@article {1240, title = {Differential white blood cell count and type 2 diabetes: systematic review and meta-analysis of cross-sectional and prospective studies.}, journal = {PLoS One}, volume = {5}, year = {2010}, month = {2010 Oct 18}, pages = {e13405}, abstract = {

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 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.

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*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.

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.

}, keywords = {Adult, Aged, Cross-Sectional Studies, Diabetes Mellitus, Type 2, Female, Humans, Leukocyte Count, Male, Middle Aged, Prospective Studies}, issn = {1932-6203}, doi = {10.1371/journal.pone.0013405}, author = {Gkrania-Klotsas, Effrossyni and Ye, Zheng and Cooper, Andrew J and Sharp, Stephen J and Luben, Robert and Biggs, Mary L and Chen, Liang-Kung and Gokulakrishnan, Kuppan and Hanefeld, Markolf and Ingelsson, Erik and Lai, Wen-An and Lin, Shih-Yi and Lind, Lars and Lohsoonthorn, Vitool and Mohan, Viswanathan and Muscari, Antonio and Nilsson, Goran and Ohrvik, John and Chao Qiang, Jiang and Jenny, Nancy Swords and Tamakoshi, Koji and Temelkova-Kurktschiev, Theodora and Wang, Ya-Yu and Yajnik, Chittaranjan Sakerlal and Zoli, Marco and Khaw, Kay-Tee and Forouhi, Nita G and Wareham, Nicholas J and Langenberg, Claudia} } @article {7550, title = {Thyroid Function Within the Normal Range, Subclinical Hypothyroidism, and the Risk of Atrial Fibrillation.}, journal = {Circulation}, volume = {136}, year = {2017}, month = {2017 Nov 28}, pages = {2100-2116}, abstract = {

BACKGROUND: Atrial fibrillation (AF) is a highly prevalent disorder leading to heart failure, stroke, and death. Enhanced understanding of modifiable risk factors may yield opportunities for prevention. The risk of AF is increased in subclinical hyperthyroidism, but it is uncertain whether variations in thyroid function within the normal range or subclinical hypothyroidism are also associated with AF.

METHODS: We conducted a systematic review and obtained individual participant data from prospective cohort studies that measured thyroid function at baseline and assessed incident AF. Studies were identified from MEDLINE and EMBASE databases from inception to July 27, 2016. The euthyroid state was defined as thyroid-stimulating hormone (TSH) 0.45 to 4.49 mIU/L, and subclinical hypothyroidism as TSH 4.5 to 19.9 mIU/L with free thyroxine (fT4) levels within reference range. The association of TSH levels in the euthyroid and subclinical hypothyroid range with incident AF was examined by using Cox proportional hazards models. In euthyroid participants, we additionally examined the association between fT4 levels and incident AF.

RESULTS: Of 30 085 participants from 11 cohorts (278 955 person-years of follow-up), 1958 (6.5\%) had subclinical hypothyroidism and 2574 individuals (8.6\%) developed AF during follow-up. TSH at baseline was not significantly associated with incident AF in euthyroid participants or those with subclinical hypothyroidism. Higher fT4 levels at baseline in euthyroid individuals were associated with increased AF risk in age- and sex-adjusted analyses (hazard ratio, 1.45; 95\% confidence interval, 1.26-1.66, for the highest quartile versus the lowest quartile of fT4; P for trend <=0.001 across quartiles). Estimates did not substantially differ after further adjustment for preexisting cardiovascular disease.

CONCLUSIONS: In euthyroid individuals, higher circulating fT4 levels, but not TSH levels, are associated with increased risk of incident AF.

}, keywords = {Adult, Aged, Aged, 80 and over, Asymptomatic Diseases, Atrial Fibrillation, Biomarkers, Chi-Square Distribution, Female, Humans, Hypothyroidism, Incidence, Male, Middle Aged, Predictive Value of Tests, Prognosis, Proportional Hazards Models, Risk Assessment, Risk Factors, Thyroid Function Tests, Thyroid Gland, Thyrotropin, Thyroxine, Time Factors, Young Adult}, issn = {1524-4539}, doi = {10.1161/CIRCULATIONAHA.117.028753}, author = {Baumgartner, Christine and da Costa, Bruno R and Collet, Tinh-Hai and Feller, Martin and Floriani, Carmen and Bauer, Douglas C and Cappola, Anne R and Heckbert, Susan R and Ceresini, Graziano and Gussekloo, Jacobijn and den Elzen, Wendy P J and Peeters, Robin P and Luben, Robert and V{\"o}lzke, Henry and D{\"o}rr, Marcus and Walsh, John P and Bremner, Alexandra and Iacoviello, Massimo and Macfarlane, Peter and Heeringa, Jan and Stott, David J and Westendorp, Rudi G J and Khaw, Kay-Tee and Magnani, Jared W and Aujesky, Drahomir and Rodondi, Nicolas} }