We used Cox proportional hazards regression models to estimate incidence rate ratios (IRRs) and 95% CIs for incident asthma. Participants contributed person-time from 1997 until diagnosis of asthma, death, loss to follow-up, or end of follow-up, whichever came first. In an initial model, we adjusted only for age and questionnaire cycle (time period). In a multivariable model, we added covariates that may be risk factors for adult-onset asthma: BMI, weight in kg/height2 in m (< 25.0, 25.0-29.9, 30.0-34.9, 35.0-39.9, ≥ 40.0); pack years of smoking (0, 1-4, 5-14, 15-24, ≥ 25); current smoking (yes, no); exposure to secondhand smoke at each of ages 0-10, 11-20, 21-30, and 31-40 years and currently (yes, no); vigorous exercise in hours/week (0, < 5, ≥ 5); female hormone use (never, < 5 years, ≥ 5 years); parental history of asthma (yes, no, unknown); mother’s smoking status (yes, no, unknown); education in years (≤ 12, 13-15, 16, ≥ 17); household income (≤ $25,000, $25,001-50,000, $50,001-100,000, > $100,000); and alcohol consumption in drinks/week (never, past any amount, current 1-3, 4-6, 7-13, ≥ 14). Alcohol consumption was a risk factor for asthma in a large Danish study28 and was associated with asthma incidence in the BWHS. The addition of indicators for having health insurance and a regular doctor, and the presence of childhood abuse (associated with asthma incidence in the BWHS),13 did not change the results. Missing values were modeled as separate categories. We tested for trend by including the everyday and lifetime racism scores in the model as ordinal variables.