Differential White Blood Cell Count and Type 2 Diabetes: Systematic Review and Meta-Analysis of Cross-Sectional and Prospective Studies

Gkrania-Klotsas, E and Ye, Z and Cooper, A J and Sharp, S J and Luben, R and Biggs, M L and Chen, L and Gokulakrishnan, K and Hanefeld, M and Ingelsson, E and Lai, W and Lin, S and Lind, L and Lohsoonthorn, V and Mohan, V and Muscari, A and Nilsson, G and Ohrvik, J and Chao Qiang, J and Jenny, N S and Tamakoshi, K and Temelkova-Kurktschiev, T and Wang, Ya-Yu and Yajnik, C S and Zoli, M and Khaw, Kay-Tee and Forouhi, N G and Wareham, N J and Langenberg, C and Fadini, G P (2010) Differential White Blood Cell Count and Type 2 Diabetes: Systematic Review and Meta-Analysis of Cross-Sectional and Prospective Studies. PLoS ONE, 5 (10). e13405. ISSN 1932-6203



Objective: Biological evidence suggests that inflammation might induce type 2 diabetes (T2D), and epidemiological studies have shown an association between higher white blood cell count (WBC) and T2D. However, the association has not been systematically investigated. Research Design and Methods: Studies were identified through computer-based and manual searches. Previously unreported studies were sought through correspondence. 20 studies were identified (8,647 T2D cases and 85,040 noncases). Estimates of the association of WBC with T2D were combined using random effects meta-analysis; sources of heterogeneity as well as presence of publication bias were explored. Results: The combined relative risk (RR) comparing the top to bottom tertile of the WBC count was 1.61 (95% CI: 1.45; 1.79, p = 1.5*10218). Substantial heterogeneity was present (I2 = 83%). For granulocytes the RR was 1.38 (95% CI: 1.17; 1.64, p = 1.5*1024), for lymphocytes 1.26 (95% CI: 1.02; 1.56, p = 0.029), and for monocytes 0.93 (95% CI: 0.68; 1.28, p = 0.67) comparing top to bottom tertile. In cross-sectional studies, RR was 1.74 (95% CI: 1.49; 2.02, p = 7.7*10213), while in cohort studies it was 1.48 (95% CI: 1.22; 1.79, p = 7.7*1025). We assessed the impact of confounding in EPIC-Norfolk study and found that the age and sex adjusted HR of 2.19 (95% CI: 1.74; 2.75) was attenuated to 1.82 (95% CI: 1.45; 2.29) after further accounting for smoking, T2D family history, physical activity, education, BMI and waist circumference. Conclusions: A raised WBC is associated with higher risk of T2D. The presence of publication bias and failure to control for all potential confounders in all studies means the observed association is likely an overestimate.

Item Type:Article
Official URL/DOI:http://dx.doi.org/10.1371/journal.pone.0013405
Uncontrolled Keywords:White Blood Cell;Type 2 Diabetes;Meta-Analysis;
Subjects:Diabetology > Diabetes Mellitus Type 2
Biochemistry,Cell and Molecular Signalling
Divisions:Department of Cell and Molecular Biology
Department of Diabetology
Department of Clinical Trials
ID Code:539
Deposited On:10 Nov 2010 14:49
Last Modified:10 Nov 2010 14:49

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