Table 4.

Odds ratios (95% confidence intervals) between 3-d moving averages of maximum DI and health outcomes stratified by individual and neighborhood factors for City of Houston residents (June–September, 2000–2015).

Strata	CIRC deaths	$p$-Valuea	HEAT deaths	$p$-Valuea	CIRC EHA	$p$-Valuea	HEAT EHA	$p$-Valuea
Sex
Female	1.16 (0.92, 1.47)		1.17 (0.95, 1.44)		1.08 (0.89, 1.31)		1.14 (0.97, 1.33)
Male	1.52 (1.17, 1.99)	0.13	1.23 (0.98, 1.55)	0.72	1.17 (0.92, 1.50)	0.60	1.09 (0.90, 1.32)	0.73
Age group (y)
65–74	1.55 (1.11, 2.17)		1.41 (1.05, 1.90)		1.14 (0.90, 1.44)		1.11 (0.92, 1.34)
$>74$	1.25 (1.01, 1.53)	0.28	1.14 (0.95, 1.36)	0.22	1.11 (0.91, 1.36)	0.88	1.13 (0.96, 1.32)	0.91
Race
White	1.39 (1.07, 1.81)		1.19 (0.94, 1.49)		0.89 (0.65, 1.20)		0.90 (0.71, 1.15)
African American	1.41 (1.07, 1.86)	0.96	1.36 (1.06, 1.73)	0.43	1.34 (1.05, 1.71)	0.04	1.24 (1.02, 1.51)	0.04
CBG percentage African Americanb
$\le 60$	1.39 (1.11, 1.73)		1.16 (0.96, 1.41)		1.01 (0.84, 1.22)		1.01 (0.87, 1.17)
$>60$	1.49 (1.05, 2.12)	0.72	1.59 (1.16, 2.17)	0.1	1.41 (1.04, 1.93)	0.07	1.43 (1.11, 1.84)	0.02
CBG percentage below povertyc
$\le 15$	1.46 (0.91, 2.33)		1.28 (0.85, 1.93)		1.17 (0.78, 1.76)		1.07 (0.78, 1.49)
$>15$	1.43 (1.16, 1.76)	0.94	1.29 (1.07, 1.55)	0.9	1.12 (0.93, 1.34)	0.83	1.12 (0.97, 1.30)	0.82
CBG percentage living aloned
$\le 24$	1.22 (0.93, 1.59)		1.17 (0.93, 1.48)		1.14 (0.92, 1.43)		1.15 (0.96, 1.38)
$>24$	1.41 (1.12, 1.78)	0.42	1.23 (1.00, 1.51)	0.77	1.09 (0.89, 1.35)	0.78	1.10 (0.93, 1.30)	0.72

Note: Mortality data were available 2000–2015; EHA data were available 2004–2013. Odds Ratios were derived from single-exposure, time-stratified case-crossover models (conditional logistic regression), that matched on U.S. CBG of subject residence, year, month, and weekday of the adverse health event. Models controlled for federal holidays, day of the warm season, maximum ambient temperature and maximum ambient dew point temperature (in degrees Celsius, modeled as cubic polynomials). CBG, U.S. Census block group; CIRC, diseases of the circulatory system; EHA, emergency hospital admission; HEAT, heat-related illnesses; OR, odds ratio.

^aStatistical evidence for effect modification was assessed by estimating the degree of heterogeneity between stratum-specific ORs in pairwise comparisons (Kaufman and MacLehose 2013). Referent groups for each stratum were female sex, 65- to 74-y-old age group, White race, $\le 60\%$ African American, $\le 60\%$ poverty, $\le 24\%$ live alone.

^bCBG-level percentage of households living below the federal poverty line.

^cCBG percentage of the $\ge 65\text{-y-old}$ population living alone.

^dCBG percentage of the population that identifies as African American.