Cohort study design question.

#1
Hi there, here are the details.

Study the association between parental knowledge of lead poisoning disease prevention practices and the incidence of lead poisoning among their children

Intervention: 1 year
Participants: 60

Program components; All participants attend 4 educational classes teaching 4 different skills to modify risk factors.

QUESTION:

1.Can the intervention be tested as a whole? I mean all 4 different risk factors will change along with incidence rates.
Or
2. Do I need to test each factor separately to see the association with disease incidence?

Thank you so much.
 
#3
Measured by blood test on children every 3 months.
Families will take tests after each class to evaluate knowledge attained.

So I am studying the causal relation of the blood lead levels and the family's level of knowledge.
Chose a cohort study using a correlation test.