Fig. 1
From: Association between pulmonary function and peak oxygen uptake in elderly: the Generation 100 study
Predicted effect plots for hockey-stick models. In separate models forced expiratory volume in 1 s (FEV1) in litres, diffusing capacity of the lung for carbon monoxide (DLCO) in mmol/min/kPa and DLCO corrected for estimated alveolar volume (DLCO/VA) in mmol/min/kPa/l were added as variables with change points. Dependent variable is peak oxygen uptake in ml/min/kg. All models included age, self-reported physical activity, resting heart rate, body-fat percentage, self-reported history of heart disease and current smoking status as control variables. To illustrate the isolated effect of the lung function parameters, control variables were set to sample mean for these plots. Vertical lines mark change-points; dashed lines mark lower limit of normal; grey fields mark 95 % confidence interval for slopes; dots mark observations. Change-points were significant (p < 0.5) for FEV1 for both sexes and for DLCO for men, but not for DLCO for women and DLCO/VA for neither sex