Table 1 Summary of risk factors of adolescent thinness

Biological

Sex

Male

9 months

Main respondent

Female

Ethnicity

White

9 months

Main respondent

Indian

Pakistani & Bangladeshi

Black

Other

Maternal BMI

Underweight (< 18.5 BMI)

9 months

Biological mother

Healthy weight (≥ 18.5 & < 25.0 BMI)

Overweight/Obese (≥ 25.0 BMI)

Paternal BMI

Underweight (< 18.5 BMI)

9 months

Biological father

Healthy weight (≥ 18.5 & < 25.0 BMI)

Overweight/Obese (≥ 25.0 BMI)

Early-life

Birthweight

Low birthweight (< 2500 g)

9 months

Main respondent

Healthy birthweight (≥ 2500 g & < 4000 g)

High birthweight (≥ 4000 g)

Premature Birth

Premature (Gestational age < 37 weeks)

9 months

Main respondent

Not Premature (Gestational age ≥ 37 weeks)

Smoking During Pregnancy

Smoked

9 months

Biological Mother

Did not smoke

Breastfeeding

Breastfed for over 3 months

9 months

Main respondent

Breastfed less than 3 months

Planned Pregnancy

Planning to get pregnant

9 months

Main respondent

Pregnancy was a surprise

Socio-economic

Maternal Education

No educational qualification

9 months

Main respondent

NVQ Level 1

NVQ Level 2

NVQ Level 3

NVQ Level 4

NVQ Level 5

Income Quintile

Lower quintile

9 months

Main respondent

Second quintile

Third quintile

Fourth quintile

Highest quintile

Psychological

Maternal Postnatal Depression

Postnatal Depression (< 14 Rutter Malaise Score)

9 months

Biological Mother

No postnatal depression (≥ 14 Rutter Malaise Score)

Mother-Infant Attachment

Secure Attachment (< 21 Condon Attachment Score)

9 months

Biological Mother

Insecure Attachment (≥ 21 Condon Attachment Score)

Socio-emotional Difficulties

Low (0–13 SDQ Score)

7 years

Cohort Member’s Parents

Borderline/High (17–40 SDQ Score)

Self-esteem

Low self-esteem (> 11 Rosenberg Score)

11 years

Cohort Member

Healthy self-esteem (≤ 11 Rosenberg Score)

Life-Style

Physical Activity

Met Recommended Physical Activity Levels (≥ 60 min activity per day)

7, 11, 14 and 17 years

Main respondent (ages 7 and 11) and cohort member (age 14 and 17)

Below Recommended Physical Activity Levels (< 60 min activity per day)