December 24 2008

Birth Weight and Risk of Type 2 DiabetesA Systematic Review

Author Affiliations

Author Affiliations: Division of Community Health Sciences, St George’s, University of London (Drs Whincup, Owen, and Cook and Ms Kaye), Medical Research Council (MRC) Centre of Epidemiology for Child Health, University College London Institute of Child Health (Drs Hyppönen and Power), London School of Hygiene and Tropical Medicine (Dr Leon), and MRC Unit for Lifelong Health and Ageing, Department of Epidemiology and Public Health, University College London (Drs Mishra and Wadsworth), London, England; the George Institute for International Health, University of Sydney, Sydney, Australia (Dr Huxley); Department of Internal Medicine, Saiseikai Central Hospital, Tokyo, Japan (Dr Anazawa); Division of Epidemiology, Department of Family and Preventive Medicine, University of California San Diego School of Medicine, San Diego (Dr Barrett-Connor); Department of Paediatrics, S. L. Jain Hospital, Delhi, India (Dr Bhargava); Unit for Nutrition Research, Faculty of Food Science and Nutrition, University of Iceland and Landspitali-University Hospital (Drs Birgisdottir and Thorsdottir), and Icelandic Heart Association Research Institute and University of Iceland (Dr Gudnason), Reykjavik; Division of Epidemiology, Stockholm Centre of Public Health, and Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden (Dr Carlsson); Department of Clinical Epidemiology, Biostatistics, and Bioinformatics, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands (Drs de Rooij and Roseboom); Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada (Dr Dyck); Diabetes Unit, Department of Health Promotion and Chronic Disease Prevention, National Public Health Institute, and Department of General Practice and Primary Health Care, University of Helsinki, Helsinki, Finland (Drs Eriksson and Forsén); Vasa Central Hospital, Vasa, Finland (Drs Eriksson and Forsén); Department of Medicine and Paediatrics, Thomas Jefferson University, Philadelphia, Pennsylvania (Dr Falkner); MRC Epidemiology Resource Centre, University of Southampton, Southampton, England (Drs Fall and Osmond and Ms Syddall); Department of Cancer Research and Molecular Biology, Norwegian University of Science and Technology, and Department of Internal Medicine, University Hospital of Trondheim, Trondheim, Norway (Dr Grill); Division of Neonatology, Crozer Chester Medical Center, Crozer-Keystone Health System, Upland, Pennsylvania (Dr Hulman); Department of Social Medicine (Dr Jeffreys) and MRC Centre for Causal Analyses in Translational Epidemiology (Dr Lawlor), University of Bristol, Bristol, England; Department of Hypertension and Cardiorenal Medicine, Dokkyo University School of Medicine, Tochigi, Japan (Dr Minami); Division of Women's Health and Connors Center for Women's Health and Gender Biology, Harvard Medical School, and Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts (Dr Rich-Edwards); Department of Paediatrics and Clinical Epidemiology, Sitaram Bhartia Institute of Science and Research, New Delhi, India (Dr Sachdev); Central Hospital of Central Finland, Jyväskylä, Finland (Dr Vanhala); Unit of Family Practice, Central Hospital of Middle Finland and Kuopio University Hospital, University of Kuopio, Kuopio, Finland (Dr Vanhala); and Sacred Heart Medical Center, Eugene, Oregon (Dr Yarbrough).

JAMA. 2008;300(24):2886-2897. doi:10.1001/jama.2008.886

Context Low birth weight is implicated as a risk factor for type 2 diabetes. However, the strength, consistency, independence, and shape of the association have not been systematically examined.

Objective To conduct a quantitative systematic review examining published evidence on the association of birth weight and type 2 diabetes in adults.

Data Sources and Study Selection Relevant studies published by June 2008 were identified through literature searches using EMBASE (from 1980), MEDLINE (from 1950), and Web of Science (from 1980), with a combination of text words and Medical Subject Headings. Studies with either quantitative or qualitative estimates of the association between birth weight and type 2 diabetes were included.

Data Extraction Estimates of association (odds ratio [OR] per kilogram of increase in birth weight) were obtained from authors or from published reports in models that allowed the effects of adjustment (for body mass index and socioeconomic status) and the effects of exclusion (for macrosomia and maternal diabetes) to be examined. Estimates were pooled using random-effects models, allowing for the possibility that true associations differed between populations.

Data Synthesis Of 327 reports identified, 31 were found to be relevant. Data were obtained from 30 of these reports (31 populations; 6090 diabetes cases; 152 084 individuals). Inverse birth weight–type 2 diabetes associations were observed in 23 populations (9 of which were statistically significant) and positive associations were found in 8 (2 of which were statistically significant). Appreciable heterogeneity between populations (I2 = 66%; 95% confidence interval [CI], 51%-77%) was largely explained by positive associations in 2 native North American populations with high prevalences of maternal diabetes and in 1 other population of young adults. In the remaining 28 populations, the pooled OR of type 2 diabetes, adjusted for age and sex, was 0.75 (95% CI, 0.70-0.81) per kilogram. The shape of the birth weight–type 2 diabetes association was strongly graded, particularly at birth weights of 3 kg or less. Adjustment for current body mass index slightly strengthened the association (OR, 0.76 [95% CI, 0.70-0.82] before adjustment and 0.70 [95% CI, 0.65-0.76] after adjustment). Adjustment for socioeconomic status did not materially affect the association (OR, 0.77 [95% CI, 0.70-0.84] before adjustment and 0.78 [95% CI, 0.72-0.84] after adjustment). There was no strong evidence of publication or small study bias.

Conclusion In most populations studied, birth weight was inversely related to type 2 diabetes risk.