Supplementary Materials
eTable 1. Descriptive statistics of temperature (ºC), relative humidity (%), and apparent temperature (ºC) by climate cluster and season.
Season Cluster Temperature (˚C) Relative Humidity (%) Apparent Temperature (˚C)
Mean SD Mean SD Mean SD
Spring 1 10.7 6.4 58.5 18.0 9.0 6.8 2 8.5 7.5 63.5 15.8 6.6 7.7 3 12.2 7.2 63.9 14.6 10.8 8.1 4 16.4 5.9 63.0 15.3 15.7 7.3 5 13.6 4.2 67.8 13.5 12.0 4.8 6 20.3 4.6 68.5 13.8 21.1 6.6 7 22.9 3.5 69.1 10.6 24.8 5.3 8 19.0 5.6 39.5 19.0 16.9 5.7 Summer 1 22.7 3.8 60.7 19.1 23.6 5.3
2 21.2 3.9 67.4 13.6 21.9 5.3 3 23.9 3.6 68.7 11.3 26.0 5.1 4 25.9 2.9 69.9 11.3 29.1 3.9 5 19.8 3.9 64.0 13.6 19.6 4.3 6 27.3 1.9 73.6 9.9 32.0 2.6 7 27.7 1.6 74.1 7.6 32.8 2.2 8 29.2 4.3 34.2 13.9 28.5 4.7 Fall 1 12.7 6.6 64.7 16.7 11.3 7.8
2 10.5 7.3 69.7 14.2 8.8 8.2 3 13.4 7.1 68.8 12.9 12.3 8.6 4 17.0 6.3 69.1 13.7 17.0 8.3 5 15.6 5.2 68.6 16.3 14.6 6.0 6 20.9 5.4 72.2 12.7 22.5 7.9 7 24.3 3.7 73.9 9.5 27.5 5.8 8 20.1 6.8 44.6 18.3 18.6 7.3 Winter 1 0.8 5.4 66.1 15.6 -0.8 4.5
2 -3.3 6.6 72.3 13.6 -4.3 4.9 3 0.4 6.6 71.0 13.4 -1.2 5.6 4 6.5 5.8 65.6 16.8 4.7 5.9 5 9.3 4.7 73.2 17.8 7.2 5.0 6 12.1 5.4 70.7 15.7 10.8 6.7 7 17.7 4.9 72.7 12.1 17.9 6.7 8 10.1 4.0 58.9 22.2 8.0 4.1
eTable 2. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day temperature (lag 0), prior day temperature (lag 1), and 2 days prior temperature (lag 2) with and without adjusting for ozone by season across 202 cities (1985-2006).
Season % increase in SIDS (95% CI) P-value Same-day (lag 0)
No adjustment Spring -0.8 (-5.3, 3.9) 0.72
Summer 10.4 (3.4, 18.0) 0.003 **
Fall 3.9 (-1.1, 9.1) 0.13 Winter -5.2 (-8.1, -2.1) 0.001 **
Ozone-adjusted Spring -0.5 (-5.0, 4.2) 0.83
Summer 11.8 (4.5, 19.5) 0.001 **
Fall 4.4 (-0.6, 9.7) 0.08 Winter -5.2 (-8.1, -2.1) 0.001 **
Lag 1 Temperature
No adjustment Spring -0.6 (-5.1, 4.1) 0.79
Summer 6.0 (-0.6, 13.2) 0.08 Fall 2.2 (-2.7, 7.3) 0.39 Winter -4.0 (-7.0, -0.9) 0.01 **
Ozone-adjusted Spring -0.4 (-4.9, 4.4) 0.88 Summer 6.8 (0.0, 14.2) 0.05 Fall 2.6 (-2.4, 7.8) 0.32 Winter -4.0 (-7.0, -0.9) 0.01 **
Lag 2 Temperature
No adjustment Spring -1.36 (-5.8, 3.3) 0.56
Summer 0.71 (-5.6, 7.4) 0.83 Fall 2.73 (-2.2, 7.9) 0.28 Winter -2.64 (-5.7, 0.5) 0.10 Ozone-adjusted Spring -1.26 (-5.7, 3.4) 0.59
Summer 0.99 (-5.4, 7.9) 0.77 Fall 2.87 (-2.1, 8.1) 0.26 Winter -2.67 (-5.7, 0.5) 0.09
eTable 3. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day temperature by race.
Est (95% CI) P-value
White Spring -3.34 (-6.99, 0.45) 0.08 Summer 3.62 (-2.27, 9.87) 0.23
Fall 0.87 (-3.00, 4.90) 0.66 Winter -2.95 (-5.24, -0.59) 0.01
Black Spring 2.03 (-2.98, 7.29) 0.43 Summer 18.48 (9.26, 28.48) <.0001
Fall 1.90 (-3.32, 7.39) 0.48 Winter -3.67 (-6.74, -0.51) 0.02 Asian/Pacific Islander Spring 10.22 (-16.64, 45.75) 0.49
Summer 26.67 (-12.82, 84.06) 0.21 Fall 1.01 (-24.33, 34.84) 0.95 Winter -11.61 (-25.40, 4.71) 0.15
Native American Spring -11.06 (-34.99, 21.69) 0.46
Summer -13.82 (-45.36, 35.93) 0.52 Fall -27.16 (-46.62, -0.62) 0.05 Winter 10.27 (-9.10, 33.77) 0.32
Other Spring 5.99 (-67.59, 246.64) 0.92 Summer 782.32 (-30.13, 11042.6) 0.09
Fall -30.80 (-77.21, 110.14) 0.52 Winter -5.90 (-58.74, 114.6) 0.89
eTable 4. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day temperature by season and age.
Age (months) n % increase in SIDS (95% CI) P-value
Spring 0 1,024 -0.9 (-12.0, 11.6) 0.88
1 3,500 -2.1 (-8.1, 4.2) 0.50 2 4,104 0.4 (-5.3, 6.5) 0.88 3 2,904 -4.0 (-10.4, 2.9) 0.25 4 1,629 2.1 (-7.0, 12.1) 0.66 5 937 -5.1 (-16.1, 7.5) 0.41 6 541 -1.1 (-16.2, 16.9) 0.90 7 313 -16.4 (-32.6, 3.7) 0.10 8 221 2.9 (-20.2, 32.7) 0.82 9 133 5.2 (-23.9, 45.4) 0.76 10 83 14.0 (-24.2, 71.5) 0.53 11 71 35.0 (-17.1, 119.8) 0.23
Summer 0 1,024 3.0 (-12.3, 21.1) 0.72
1 2,839 5.2 (-4.4, 15.7) 0.30 2 2,705 -0.2 (-9.3, 9.8) 0.96
3 1,895 15.4 (3.3, 28.9) 0.01 **
4 1,150 20.9 (4.3, 40.2) 0.01 **
5 636 18.2 (-3.1, 44.3) 0.10 6 444 5.4 (-17.2, 34.2) 0.67 7 288 20.5 (-11.4, 63.9) 0.23 8 166 5.1 (-27.7, 52.8) 0.79 9 124 30.0 (-18.5, 107.5) 0.27 10 76 -6.3 (-46.5, 64.3) 0.82 11 66 100.4 (-1.7, 308.5) 0.06
Fall 0 1,101 2.0 (-9.5, 15) 0.74
1 3,655 -4.6 (-10.5, 1.7) 0.15 2 3,866 2.9 (-3.2, 9.3) 0.35 3 2,727 2.2 (-4.8, 9.8) 0.54 4 1,545 3.0 (-6.4, 13.3) 0.55 5 824 3.1 (-9.3, 17.2) 0.64 6 488 3.6 (-13.2, 23.7) 0.70 7 287 -2.7 (-22.4, 22.2) 0.82 8 185 -7.0 (-29.4, 22.6) 0.61 9 125 -0.6 (-29.7, 40.6) 0.98 10 86 33.8 (-11.7, 102.8) 0.17 11 63 4.5 (-38.5, 77.6) 0.87
Winter 0 1,147 -1.0 (-8.3, 6.9) 0.80
1 4,276 -0.7 (-4.5, 3.3) 0.74
2 4,860 -4.2 (-7.7, -0.6) 0.02 **
3 3,560 -6.2 (-10.2, -2.1) 0.004 **
4 2,097 -4.4 (-9.7, 1.2) 0.12 5 1,127 -4.4 (-11.5, 3.4) 0.26 6 572 -1.5 (-11.6, 9.8) 0.79 7 374 8.7 (-5.5, 25.1) 0.24 8 235 7.3 (-8.6, 26.0) 0.39 9 134 -3.5 (-22.0, 19.5) 0.75 10 95 1.6 (-20.8, 30.4) 0.90 11 62 -17.8 (-42.1, 16.6) 0.27
eFigure 1. Mean air temperature (ºC) and relative humidity (%) by climate cluster.
eFigure 2. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day apparent temperature and air temperature.
eFigure 3. Temperature-SIDS relationship in the summer derived from penalized spline function to test for non-linearity. Shaded area represents the 95% confidence interval.
eFigure 4. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day temperature by sex.
eFigure 5. Relationship between summertime temperature-SIDS risk coefficient and mean summer temperature in each climate cluster.
15 20 25 30 35
-0.06 -0.04 -0.02 0.00 0.02 0.04
1 2
3
4 5
6
7 8
p=0.14
Mean Summer Temperature (C)
Risk Coefficient
eFigure 6. Average air conditioning prevalence in each climate cluster in 1985-2005.
eFigure 7. Percent increase in SIDS for a 5.6 ºC (10 ºF) increase in same-day temperature by AC prevalence (tertiles). Low: <77.4% prevalence, Moderate: 77.4-95.7% prevalence, High: >95.7%
prevalence)
Low Moderate High -10
0 10 20 30