Table 1

Description of included studies

Author, study	Country, region	Direction	Population	Sample size	Age at baseline	Gender (male %)	Income measure	Obesity measure	Follow-up duration	Covariates in multivariate analysis
Brophy et al 40 MCS	UK (national)	Causation	Children	17 561	5 (mean)	NA	Income	95th BMI-percentile	4 years	Ethnic group, birth weight, enjoyment of physical activity, sedentary behaviour (watching TV), indoor activities, early introduction of solid food, smoking near child, mothers prepregnancy weight, education.
Chaffee et al 41 NLSY79	USA (national)	Causation	Women	4780	40 (mean)	0	Household income	BMI ≥30	31 years	Birth outside the USA, urban residence as a child, and residence in the South as a child, maternal variables (age, marital status, smoking during pregnancy, educational attainment, pregnancy BMI, previous excessive/inadequate gestational weight gain).
Chia42 NLSY79	USA (national)	Causation	Children	3958	8.6 (mean)	51.3	Family income	95th BMI-percentile	6 years	Mother’s characteristics (education, armed forces qualification test, age at birth of child, health limitations, migration status, marital status, overweight/obesity, living with both parents at age 14), child’s characteristics (age, gender, region of residence, birth weight, firstborn status, race, breast feeding), household size.
Demment et al 43 BMHP1	USA (New York state)	Causation	Children	595	2 (mean)	53.0	Family income	BMI z-scores	16 years 2 years	Mother’s age at time of delivery, multiparty, maternal overweight/obesity, child’s characteristics (birth weight, sex, ADHD medication use, asthma medication use, antidepressant medication use, puberty status, early life rapid weight gain).
Goisis et al 44 MCS	UK (national)	Causation	Children	11 965	5 (mean)	50.8	Family income	95th BMI-percentile	8 years	Mother smoking during pregnancy, length of breast feeding, maternal BMI, early introduction to solid foods, child’s gender, physical activity (frequency of sport, active playing with parent, use of a playground, use of a bike), sedentary behaviour (watching TV, PC use), bedtime, fruit portion per day, skipping breakfast, sweet drinks consumption.
Hoyt et al 45 CYGNET	USA (national)	Causation	Girls	174	8–10 (range)	0	Household income	95th BMI-percentile	4 year	Race/ethnicity, baseline BMI, puberty status, year of outcome measure, no of street segments household size, education (of financial provider), neighbourhood SES, food and service retail scale.
Jo46 ECLS-K	USA (national)	Causation	Children	9287	5.9 (mean)	0.51	Family income	95th BMI-percentile	9 years	Grade level, race, gender, household size, mother’s age, father’s age, school lunch, school fixed effects.
Kakinami et al 47 QLSCD	Canada (Québec)	Causation	Children	698	9.2 (mean)	45.6	Household income	85th BMI-percentile	12 years	Child’s birth weight and sex, mother’s education and migration status.
Kim and Leigh48 PSID	USA (national)	Causation	Adults	6312	41.9 (mean)	0.85	Log hourly wage	BMI ≥30	4 years	Age, sex, race, marital status, education, health insurance, smoking, region of residence, survey year.
Lee et al 49 Add health	USA (national)	Causation	Adolescents	9730	12–19 (range)	49.2	Poverty status	BMI ≥30	7 years	Age, low parental education, family structure, trouble paying bills, neighbourhood poverty, parental monitoring (watching TV, eating dinner, low-parent-child interaction, no curfew, full-time working mother), physical activity, skipping breakfast, inadequate sleep, race/ethnicity, parent obesity status.
Lee et al 50 SECCYD	USA (national)	Causation	Children, adolescents	1150	3–15 (range)	50.7	Family income	95th BMI-percentile	15 years	Age, poverty status lagged, sex, race/ethnicity, birth weight, maternal variables: age, education, figure rating scale score, marital status lagged.
Pearce et al 51 NCMP, MCS	UK (national)	Causation	Children	2 620 422	3–7 (range)	51.2	Household income	95th BMI-percentile	4 years	Maternal education, area deprivation, maternal social class.
Salsberry and Reagan52 NLSY79	USA (national)	Causation	Young women	3707	14–21 (range)	0	Income	BMI ≥30	33 years	Age, parental education, own education.
Strauss and Knight53 NLSY	USA (national)	Causation	Children	2913	0–8 (range)	56.0	Family income	95th BMI-percentile	6 years	Maternal BMI, initial weight-for-height z-score, gender, race, maternal education, marital status, cognitive score, emotional score.
Amis et al 54 Add health	USA (national)	Reverse causality	Adolescents	11 308	16 (mean)	47.2	Annual income	95th BMI percentile	13 years	Age, sex, race, no of siblings, mother’s education, mother works, father works, closeness to mother, closeness to father, school skipped, grade repeated, attention problem, watching TV (hours), playing sports, playing computer games, hanging out with friends, type of school, neighbourhood environment, mental health, general health, smoking, alcohol use, drug use, ever had sex.
Baum and Ford55 NLSY	USA (national)	Reverse causality	Young adults	51 500 (PY)	28–31 (range)	51.7	Log real wage	BMI ≥30	17 years	Race, age, education, marital status, no of children, human capital accumulation, area of residence, local unemployment rate, industry working in, AFQT score (Armed Forces Qualifying Test), migration status, speaking foreign language, mother’s education, father’s education, siblings, rotter test score (efficacy), attitudes about family roles, health limitations, At age 14: lived with both parents, received magazines, received newspaper, library card, area of residence, mother worked.
Cawley and Danziger56 WES	USA (national)	Reverse causality	Women	874	18–54 (range)	0	Earnings	BMI ≥30	6 years	No of children the respondent cares for, the no of children between the ages of 0 and 2 that the respondent cares for, indicator variables for no job market skills, low job market skills, less than a high school education, more than a high school education, one of the respondent’s children has a physical or mental health problem, respondent is currently cohabitating with a husband or boyfriend, never married, age, wave 3, wave 4, respondent has a conviction for other than a traffic offence, and respondent has a learning disability.
Conley et al 57 PSID	USA (national)	Reverse causality	Adults	3340	46–49 (range)	46.5	Log wages	BMI ≥30	18 years	Educational attainment, labour market experience, age of youngest child and age.
Han et al 36 NLSY79	USA (national)	Reverse causality	Adolescents	1974	16–20 (range)	54.1	Hourly wage	BMI ≥30	12 years	Age, race, marital status, time from latest pregnancy to the interview, education of the parents, AFQT score, self-esteem, years of employment, participated in on-the-job training, area of residence, unemployment rate in the residential unit, no of private businesses at state level, average income by state, consumer price index, education, occupation, occupation requiring social interaction.
Larose et al 35 NPHS	Canada (national)	Reverse causality	Adults	3993	40.2 (mean)	50.71	Hourly wage rate	BMI ≥30	6 years	Age, presence of small children in the household, migration status, area of residence, marital status, non-wage/spouse income, home ownership, education, smoking behaviour, drinking behaviour.
Mason37 NLSY97	USA (national)	Reverse causality	Young adults	2427	12–17 (range)	50.72	Income	BMI ≥30	9 years	Education, parental status, work experience, occupation, race, socioeconomic background (1997), household income, mother’s education, father’s education), health limitations, (Armed Services Vocational Aptitude Battery).

Add Health, National Longitudinal Study of Adolescent to Adult Health; ADHD, Attention Deficit Hyperactivity Disorder; BMHP1, Bassett Mothers Health Project; BMI, body mass index; Cygnet Study, Cohort Study of Young Girls Nutrition, Environment and Transitions; ECLS-K, Early Childhood Longitudinal Study Kindergarten; MCS, Millennium Cohort Study; NA, not available; NCMP, National Child Measurement Programme; NLSY (97), US National Longitudinal Survey of Youth (1997); NPHS, Canadian National Population Health Survey; PSID, Panel Study of Income Dynamics; PY, person-years; QLSCD, Québec Longitudinal Study of Child Development; SECCYD, Study of Early Child Care and Youth Development; SES, socioeconomic status; WES, Women’s Employment Study.