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Table 2 Decomposition of the total time effect on good / poor SRH into direct and indirect effects via leisure time physical activity (LTPA) – using KHB-method for GEE logistic regression

From: Trends in self-rated health among the elderly population in Germany from 1995 to 2015 – the influence of temporal change in leisure time physical activity

  Good SRH
  Men Women
  Model 1 Model 2 Model 1 Model 2
  OR 95% CI OR 95% CI OR 95% CI OR 95% CI
Total time effect 1.38*** 1.25–1.52 1.13* 1.04–1.29 1.77*** 1.63–1.98 1.34*** 1.20–1.41
Direct time effect 1.14* 1.03–1.25 1.00 0.93–1.15 1.38*** 1.26–1.52 1.15** 1.03–1.28
Indirect time effect 1.21*** 1.19–1.24 1.13*** 1.11–1.15 1.28*** 1.24–1.31 1.17*** 1.14–1.19
  APE
(%-points)
95% CI APE
(%-points)
95% CI APE
(%-points)
95% CI APE
(%-points)
95% CI
Total time effect 7.3 5.1–9.4 2.7 0.9–5.7 12.4 10.4–14.4 6.8 4.5–9.1
Direct time effect 2.9 0.7–5.1 0.0 −1.6-3.1 7.1 5.0–9.2 3.5 1.2–5.9
Indirect time effect 4.4 ---a 2.7 --- a 5.3 --- a 3.3 --- a
Conf_ratio 2.5 --- b 1.7 2.1
Conf_pct 60.1 100.0 42.8 53.4
  Poor SRH
  Men Women
  Model 1 Model 2 Model 1 Model 2
  OR 95% CI OR 95% CI OR 95% CI OR 95% CI
Total time effect 0.75*** 0.67–0.84 1.04 0.91–1.18 0.72*** 0.65–0.80 0.99 0.88–1.12
Direct time effect 0.96 0.86–1.08 1.21** 1.07–1.38 0.92 0.83–1.03 1.18** 1.04–1.33
Indirect time effect 0.79*** 0.77–0.81 0.86*** 0.84–0.88 0.78*** 0.76–0.80 0.85*** 0.83–0.87
  APE
(%-points)
95% CI APE
(%-points)
95% CI APE
(%-points)
95% CI APE
(%-points)
95% CI
Total time effect −4.7 −6.6-2.8 0.6 −1.4-2.6 −6.0 −8.2-0.4 −0.1 −0.22-0.20
Direct time effect −0.7 −2.6-1.2 3.0 1.0–5.0 −1.4 −3.5-0.5 2.8 0.70–4.94
Indirect time effect −4.0 --- a −2.4 --- a −4.6 --- a −2.9 --- a
Conf_ratio 6.9 --- c 4.2 --- c
Conf_pct 85.5 --- c 76.3 --- c
  1. OR Odds ratio, APE Average partial effects (change in average probability of good / poor health over time in percentage points), model 1 adjusted for age, model 2 additionally adjusted for school education, income and occupational position. Conf_ratio: Confounding ratio, gives information on the total effect size relative to the direct effect size, calculated by: total effect / direct effect. Conf_pct: Confounding percentage measures the percentage change of effect attributable to confounding net of rescaling, calculated by: indirect effect / total effect. *p < 0.05, **p < 0.01, ***p < 0.001,--- a95% Confidence intervall cannot be calculated since standard errors of indirect effects are not known for APE method, −--bConf_ratio cannot be calculated in case of direct effect = 0, −--cConf_ratio and Conf_pct cannot be meaningfully interpreted in case of non-significant total effect