That this relationship is causal is supported by the evidence of a dose-response, risk increasing with amount smoked and pack-years for all three outcomes, and (based on more limited data) decreasing with increasing age of starting to smoke for COPD and CB, and with increasing duration of quitting for COPD.
These results demonstrated that T lymphocytes have lysed with increasing duration of exposure for 72 h, and the cell membrane was destroyed, which cause the leakage of cytoplasm and the decrease of cell volume.
Stratified analyses by maternal region of birth were consistent, and showed increases in PTB with increasing duration of stay for all regions of the world.
Breast cancer increased with increasing duration of use and for 48 120 months use the SIR was 1.92 (95% CI 1.32 2.70).
Among recent users, risk increased with increasing duration of OC use for both ER+ and ER– cancer.
However, we found a significant increase in breast cancer risk with increasing duration of use (P for trend=0.012, Table 2).
There was a significant trend for increasing duration of disease and lower percentage of total brain volume (Ptrend < 0.001), lower percentage of gray matter (Ptrend < 0.001) and white matter (Ptrend < 0.001), and higher percentage of WMLs (Ptrend = 0.05) (Table 3).
An increasing trend of risk with increasing duration of use was found for sequential formulations but not for continuous-combined, although the confidence intervals were largely overlapping and the numbers in the strata for duration small in continuous-combined HRTs.
In contrast, after controlling for dose, increasing duration of use did not appear to be associated with risk (Ptrend = 0.749).
The program included successive steps, in which they had to maintain immobility for an increasing duration (from 5 to 60 seconds, cf. table 1).
Statistical models to analyze such data should thus adequately account for the increasing duration of follow-ups.
