Relationships between exposure to specific allergens and asthma; probability of asthma at age 7 years determined by logistic regression according to the sum of exposure tertiles (cockroach, mouse, cat and dog). Fig 1, A shows sum of the exposures in the first year of life; Fig 1, B shows the same stratified by aeroallergen sensitization at age 3 (pink=sensitive, blue=not sensitive). Fig 1, C shows the cumulative sum of exposures across years 1, 2, and 3; Fig 1, D shows the same stratified by aeroallergen sensitization at age 3. P-values are from a logistic regression model testing a relationship between exposure levels and asthma, stratified by sensitization in panels B and D.