Variables | Instrument | Wave 1a | Wave 2a | Wave 3a | Objective |
---|---|---|---|---|---|
Sociodemographic and health-related variables | Â | Â | Â | Â | Â |
 Demographics (education, marital status, employment status) | Demographic questions | x | x | x | 1b |
 Comorbidities | Self-administered Comorbidity Questionnaire (SCQ) [60] | x | x | x | 1b |
 Estrogen/breast cancer related variables | Questionnaire items concerning age of onset menarche in years, number of pregnancies, total duration of breastfeeding, age of onset menopause in years | x |  |  | 1b |
 Cancer-specific health related quality of life | European Organization for Research and Treatment Quality of Life Questionnaire (EORTC QLQ-C30) [61] |  | x | x | 1a |
Overweight and body fat distribution | Â | Â | Â | Â | Â |
 BMI | Weight in kg/(Height in m)2 | x | x | x | 1a, 2a |
 Hip- and waist circumference | Self-administrated measurement by use of measurement tape | x | x | x | 1a, 2a |
Physical activity + sedentary behavior |  |  |  |  |  |
 Physical activity level and sedentary behavior | Physical Activity Scale for the Elderly (PASE) [42] | x | x | x | 1a, 2a |
 Physical activity accelerometry | 7-day accelerometer data (ActiGraph) [46] Physical activity measures: Average acceleration (AvAcc), Intensity Gradient (IG), total minutes light, moderate and vigorous physical activity per day, total minutes of inactive time per day, most active continuous 30 min (M30) per day |  | x | x | 1a, 2a |
 Functional muscle strength | 5Times-Sit-To-Stand functional muscle strength measurement: self-administrated measurement by use of stopwatch [50] |  | x | x | 2b |
Dietary intake | Â | Â | Â | Â | Â |
 Diet quality (including alcohol consumption) | Dutch Healthy Diet—index 15 (DHD-15), with minor adjustments [54] | x (shortened) | x | x | 1a, 2a |
 Dietary intake: energy and macronutrients | Online 3-day food diary: registration of all foods and drinks, in portion sizes of gram/ml, they have consumed during the day using the ‘Eetmeter’ from the Dutch ‘Voedingscentrum’ |  | x | x | 1a, 2a |
Smoking | Â | Â | Â | Â | Â |
 Smoking behaviours | Smoking behaviour questions | x | x | x | 1a, 2a |
Sleep | Â | Â | Â | Â | Â |
 Sleep quality and disturbances | Pittsburgh Sleep Quality Index (PSQI) [55] |  | x | x | 1a, 2a |
 Sleep accelerometry | 7-day accelerometer data (wristworn ActiGraph wGT3X) [46] Sleep measures: sleep latency, sleep efficiency, daytime sleep, frequency of long sleep interruptions (> 5 min), total minutes of sleep per night |  | x | x | 1a, 2a |
Lifestyle and health related measures | Â | Â | Â | Â | Â |
 Readiness for lifestyle change | Assessed according to the transtheoretical model (not ready: pre-contemplation/contemplation); (ready: preparation/action/maintenance); (relapse: relapse) [29] with 1 item per recommendation | x | x | x | 2a, 2b, 2c |
 Need for support | Need for support assessed with 1 item per recommendation | x | x | x | 1a, 2a, 2b, 2c |
 Posttraumatic growth | Posttraumatic Growth Inventory (PGI) [62] |  | x | x | 2b, 2c |
 Self-compassion | Short Form Self-Compassion Scale [63]: 6 positive items only | x | x | x | 2b, 2c |
 Emotion regulation | Cognitive Emotion Regulation Questionnaire (CERQ)—short [64] |  | x | x | 2b, 2c |
 Mental and physical fatigue | Multidimensional Fatigue Inventory (MFI) [65] |  | x | x | 2b, 2c |
 Symptoms of depression and anxiety | Hospital anxiety and depression scale (HADS) [66] |  | x | x | 2b, 2c |
Biological determinants of cancer prognosis | Â | Â | Â | Â | Â |
 Inflammation | Pro- and anti-inflammatory cytokines (TNFα, IL-6, IL-10, IL-1Ra) and CRP |  | x | x | 1c |
 Metabolism | leptin, insulin, insulin growth factor-1, glucose, HbA1C, total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, Vitamin D |  | x | x | 1c |