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Phenotype definitions

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gracemarionpower edited this page Jun 18, 2025 · 36 revisions

We are currently including the following set of phenotypes in this analysis round. To be included a cohort will need to provide at least one phenotype. The list is somewhat aspirational and if bandwidth limits the number of phenotypes that can be contributed, that is fine.

All traits will use the following static covariates

  • sex (1=Male, 2=Female)
  • yob (Can be approximate to distinguish generations if exact values are not available)

Any phenotype-specific covariates required are listed below. Note that Phenotype-specific covariates can be time-varying (e.g. medications may start and stop over the lifecourse if there is longitudinal data for an individual).

To see an example of the relevant data files and their columns / formats required for each phenotype please see here: https://github.com/MRCIEU/Lifecourse-GWAS/tree/main/test/example-data

To ensure consistency and comparability across cohorts, we request that measures collected during pregnancy be excluded, as physiological changes during this period may introduce systematic differences.

Additionally, measures should be sourced from regularly scheduled cohort visits rather than opportunistic data capture, such as emergency room visits or other unplanned medical encounters. This approach enhances data reliability and ensures greater standardisation across cohorts.

Anthropometric

Body Mass Index (BMI)

  • Units: kilograms/metres2 (kg/m2)

Note: These data will also be used to calculate BMI-for-age z-scores, applying the WHO growth reference standards for individuals aged 0 to 19 years. This standardised approach ensures accurate age- and sex-specific assessments based on internationally recognised benchmarks.

Height

  • Definition: Standing height
  • Units: centimeters (cm)

Waist circumference

  • Units: centimeters (cm)

Waist to hip ratio (WHR)

  • Definition: Divide the waist measurement (cm) by hip measurement (cm) (cm/cm)
  • Units: Absolute ratio

Bone mineral density (BMD)

  • Definition: Total body bone mineral density (TB-BMD) measured using Dual-Energy X-ray Absorptiometry (DXA) scanning equipment.
  • Units: grams/centimeters^2 (g/cm2)

Lung function

Forced expiratory volume in 1 second (FEV1)

  • Units: Litres (l)

 FEV1/FVC ratio

  • Definition: Ratio of Forced expiratory volume in 1 second (litres) to Forced Vital Capacity (litres)
  • Units: Please state whether absolute ratio value or Z-scores are being provided.

Cardiovascular

Systolic blood pressure (SBP)

  • Definition: Automated reading
  • Units: millimetres of mercury (mmHg)
  • Covariates
    • bp_med: blood pressure medication (1=Yes, 0=No). We will adjust for blood pressure medication by applying a constant increase of 15mmHg in individuals taking medication.

Diastolic blood pressure (DBP)

  • Definition: Automated reading
  • Units: millimetres of mercury (mmHg)
  • Covariates:
    • bp_med: blood pressure medication (1=Yes, 0=No). We will adjust for blood pressure medication by applying a constant increase of 10mmHg in individuals taking medication.

Pulsatile blood pressure (PP)

Pulsatile blood pressure (PP) will be calculated as the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP), using the formula: PP = SBP - DBP.

Blood measures

Low density lipoprotein (LDL) cholesterol

  • Definition: blood measure
  • Units: millimoles per liter (mmol/L)
  • Covariates:
    • cholesterol_med: statin medication use (1 = Yes, 0 = No). We will adjust for statin/cholesterol lowering medication by applying a relative reduction to the measured value of 40%.

High density lipoprotein (HDL) cholesterol

  • Definition: blood measure
  • Units: millimoles per liter (mmol/L)
  • Covariates:
    • cholesterol_med: statin medication use (1 = Yes, 0 = No). This will be included as a binary covariate.

Triglycerides

  • Definition: blood measure
  • Units: millimoles per liter (mmol/L)
  • Covariates:
    • cholesterol_med: statin medication use (1 = Yes, 0 = No). This will be included as a binary covariate.

Glycated haemoglobin (HbA1c)

  • Definition: blood measure
  • Units: millimoles per liter (mmol/mol)
  • Covariates:
    • insulin_med: Insulin medication use (1 = Yes, 0 = No).

Leptin

  • Definition: blood measure
  • Units: nanogram per milliliter (ng/ml)

Insulin

  • Definition: blood measure. Conversion factor 1 μIU/mL = 6.00 pmol/L.
  • Units: pmol/L
  • Covariates:
    • insulin_med: Insulin medication use (1 = Yes, 0 = No).

Adiponectin

  • Definition: blood measure
  • Units: micrograms per milliliter (μg/ml)

Calcium

  • Definition: blood measure
  • Units: millimoles per liter (mmol/L)

Vitamin D

  • Definition: blood measure
  • Units: nanomoles per liter (nmol/L)

Immune markers

C-reactive protein (CRP)

  • Definition: blood measure
  • Units: milligrams per liter (mg/L)

Interleukin-6 (Il6)

  • Definition: blood measure
  • Units: picograms per millilitre (pg/ml)

Sex hormones

Estradiol

  • Definition: blood measure
  • Units: picomoles per liter (pmol/L)
  • Covariates:
    • hormone_med: hormonal contraception or hormone replacement therapy (1 = Yes, 0 = No). If data is missing or not available then set this value to 0. We will conduct a sensitivity analysis at the meta-analysis stage, to assess whether potential heterogeneity in GxAge interaction effects observed are attributed to unadjusted drug use.

Total testosterone

  • Definition: blood measure
  • Units: nanomoles per liter (nmol/L)
  • Covariates:
    • hormone_med: hormonal contraception or hormone replacement therapy (1 = Yes, 0 = No). If data are missing or not available then set this value to 0. We will conduct a sensitivity analysis at the meta-analysis stage, to assess whether potential heterogeneity in GxAge interaction effects observed are attributed to unadjusted drug use.

Bioavailable testosterone

  • Definition: blood measure
  • Units: nanomoles per liter (nmol/L)
  • Covariates:
    • hormone_med: hormonal contraception or hormone replacement therapy (1 = Yes, 0 = No). If data are missing or not available then set this value to 0. We will conduct a sensitivity analysis at the meta-analysis stage, to assess whether potential heterogeneity in GxAge interaction effects observed are attributed to unadjusted drug use.

Sex hormone binding globulin

  • Definition: blood measure
  • Units: nanomoles per liter (nmol/L)
  • Covariates:
    • hormone_med: hormonal contraception or hormone replacement therapy (1 = Yes, 0 = No). If data are missing or not available then set this value to 0. We will conduct a sensitivity analysis at the meta-analysis stage, to assess whether potential heterogeneity in GxAge interaction effects observed are attributed to unadjusted drug use.

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