day 1.



### 7

# Conclusions  

# At 1500 and 4500 μg/day there were decreases in serum and free T4  

# No change in T3 charcoal uptake or serum T3  

# At 500,1500 and 4500 μg/day there were increases in both basal and TRH induced TSH 89 Kelly Sherman Office of Pesticide Programs U.S. Environmental Protection Agency 

# EP A Ethics Assessment of Gardner et al. (1988)10



# Introduction  

### Research was conducted in the 1980s, before promulgation of the 2006 Human Studies Rule  

### Considered an intentional exposure human toxicity study because it evaluated potential the toxic effects of iodine intake on thyroid function  

### 40 CFR § 26.1602 requires HSRB review for pre- rule intentional exposure toxicity studies upon which EPA intended to rely  

### Study was located by EPA, not submitted to the Agency, so 40 CFR § 26.1303 does not apply11



# Value to Society

 

## Provides data about whether small increases in iodine intake affect thyroid function  

## The research was important because at the time of the study, dietary changes were resulting in increased iodine intake  

## The data are potentially useful in EPA’s human health risk assessments for products containing iodine12



# Subject Selection
 

## 30 male subjects, ages 22-40  

## The subjects were medical students or employees of the Medical College of Virginia, or people whose names appeared on a list of interested research candidates maintained by the research center  

## Inclusion/exclusion criteria: 

##  Subjects had to be healthy, euthyroid , not on any medications that affect thyroid function, no history of thyroid disease13 

# Risks, Risk Minimization, Benefits & Risk:Benefit Balance  

## Article is silent  

## Benefits 

#  No benefits to subjects; Societal benefit from knowledge about iodine intake  

## Risk:Benefit Balance 

#  Not discussed in article 

#  Risks were minimal, so the potential benefits to society outweigh the risks14



# Ethics Oversight
 

## Research was reviewed and approved by the Virginia Commonwealth University Committee on the Conduct of Human Research

# Informed Consent

15 

# • Article states that each subject provided written inf

ormed consent 

# • Dr . Gardner stated: 

# • Subjects were given the opportunit y to read the protocol and ask questions 

# • I nvestigators confirmed subject’ s understanding 

# • Copy of the consent f orm not ava ilable

# Respect for Subjects  

# Dr. Gardner stated that subjects were paid approximately $150- 200 to participate  

# Subjects’ privacy protected  

# We do not know whether subjects were free to withdraw during the study
1617 

# Standards for Documentation  

## The requirement at 40 CFR § 26.1303 to document the ethical conduct of research submitted to EPA does not apply: 

#  Study was obtained from the public literature, not submitted to EPA 

#  EPA located the study at its own initiative

# Standards of Conduct  

## Conducted prior to 1988, before EPA’s Rule at 40 CFR part 26 took effect  

## FIFRA § 12(a)(2)(P) does not apply 

#  Did not involve use of a pesticide  

## Declaration of Helsinki (1983) 

#  Research must be scientifically sound 

#  Clear purpose and protocol, reviewed and approved by an independent ethics committee 

#  Prior informed consent 1819 

# Standards for EPA Reliance  

## 40 CFR **§ 26.1703**  

##  Prohibits EPA reliance on data involving intentional exposure of pregnant or nursing women or of children  

## 40 CFR **§ 26.1704**  

##  Prohibits EPA reliance on data if there is clear and convincing evidence that: (1) Conduct of the research was fundamentally unethical; or (2) Conduct of research was deficient relative to the ethical standards prevailing at the time the research was conducted in a way that placed participants at increased risk of harm or impaired their informed consent.20 

# Compliance with Standards for EPA Reliance  

## 40 **CFR §**  **26.1703**  The subjects were all males above the age of 18  

## 40 **CFR §**  **26.1704**  

### No clear and convincing evidence that the conduct of the research was fundamentally unethical  

### No clear and convincing evidence that the conduct of the research was deficient relative to prevailing ethical standards21



# Conclusion If it is deemed scientifically valid and relevant, there are no barriers in FIFRA or in 40 CFR § 26.1703 or § 26.1704 to EPA’s reliance on the Gardner et al. (1988) study in actions taken under FIFRA or §408 of FFDCA22



# Charge Questions 1. Is the Gardner et al. (1988) study scientifically sound, providing reliable data? 2. If so, is this study relevant for quantitative use in support of an assessment of the oral risk of exposure to iodine? 3. Does the study meet the applicable requirements of 40 CFR part 26 subpart Q?