Table 2.
RR (95% CI) of kidney stone presentation cumulated over a 20-day lag period associated with mean daily temperature (°C) relative to 10°C based on data from privately insured residents of Atlanta, Chicago, Dallas, Los Angeles, and Philadelphia, 2005–2011.
| Mean daily temperature (°C) | Atlanta | Chicago | Dallas | Los Angeles | Philadelphia |
|---|---|---|---|---|---|
| 36 | NA | NA | 1.39 (1.06, 1.82)* | NA | NA |
| 34 | NA | NA | 1.38 (1.08, 1.77)* | NA | NA |
| 32 | NA | 1.46 (1.10, 1.95)* | 1.37 (1.09, 1.72)* | NA | 1.68 (1.07, 2.64)* |
| 30 | 1.38 (1.07, 1.79)* | 1.37 (1.07, 1.76)* | 1.36 (1.10, 1.69)* | 1.11 (0.73, 1.68) | 1.47 (1.00, 2.17)* |
| 28 | 1.34 (1.06, 1.69)* | 1.28 (1.04, 1.58)* | 1.35 (1.10, 1.65)* | 1.12 (0.81, 1.54) | 1.30 (0.93, 1.80) |
| 26 | 1.30 (1.05, 1.60)* | 1.20 (1.01, 1.44)* | 1.32 (1.09, 1.62)* | 1.12 (0.86, 1.47) | 1.16 (0.87, 1.54) |
| 24 | 1.26 (1.03, 1.53)* | 1.14 (0.99, 1.31) | 1.30 (1.07, 1.57)* | 1.13 (0.89, 1.44) | 1.05 (0.82, 1.34) |
| 22 | 1.21 (1.00, 1.46)* | 1.08 (0.96, 1.21) | 1.26 (1.06, 1.50)* | 1.14 (0.90, 1.43) | 0.97 (0.77, 1.21) |
| 20 | 1.17 (0.98, 1.39) | 1.03 (0.95, 1.13) | 1.22 (1.04, 1.42)* | 1.14 (0.93, 1.40) | 0.91 (0.75, 1.12) |
| 18 | 1.12 (0.97, 1.31) | 1.00 (0.94, 1.07) | 1.17 (1.03, 1.33)* | 1.14 (0.96, 1.36) | 0.89 (0.74, 1.06) |
| 16 | 1.08 (0.96, 1.22) | 0.98 (0.93, 1.03) | 1.12 (1.02, 1.23)* | 1.13 (0.97, 1.31) | 0.89 (0.77, 1.03) |
| 14 | 1.04 (0.97, 1.13) | 0.97 (0.94, 1.01) | 1.07 (1.01, 1.14)* | 1.10 (0.97, 1.25) | 0.91 (0.83, 1.01) |
| 12 | 1.02 (0.98, 1.05) | 0.98 (0.96, 1.00)* | 1.03 (1.00, 1.06)* | 1.06 (0.97, 1.15) | 0.95 (0.90, 1.00)* |
| 10 | Referent | Referent | Referent | Referent | Referent |
| 8 | 1.00 (0.97, 1.03) | 1.03 (1.01, 1.05)* | 0.98 (0.95, 1.00) | 0.93 (0.83, 1.05) | 1.06 (1.01, 1.11)* |
| 6 | 1.02 (0.97, 1.08) | 1.07 (1.02, 1.11)* | 0.97 (0.92, 1.02) | 0.86 (0.66, 1.12) | 1.11 (1.02, 1.21)* |
| 4 | 1.07 (0.99, 1.16) | 1.11 (1.04, 1.18)* | 0.97 (0.88, 1.07) | 0.79 (0.52, 1.21) | 1.15 (1.03, 1.30)* |
| 2 | 1.14 (1.01, 1.29)* | 1.15 (1.05, 1.25)* | 0.99 (0.85, 1.15) | NA | 1.18 (1.03, 1.35)* |
| 0 | 1.23 (1.03, 1.47)* | 1.18 (1.06, 1.31)* | 1.01 (0.81, 1.27) | NA | 1.19 (1.02, 1.38)* |
| –2 | 1.34 (1.04, 1.73)* | 1.20 (1.07, 1.35)* | 1.05 (0.77, 1.43) | NA | 1.18 (0.99, 1.40) |
| –4 | 1.47 (1.06, 2.05)* | 1.21 (1.06, 1.37)* | 1.09 (0.73, 1.63) | NA | 1.16 (0.94, 1.42) |
| –6 | NA | 1.19 (1.04, 1.35)* | 1.15 (0.70, 1.89) | NA | 1.12 (0.87, 1.45) |
| –8 | NA | 1.15 (1.01, 1.31)* | 1.20 (0.66, 2.20) | NA | 1.09 (0.79, 1.49) |
| –10 | NA | 1.10 (0.96, 1.25) | NA | NA | 1.05 (0.71, 1.55) |
| –12 | NA | 1.03 (0.90, 1.18) | NA | NA | NA |
| –14 | NA | 0.95 (0.81, 1.12) | NA | NA | NA |
| –16 | NA | 0.87 (0.72, 1.06) | NA | NA | NA |
| –18 | NA | 0.80 (0.63, 1.00) | NA | NA | NA |
| –20 | NA | 0.72 (0.55, 0.95)* | NA | NA | NA |
| –22 | NA | 0.65 (0.47, 0.90)* | NA | NA | NA |
| Estimates of RR and CIs were not available (NA) for temperatures that were outside of the temperature range for each city. Distributed lag nonlinear models allowing for overdispersion were used to estimate the results for each city: Yt ~ Poisson(μ) = α + βTt,l + S(RHt) + DOWt + montht + yeart, where t = day of observation; Yt = observed stone counts on t; α = intercept; l = lag days; Tt,l = cross-basis matrix of temperature and lag; S(RH) = cubic spline of relative humidity; DOWt = indicator variable for day of the week at t to control for daily fluctuations in outdoor activities; month and year are indicator variables to control for season, temperature trends, and differences in the annual at-risk population. *p < 0.05. | |||||