Cohort Summary Statistics

The Airwave Tissue Bank is an epidemiological study of police officers and staff in Britain. It is managed and run by the Department of Epidemiology & Biostatistics at Imperial College London, and we believe it to be the only large-scale cohort study of police employees anywhere in the world.

The cohort has been richly phenotyped, flagged to routine records, and has a substantial biobank of blood and urine samples. It provides an excellent and unique resource to study the genetic, metabolic, occupational and lifestyle factors associated with mental health and cognitive performance among a predominantly male and young adult workforce with a well-defined organisational hierarchy.

The cohort was established in 2004 to investigate possible long-term health effects associated with use of TETRA, the radio system used by the police service. Mean age at recruitment was 39.8 y (σ = 16.0) and ranged from 16 - 80 y. The mean duration of follow-up at December 2022 is 13.1 y (σ = 2.9). It includes a group – younger men aged between twenty and forty years – who are particularly under-represented in the UK research portfolio, who have proven hard to engage in primary prevention, and have least routine contact with primary care. Some further statistics on the cohort are set out in the table below.

Recruitment was completed in 2015, and over the next four years a series of papers were published to evaluate the effect of TETRA on health. Whilst our overall assessment was that insufficient time has passed to form any final conclusions, we continue to follow-up the cohort through national registers, via follow-up screening and self-administered surveys.

We have also successfully re-purposed the cohort to support broader research goals into common diseases affecting this well-defined occupational group. For example, the cohort made a significant contribution to COVID-19 research, by providing 5985 volunteers for studies into novel methods for diagnosis of SAR-CoV-2 infection. We are core members of Dementia Platform UK (DPUK), UK Longitudinal Linkage Collaboration, and are listed on eight other directories supporting researchers worldwide.

Researchers can apply to our Access Committee for access to samples and data in order to carry out their own research projects. As members of the DPUK public-private partnership, researchers can build a virtual cohort of participants from the many cohorts registered with DPUK. Participants can be selected from their genotype and / or phenotype, and participants may be invited to join researchers' own projects or clinical trials.

Asset

N (participants)

Questionnaire data at baseline, net of withdrawals

53,245

Clinic-based measurements – baseline

45,594

Clinic-based measurements – follow-up

18,317

Cognitive assessment – baseline

30,944

Cognitive assessment – follow-up

14,720

7-day food diaries – baseline

23,388

7-day food diaries – follow-up

11,626

GWAS

20,193

Exome array

1,947

Methylation array

920

Metabolomics (NMR, mass spectrometry)

6,242

Blood, urine & DNA samples

45,655

Proteomics

4,972

Biological Samples

When participants attend clinics, we generally collect a sample of blood and urine in a variety of collection tubes. Following biochemistry and haematology assays, which are carried out generally within 24-hours, we store the remaining material in cryogenic conditions for more detailed assays at a later date. These have included genetic and metabolomic assays, with proteomics planned.

The following is a summary of the biological material available according to our inventories.

Collection TubeMaterial CollectedSubjectsSamplesAliquots

ACD

Immortalised Lymphocytes

43892

54503132689
Dried Blood Spot Card

Dry Blood Spot

4240

42404240
EDTA

DNA

21980

2210437520
 

FTA IsoCode card

13079

1354113550
 

Plasma

45805

67096114604
 

Red Cells

45069

66714109906
 

White Cells

34092

4666447221
 

Whole Blood

718

7185590
Lithium Heparin

Plasma

43271

58501109544
 

Red Cells

18844

1924442406
 

White Cells

33366

3397537376
Nasopharyngeal Swab

Nasopharyngeal Mucus

5435

54365436
Serum Separating Tube

Serum

45843

68013209671
Salimetrics SalivaBio Kit

Saliva

785

785788
Sodium Citrate

Plasma

43348

4417947905
 

Red Cells

18864

1926622597
 

White Cells

43204

4401947642
Tempus Tube

Whole Blood

24744

3076061949
Tempus Cryovials

Whole Blood

790

790793
Urine Pot

Urine

44352

60762210257

Descriptive Statistics by Gender

In the tables below, participants with no information on gender (N=17) are excluded. Means (SD) are presented for age and percentages are presented for all other variables; n refers to the number of participants for whom each variable is available.

Means (SD) and percentages are presented for continuous and categorical variables respectively; n refers to the number of participants for whom each variable is available. The following definitions apply:

  • SBP: systolic blood pressure.
  • DBP: diastolic blood pressure.
  • HbA1c: glycosylated haemoglobin.
  • GCSE: General Certificate of Secondary Education (usually taken at 16-years)
  • Hypertension is defined as systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg.

Demographics

MetricWomenMenTotal
N (%)19,567 (36.8)33,661 (63.3)53,228
Age (years) (n = 53,167)38.5 (9.4)40.6 (8.9)39.8 (9.1)
Marital status (%) (n = 40,889)   
Married46.768.660.5
Cohabiting20.815.117.2
Single18.77.811.9
Divorced/separated10.36.88.1
Other3.41.72.3
White (n = 38,725)9594.694.8
Black (n = 441)1.50.81.1
South Asian (n = 547)1.31.41.3
Mixed (n = 454)1.11.11.1
Other (n = 699)1.121.7
Education (%) (n = 40,889)   
Left school before taking GCSEs3.343.8
GCSE or equivalent27.631.129.8
Vocational qualification7.177
A-levels or equivalent31.132.131.7
Bachelor degree or equivalent23.120.121.2
Postgraduate qualifications7.95.76.5
Rank (%) (n = 37,251)   
Police staff47.516.427.9
Police Constable/Sergeant46.67262.6
Inspector/Chief Inspector3.3107.5
Other2.71.62
Smoking status (%) (n = 41,345)   
Non-smoker65.268.567.3
Past smoker22.72322.9
Current smoker12.18.59.8

Clinical and Biological Measurements by Gender

MetricWomenMenTotal
N (%)17,059 (36.9%)29,165 (63.1%)46,224
BMI (kg/m2) (n = 45,471)26.0 (4.7)28.0 (3.7)27.2 (4.2)
BMI < 25 kg/m2 (%)49.320.531.1
25 kg/m2 < BMI < 30 kg/m2 (%)33.854.446.8
BMI > 30 kg/m2 (%)16.925.122.1
SBP (mmHg) (n = 45,483) 122.2 (14.1)134.8 (13.7)130.1 (15.1)
DBP (mmHg) (n = 45,483)76.1 (9.5)81.2 (9.9)79.3 (10.1)
Hypertension12.934.926.8
Total cholesterol (mmol/l) (n = 45,186)5.1 (1.0)5.4 (1.1)5.3 (1.0)
Total cholesterol > 5 mmol/l53.564.760.6
HbA1c % (n = 45,019)5.6 (0.6)5.6 (0.6)5.6 (0.6)
HbA1c % < 6 (%)81.285.583.9
6 < HbA1c % < 6.5 (%)14.911.412.7
HbA1c % > 6.5 (%)3.93.13.4
Self-reported diabetes diagnosis (n = 41,100) (%)0.810.9