Blood pressure was measured in all Lifelines participants aged 8 years and older who underwent 1A Visit 1 and 2A Visit 1 (section: physical state).
Blood pressure was measured with the participant seated. The size of the cuff was chosen according to the arm circumference of the participant. For systolic and diastolic blood pressure, the average of the final three readings was recorded.

Blood pressure was measured automatically using the DinaMap PRO100 or DinaMap PRO100V2 critikon-dinamap-pro-op-manual.pdf.

• Participant is seated and informed about the procedure. Participant is requested to sit still, to keep quiet, and to not move the arm.
• Research nurse informs about contraindications: recent axillary lymph node dissection; dialysis arterial-venous shunt; complaints of quick fluid retention/edema in the arm.
• If none are present, measurement is taken at the bare upper right arm. If any are present (in the right arm) the blood pressure measurement is taken at the left upper arm. This registered by the research nurse.
• The cuff, standard size M, is placed on the bare upper arm. For proper fit of the cuff check if the end of the cuff falls within the two indicated lines. If this is not the case use a smaller (S) or a larger (L or XL) cuff to avoid errors.
• The arrow on the cuff is placed over the branchial artery, 2.5 cm above the elbow crease. It should fit snugly without being too tight.
• Dinamap is connected to a PC and recordings are processed automatically, the research nurse checks if readings are complete and additionally takes notes of the measurements.
• In total 10 (1A Visit 1) or 3 (2A Visit 1) measurements are taken.
• Cuff is removed. And if requested by participant, the last recording is given.

Blood pressure was not taken in case of:

• Lymph node surgery on the right breast or armpit
• Complaints of fluid accumulation in the right arm
• No blood pressure measurement on the side of a dialysis shunt

The following variables were measured: