BACKGROUND: A previous study of homes in Wellington, New Zealand showed that having carpets on floors was the most important determinant of floor Der p 1 levels, but there was much unexplained variability between houses in carpet levels. OBJECTIVE: To determine to what extent housing characteristics might explain this variability in Der p 1 levels between houses. METHODS: We returned to a selection of houses with carpets and sampled living room dust from 1 square metre for 1 min and from the whole floor at 5 m(2) per min. Der p 1 levels were estimated by double monoclonal antibody ELISA and are expressed as geometric mean microg/g and microg/m(2) (95% confidence intervals). Questionnaires were used to collect information on housing characteristics. RESULTS: Der p 1 levels were significantly higher in the 1 square metre sample (40.0, 31.9-50.2 microg/g; 53.4, 41.4-68.9 microg/m(2)) than in the whole room (25.8, 21.3-31.1 microg/g; 5.3, 3.8-7.4 microg/m(2)). However, results from the different sampling methods were correlated (r = 0.51, P = 0.001 for microg/g and r = 0.58, P = 0.001 for microg/m(2)). After controlling for possible confounders, houses with insulation or a room or garage below the living room had approximately half the Der p 1 concentration (P = 0.05 for both samples) and the amount of Der p 1 per m(2) (P = 0.004 for the 1 square meter sample, P = 0.06 for the whole room sample) than houses without these features. Having more than two children was associated with higher levels of Der p 1 in 1 square meter, significant (P = 0.05) for microg/m(2). Carpet underlay less than 8 mm thick was associated with an almost 3-fold increase in microg/m(2) Der p 1 (P = 0.03) and a 1.6-fold increase in microg/g Der p 1 (P = 0.08) in the whole room sample, when compared with thicker carpet underlays. CONCLUSION: The presence of insulation is the single most important housing characteristic explaining the between-house variability in Der p 1 levels on carpeted living room floors.
BACKGROUND: A previous study of homes in Wellington, New Zealand showed that having carpets on floors was the most important determinant of floor Der p 1 levels, but there was much unexplained variability between houses in carpet levels. OBJECTIVE: To determine to what extent housing characteristics might explain this variability in Der p 1 levels between houses. METHODS: We returned to a selection of houses with carpets and sampled living room dust from 1 square metre for 1 min and from the whole floor at 5 m(2) per min. Der p 1 levels were estimated by double monoclonal antibody ELISA and are expressed as geometric mean microg/g and microg/m(2) (95% confidence intervals). Questionnaires were used to collect information on housing characteristics. RESULTS: Der p 1 levels were significantly higher in the 1 square metre sample (40.0, 31.9-50.2 microg/g; 53.4, 41.4-68.9 microg/m(2)) than in the whole room (25.8, 21.3-31.1 microg/g; 5.3, 3.8-7.4 microg/m(2)). However, results from the different sampling methods were correlated (r = 0.51, P = 0.001 for microg/g and r = 0.58, P = 0.001 for microg/m(2)). After controlling for possible confounders, houses with insulation or a room or garage below the living room had approximately half the Der p 1 concentration (P = 0.05 for both samples) and the amount of Der p 1 per m(2) (P = 0.004 for the 1 square meter sample, P = 0.06 for the whole room sample) than houses without these features. Having more than two children was associated with higher levels of Der p 1 in 1 square meter, significant (P = 0.05) for microg/m(2). Carpet underlay less than 8 mm thick was associated with an almost 3-fold increase in microg/m(2) Der p 1 (P = 0.03) and a 1.6-fold increase in microg/g Der p 1 (P = 0.08) in the whole room sample, when compared with thicker carpet underlays. CONCLUSION: The presence of insulation is the single most important housing characteristic explaining the between-house variability in Der p 1 levels on carpeted living room floors.
Authors: Megan Sandel; Johnna S Murphy; Sherry L Dixon; John L Adgate; Ginger L Chew; Samuel Dorevitch; David E Jacobs Journal: J Expo Sci Environ Epidemiol Date: 2014-05-07 Impact factor: 5.563
Authors: Philippa Howden-Chapman; Anna Matheson; Julian Crane; Helen Viggers; Malcolm Cunningham; Tony Blakely; Chris Cunningham; Alistair Woodward; Kay Saville-Smith; Des O'Dea; Martin Kennedy; Michael Baker; Nick Waipara; Ralph Chapman; Gabrielle Davie Journal: BMJ Date: 2007-02-26
Authors: Rob T van Strien; Laurens P Koopman; Marjan Kerkhof; Jack Spithoven; Johan C de Jongste; Jorrit Gerritsen; Herman J Neijens; Rob C Aalberse; Henriette A Smit; Bert Brunekreef Journal: Environ Health Perspect Date: 2002-11 Impact factor: 9.031