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. Author manuscript; available in PMC: 2017 Jul 19.
Published in final edited form as: Ann Allergy Asthma Immunol. 2008 Nov;101(5):517–523. doi: 10.1016/S1081-1206(10)60291-8

TABLE I.

Geometric mean concentrations for the Can f 1 and Fel d 1 house indices by demographic and housing characteristics

Geometric Mean (SE) Concentration in µg/g

Characteristic N Can f 1 P Fel d 1 P
Total 825 4.69 (0.56) 4.73 (0.46)
Year home constructed
  1978–1998 219 6.15 (1.52) 5.15 (0.95)
  1977 or earlier 606 4.15 (0.43) .116 4.55 (0.63) .635
1990 census region
  Northeast 153 2.92 (0.74) 4.34 (1.15)
  Midwest 195 4.68 (1.20) 5.16 (0.86)
  South 277 5.41 (1.22) 3.19 (0.41)
  West 200 5.82 (1.06) .158 9.88 (2.26) .001
Metropolitan Statistical Area (MSA)
  MSA ≥ 1 million 273 3.82 (0.77) 4.34 (0.93)
  MSA < 1 million 414 4.50 (0.83) 5.24 (0.68)
  Not an MSA 138 6.45 (1.49) .234 4.27 (0.76) .575
Housing unit type
  Single family 700 5.83 (0.74) 4.90 (0.53)
  Multifamily 125 1.19 (0.25) < .001 3.78 (1.18) .452
Owner/renter
  Owner occupied 538 6.68 (1.01) 4.73 (0.58)
  Renter occupied 284 2.10 (0.33) < .001 4.77 (1.08) .972
Number of persons in household
  1 124 2.51 (0.60) 5.05 (1.48)
  2 252 5.93 (1.24) 4.29 (0.77)
  3 171 4.37 (0.92) 5.27 (0.98)
  4 or more 278 5.56 (0.89) .007 4.75 (0.81) .901
Child < 18 years of age
  Yes 395 4.83 (0.62) 4.83 (0.73)
  No 427 4.61 (0.80) .825 4.66 (0.62) .859
Household income
  < $20,000 187 2.54 (0.49) 2.70 (0.60)
  $20,000–39,999 227 3.40 (0.64) 4.03 (0.91)
  $40,000–59,999 150 8.56 (2.24) 7.06 (1.65)
  ≥$60,000 202 6.81 (1.30) < .001 6.83 (1.63) .007
Race of youngest member
  White 619 6.34 (0.82) 6.51 (0.74)
  Black 115 1.09 (0.28) 0.69 (0.14)
  Other 76 1.86 (0.44) < .001 2.40 (0.70) < .001
Youngest member Hispanic
  Yes 85 1.29 (0.32) 1.33 (0.28)
  No 731 5.34 (0.69) < .001 5.20 (0.52) < .001
Highest education any member
  Less than high school 82 2.87 (1.04) 3.90 (1.27)
  High school diploma 175 3.96 (0.95) 2.28 (0.63)
  Above high school 554 5.34 (0.69) .237 6.03 (0.72) .012
Household poverty level
  At or below 137 2.46 (0.56) 3.12 (0.82)
  Above 645 5.34 (0.65) .003 5.08 (0.55) .088
Home’s main heating source
  Gas or electric forced air 559 5.47 (0.80) 4.90 (0.63)
  Steam or hot water radiator 75 3.60 (1.33) 4.99 (1.25)
  Other (space heater, etc) 188 3.43 (0.51) .045 4.00 (0.83) .686
Air conditioner in the home
  Yes 650 5.19 (0.72) 4.86 (0.57)
  No 174 3.12 (0.48) .022 4.31 (1.34) .737
Air filtration device in the home
  Yes 101 3.98 (1.02) 4.00 (1.32)
  No 705 4.92 (0.63) .437 4.88 (0.52) .576
Season sampled
  Winter 195 5.52 (1.32) 6.40 (1.50)
  Summer 285 5.08 (0.91) 4.09 (0.73)
  Fall 345 3.84 (0.71) .427 4.40 (0.65) .316
Dog currently living in the home
  Yes 247 69.23 (7.88) 7.33 (1.41)
  No 570 1.33 (0.12) < .001 3.84 (0.55) .020
Cat currently living in the home
  Yes 187 9.42 (2.24) 199.70 (31.22)
  No 630 3.78 (0.51) .001 1.47 (0.09) < .001

For each allergen, the house index represents the mean of the sample location concentrations.