Table 3.

Estimated Relationship between Early Exposure to Great Smog and Asthma Development

	Childhood Asthma		Adult Asthma
	Not Covariate Adjusted (1)	Covariate Adjusted (2)	Not Covariate Adjusted (3)	Covariate Adjusted (4)
0–1 yr × born in London	0.1987 (0.0337 to 0.364)	0.1929 (0.0274 to 0.358)	0.0953 (−0.0485 to 0.239)	0.0934 (−0.0469 to 0.2340)
In utero × born in London	0.0791 (−0.0239 to 0.182)	0.0793 (−0.0233 to 0.182)	0.0075 (−0.0534 to 0.0683)	0.0055 (−0.0561 to 0.0671)
R2	0.0433	0.0788	0.013	0.041
Observations	2,915	2,743	2,915	2,740

95% confidence intervals in parentheses are calculated using SEs clustered by born in London status and month of birth. All regressions control for a quadratic term in year of birth, indicators for month of birth, indicators for in utero and 0–1 years old, and an indicator for born in London. Covariate-adjusted regressions include controls for respondent’s sex and housing characteristics at age 10 (number of bedrooms, number of people living in the house, cold running water, hot running water, inside toilet, central heat, and fixed bath). The first coefficient in column 1 reveals that exposure to the Great Smog between birth and age 1 (i.e., being born in London between December 1951 and November of 1952) is associated with a 19.87 percentage point increase in the likelihood of developing childhood asthma.