Table 2.

Confounding Variables Used in Multivariate Analysis

Infants’s age*
 3, 4, 5, 6, and 7 months
Other liquid intake last month
Solid intake last month
Infant’s gender
 Female
 Male
Maternal education
 0–11 y of school
 12 y of school
 1–4 y of college
 More than 4 y of college
Maternal occupation
 Full-time homemaker
 Unemployed, student or retired
 Professional or executive
 Clerical or sales
 Craftsperson, fabricator, technician, farmer,  service worker, etc
Maternal smoking
 No smoking
 10 or fewer cigarettes/day
 11–20 cigarettes/day
 More than 20 cigarettes/day
Household size
 1–2 people
 3 people
 4–8 people
Household income
 Less than $22 500
 $22 500–$34 999
 $35 000–$50 000
 More than $50 000
Day care
 None
 In the home, any amount of time
 With other children 1–2 days/wk
 With other children 3–5 days/wk
 With other children 6–7 days/wk
  • * Adjusted at months 3 through 7 due to the lagged nature of the analysis.