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Differential white blood cell count and type 2 diabetes: systematic review and meta-analysis of cross-sectional and prospective studies.

TitleDifferential white blood cell count and type 2 diabetes: systematic review and meta-analysis of cross-sectional and prospective studies.
Publication TypeJournal Article
Year of Publication2010
AuthorsGkrania-Klotsas, E, Ye, Z, Cooper, AJ, Sharp, SJ, Luben, R, Biggs, ML, Chen, L-K, Gokulakrishnan, K, Hanefeld, M, Ingelsson, E, Lai, W-A, Lin, S-Y, Lind, L, Lohsoonthorn, V, Mohan, V, Muscari, A, Nilsson, G, Ohrvik, J, Qiang, JChao, Jenny, NSwords, Tamakoshi, K, Temelkova-Kurktschiev, T, Wang, Y-Y, Yajnik, CSakerlal, Zoli, M, Khaw, K-T, Forouhi, NG, Wareham, NJ, Langenberg, C
JournalPLoS One
Volume5
Issue10
Paginatione13405
Date Published2010 Oct 18
ISSN1932-6203
KeywordsAdult, Aged, Cross-Sectional Studies, Diabetes Mellitus, Type 2, Female, Humans, Leukocyte Count, Male, Middle Aged, Prospective Studies
Abstract<p><b>OBJECTIVE: </b>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.</p><p><b>RESEARCH DESIGN AND METHODS: </b>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 non-cases). 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.</p><p><b>RESULTS: </b>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*10(-18)). Substantial heterogeneity was present (I(2) = 83%). For granulocytes the RR was 1.38 (95% CI: 1.17; 1.64, p = 1.5*10(-4)), 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*10(-13)), while in cohort studies it was 1.48 (95% CI: 1.22; 1.79, p = 7.7*10(-5)). 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.</p><p><b>CONCLUSIONS: </b>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.</p>
DOI10.1371/journal.pone.0013405
Alternate JournalPLoS ONE
PubMed ID20976133
PubMed Central IDPMC2956635
Grant ListP30 AG024827 / AG / NIA NIH HHS / United States
R01 HL075366 / HL / NHLBI NIH HHS / United States
MC_UP_A100_1003 / / Medical Research Council / United Kingdom
R01 AG015928 / AG / NIA NIH HHS / United States
U01 HL080295 / HL / NHLBI NIH HHS / United States
T37 TW000049 / TW / FIC NIH HHS / United States
N01 HC015103 / HC / NHLBI NIH HHS / United States
N01HC55222 / HL / NHLBI NIH HHS / United States
R01 HL094555 / HL / NHLBI NIH HHS / United States
N01HC85086 / HL / NHLBI NIH HHS / United States
MC_U106179471 / / Medical Research Council / United Kingdom
G0701652 / / Medical Research Council / United Kingdom
G0401527 / / Medical Research Council / United Kingdom
R01 AG020098 / AG / NIA NIH HHS / United States
N01HC75150 / HL / NHLBI NIH HHS / United States
N01HC85079 / HL / NHLBI NIH HHS / United States
R01 AG023629 / AG / NIA NIH HHS / United States
R01 AG027058 / AG / NIA NIH HHS / United States
N01 HC045133 / HC / NHLBI NIH HHS / United States
N01 HC035129 / HC / NHLBI NIH HHS / United States