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Table 1 Health and social factors at 33y and 50ya and early-life covariatesb, from the 1958 British birth cohort

From: Change in health and social factors in mid-adulthood and corresponding changes in leisure-time physical inactivity in a prospective cohort

 

Age

Description

Categories/units

N(%) / Mean(SD)

Health and social factors at 33y and 50y (main exposures)

 Poor self-rated health

33y

50y

one question with 4 categories at 33y (5 categories at 50y) ranging from excellent to poor

dichotomised: ‘poor’ refers to two categories (‘fair’ and ‘poor’) combined

1444 (13.3)

1789 (18.4)

 Obesity

33y

50y

body mass index (weight (kg) /height (m)2) ≥ 30 kg/m2

No; Yes

1227 (11.5)

2395 (25.6)

 Depression

33y

50y

15 (yes/no) items at 33y (8 at 50y) from the psychological sub-scale of the Malaise Inventory

top (gender-specific) 10% defined as ‘depressed’c

1294 (11.8)

998 (10.4)

 Low self-efficacy

33y

50y

3 (yes/no) questions: feel you get what you want out of life; have free choice and control over life; run life more or less as you want to. Items summed to create a score (0–3)

defined as scores 0–2

3036 (29.6)

2552 (26.6)

 Manual SEP

33y

50y

categorized using the Registrar General’s Classification of occupations (if missing at 50y, 46y data used)

includes skilled manual and semiskilled/unskilled classes

4082 (40.1)

3063 (32.9)

 Not in paid employment

33y

50y

derived from participant reports of their current main economic activity; includes unemployed, full time education/government training, temporary/permanently sick, looking after home/family, retired, other

No; Yes

2281 (20.8)

1489 (15.3)

 Not married/co-habiting

33y

50y

not living with a lawful or live in partner, derived from household composition data

No; Yes

2263 (20.5)

1975 (20.3)

 Parenthood (number of children)

33y

50y

all children (natural/adopted/partner’s/fostered) living in the household; identified from household composition data

dichotomised as ≥2 children living in the household

5600 (55.5)

3129 (32.1)

Early-life covariates

 Pre-pubertal stature

7y

measured by trained medical staff, to the nearest inch

cm

122.4 (5.9)

 Hand control/ co-ordination problems

7y,

11y,

16y

at each age recorded as: no problems (score: 0); somewhat or certainly applies (score: 1); the three variables were summed across ages

Number of ages with problem: 0 (i.e. no problem at 7y, 11y and 16y), 1, 2, 3 (problems at 7y, 11y and 16y)

0: 6388 (57.9)

1: 3063 (27.8)

2: 1276 (11.6)

3: 308 (2.8)

 Cognitive ability

16y

derived age standardised score for reading and mathematics tests and converted to 0–100 scale. Average of tests used (if missing, average from 11/7y used); converted to internally standardised z-scores.

NAd

NAd

 SEP

birth

father’s occupation at birth (if missing at 7y); categorized using the Registrar General’s (1951) Classification

1. professional/managerial

2. skilled non-manual

3. skilled manual

4. semiskilled/unskilled/no male head

1: 2141 (18.0)

2: 1171 (9.9)

3: 5817 (48.9)

4: 2760 (23.2)

 Household amenities

7y,

11y,

16y

three questions at each age on access to bathroom/indoor lavatory/hot water, scored as: sole use (0), shared (1), not available (2); the nine questions are summed across ages.

Score range: 0–18

1.07 (2.6)

 Minimal parental education

birth, 7y

two questions on (i) mother and (ii) father having minimal schooling

No; Yes

6334 (60.1)

 Parental divorce

33y

single question on parents ever permanently separating or divorced

No; Yes

1672 (15.4)

  1. N varies dues to missing data
  2. SEP Socio-economic position
  3. a33y obesity is measured; all other 33y and 50y measures are self-reported
  4. bEarly-life covariates: measured (pre-pubertal stature), teacher reported (hand control/ co-ordination problems), tested (cognitive ability), parent-reported (social class, household amenities and parental education) or self-reported (parental divorce)
  5. csee Pinto Pereira SM et al. JAMA Psychiat. 2014; 71 (12):1373–1380
  6. dnon-standardised values are not available because measures for the combination of ages are not meaningful