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Table 1 Description of study participants by cluster, NHANES 2005–2006

From: Endotoxin clustering with allergens in house dust and asthma outcomes in a U.S. national study

Participants and home characteristicsCluster 1Cluster 2Cluster 3P-valueAll participants
Prevalence, %17.848.933.3 100
Age groups, %   < 0.001 
  < 6 year5.96.18.9 7.0
 6–17 year9.619.917.5 17.3
  ≥ 18 year84.673.973.5 75.7
Gender, %   0.25 
 Male48.748.050.3 48.9
 Female51.352.049.7 51.1
Race/ethnicity, %   < 0.001 
 Non-Hispanic Whites58.180.455.3 68.1
 Non-Hispanic Blacks23.84.118.3 12.3
 Mexican-Americans9.56.314.0 9.4
 Other8.69.212.4 10.1
PIR, %   < 0.001 
  < 1.8532.523.946.3 32.8
  ≥ 1.8567.576.153.7 67.2
Smoker in home, %17.821.219.40.4520.0
Mildew or musty smell, %14.514.321.00.00616.6
Cockroaches in home, %12.49.523.8< 0.00114.8
Dog in home, %15.576.729.8< 0.00148.0
Cat in home, %9.969.114.1< 0.00136.9
Floor covering, %   0.38 
 Carpeted floor84.587.488.8 87.3
 Smooth surface11.69.07.9 9.1
 Combination carpet and smooth surface3.93.63.3 3.6
When was home built, %   < 0.001 
 Before 197841.044.257.8 47.8
 After 197859.055.842.2 52.2
Type of home, %   < 0.001 
 Trailer4.86.310.4 7.4
 Detached family house59.873.063.0 67.3
 Attached family house11.08.39.0 9.0
 Apartment24.412.317.6 16.2
Respiratory outcomes, %     
 Current asthma7.210.07.80.018.8
 Wheezing in past 12 months13.618.314.3< 0.00116.2
  1. Abbreviations: PIR poverty income ratio. P-value for difference in prevalence between clusters calculated using chi-square test