Brief observation

Obstructive and restrictive lung disease and markers of inflammation: data from the third national health and nutrition examination

Interest in lifetime lung function trajectories has increased in the context of emerging evidence that chronic obstructive pulmonary disease (COPD) can arise from multiple disadvantaged lung function pathways, including those that stem from poor lung function in childhood. To our knowledge, no previous study has investigated both obstructive and restrictive lifetime patterns concurrently, while accounting for potential overlaps between them. We aimed to investigate lifetime trajectories of the FEV₁/forced vital capacity (FVC) ratio, FVC, and their combinations, relate these combined trajectory groups to static lung volume and gas transfer measurements, and investigate both risk factors for and consequences of these combined trajectory groups.

Using z scores from spirometry measured at ages 7, 13, 18, 45, 50, and 53 years in the Tasmanian Longitudinal Health Study (n=2422), we identified six FEV₁/FVC ratio trajectories and five FVC trajectories via group-based trajectory modelling. Based on whether trajectories of the FEV₁/FVC ratio and FVC were low (ie, low from childhood or adulthood) or normal, four patterns of lifetime spirometry obstruction or restriction were identified and compared against static lung volumes and gas transfer. Childhood and adulthood characteristics and morbidities of these patterns were investigated.

The prevalence of the four lifetime spirometry patterns was as follows: low FEV₁/FVC ratio only, labelled as obstructive-only, 25·8%; low FVC only, labelled as restrictive-only, 10·5%; both low FEV₁/FVC ratio and low FVC, labelled as mixed, 3·5%; and neither low FEV₁/FVC ratio nor low FVC, labelled as reference, 60·2%. The prevalence of COPD at age 53 years was highest in the mixed pattern (31 [37%] of 84 individuals) followed by the obstructive-only pattern (135 [22%] of 626 individuals). Individuals with the mixed pattern also had the highest prevalence of parental asthma, childhood respiratory illnesses, adult asthma, and depression. Individuals with the restrictive-only pattern had lower total lung capacity and residual volume, and had the highest prevalence of childhood underweight, adult obesity, diabetes, cardiovascular conditions, hypertension, and obstructive sleep apnoea.

To our knowledge, this is the first study to characterise lifetime phenotypes of obstruction and restriction simultaneously using objective data-driven techniques and unique life course spirometry measures of FEV₁/FVC ratio and FVC from childhood to middle age. Mixed and obstructive-only patterns indicate those who might benefit from early COPD interventions. Those with the restrictive-only pattern had evidence of true lung restriction and were at increased risk of multimorbidity by middle age.

National Health and Medical Research Council of Australia, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, The Victorian, Queensland & Tasmanian Asthma Foundations, The Royal Hobart Hospital, Helen MacPherson Smith Trust, and GlaxoSmithKline.

Objective Most previous studies focusing on the association between depressive symptoms and lung function were conducted in patients with chronic lung diseases. This study aims to investigate the association of depressive symptoms with lung function among general Chinese middle-aged and older adults.

Participants This study used data from the China Health and Retirement Longitudinal Study (CHARLS). Analyses were conducted with data from three waves (2011, 2013, and 2015) and restricted to those respondents aged 45 and older. Finally, 9487 individuals [mean age (SD) = 58.47 (9.19); female, 53.1%] were included in analysis.

Methods Depressive symptoms were measured by the Chinese version of 10-item Center for Epidemiological Studies Depression Scale (CESD-10). Lung function was assessed by peak expiratory flow (PEF). Two-level linear mixed growth models were used to evaluate the longitudinal association between depressive symptoms and PEF.

Results Depressive symptoms were significantly associated with PEF among general middle-aged and older adults (b = $-$1.85, p < 0.001) after adjusting for multiple confounding factors. A significant interaction between depressive symptoms and gender was found (b = 1.29, p < 0.001). The association between depressive symptoms and PEF was greater for men (b = $-$2.36, p < 0.001) than for women (b = $-$1.46, p < 0.001).

Conclusions This longitudinal study found that increased depressive symptoms were associated with reduced PEF in middle-aged and older adults in China. Compared with women, men with a higher level of depressive symptoms experienced a greater decrement in PEF. Our findings suggest that it is possible to reduce the effects of PEF by improving psychological health among general middle-aged and older populations.

Chronic obstructive pulmonary disease (COPD) and ischemic heart disease (IHD) are common causes of mortality worldwide, with shared risk factors. COPD continues to be largely underdiagnosed and undertreated, especially in patients with IHD.

To investigate the prevalence of COPD in smokers with confirmed IHD and to compare IHD characteristics between COPD patients and those without COPD.

It was a cross-sectional study, conducted between August and December 2017, including patients over 40 years of age, current or former smokers, with stable and confirmed IHD. Spirometry was undertaken for all participants, and COPD was defined according to GOLD criteria.

A total of 122 patients, with mean age of 59.3 years and mean pack-year of 52.3, were enrolled. Spirometry was normal in 63.2% of patients and airflow limitation was the most frequent ventilatory disorder (20.5%). COPD was diagnosed in 19.7% of patients. Of the 24 COPD patients, 17 (70.8%) were previously undiagnosed. Airflow limitation severity in COPD patients was classified mild, moderate, severe and very severe in 25%, 62.5%, 8.3% and 4.2% of patients. Comparison between COPD patients and non-COPD patients showed that comorbidities, respiratory symptoms, chest x-ray abnormalities, life-threatening lesions, three vessel disease, pulmonary hypertension and right ventricle dysfunction were significantly more frequent in COPD patients.

There was a high prevalence of COPD among smoking patients with IHD, and most were undiagnosed despite being symptomatic. Smokers with IHD, especially if having respiratory symptoms, radiological or ultrasound abnormalities or life-threatening coronary lesions should be evaluated for airflow limitation.