White blood cell count and renin–angiotensin system inhibitors for the risk of cancer in type 2 diabetes
Received 12 May 2009; received in revised form 14 October 2009; accepted 22 October 2009. published online 23 November 2009.
Abstract
Background
High white blood cell (WBC) predicted cancer-associated mortality and renin–angiotensin system (RAS) inhibitors have immunomodulating effects. We hypothesize that RAS inhibitors may reduce cancer risk associated with high WBC in type 2 diabetes mellitus (T2DM).
Methods
A prospective cohort of 4570 Chinese T2DM patients, free of cancer at enrolment, were analyzed. Biological interaction between WBC groups and use of RAS inhibitors was estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (S). RERI>0, AP>0 or S>1 indicates biological interaction.
Results
During 4.89 years of follow-up, 205 (4.49%) patients developed cancer. WBC≥8.2×109counts/L plus non-use of RAS inhibitors was associated with elevated cancer risks in multivariable models. The RERI and AP for interaction between WBC≥8.2×109counts/L and non-use of RAS inhibitors were, respectively, 1.26 (95% CI: 0.22–2.31) and 0.50 (0.23–0.78). In patients with WBC≥8.2×109counts/L, use of RAS inhibitors was associated with 64% (31–81%) cancer risk reduction in multivariable analysis.
Conclusions
In T2DM, increased WBC predicts cancer while use of RAS inhibitors may reduce cancer risks associated with high WBC count.
aDepartment of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
bHong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
cLi Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong, SAR, China
Corresponding author at: Room 507, Li Ka Shing Institute of Health Sciences, c/o Department of Medicine and Therapeutics, The Prince of Wales Hospital, Shatin, Hong Kong, SAR, China. Tel.: +852 3763 6052; fax: +852 2637 3852.
ABSTRACT