Findings and impact of the 1970 British Cohort Study

Over the years, the 1970 British Cohort Study has proven to be a valuable source of information for researchers and policymakers. Since its creation, it has had a significant impact on UK policy, on issues such as smoking during pregnancy, education and wellbeing.

Key findings


Parents’ smoking

Researchers have used the 1970 British Cohort Study (BCS70), to investigate the effects of smoking during pregnancy, and of parents’ smoking in general. Various studies have found that parents’ smoking is connected to outcomes in their children from birth through to adulthood.

One study revealed that babies born to mothers who smoked had lower birth weights than those born to mothers who did not smoke [1]. The same study also found that children of disadvantaged women who smoked during pregnancy were at higher risk of being stillborn or dying in the first few weeks of life.

Findings have shown that children whose mothers smoke are more likely to be admitted to hospital for lower respiratory tract illness during their first five years of life [2]. In addition, research suggests they are also more likely to suffer hearing problems and ear discharge at age 5 [3].

The likelihood of children experiencing wheezy bronchitis at age 10 increased with the number of cigarettes mothers smoked [4]. The study noted a 14 per cent increase in childhood wheezy bronchitis when mothers smoked over four cigarettes per day. This figure jumped to 49 per cent when mothers smoked over 14 cigarettes daily.

Information from BCS70 has shed light on links between parents’ smoking and their adolescent children’s health. Teenagers living in households where parents smoked had lower levels of fibre, vitamin C, vitamin E, folates and magnesium [5]. The same study found that teenagers living with parents who smoked were more likely to consume food with lower levels of nutrients than those living in non-smoker households.

Researchers have also used BCS70 to investigate the effects of smoking during pregnancy on adult health. Men and women whose mothers smoked while pregnant showed more signs of physical and mental distress at age 30 [6].


Information from BCS70 has been used to explore the issue of overweight and obesity in mid-adulthood.

One study found that men are significantly more likely to be overweight or obese in middle age than women [7]. At age 42, more than two thirds of British men were either overweight (45 per cent) or obese (23 per cent). At the same age, 29 per cent of women were classed as overweight and 20 per cent as obese.

The same study compared rates of overweight and obesity across two generations. It found that those born in 1970 were more likely to be obese at age 42 compared to those born in 1958. Researchers explained that people born in 1970 grew up at a time when lifestyles were becoming more inactive and high-calorie convenience food more widely available. They discovered that 47 per cent of men and women reported eating convenience food at least once or twice a week. Of those classed as obese, 32 per cent ate takeaways at least once a week compared to 21 per cent of those of a normal weight [7].

One team of researchers tracked changes in BMI across three different generations using measurements taken from people born in 1946, 1958 and 1970. The study found that over the years, children from disadvantaged backgrounds entered middle age at greater risk of obesity compared to their better-off peers [8]. Among the 1970 generation, women in unskilled jobs had BMIs almost four points higher, on average, than their professional peers at age 42.

Findings from BCS70 have found a link between parents’ and children’s weight throughout their early years and into mid-adulthood. Children with obese mothers and fathers were up to five times more likely to be overweight or obese by the time they reached their forties [9]. The evidence suggests the higher the parents’ BMI, the more the children were at risk of being overweight or obese by the time they were 42.

One study explored the link between watching television and weight by comparing the television viewing habits of Generation X at age 10 with age 30. It found that 10-year-olds who reported ‘often’ watching television were much more likely to spend three or more hours in front of television a day at age 42 [10]. Those 42-year-olds were more likely to report being overweight or obese.

Nutrition and exercise

BCS70 has been used to look at the role of nutrition and exercise on different aspects of our lives.

Evidence from the study has shown that there is an association between breastfeeding and social mobility. Researchers found that children who were breastfed were 24 per cent more likely to have moved upwards on the social ladder by the time they were age 34 [11]. Breastfeeding also reduced an individual’s odds of downward social mobility by around 20per cent.

One group of researchers examined whether motor coordination in childhood is linked to sedentary behaviour in mid-adulthood. Findings revealed that children with good motor coordination at age 10 tended to lead more physically active lifestyles at age 42 [12]. They were also less likely to spend three or more hours in front of TV and computer screens per day.

Information from BCS70 has been used to show that private school pupils are less likely than their comprehensive school peers to be overweight or obese by their forties. At age 42, those who attended a state school had BMIs that were, on average, 1.8 points higher than those who were enrolled at a private school [13].

The study also found that at age 42, those who attended private schools displayed healthier behaviours, such as watching less television and eating fewer takeaway meals.


[1]  Relationship of cigarette smoking and social class to birth weight and perinatal mortality among all births in Britain, 5-11 April 1970. (1982) Rush, D and Cassano, P. Journal of Epidemiology and Community Health.

[2] Maternal smoking during pregnancy and lower respiratory tract illness in early life. (1987) Taylor, B and Wadsworth, J. Archives of Disease in Childhood.

[3] Accumulation of factors influencing children’s middle ear disease: risk factor modelling on a large population cohort. (1998) Bennett, K.E and Haggard, M.P. Journal Of Epidemiology & Community Health.

[4] Parental smoking and post-infancy wheezing in children: a prospective cohort study. (1989) Neuspiel, D.R, Rush, D, Butler, N.R, Golding, J, Bijur, P.E and Kurzon, M. American Journal of Public Health

[5] Parental smoking and the nutrient intake and food choice of British teenagers aged 16-17 years. (1996). Crawley, H. F. and While, D. Journal of Epidemiology & Community Health

[6] Early origins and adult correlates of psychosomatic distress. (2002) CHEUNG, Y.B. Social Science and Medicine

[7] Overweight and obesity in mid-life: Evidence from the 1970 British Cohort Study at age 42. (2013) Centre for Longitudinal Studies

[8] Socioeconomic inequalities in body mass index across adulthood: coordinated analyses of individual participant data from three British birth cohort studies initiated in 1946, 1958 and 1970. (2017). Bann, D., Johnson, W., Li, L., Kuh, D. and Hardy, R. PLoS Medicine

[9] Additive influences of maternal and paternal body mass index on weight status trajectories from childhood to mid-adulthood in the 1970 British Cohort Study. (2015) Costa, S., Johnson, W. and Viner, R. M. Longitudinal and Life Course Studies

[10] Childhood correlates of adult TV viewing time: a 32-year follow-up of the 1970 British Cohort Study. (2015) Smith, L., Gardner, B. and Hamer, M. Journal of Epidemiology and Community Health

[11] Breast feeding and intergenerational social mobility: what are the mechanisms? (2013) Sacker, A., Kelly, Y., Iacovou, M., Cable, N. and Bartley, M. Archives of Disease in Childhood

[12] Prospective association between objective measures of childhood motor coordination and sedentary behaviour in adolescence and adulthood. (2015) Smith, L., Fisher, A. and Hamer, M. International Journal of Behavioral Nutrition and Physical Activity

[13] Does an elite education benefit health? Findings from the 1970 British Cohort Study. (2017) Bann, D., Hamer, M., Parsons, S., Ploubidis, G. and Sullivan, A. International Journal of Epidemiology.


1970 British Cohort study Age 42 initial findings – Overweight and obesity in mid-life

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Impact case study: The impact of adult literacy and numeracy research based on the 1970 British Cohort Study

Research by Professor John Bynner and Dr Sam Parsons of the Institute of Education, University of London, has highlighted the…


Evidence and impact

Search our briefings and impact library which includes summaries of our research findings as well as reports highlighting the impact of our cohort studies.

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