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Lung function and cardiovascular risk in young adults
thesisposted on 2023-05-26, 01:46 authored by Curry, BA
Associations between poor lung function (LF) and cardiovascular disease (CVD) have been reported in patients with chronic obstructive pulmonary disease and in population samples of older adults, including lifelong non-smokers. There are few studies of this association in young adults. Common modifiable risk factors for poor LF and CVD that might explain the association include smoking, low levels of physical activity, low cardiorespiratory fitness (CRF) and obesity. Systemic inflammation indicated by markers such as C-reactive protein (CRP), might also be explanatory. Aim The aims of this study were: 1) to investigate the cross-sectional and longitudinal associations of modifiable CVD risk factors with adult LF and 2) to investigate cross-sectional associations of young adult LF with CRP and carotid artery structure and function as subclinical indicators of atherosclerosis. Methods Data for this study were obtained from sub-samples of 2,410 participants of the 1985 Australian Schools Health and Fitness Survey who had follow up health assessments between 2004-2006 when aged 26-36 years of age. Data from at least 1,700 participants were used to investigate cross-sectional associations of smoking, CRF, adiposity and CRP with adult LF (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Longitudinal data were also examined to determine the effects on adult LF of: childhood and parental smoking (in 278 daily and 1,515 never smokers respectively), poor childhood CRF and obesity (among approximately 600 participants with baseline data). Associations between adult lung function and ultrasound measures of carotid intima-media thickness (cIMT) and arterial elasticity were also assessed. Results Adult smokers had higher mean lung volumes than non-smokers. Among daily smokers, cumulative cigarette exposure and childhood smoking had significant independent negative effects on adult LF. Higher CRF was positively associated with LF and was independent of adiposity among females. Adiposity was negatively associated with LF. Adult fitness and adiposity were much more strongly associated with adult LF than were childhood measures.Weak negative associations between CRP and adult LF were observed which were stronger in participants with greater than average adiposity. Lower FEV1 and FVC in female never-smokers and lower FEV1/FVC in ever-smoking males were associated with thicker cIMT, but the latter associations were confounded by cumulative smoke exposure. No independent associations between lung function and arterial elasticity were observed for males or females. Conclusion Overall, adiposity was more strongly associated with LF than either smoking, CRF or CRP. In these young adults, there was little evidence of an independent association between LF and subclinical atherosclerosis in males. However, a significant association between LF and cIMT was evident for female never smokers independent of other known CVD risk factors.
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