Comparison of responders and non-responders to the mental health online questionnaire containing childhood maltreatment in the UK Biobank
| Men | Women | |||
| Non-responders n=160 894 (70.2%) | Responders* n=68 240 (29.8%) | Non-responders n=184 240 (67.4%) | Responders* n=89 071 (32.6%) | |
| Continuous variables: mean (SD) | ||||
| Age (years) | 56.8 (8.4) | 56.6 (7.8) | 56.8 (8.1) | 55.5 (7.7) |
| SBP (mmHg) | 141.3 (17.8) | 140.0 (16.8) | 136.3 (19.5) | 133.4 (18.4) |
| DBP (mmHg) | 84.2 (10.1) | 83.8 (9.8) | 81.0 (10.1) | 80.1 (9.8) |
| BMI (kg/m2) | 28.0 (4.3) | 27.3 (4.0) | 27.4 (5.3) | 26.4 (4.9) |
| Categorical variables: % | ||||
| Ethnicity (white) | 93.5 | 97.1 | 93.4 | 97.1 |
| Townsend deprivation index | ||||
| First quintile (20% least deprived) | 18.7 | 23.5 | 19.0 | 22.1 |
| Fifth quintile (20% most deprived) | 22.9 | 15.2 | 21.2 | 15.9 |
| Qualifications | ||||
| None of the below | 22.0 | 7.2 | 22.2 | 6.8 |
| Other/NVQ/CSE | 20.8 | 15.5 | 17.3 | 12.8 |
| O-level | 19.3 | 17.4 | 24.4 | 21.9 |
| A-level | 9.6 | 12.3 | 10.7 | 14.5 |
| College/university degree | 28.4 | 47.5 | 25.4 | 44.1 |
| Maternal smoking | ||||
| No | 60.2 | 62.0 | 62.6 | 63.9 |
| Yes | 26.5 | 25.8 | 25.1 | 25.2 |
| Do not know | 13.4 | 12.2 | 12.3 | 10.9 |
| Smoking status | ||||
| Never smoker | 34.4 | 35.5 | 45.2 | 43.9 |
| Former smoker | 51.4 | 55.9 | 44.5 | 49.9 |
| Current smoker | 14.3 | 8.6 | 10.3 | 6.2 |
| Alcohol intake | ||||
| Daily or almost daily | 24.0 | 28.6 | 14.6 | 19.1 |
| 3–4 x/week | 24.9 | 28.7 | 18.8 | 23.9 |
| 1–2 x/week | 26.6 | 24.2 | 25.9 | 25.4 |
| 1–3 x/month | 9.1 | 8.5 | 13.1 | 12.9 |
| Special occasions only | 8.1 | 5.6 | 16.6 | 12.0 |
| Never | 7.2 | 4.4 | 11.0 | 6.5 |
| Depression | 27.2 | 25.6 | 42.4 | 40.2 |
| Use of blood pressure medication | 26.6 | 20.5 | 20.2 | 12.6 |
| Use of cholesterol-lowering medication | 24.5 | 19.7 | 14.7 | 8.8 |
| Family history of CVD | 70.7 | 72.5 | 77.4 | 77.7 |
| Any CVD | 63.2 | 54.3 | 52.0 | 40.3 |
| Hypertensive disease | 51.9 | 43.4 | 40.1 | 29.4 |
| Ischaemic heart disease | 15.6 | 10.0 | 7.1 | 3.6 |
| Cerebrovascular disease | 5.1 | 2.5 | 3.3 | 1.4 |
| Early onset | 12.6 | 10.0 | 9.4 | 7.1 |
All P-values for comparisons between non-responders and responders were <0.001, except for family history of CVD in women, which was 0.022.
*From the responders to the childhood maltreatment questionnaire, 98.4% of men and 97.1% of women responded to all questions on childhood maltreatment.
A-level, advanced level or equivalent; BMI, Body mass index; CSE, certificate of secondary education or equivalent; CVD, cardiovascular disease; DBP, diastolic blood pressure; HND, higher national diploma of equivalent; NVQ, national vocational qualification; O-level, ordinary level; SBP, systolic blood pressure.