RESEARCH REPORTS

Loss and representativeness in a biomedical survey at age 45 years: 1958 British birth cohort

K Atherton¹, E Fuller², P Shepherd³, D P Strachan⁴ and C Power¹

¹ Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, London, UK
² National Centre for Social Research, London, UK
³ Centre for Longitudinal Studies, Bedford Group for Lifecourse and Statistical Studies, Institute of Education, London, UK
⁴ Division of Community Health Sciences, St George’s, University of London, London, UK

Correspondence to:
Professor C Power, Centre for Paediatric Epidemiology and Biostatistics, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK; c.power{at}ich.ucl.ac.uk

Objective: A biomedical survey of the 1958 British birth cohort at age 45 years provides a baseline for future studies of chronic disease. The extent and nature of bias in this sample was examined.

Methods: Follow-up of all births in Great Britain in one week in March 1958. At 45 years the sample was compared with the surviving cohort on characteristics recorded at birth and seven years, and in adulthood (42 years).

Results: Sample attrition to age 45 years was chiefly through avoidable (35.8%) than unavoidable loss through death or emigration (13.7%). 11 971 individuals were invited to participate at 45 years. Of 9377 participants (78.3%), most consented to, and had valid values for, physical and mental measurements, survey questionnaires, and blood and saliva sampling; 8302 (88.5%) provided a blood sample. Groups moderately underrepresented in the 45-year sample included those with externalising or internalising behaviours, poor reading or maths scores, and shorter stature. For example, 8.8% of the 45-year sample had been poor readers at age seven years compared with 11.1% of the total surviving cohort; for shorter stature the figures were 7.2% versus 8.4%, respectively. There was also underrepresentation of some minority groups (non-whites, births in households with no male head and children in social care). Most bias was present before the 45-year survey.

Conclusion: The 45-year sample remains broadly representative of the surviving cohort, but specific biases may need to be taken into account in future research. Renewed efforts to re-engage all cohort members will improve the representativeness and value of the study.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

In this issue

Carlos Alvarez-Dardet, Joint Edit and John R Ashton, Joint Edit
J Epidemiol Community Health 2008 62: 185. [Extract] [Full Text] [PDF]

This article has been cited by other articles:

• Atherton, K, Berry, D J, Parsons, T, Macfarlane, G J, Power, C, Hypponen, E (2009). Vitamin D and chronic widespread pain in a white middle-aged British population: evidence from a cross-sectional population survey. Ann Rheum Dis 68: 817-822 [Abstract] [Full Text]  
• Richards, M, Power, C, Sacker, A (2009). Paths to literacy and numeracy problems: evidence from two British birth cohorts. J. Epidemiol. Community Health 63: 239-244 [Abstract] [Full Text]  
• Cooper, R., Atherton, K., Power, C. (2009). Gestational age and risk factors for cardiovascular disease: evidence from the 1958 British birth cohort followed to mid-life. Int J Epidemiol 38: 235-244 [Abstract] [Full Text]  
• Kvaavik, E., Klepp, K.-I., Tell, G. S., Meyer, H. E., Batty, G. D. (2009). Physical Fitness and Physical Activity at Age 13 Years as Predictors of Cardiovascular Disease Risk Factors at Ages 15, 25, 33, and 40 Years: Extended Follow-up of the Oslo Youth Study. Pediatrics 123: e80-e86 [Abstract] [Full Text]  
• Power, C, Atherton, K, Manor, O (2008). Co-occurrence of risk factors for cardiovascular disease by social class: 1958 British birth cohort. J. Epidemiol. Community Health 62: 1030-1035 [Abstract] [Full Text]  
• Stansfeld, S A, Clark, C, Caldwell, T, Rodgers, B, Power, C (2008). Psychosocial work characteristics and anxiety and depressive disorders in midlife: the effects of prior psychological distress. Occup. Environ. Med. 65: 634-642 [Abstract] [Full Text]  
• Rahi, J S, Peckham, C S, Cumberland, P M (2008). Visual impairment due to undiagnosed refractive error in working age adults in Britain. Br. J. Ophthalmol. 92: 1190-1194 [Abstract] [Full Text]  
• Tabassum, F., Kumari, M., Rumley, A., Lowe, G., Power, C., Strachan, D. P. (2008). Effects of Socioeconomic Position on Inflammatory and Hemostatic Markers: A Life-Course Analysis in the 1958 British Birth Cohort. Am J Epidemiol 167: 1332-1341 [Abstract] [Full Text]  
• Thomas, C., Hypponen, E., Power, C. (2008). Obesity and Type 2 Diabetes Risk in Midadult Life: The Role of Childhood Adversity. Pediatrics 121: e1240-e1249 [Abstract] [Full Text]