The association between impaired lung function and diabetes risk has been established in the past, however the temporal and causal relationships between the two remain unclear. We assessed the relationship between baseline FEV1 and FVC and risk of incident diabetes at different time intervals for participants in the Malmö Preventive Project cohort. Baseline lung function was assessed in 20,295 men and 7416 women during 1974–1992; mean age 43.4 ± 6.6 and 47.6 ± 7.8, respectively. Sex-specific quartiles of FEV1%predicted and FVC%predicted were created (Q4 = highest; reference). Follow-up time was divided into 10-year time intervals from baseline examination. Cox proportional hazards regression was used to assess the incidence of diabetes according to quartiles of FEV1 and FVC%predicted, after adjustments for baseline glucose and potential confounding factors. Over 37-years’ follow-up there were 3753 and 993 incident diabetes events in men and women, respectively. When comparing FEV1%predicted in men (Q1 vs. Q4), the HR for diabetes was 1.64 (1.21–2.22) for events 30 years after baseline. A broadly similar pattern was seen for FVC%predicted and for women. Low FEV1 precedes and significantly predicts future diabetes. This risk is still significant many years after the baseline FEV1 measurement in middle-aged men. These results suggest that there is a relationship between impaired lung function and diabetes risk beyond the effects of hyperglycemia on lung function.

Background: Impulse oscillometry (IOS) is sensitive in detecting lung function impairment. In small studies, impaired IOS relates better to respiratory symptoms than spirometry. We studied how IOS related to spirometry and respiratory symptoms in a large population of individuals (n=10 360) in a cross-sectional analysis.Methods: Normal values for IOS and spirometry were defined in healthy, never-smoking individuals, aged 50–64 years, from the Swedish CArdioPulmonary bioImage Study (n=3664 for IOS and 3608 for spirometry). For IOS, abnormal values for resistance at 5 Hz (R₅) and at 20 Hz and area of reactance were defined using the 95th percentile. Abnormal reactance at 5 Hz for IOS and abnormal conventional spirometry indices (forced expiratory volume in 1 s (FEV₁), forced and slow vital capacity and their ratios) were defined using the 5th percentile.Results: Abnormal IOS parameters were found in 16% of individuals and were associated with increased odds ratios for nearly all respiratory symptoms when adjusted for age, gender and smoking. In individuals with normal spirometry, abnormal IOS resistance was related to cough and dyspnoea, while abnormal reactance was related to wheeze. In these individuals, the combination of abnormalR₅with abnormal reactance resulted in approximately two-fold higher likelihood for having cough, chronic bronchitis and dyspnoea, even when further adjusting for FEV₁, expressed as % predicted.Conclusions: Abnormal IOS is related to increased respiratory burden in middle-aged individuals with normal spirometry, especially when resistance and reactance parameters are combined. The different relationships between respiratory symptoms and reactance and resistance warrant further research.

Purpose: The triglyceride-glucose index (TyG index) is a marker of insulin resistance and metabolic dysfunction and has the advantage of being universally available. Although recent evidence suggests the TyG index has relevance to respiratory health, there have been no prospective studies assessing its value as a biomarker for chronic lung diseases. We aim to assess the TyG index as a potential risk marker for future incident COPD events in the general population. Patients and Methods: Baseline TyG index was assessed in 28,282 middle-aged men and women without previous history of chronic obstructive pulmonary disease (COPD) from the Malmö Preventive Project (men between 1974 and 1982 and women between 1982 and 1992). All subjects were followed up prospectively, and Cox proportional hazards regression was used to assess incident COPD events according to quartiles of TyG index. Results: After an average of 31 years of follow-up, TyG index was a strong predictor of future COPD events even after adjusting for potential confounders (Q4 (highest TyG index) HR (95% CI): 1.21 (1.09– 1.35) vs Q1 (reference), p-trend < 0.001). After stratifying by sex, the results remained statistically significant in women only (Q4 vs Q1 HR 1.72 (1.41– 2.09)). Additionally, the risk remained significant in a cohort of life-long never smokers (Q4 vs Q1 HR 1.47 (1.08– 2.01)). Conclusion: A raised TyG index is a novel risk marker of future incident COPD events in women. Insulin resistance as reflected by the TyG index can precede the development of obstructive lung disease and as such may be an easily measurable and useful predictor of COPD in women.

Rationale: Postbronchodilator spirometry is used for the diagnosis of chronic obstructive pulmonary disease. However, prebronchodilator reference values are used for spirometry interpretation. Objectives: To compare the resulting prevalence rates of abnormal spirometry and study the consequences of using pre- or postbronchodilator reference values generated within SCAPIS (Swedish CArdioPulmonary bioImage Study) when interpreting postbronchodilator spirometry in a general population. Methods: SCAPIS reference values for postbronchodilator and prebronchodilator spirometry were based on 10,156 and 1,498 never-smoking, healthy participants, respectively. We studied the associations of abnormal spirometry, defined by using pre- or postbronchodilator reference values, with respiratory burden in the SCAPIS general population (28,851 individuals). Measurements and Main Results: Bronchodilation resulted in higher predicted medians and lower limits of normal (LLNs) for FEV1/FVC ratios. The prevalence of postbronchodilator FEV1/FVC ratio lower than the prebronchodilator LLN was 4.8%, and that of postbronchodilator FEV1/FVC lower than the postbronchodilator LLN was 9.9%, for the general population. An additional 5.1% were identified as having an abnormal postbronchodilator FEV1/FVC ratio, and this group had more respiratory symptoms, emphysema (13.5% vs. 4.1%; P < 0.001), and self-reported physician-diagnosed chronic obstructive pulmonary disease (2.8% vs. 0.5%, P < 0.001) than subjects with a postbronchodilator FEV1/FVC ratio greater than the LLN for both pre- and postbronchodilation. Conclusions: Pre- and postbronchodilator spirometry reference values differ with regard to FEV1/FVC ratio. Use of postbronchodilator reference values doubled the population prevalence of airflow obstruction; this was related to a higher respiratory burden. Using postbronchodilator reference values when interpreting postbronchodilator spirometry might enable the identification of individuals with mild disease and be clinically relevant.

Background: Interstitial lung abnormalities (ILA) are incidental findings on chest computed tomography (CT). These patterns can present at an early stage of fibrotic lung disease. Our aim was to estimate the prevalence of ILA in the Swedish population, in particular in never-smokers, and find out its association with demographics, comorbidities and symptoms.Methods: Participants were recruited to the Swedish CArdioPulmonary BioImage Study (SCAPIS), a population-based survey including men and women aged 50–64 years performed at six university hospitals in Sweden. CT scan, spirometry and questionnaires were performed. ILA were defined as cysts, ground-glass opacities, reticular abnormality, bronchiectasis and honeycombing.Findings: Out of 29 521 participants, 14 487 were never-smokers and 14 380 were men. In the whole population, 2870 (9.7%) had ILA of which 134 (0.5%) were fibrotic. In never-smokers, the prevalence was 7.9% of which 0.3% were fibrotic. In the whole population, age, smoking history, chronic bronchitis, cancer, coronary artery calcium score and high-sensitive C-reactive protein were associated with ILA. Both ILA and fibrotic ILA were associated with restrictive spirometric pattern and impaired diffusing capacity of the lung for carbon monoxide. However, individuals with ILA did not report more symptoms compared with individuals without ILA.Interpretation: ILA are common in a middle-aged Swedish population including never-smokers. ILA may be at risk of being underdiagnosed among never-smokers since they are not a target for screening.

Background: Although the prevalence of kidney disease is higher in those with reduced lung function, the longitudinal relationship between low lung function and future risk of chronic kidney disease (CKD) has not been widely explored.Methods: Baseline lung function was assessed in 20,700 men and 7325 women from 1974 to 1992. Mean age was 43.4 (±6.6) and 47.5 (±7.9) for men and women respectively. Sex-specific quartiles of FEV₁and FVC (L) were created (Q4: highest, reference) and the cohort was also divided by the FEV₁/FVC ratio (≥ or < 0.70). Cox proportional hazards regression was used to determine the risk of incident CKD events (inpatient or outpatient hospital diagnosis of CKD) in relation to baseline lung function after adjustment for various confounding factors.Results: Over 41 years of follow-up there were 710 and 165 incident CKD events (main diagnosis) in men and women respectively. Low FEV₁was strongly associated with future risk of CKD in men (Q1 vs Q4 adjusted HR: 1.46 (CI:1.14–1.89), p-trend 0.002). Similar findings were observed for FVC in men (1.51 (CI:1.16–1.95), p-trend 0.001). The adjusted risks were not found to be significant in women, for either FEV₁or FVC. FEV₁/FVC < 0.70 was not associated with increased incidence of CKD in men or women.Conclusion: Low FEV₁and FVC levels at baseline are a risk factor for the development of future incident CKD in men. Monitoring kidney function in those with reduced vital capacity in early life could help with identifying those at increased risk of future CKD.