Clinical Trial Details
— Status: Completed
Administrative data
NCT number |
NCT05729451 |
Other study ID # |
Dnr 2015/1864-31/2 |
Secondary ID |
|
Status |
Completed |
Phase |
|
First received |
|
Last updated |
|
Start date |
January 1, 1990 |
Est. completion date |
December 31, 2019 |
Study information
Verified date |
February 2023 |
Source |
The Swedish School of Sport and Health Sciences |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Observational [Patient Registry]
|
Clinical Trial Summary
The aim of this observational study is to investigate the association between mid-life
changes in cardiorespiratory fitness and the risk of breast cancer incidence and mortality
among Swedish women.
The main questions to answer are:
- Are changes in cardiorespiratory fitness associated with the risk of being diagnosed or
dying from/with breast cancer later in life?
Participants performed at least two occupational health assessment tests, which consisted of
a submaximal ergometer cycle test, measurement of body mass and height to calculate BMI, and
a questionnaires on physical and life style habits.
Description:
PLAN FOR THE STATISTICAL ANALYSES
This plan has been made before any data analysis has been conducted.
The primary statistical analysis aims to determine if there is any association between
changes in estimated cardiorespiratory fitness (both absolute L/min and relative ml/min/kg)
and breast cancer incidence and mortality.
Cox proportional hazards models will be analysed with inverse probability treatment weights
of time-varying confounders such as BMI, physical activity smoking and alcohol. Time stable
confounders will be baseline cardiorespiratory fitness, education, co-morbidities. Risk time
will be calculated as the time from last cardiorespiratory fitness test to the diagnosis of
breast cancer or the end of study. In addition, restricted cubic splines will be performed.
Secondary analysis will be performed to determine if the association remains after dividing
into prespecified groups. The first analysis will be conducted by grouping individuals who
decrease, stay stable or increase in cardiorespiratory fitness. The second analysis, we will
conduct is an analysis to investigate if age (proxy for menopausal status) modifies the
relationships between change in cardiorespiratory fitness and breast cancer incidence or
mortality. This will be performed in two analyses by splitting on age 50 and 60,
respectively. In the third analysis we will investigate if baseline fitness modifies the
association. This will be done with fitness both as a continuous and stratified into
tertiles.
Proportional hazard assumption was checked using scaled Schönfelts residuals.
Analysis will include four models and include confounders relevant to the outcomes and
research questions. These will be as follows:
Model 1: Baseline cardiorespiratory fitness Model 2: Baseline cardiorespiratory fitness, age,
education and date of last health assessment test Model 3: Baseline cardiorespiratory
fitness, age, education and date of last health assessment test, BMI Model 4: Baseline
cardiorespiratory fitness, age, education and date of last health assessment test, BMI,
physical activity, smoking and alcohol intake.
Sensitivity analysis: To address potential reverse causality we will exclude individuals who
are diagnosed with breast cancer within two years after the last health assessment.