Unadjusted and adjusted risk ratios of unexplained death (compared with unintentional asphyxia deaths)
| Characteristic | RR (95% CI) | aRR (95% CI)* |
| Age (months) | ||
| <2 | Reference | Reference |
| 2–4 | 0.95 (0.72 to 1.25) | 1.05 (0.77 to 1.43) |
| 5–11 | 0.91 (0.66 to 1.27) | 1.05 (0.71 to 1.56) |
| Race/ethnicity | ||
| White, non-Hispanic | Reference | Reference |
| Black, non-Hispanic | 1.01 (0.76 to 1.33) | 1.05 (0.76 to 1.46) |
| Hispanic | 1.05 (0.74 to 1.48) | 1.03 (0.70 to 1.50) |
| Other, non-Hispanic | 1.21 (0.77 to 1.91) | 1.19 (0.72 to 1.96) |
| Unknown | 1.01 (0.47 to 2.18) | 1.42 (0.64 to 3.18) |
| Gestational age (weeks) | ||
| ≥37 | Reference | Reference |
| <37 | 1.08 (0.80 to 1.44) | 0.98 (0.65 to 1.47) |
| Unknown | 2.88 (0.40 to 20.53) | 5.21 (0.64 to 42.23) |
| Birth weight (g) | ||
| ≥2500 | Reference | Reference |
| <2500 | 1.10 (0.82 to 1.47) | 1.13 (0.75 to 1.71) |
| Maternal age | ||
| <20 | Reference | Reference |
| 20–25 | 1.21 (0.79 to 1.87) | 1.22 (0.76 to 1.94) |
| 26–35 | 1.22 (0.79 to 1.89) | 1.12 (0.69 to 1.83) |
| >35 | 1.58 (0.90 to 2.79) | 1.44 (0.77 to 2.70) |
| Maternal education level | ||
| Less than high school | Reference | Reference |
| High school graduate | 0.84 (0.62 to 1.16) | 0.78 (0.56 to 1.10) |
| Some college | 1.20 (0.86 to 1.65) | 1.14 (0.80 to 1.64) |
| College graduate | 0.99 (0.57 to 1.70) | 0.84 (0.47 to 1.51) |
| Unknown | 1.04 (0.60 to 1.82) | 1.14 (0.40 to 3.26) |
| Sex | ||
| Male | Reference | Reference |
| Female | 1.29 (1.02 to 1.64) | 1.36 (1.06 to 1.76) |
| Place of death | ||
| Child’s home | Reference | Reference |
| Friend or relative’s home | 0.83 (0.60 to 1.15) | 0.87 (0.60 to 1.26) |
| Other | 1.25 (0.78 to 2.00) | 0.93 (0.53 to 1.63) |
| Type of area | ||
| Urban | Reference | Reference |
| Suburban or rural | 0.75 (0.58 to 0.98) | 0.78 (0.58 to 1.04) |
| Unknown | 0.88 (0.64 to 1.22) | 0.77 (0.51 to 1.16) |
| Sleep location | ||
| Crib/bassinet | Reference | Reference |
| Adult bed | 0.80 (0.59 to 1.08) | 1.05 (0.68 to 1.63) |
| Couch/chair | 0.65 (0.40 to 1.05) | 1.06 (0.65 to 1.74) |
| Other | 0.91 (0.60 to 1.39) | 0.90 (0.56 to 1.43) |
| Unknown | 1.89 (0.68 to 5.20) | 2.32 (0.76 to 7.04) |
| Sharing sleep surface | ||
| No | Reference | Reference |
| Yes | 0.80 (0.63 to 1.02) | 0.77 (0.53 to 1.11) |
| Unknown | 1.36 (0.60 to 3.09) | 0.68 (0.23 to 2.04) |
| Position placed to sleep | ||
| On back | Reference | Reference |
| On side/stomach | 0.80 (0.61 to 1.05) | 0.87 (0.62 to 1.21) |
| Unknown | 1.15 (0.84 to 1.57) | 1.02 (0.69 to 1.51) |
| Position when found | ||
| On back | Reference | Reference |
| On side/stomach | 0.79 (0.59 to 1.05) | 0.91 (0.63 to 1.31) |
| Unknown | 0.93 (0.65 to 1.32) | 0.78 (0.51 to 1.21) |
| Airway condition | ||
| Unobstructed | Reference | Reference |
| Fully obstructed | 0.32 (0.20 to 0.52) | 0.28 (0.16 to 0.49) |
| Partially obstructed | 1.07 (0.66 to 1.72) | 0.92 (0.53 to 1.59) |
| Unknown | 1.03 (0.71 to 1.50) | 0.99 (0.65 to 1.52) |
| Death scene investigation performed | ||
| Yes | Reference | Reference |
| No | 1.23 (0.72 to 2.10) | 1.24 (0.70 to 2.20) |
| Unknown | 1.60 (1.04 to 2.45) | 1.45 (0.89 to 2.39) |
| Year of death | ||
| 2014 | Reference | Reference |
| 2015 | 0.95 (0.67 to 1.37) | 0.97 (0.65 to 1.46) |
| 2016 | 0.93 (0.65 to 1.33) | 0.96 (0.65 to 1.44) |
| 2017 | 0.64 (0.43 to 0.94) | 0.65 (0.42 to 0.99) |
| 2018 | 0.91 (0.63 to 1.32) | 0.91 (0.60 to 1.38) |
*Adjusted for all independent variables in this table.
aRR, adjusted risk ratio; RR, risk ratio.