Association Of White Blood Cell Count And Its Change With Incident Cardiovascular Disease In The Middle-aged And Elderly Chinese

Objective:Increasing evidence supports the association of total and differential white blood cell（WBC）counts with cardiovascular disease（CVD）.But previous studies were mostly limited by non-general populations or a single endpoint,and the data linking long-term temporal change in WBC count to CVD is also scarce.This study aims to assess the correlation of total WBC and classified WBC counts with generalized environmental factors and further investigate associations of WBC count and its change with incident CVD in the middle-aged and elderly Chinese.Methods:Total and differential WBC counts were measured during the baseline survey and the first follow-up survey,with a mean（SD）interval of 4.6（0.2）years.After excluding those with coronary heart disease（CHD）,stroke,cancer,severely abnormal electrocardiogram（ECG）at baseline,lost of follow-up or the missing or extreme data of WBC count,we included 26655 participants for the analysis of the correlation between WBC count and generalized environment factors and the analysis of the association of baseline WBC count with incident CVD.For those who had two measurements of WBC count,we enrolled 11594 eligible paticipants for the anlysis of change in WBC count with incident CVD.We determined incident CVD events by review of medical insurance documentation,hospital records and death certificates until December 31,2016.We used Spearman rank correlation and generalized linear regression model to estimate the correlation between WBC count and environment factors.Cox proportional hazard models were used to estimate the hazard ratio（HR）and 95%confidence interval（CI）of incident CVD and its subtypes related to total and differential WBC counts and their changes.Results:（1）Correlation analysis showed:total WBC count was positively correlated with age,BMI,waist circumference,SBP,DBP,FBG,TC,TG,LDL-C（P<0.01）,and negatively correlation with HDL-C（P<0.01）.Generalized linear regression analysis showed:the older,the male,the obese,participants with hypertension,hyperlipidemia or diabetes,the current smokers,participants with long sleep duration and participants under stress had higher total WBC count;the current drinkers,participants with egg intake or beans intake≥5 times per week had lower total WBC count.（2）Compared with participants with total WBC count in the lowest quartile,the adjusted HRs（95%CIs）of those in the highest quartile were 1.15（1.06-1.25）,1.15（1.04-1.26）and 1.21（1.02-1.45）for incident CVD,CHD and stroke,respectively.The highest quartile of neutrophil count was associated with increased risk when compared to lowest quartile for CVD（HR=1.13;95%CI,1.03-1.23）and CHD（HR=1.12;95%CI,1.02-1.23）.The adjusted HRs（95%CIs）comparing neutrophil-to-lymphocyte ratio （NLR）in the fourth quartile versus the first quartile for CVD and stroke were 1.12（1.03-1.22）and 1.25（1.04-1.49）.（3）Compared with a stable total WBC count（-1.15≤change≤0.44,×10⁹/L）,a change>0.44×10⁹/L in total WBC count was associated with higher risks of CVD（HR=1.18;95%CI,1.03-1.33）,CHD（HR=1.24;95%CI,1.09-1.41）and stroke （HR=1.37;95%CI,1.04-1.82）.Compared with a stable neutrophil count（-0.65≤change≤0.49,×10⁹/L）,a change>0.49×10⁹/L in neutrophil count was associated with higher risks of CVD（HR=1.20;95%CI,1.05-1.36）and CHD（HR=1.13;95%CI,1.01-1.30）.Compared with a stable NLR（-0.24≤change≤0.73）,a change>0.88 in NLR was associated with a higher risk of CVD（HR=1.21;95%CI,1.06-1.37）.（4）Participants with baseline total WBC count>6.70×10⁹/L and change in total WBC count>0.44×10⁹/L were at the highest risk of CVD（HR=1.69;95%CI,1.30-2.21）,compared with those with baseline total WBC count in the lowest quartile and its change between the 25^th and 75^th percentiles.Conclusions:WBC count was closely related to age,gender,obesity,blood pressure,blood lipids,blood sugar,smoking and drinking status,sleeping,diet and so on.Elevated baseline total WBC count,neutrophil count and NLR were significantly related to a higher risk of incident CVD in the middle-aged and elderly Chinese.Upward changes in total WBC count,neutrophil count and NLR were associated with higher hazards of incident CVD.And there was a significant joint effect of baseline total WBC count and its change with incident CVD.