Compare the primary developmental consequences of iodine deficiency versus zinc deficiency in early childhood and explain how these deficits might present differently in a population survey.

Iodine deficiency causes acute wasting and edema, while zinc deficiency causes immediate blindness, so surveys would show increased edema and vision impairment respectively.

Both iodine and zinc deficiencies are indistinguishable clinically and in surveys because they both only affect adult body composition and do not change childhood development measures.

Iodine deficiency primarily affects thyroid function, leading to cretinism and cognitive impairment evident as reduced IQ and developmental delays; zinc deficiency more commonly impairs growth and increases infection susceptibility, reflected as higher stunting rates and morbidity in surveys.

Iodine deficiency increases appetite and weight gain, whereas zinc deficiency reduces cognitive ability but always increases linear growth in children, therefore surveys should show opposite trend lines for height and cognitive tests.