Table I.

Characteristics of adults 18 years and older^*, NHIS 1997–2013

Variables	Categories	All	Hay Fever	EHE95 Quartiles§
				0–10 days	11–16 days	17–24 days	25 days or more
		(n=505,386)	(n=42,601)	(n=111,524)	(n=113,255)	(n=123,998)	(n=156,609)
Total Percent		100	8.43	21.91	22.49	24.65	30.94
Hay Fever
	No	91.57	-----	21.99	22.47	24.66	30.88
	Yes	8.43	-----	21.05	22.72	24.61	31.61
Race/ethnicity
	non-Hispanic white	71.28	9.20	22.46	23.07	24.33	30.14
	non-Hispanic black	11.50	6.78	22.55	20.99	24.81	31.66
	Hispanic	12.52	5.73	18.98	20.65	25.81	34.56
	All other races and ethnicities	4.70	8.05	19.78	22.33	26.17	31.71
Sex
	Male	48.13	7.45	21.89	22.54	24.77	30.80
	Female	51.87	9.35	21.93	22.45	24.55	31.08
Age
	18–34 years	31.27	6.21	21.69	22.58	25.04	30.69
	35–49 years	29.40	10.34	21.86	22.50	24.76	30.88
	50–64 years	22.86	10.07	21.66	22.59	24.31	31.43
	65 years and older	16.48	6.98	22.78	22.16	24.21	30.85
Education
	<High school/GED	16.24	6.00	21.92	22.12	25.19	30.77
	High school/GED	28.65	6.89	22.65	22.52	24.47	30.36
	Some college	29.48	9.19	22.11	22.57	24.55	30.78
	Bachelor’s degree	16.83	10.29	21.11	22.56	24.59	31.74
	Graduate degree	8.79	11.88	20.36	22.7	24.75	32.19
Poverty Status^
	Less than 100%	12.33	6.92	21.99	21.92	24.88	31.22
	100 to less than 200%	18.40	6.96	22.79	21.91	24.70	30.60
	200 to less than 400%	31.17	7.99	22.55	22.48	24.51	30.46
	400% or greater	38.09	10.00	20.94	22.97	24.67	31.42
Urban-rural classification+
	Large central metro	28.22	8.09	17.93	22.68	27.43	31.97
	Large fringe metro	24.00	9.08	23.10	22.94	23.39	30.57
	Medium metro	20.99	8.63	22.27	21.85	23.37	32.51
	Small metro	10.13	8.56	23.00	23.26	24.63	29.12
	Micropolitan	10.20	7.86	25.52	20.43	23.83	30.22
	Non-core	6.46	7.55	26.34	24.14	22.76	26.75

All percentages were weighted using NHIS survey weights.

^*Includes sample adults 18 years and older with complete data for analytic covariates.

^§The categories of days represent the quartiles of exposure based on county of residence

⁺Counties were classified into urbanization levels based on the 2006 NCHS Urban-Rural Classification Scheme for Counties.

^{^}Family income as a percent of Poverty Threshold

EHE₉₅: Extreme heat events – days where the daily TMAX value exceeded the county and calendar month specific 95^th percentile threshold, calculated using 30 year of baseline data.