Table 3.
Multiplicative change and 95% confidence intervals for serum and hair cotinine by potential determinants, unadjusted and adjusted, from the Cincinnati Asthma Prevention Study (2000–2003)
| Serum cotinine |
Hair cotinine |
|||
|---|---|---|---|---|
| Unadjusteda n=203/374b |
Adjusteda n=203/374b |
Unadjusteda n=197/348b |
Adjusteda n=197/348b |
|
| Parent report of SHS at home | ||||
| Hours at home | ||||
| Per additional 10 h | 1.1 (0.9, 1.2) | NIM | 1.1 (0.9, 1.3) | NIM |
| Hours in a room with smoking | ||||
| >2 vs 0 | 2.3 (1.6, 3.3) | 1.9 (1.4, 2.6) | 1.5 (1.1, 2.0) | NIM |
| ≤2 vs 0 | 1.8 (1.3, 2.4) | 1.4 (1.1, 1.7) | 1.2 (1.0, 1.6) | NIM |
| Number of cigarettes/day | ||||
| Per 10 additional | 1.3 (1.2, 1.4) | 1.2 (1.1, 1.3) | 1.0 (0.9, 1.2) | 1.1 (1.0, 1.2) |
| Number of smokers in the home | ||||
| 3+ vs 0 or 1 | 1.9 (1.2, 2.8) | NIM | 0.9 (0.5, 1.5) | NIM |
| 2 vs 0 or 1 | 1.3 (1.1, 1.6) | NIM | 1.1 (0.9, 1.4) | NIM |
| Maternal smoking | ||||
| Yes vs no | 2.1 (1.5, 2.9) | 1.5 (1.1, 1.9) | 1.5 (1.1, 2.0) | NIM |
| Paternal smoking | ||||
| Yes vs no | 1.1 (0.8, 1.5) | 1.3 (1.0, 1.7) | 0.7 (0.5, 1.0) | 1.2 (0.9, 1.5) |
| Environmental measures of SHS | ||||
| Household nicotinec (μg/m3) | ||||
| 3 vs 0.5 | 1.9 (1.8, 2.2) | 1.5 (1.4, 1.7) | 1.2 (1.1, 1.4) | 1.1 (1.0, 1.2) |
| Staff perception of smokiness | ||||
| Smoky vs not smoky | 1.5 (1.2, 2.0) | 1.4 (1.1, 1.8) | 1.3 (1.0, 1.6) | NIM |
| Housing and ventilation | ||||
| Home volume (m3) | ||||
| Per 100 m3 smaller | 1.7 (1.4, 2.1) | 1.2 (1.1, 1.4) | 1.3 (1.1, 1.5) | NIM |
| Number of rooms | ||||
| Per 2 fewer | 1.4 (1.3, 1.7) | NIM | 1.3 (1.2, 1.6) | 1.1 (1.0, 1.2) |
| Open floor plan | ||||
| Traditional vs open | 1.2 (0.6, 2.6) | NIM | 1.3 (0.6, 2.5) | NIM |
| Air conditioning | ||||
| None vs central air | 1.8 (1.2, 2.8) | NIM | 3.1 (2.1, 4.5) | 1.5 (1.1, 2.1) |
| Window unit vs central air | 1.8 (1.2, 2.7) | NIM | 2.2 (1.5, 3.2) | 1.1 (0.8, 1.5) |
| Fan running during visit | ||||
| Yes vs no | 0.9 (0.8, 1.8) | NIM | 1.2 (0.9, 1.7) | 1.4 (1.0, 1.9) |
| Season | ||||
| Spring vs fall | 1.4 (1.1, 1.7) | 1.5 (1.2, 1.8) | 1.0 (0.8, 1.3) | NIM |
| Summer vs fall | 1.1 (0.7, 1.7) | 1.3 (1.0, 1.7) | 1.4 (1.0, 2.0) | NIM |
| Winter vs fall | 1.3 (0.8, 1.9) | 1.2 (0.9, 1.6) | 1.1 (0.8, 1.5) | NIM |
| SHSb outside of home | ||||
| Vehicles | ||||
| >1 h vs none | 1.8 (1.2, 2.7) | 1.5 (1.0, 2.3) | 1.3 (0.7, 2.2) | 1.5 (0.9, 2.4) |
| ≤1 h vs none | 1.0 (0.7, 1.3) | 1.0 (0.7, 1.2) | 1.3 (0.9, 1.8) | 1.5 (1.1, 2.0) |
| Others homes | ||||
| Any vs none | 1.2 (0.9, 1.6) | 1.3 (1.0, 1.7) | 1.1 (0.9, 1.4) | NIM |
| Child characteristics | ||||
| African-American race | ||||
| Yes vs no | 1.6 (1.1, 2.3) | 1.2 (0.9, 1.6) | 4.1 (3.1, 5.4) | 3.6 (2.7, 4.9) |
| Gender | ||||
| Female vs male | 1.5 (1.0, 2.2) | 1.3 (1.0, 1.6) | 1.1 (0.8, 1.5) | NIM |
| Age (years) | ||||
| Per 5 years younger | 1.2 (0.7, 1.9) | NIM | 1.0 (0.6, 1.5) | NIM |
| Family social class | ||||
| Parental education | ||||
| <HS vs college degree | 2.4 (1.2, 4.7) | 0.8 (0.5, 1.3) | 2.1 (1.2, 3.9) | 1.2 (0.8, 1.9) |
| HS degree vs college degree | 1.0 (0.5, 1.8) | 0.6 (0.4, 0.9) | 1.3 (0.8, 2.3) | 0.9 (0.6, 1.3) |
| Some college vs college degree | 1.1 (0.5, 2.1) | 0.8 (0.5, 1.2) | 1.2 (0.7, 2.2) | 1.0 (0.7, 1.6) |
| Income ($/year) | ||||
| Per $30,000 reduction | 2.1 (1.7, 2.6) | NIM | 2.0 (1.7, 2.4) | NIM |
| Health insurance | ||||
| Public or none vs private | 2.7 (1.9, 3.9) | 1.6 (1.2, 2.1) | 3.1 (2.3, 4.2) | 1.4 (1.1, 1.9) |
| Currently married | ||||
| No vs yes | 2.2 (1.6, 3.0) | NIM | 2.6 (1.9, 3.4) | NIM |
| Persons per room | ||||
| Additional 1 person per 2 rooms | 1.5 (1.1, 1.9) | NIM | 1.6 (1.3, 2.0) | NIM |
| HOME score | ||||
| Per 10 point reduction | 1.9 (1.5, 2.4) | 1.2 (1.0, 1.5) | 1.8 (1.5, 2.3) | 1.1 (0.9, 1.3) |
SHS, secondhand smoke; NIM, variable not in the final model; HS, high school; HOME Inventory, Home Observation for Measurement of the Environment (Caldwell and Bradley, 1984).
All estimates arise from a linear mixed model predicting log cotinine, adjusted for intervention status (intervention, placebo) and study visit (baseline, 6 months, 12 months). Adjusted estimates additionally include all variables with multiplicative change values given.
Number of observations is listed as children/repeated observations.
To improve model fit we coded nicotine dosimeter values with a log transformation.