TY - JOUR
T1 - Abdominal adiposity and obstructive airway disease
T2 - Testing insulin resistance and sleep disordered breathing mechanisms
AU - Haren, Matthew T.
AU - Misan, Gary
AU - Paterson, Tracey Jayne
AU - Ruffin, Richard E.
AU - Grant, Janet F.
AU - Buckley, Jonathan D.
AU - Howe, Peter R.C.
AU - Newbury, Jonathan
AU - Taylor, Anne W.
AU - McDermott, Robyn A.
N1 - Funding Information:
South Australian Premiers Science Research Fund (RAM). MTH is supported by a Post-doctoral Training Fellowship (Public Health) from the National Health and Medical Research Council (NHMRC) of Australia (# 511345). RAM is supported by an NHMRC Public Health Practitioner Fellowship.
PY - 2012/6/28
Y1 - 2012/6/28
N2 - Background: This study examined associations of abdominal adiposity with lung function, asthma symptoms and current doctor-diagnosed asthma and mediation by insulin resistance (IR) and sleep disordered breathing (SDB).Methods: A random sample of 2500 households was drawn from the community of Whyalla, South Australia (The Whyalla Intergenerational Study of Health, WISH February 2008 - July 2009). Seven-hundred twenty-two randomly selected adults (≥18 years) completed clinical protocols (32.2% response rate). Lung function was measured by spirometry. Post-bronchodilator FEV1/FVC was used to measure airway obstruction and reversibility of FEV1 was calculated. Current asthma was defined by self-reported doctor-diagnosis and evidence of currently active asthma. Symptom scores for asthma (CASS) and SDB were calculated. Intra-abdominal fat (IAF) was estimated using dual-energy x-ray absorptiometry (DXA). IR was calculated from fasting glucose and insulin concentrations.Results: The prevalence of current doctor-diagnosed asthma was 19.9% (95% CI 16.7 - 23.5%). The ratio of observed to expected cases given the age and sex distribution of the population was 2.4 (95%CI 2.1, 2.9). IAF was not associated with current doctor-diagnosed asthma, FEV1/FVC or FEV1 reversibility in men or women but was positively associated with CASS independent of IR and SDB in women. A 1% increase in IAF was associated with decreases of 12 mL and 20 mL in FEV1 and FVC respectively in men, and 4 mL and 7 mL respectively in women. SDB mediated 12% and 26% of these associations respectively in men but had minimal effects in women.Conclusions: In this population with an excess of doctor-diagnosed asthma, IAF was not a major factor in airway obstruction or doctor-diagnosed asthma, although women with higher IAF perceived more severe asthma symptoms which did not correlate with lower FEV1. Higher IAF was significantly associated with lower FEV1 and FVC and in men SDB mechanisms may contribute up to one quarter of this association.
AB - Background: This study examined associations of abdominal adiposity with lung function, asthma symptoms and current doctor-diagnosed asthma and mediation by insulin resistance (IR) and sleep disordered breathing (SDB).Methods: A random sample of 2500 households was drawn from the community of Whyalla, South Australia (The Whyalla Intergenerational Study of Health, WISH February 2008 - July 2009). Seven-hundred twenty-two randomly selected adults (≥18 years) completed clinical protocols (32.2% response rate). Lung function was measured by spirometry. Post-bronchodilator FEV1/FVC was used to measure airway obstruction and reversibility of FEV1 was calculated. Current asthma was defined by self-reported doctor-diagnosis and evidence of currently active asthma. Symptom scores for asthma (CASS) and SDB were calculated. Intra-abdominal fat (IAF) was estimated using dual-energy x-ray absorptiometry (DXA). IR was calculated from fasting glucose and insulin concentrations.Results: The prevalence of current doctor-diagnosed asthma was 19.9% (95% CI 16.7 - 23.5%). The ratio of observed to expected cases given the age and sex distribution of the population was 2.4 (95%CI 2.1, 2.9). IAF was not associated with current doctor-diagnosed asthma, FEV1/FVC or FEV1 reversibility in men or women but was positively associated with CASS independent of IR and SDB in women. A 1% increase in IAF was associated with decreases of 12 mL and 20 mL in FEV1 and FVC respectively in men, and 4 mL and 7 mL respectively in women. SDB mediated 12% and 26% of these associations respectively in men but had minimal effects in women.Conclusions: In this population with an excess of doctor-diagnosed asthma, IAF was not a major factor in airway obstruction or doctor-diagnosed asthma, although women with higher IAF perceived more severe asthma symptoms which did not correlate with lower FEV1. Higher IAF was significantly associated with lower FEV1 and FVC and in men SDB mechanisms may contribute up to one quarter of this association.
KW - Abdominal adiposity
KW - Airway obstruction
KW - Asthma
KW - Forced Expiratory Volume
KW - Forced Vital Capacity
KW - Sleep disordered breathing
UR - http://www.scopus.com/inward/record.url?scp=84950170859&partnerID=8YFLogxK
U2 - 10.1186/1471-2466-12-31
DO - 10.1186/1471-2466-12-31
M3 - Article
C2 - 22742416
AN - SCOPUS:84950170859
SN - 1471-2466
VL - 12
JO - BMC Pulmonary Medicine
JF - BMC Pulmonary Medicine
M1 - 31
ER -