Table 1

Demographic characteristics of participants in different exposure groups

Demographic characteristicsNo exposureIndirect exposureDirect exposure
*p<0.05; all other group differences are not statistically significant (p>0.10).
Sample size171715
Female (%)595647
Mean age (months)
Race/ethnicity (%)
    African American18619
    White non-Hispanic296963
    Mexican American1206
Race/ethnicity (%)
    African American18613
    White non-Hispanic416975
    Mexican American1800
Education level*
    Did not complete high school18013
    Completed high school124444
    Technical/vocational school0625
    Some college414419
    Completed college3560
Employment status
    Not employed718156
    Part time (<40 hours12625
    full-time (⩾40 hours)191319
Total income (median)$24000$21000$25000
Size of residence (median, square feet)639586736
Number residents (median)44.54